Dissertations / Theses: 'Glycaemic index'

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Mulholland, H. G. "Dietary glycaemic index, glycaemic load and carbohydrate intake and cancer risk." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517080.

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Seyoum, Teodros Alfred. "The role of micronutrients on glycaemic response, glycaemic index and energy metabolism." Thesis, Oxford Brookes University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495950.

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This study investigated the effects of potassium gluconate (K), calcium carbonate (Ca) and zinc gluconate (Zn) on glycaemic response (GR), energy expenditure (EE) and glycaemic index (GI). At the current time, gastric emptying rate is attributed to GI value alterations - the faster the gastric release compared to the reference food, the higher the blood glucose concentration and therefore the higher the GI of the food. The purpose of this study was to investigate whether faster blood glucose removal from the systemic circulation influences the GR or the GI.

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Haji, Faraji Majid. "Dietary glycaemic index and urinary chromium excretion." Thesis, King's College London (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419894.

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George, Ramlah. "Dietary glycaemic index, glycaemic load and insulin resistance (HOMAIR) of healthy South Asians in Glasgow, UK." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6600/.

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High habitual dietary glycaemic index (GI) and glycaemic load (GL) may relate to elevated insulin resistance and therefore may be more important and relevant in South Asian populations known for high prevalence of insulin resistance. The main objective of this research was to investigate the dietary GI, GL and insulin resistance of a sample of healthy South Asians in Glasgow, UK (a total of 111 healthy individuals: 60 males, 30 South Asians and 30 Europeans; 51 females, 22 South Asians and 29 Europeans). Estimation of dietary GI and GL (from weighed food intake records) considered the GI values of single foods and mixed-meals from relevant publications and from laboratory food/mixed-meal GI measurements (Chapter 3). The GI of key staple South Asian foods alone (chapatti, rice, pilau rice) and as mixed meals with curried chicken was measured using standard methods on 13 healthy subjects. The key staples had medium GI (chapatti, 68; rice, 66 and pilau rice, 60) and glycaemic responses to the mixed-meal of staples with curried chicken were found to be lower than the staples eaten alone. GI of the mixed-meals fell in the low GI category (chapatti with curried chicken, 45 and pilau rice with curried chicken, 41). Weighed food intake records (WFR) (recorded for 3-7 days) and self-administered previously validated food frequency questionnaires (FFQ) (applied to habitual food intakes in the past 6 months) was assessed for agreement through correlation analyses, cross-classification analysis, weighted Kappa statistics and Bland and Altman statistics. The two methods mostly agreed in carbohydrate (CHO) food intakes implying that the WFR reflected habitual intakes (Chapter 4). In consideration of potential confounding effect of physical activity on the relationship between dietary variables and HOMAIR, physical activity level (PAL) and Metabolic equivalent score (METS) of main daily activities of study subjects were derived from self-reported physical activity records (Chapter 5). Mean PAL were similar between South Asian and European males (median PAL of 1.61 and 1.60, respectively) but South Asian females tended to be less physically active than European females (mean PAL of 1.57 and 1.66, respectively). South Asians were less physically active in structured exercise and sports activities, particularly South Asian females and South Asians (males and females combined) with reported family history of diabetes showed inverse relationship between daily energy expenditure and HOMAIR. South Asians were found to be more insulin resistant than Europeans (HOMAIR median (IQR) of 1.06 (0.58) and 0.91 (0.47), p-value= 0.024 respectively in males; mean (SD) of 1.57 (0.80) and 1.16 (0.58), p-value= 0.037, respectively in females) despite similarities in habitual diet including dietary GI and GL. The mean habitual dietary GI of South Asians was within the medium GI category and did not differ significantly from Europeans. South Asian and European males’ dietary GI (mean, SD) was: 56.20, 2.78 and 54.77, 3.53 respectively; p-value=0.086. South Asian and European females also did not differ in their dietary GI (median, IQR) was: 54, 4.25 and 54, 5.00; p-value=0.071). Top three staples ranked from highest to lowest intakes in the South Asian diet were: unleavened breads (chapatti, Naan/Pitta, Paratha), rice, bread (white, wholemeal, brown), and potatoes. After statistically controlling for energy intake, body mass index, age, physical activity level and socio-demographic status, an inverse relationship (Spearman partial correlation analyses) between dietary GI and HOMAIR was observed (r, -0.435; p-value, 0.030) in South Asian males. This may be explained by the observation that the lower the dietary GI, the lower also, the total carbohydrates and fibre intakes and the higher the fat intake. In South Asian females, dietary GI and GL respectively, did not relate to HOMAIR but sugars intake related positively with HOMAIR (r, 0.486; p-value, 0.048). South Asian females, compared to European females, reported higher intakes of dietary fat (38.5% and 34.2% energy from fat, respectively; p-value=0.035). Saturated fatty acid (SFA) intakes did not differ between ethnic groups but SFA intakes were above the recommended level of 10% of total dietary energy for the UK in all groups, the highest being in SA females. In conclusion, Ethnicity (South Asian), having family history of diabetes, the wider diet profile rather than habitual dietary glycaemic index and glycaemic load alone (low GI, low fibre and high fat diets in males for instance; and high fat, high sugar diets in females) as well as low physical activity particularly in structured exercise and sports may contribute to insulin resistance in South Asians. These observations should be confirmed in larger future studies.

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Aston, L. M. "Impact of dietary glycaemic index on metabolic disease risk." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596202.

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An initial study determined the GI values of a number of key ‘staple’ carbohydrate-rich foods (chapter 2). This allowed consideration of some of the factors which influence the GI of foods, and also identified low and high FI versions of these staple foods for use in a controlled dietary intervention study. This intervention study investigated the effects of ad libitum low and high GI diets in overweight, hyperinsulinaemic female subjects (chapter 4). It also explored some of the potential mechanism for any effects on metabolic disease risk. The study employed a novel method for the assessment of insulin sensitivity, and the acceptability and suitability of this for use in intervention studies was examined (chapter 3). Data from the cohort of subjects reported here indicate beneficial effects of a reduction in dietary GI by 8 units on insulin sensitivity and secretion. An improvement was also seen in circulating IL-6 levels, as a marker of inflammatory status, and it is possible that this could, at least in part, have mediated the effect on insulin sensitivity. There was no improvement in a range of other markers of cardiovascular disease risk, no effects on appetite or energy intake, either in the short or long-term, and no effects on body weight. Neither was any difference seen in 24-hour glucose profiles between the diets. This calls into question these putative mechanisms for beneficial effects of low GI diets. In conclusion, the work described here is largely consistent with the wider literature in suggesting a beneficial effect of low GI diets on metabolic disease risk, although effects appear to be subtle, which may explain the inconsistencies in the literature. Longer, better-controlled studies with precise outcome measures are still needed.

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Gibson, Nicolette. "Development of a rapid assessment method for the glycaemic index." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/25797.

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The glycaemic index (GI) is a measurement used to classify foods according to their potential for raising blood glucose levels. The GI of a foodstuff is generally measured by determining the increment in blood glucose concentration after the consumption of a test meal over a set period of time and comparing it with an isoglucosidic control meal (normally white bread or glucose) and expressed as a percentage within a group of individuals (in vivo). Rapid analysis methods (in vitro) are being developed and evaluated worldwide, and in many cases the values obtained have correlated well with the GI values determined by in vivo methods. The criticism against rapid analysis methods is that the methods do not provide numerical GI values. Proposed labelling legislation in South Africa recommends that suppliers should only indicate if the product has a high, intermediate or low GI. The purpose of this study was to investigate existing rapid assessment methods for the prediction of GI, and develop such a method for South Africa to be used by food producers as a screening tool during product development in line with the newly proposed national labelling requirements. The preliminary studies on the developed rapid assessment method indicated good repeatability (CV 0.78%), reproducibility and precision (CV 3.5%). Further comparative trials indicated that the in vitro method accurately predicts the GI category of Almera potatoes (Solanum Tuberosum L. cultivar Almera) and Gero fat free litchi and raspberry flavoured yoghurt, in line with results found from in vivo analysis. Significant inter-laboratory variability of in vivo analysis of GI values obtained for the Almera potato cultivar was found, and the need for future alignment of methodology and sample preparation is recommended./p>
Dissertation (MSc)--University of Pretoria, 2011.
Food Science
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Al, Hamli Sarah. "Prediction of the glycaemic index of simple and composite dishes." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/6392/.

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Dietary carbohydrates play a crucial role in human nutrition. They are considered one of the major sources of energy and provide between 55-75 % energy of the human diet (FAO/WHO, 1998). In 1980, the glycaemic index (GI) concept was developed as a tool to compare foods for their ability to provide glucose to the blood circulation after ingestion and absorption in individuals. Epidemiological studies have shown a relationship between GI and non-communicable diseases such as type 2 diabetes using published GI values (Barclay et al., 2008b). However, measuring GI in vivo for every food used in the epidemiological field, for example, is time-consuming, expensive and requires the participation of human volunteers (Jenkins, 2007). The aim of the study is to develop methodology to estimate GI from the macronutrient composition of mixed foods, and the hypothesis is that GI can be predicted from composition data without the need for human volunteers. Available carbohydrate (av.CHO) analysis of 16 foods from the cereal and legume groups were undertaken and values were used to generate the prediction models. The relationship between GI and macronutrient composition was investigated in the 16 foods using multiple regression analysis methods. The results indicate that starch and fat are the only macronutrients that correlate significantly with published GI values. Three foods were used to validate the prediction models using in vitro and in vivo measurements and these correlated significantly with the statistically predicted GI values. In conclusion, statistically predicted GI might be a useful approach to eliminate the need for human subject or blood analysis to measure GI in multi-component foods.

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Robertson, C. E. "The role of carbohydrate and the glycaemic index concept in cardiovascular risk." Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391106.

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Oladele, Ebun-Oluwa Peace. "Resistant starch in plantain (Musa AAB) and implications for the glycaemic index." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/5239/.

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Consumption of foods rich in resistant starch and slowly digestible starches has been associated with lower postprandial glycaemic responses. The need to identify and quantify resistant starch in potential resistant starch sources and optimise processing conditions to maximise their benefit is vital in the quest for more healthy diets required for the control and management of diabetes and related conditions. Significant quantities of three types of resistant starch were identified in plantains: these are physically entrapped starch (RS1), native resistant starch (RS2) and retrograded starch (RS3). However, the relative quantities of each type vary with the conditions/state of processing/storage conditions applied to the food before consumption. The high correlation (r2 = 0.8) obtained between increased total resistant starch content of plantain products and reduced glycaemic index suggests that factors which promote the formation of enzyme resistant starch in plantain can also influence the glycaemic response to the available carbohydrates. Apart from native resistant starch which has been commonly reported for the Musa ssp, our data suggest that some alcohol extractable components of plantain may act as enzyme inhibitors. The presence of these components resulted in an increase in the value of RS2 in flours when compared to the starch isolates. It may be necessary therefore to distinguish between resistant starch type 2 (RS2), which is due to the inherent nature of starch and resistant starch produced from the interference from other food components such as enzyme inhibitors. This type of resistant starch may not be present in all foods and its properties need to be further investigated.

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DI, CAIRANO MARIA. "Formulation of gluten free biscuits with underexploited flours: focus on glycaemic index." Doctoral thesis, Università degli studi della Basilicata, 2021. http://hdl.handle.net/11563/149623.

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In recent years, many progresses have been made in the production of gluten free baked goods. In the past, the main and only goal of gluten free producers was to ensure the safety of consumption to celiac consumers without any attention to nutritional and sensory quality. Albeit to date, more attention is paid to them, the quality of gluten free products is in the spotlight. Efforts from research and industries are required to offer gluten free products with improved nutritional and sensory properties. It has indeed been seen that gluten free diet often presents nutritional deficiencies and high intake of some nutrients; in addition, the products often have impaired sensory properties compared to their gluten containing counterparts. Currently glycaemic index of food products is a topic of rising interest in food technology and nutrition science. It has been reported that a high glycaemic diet increases metabolic risk factors. This topic is awfully relevant also for consumers constrained to follow a gluten free diet. Food specifically formulated for celiacs generally have a higher glycaemic index, due to their richness in rapidly digestible starch. In addition, an association between celiac disease and type I diabetes has been recognised. Hence, it is important for celiacs to maintain the glycaemic control whilst following a gluten free diet. Biscuits represent one of the favourite carbohydrate source for celiacs. Flour, sugar and fat are the main ingredients constituting biscuits. Rice and maize flour and their starches are widely employed in gluten free biscuits. Hence, due to their starch rich composition and the presence of sugars, gluten free biscuits are generally medium or high glycaemic index foods. The employ of flours with a higher amount of slowly digestible starch, resistant starch, phenolic compounds together with sugar replacers and fibres could contribute to the reduction of the glycaemic index of gluten free biscuits. Taking into consideration the production activities carried out by the industrial partner, biscuit factory Di Leo Pietro spa, and the aforementioned premises, the general objective of the following doctoral thesis is the development of low glycemic index gluten free biscuits through the employ of flours that are little exploited in commercial biscuits.

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Aldhaheri, Ayesha Salem. "The influence of ethnicity, body composition and food components on glycaemic response/index." Thesis, Oxford Brookes University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444310.

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Wee, Shiou-Liang. "Influence of the type of carbohydrate breakfasts on metabolism and endurance running capacity in man." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/13775.

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Compared to the overnight fasted state, a high carbohydrate (CHO) breakfast 3-4 hours before exercise enhances endurance performance. However, the optimal type or composition of the pre-exercise meal to be consumed is less clear. Glycaemic and insulinaemic responses to a meal play a key role in subsequent metabolism during exercise. The investigations described in this thesis focused on the influence of I) the composition and 2) glycaemic index (GI) of CHO breakfasts 3 hours before exercise on postprandial and exercise metabolism and endurance running capacity.

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Armaghanian, Natasha. "Abnormal Glucose Tolerance in Cystic Fibrosis and the Role of Low Glycaemic Index Diets." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20456.

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Abnormal glucose metabolism states have increased in prevalence in cystic fibrosis (CF). Hypoglycaemia without glucose lowering therapies is a novel complication, with no unifying definition or hypothesis for its aetiology. Thus optimal management strategies for discomforting symptoms remain unclear. Furthermore, there is little evidence for what might prevent progression of impaired glucose tolerance in CF and modifiable factors such as dietary intake in abnormal glucose tolerance may be useful. Five studies were conducted in this thesis: 1) a systematic review of hypoglycaemia in CF in the absence of glucose lowering therapies; 2) a review of an adult CF clinic describing the prevalence of hypoglycaemia on an oral glucose tolerance test (OGTT) and in free-living situations; 3) an extended OGTT study exploring hormonal responses to and the prevalence of post-prandial hypoglycaemia; 4) a study utilising a semi-structured questionnaire and continuous glucose monitoring (CGM) to report on the prevalence of hypoglycaemia in free-living states; 5) a study describing diet quality and the relationship between dietary intake, including dietary glycaemic index (GI) and glucose load (GL), and glucose dysmetabolism using CGM. The systematic review found hypoglycaemia in the absence of glucose lowering therapies occurred during OGTT and CGM. Hypoglycaemia was confirmed on OGTTs and a sub-group of participants reported symptoms suggestive of hypoglycaemia in free-living states. The prevalence of hypoglycaemia may be unmasked by extension of the OGTT out to 3 hours. Abnormal insulin release appears to have a role in its aetiology. The semi-structured questionnaire and CGM confirmed episodes of hypoglycaemia in free-living situations. A detailed food record and formal dietary analysis provided some support for a correlation between dietary GI, GL and glycaemic response variables on CGM. These studies provide empirical support for randomised controlled trials of dietary intervention in CF related glucose dysmetabolism.

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Moore, Laura Jayne Suzanne. "The effects of the glycaemic index of carbohydrate meals on metabolism, recovery and endurance performance." Thesis, University of Hull, 2009. http://hydra.hull.ac.uk/resources/hull:5822.

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The aim of this thesis was to investigate the effect that consuming pre- and post exercise meals, varying in GI, would have on physiological responses and subsequent endurance performance. Study 1 investigated the effects of consuming either a low or high GI meal 45 min prior to exercise on cycling TT performance. It was observed that consuming a low GI meal 45 minutes prior to performing a 40k TT, resulted in a significantly improved performance (p = 0.009) compared to the ingestion of an isocaloric high GI pre- exercise meal (93 ± 8 min vs. 96 ±7 min for low and high GI, respectively). The results suggested that the ingestion of the low GI food led to an increase in the availability of CHO and greater CHO oxidation throughout the exercise period and subsequently spared limited muscle and liver glycogen stores. Study 2 investigated the effects of low and high GI 24 h diets, following glycogen depleting exercise, on TT performance the following day. No difference was observed in TT performance following low (90.7 ±11.1 min) and high (93.5 ± 9.29 min) GI, 24 h recovery diets (p = 0.35). This study concluded that provided the amount of CHO consumed during the recovery period is sufficient enough to replenish depleted muscle glycogen stores, the GI of the recovery diet offers no further benefit to performance. Study 3 investigated the effects of high and low GI recovery meals on TT performance following a short term recovery period from a glycogen depleting exercise. No significant difference was observed in TT performance between the low (90.7 ± 11.1 min) and high GI (93.5 ± 9.3 min) trials (t = 1.1; p = 0.35). This study concluded that if the following exercise bout is of short duration, and not long enough to challenge glycogen stores, provided the amount of CHO is sufficient during the recovery period, the GI of short- term recovery diets has no influence on subsequent exercise performance. In conclusion, the findings presented in this thesis should contribute to and support previous research within this area and help to contribute to the body of knowledge through greater ecological validity.

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Lamport, David Joseph. "The impact of impaired glucose tolerance, Type 2 diabetes, and glycaemic index on cognitive performance." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555867.

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Abnormalities in glucose tolerance such as Type 2 diabetes (T2DM) are associated with cognitive impairment. However, there is an absence of research which investigates whether impaired glucose tolerance (IGT), a precursor of T2DM, is also associated with cognitive impairment. It can be hypothesised that progressively poorer glucose tolerance is associated with a trajectory of increasing cognitive impairment. Low glycaemic index (LGI) and low glycaemic load (LGL) foods are recommended as a method for managing T2DM and IGT. They have also been associated with effects on cognitive function. The potential for LGI and LGL foods to attenuate cognitive impairment associated with abnormalities in glucose tolerance remains unexplored. The main aim of this thesis was to investigate the relationship between glucose tolerance and cognitive performance, across the range of normal glucose tolerance through to seriously impaired glucose tolerance. Study 1, in 23 healthy young adults, demonstrated that the GI of an evening meal can affect objective and subjective cognitive performance the next morning. These findings indicate that an overnight fast is not sufficient to control for the effects of previous nutritional intake, and guided the, design of studies 2 and 3. Study 2 examined cognitive performance and subjective ratings of appetite, mood and alertness in middle-aged females with IGT (n=18) and NGT (n=47) over the morning following the consumption of LGL, HGL, and water breakfasts in a repeated measures design. Study 3 used an identical design to examine cognitive performance in older adults with T2DM (n=24) and age matched non-diabetic adults (n=10). Adults with T2DM showed cognitive impairment on a wide range of cognitive domains, whereas, in those with IGT primarily memory was impaired. Subclinical abnormalities in glucose tolerance can therefore have demonstrable negative effects on cognitive performance, even in ostensibly healthy middle-aged females. As hypothesised, worsening glucose tolerance was associated with a trajectory of cognitive decline. Manipulating the GL of breakfast did not acutely attenuate cognitive impairment in IGT or T2DM. Taken together, these findings suggest that maintaining a state of good health, by preventing the onset of glucose tolerance abnormalities is important for protecting and maintaining cognitive function.

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Price, Joanna McMillan. "The effect of four reduced-fat diets varying in glycaemic index, glycaemic load, carbohydrate and protein, on weight loss, body composition and cardiovascular disease risk factors." Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1606.

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Introduction: The conventional approach to weight loss, recommended by almost all health authorities around the world, has been to reduce the total amount of fat in the diet and replace with carbohydrates. However, research trials using this approach have produced only modest results at best, and despite the active promotion of low fat eating and an apparent decline in fat consumption, rates of overweight and obesity have continued to climb. More recently low glycaemic index (GI) and high protein diets have become popular and are widely used by the public. However, only a small number of randomised controlled trials have been conducted and none directly comparing the two. Both approaches effectively reduce glycaemic load (GL) and aim to reduce post-prandial glycaemia and insulinaemia. This study aimed to evaluate the ability of diets with reduced GL to enhance the weight loss effects of a reduced-fat diet, to compare the two approaches of reducing GL on metabolic and anthropometric changes, and to investigate any benefit of combining both approaches to produce the lowest GL. Methods: We conducted a 12-week intervention in 129 overweight or obese young adults who were assigned to one of four diets with varying GL, protein, carbohydrate and GI, but similar fat (30% energy), fat type and fibre content. DIET 1 (highest GL) contained 55% E as carbohydrate; DIET 2 was a low-GI version of DIET 1; DIET 3 was a high protein diet with 25% E as protein; DIET 4 (lowest GL) was a low-GI version of DIET 3. The increase in protein in DIETS 3 and 4 came primarily from lean red meat. All key foods and some pre-prepared frozen meals were provided to maximise dietary compliance. Outcome measures were body weight, body fat, lean mass, waist circumference and the following blood parameters: total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerols (TAG), free fatty acids, C-reactive protein, fasting insulin, fasting glucose and leptin. Insulin resistance and β-cell function were assessed using homeostatic model assessment (HOMA) and the newer computer models HOMA2-insulin sensitivity and HOMA2-β-cell function. Results: While all groups lost similar amounts of weight (4.2 to 6.2% of initial weight, p=0.09), the proportion who lost >5% of body weight varied significantly by diet: 31%, 56%, 66% and 33% in groups 1, 2, 3 and 4 respectively (p=0.011). Differences were strongest in women (76% of the total group) who showed significant differences among groups in percentage weight change (-3.7 ± 0.6%, -5.7 ± 0.6%, -6.5 ± 0.5%, -4.1 ± 0.7% respectively, p=0.005) and fat loss (-3.1 ± 0.4kg, -4.9 ± 0.6kg, -4.8 ± 0.4kg, -3.6 ± 0.7kg respectively, p=0.007). Total and LDL-cholesterol increased on DIET 3 (high protein) compared to a fall on diet 2 (high carbohydrate/low-GI, p=0.013). TAG, HDL-cholesterol and glucose homeostasis improved on all four diets, with no effect of diet composition. Goals for energy distribution were not achieved exactly: both carbohydrate groups ate less fat and the diet 2 group ate more fibre. Conclusions: Reducing GL, through either substituting low-GI foods or replacing some carbohydrate with protein, improved the efficacy of a reduced-fat diet in women and in those with high TAG. Combining both approaches to produce the lowest GL did not promote further weight or body fat loss. Although weight loss was similar in all four diets for the group as a whole, overall clinical outcomes were superior on the high carbohydrate, low-GI diet.

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Price, Joanna McMillan. "The effect of four reduced-fat diets varying in glycaemic index, glycaemic load, carbohydrate and protein, on weight loss, body composition and cardiovascular disease risk factors." University of Sydney, 2006. http://hdl.handle.net/2123/1606.

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Doctor of Philosophy (PhD)
Introduction: The conventional approach to weight loss, recommended by almost all health authorities around the world, has been to reduce the total amount of fat in the diet and replace with carbohydrates. However, research trials using this approach have produced only modest results at best, and despite the active promotion of low fat eating and an apparent decline in fat consumption, rates of overweight and obesity have continued to climb. More recently low glycaemic index (GI) and high protein diets have become popular and are widely used by the public. However, only a small number of randomised controlled trials have been conducted and none directly comparing the two. Both approaches effectively reduce glycaemic load (GL) and aim to reduce post-prandial glycaemia and insulinaemia. This study aimed to evaluate the ability of diets with reduced GL to enhance the weight loss effects of a reduced-fat diet, to compare the two approaches of reducing GL on metabolic and anthropometric changes, and to investigate any benefit of combining both approaches to produce the lowest GL. Methods: We conducted a 12-week intervention in 129 overweight or obese young adults who were assigned to one of four diets with varying GL, protein, carbohydrate and GI, but similar fat (30% energy), fat type and fibre content. DIET 1 (highest GL) contained 55% E as carbohydrate; DIET 2 was a low-GI version of DIET 1; DIET 3 was a high protein diet with 25% E as protein; DIET 4 (lowest GL) was a low-GI version of DIET 3. The increase in protein in DIETS 3 and 4 came primarily from lean red meat. All key foods and some pre-prepared frozen meals were provided to maximise dietary compliance. Outcome measures were body weight, body fat, lean mass, waist circumference and the following blood parameters: total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerols (TAG), free fatty acids, C-reactive protein, fasting insulin, fasting glucose and leptin. Insulin resistance and β-cell function were assessed using homeostatic model assessment (HOMA) and the newer computer models HOMA2-insulin sensitivity and HOMA2-β-cell function. Results: While all groups lost similar amounts of weight (4.2 to 6.2% of initial weight, p=0.09), the proportion who lost >5% of body weight varied significantly by diet: 31%, 56%, 66% and 33% in groups 1, 2, 3 and 4 respectively (p=0.011). Differences were strongest in women (76% of the total group) who showed significant differences among groups in percentage weight change (-3.7 ± 0.6%, -5.7 ± 0.6%, -6.5 ± 0.5%, -4.1 ± 0.7% respectively, p=0.005) and fat loss (-3.1 ± 0.4kg, -4.9 ± 0.6kg, -4.8 ± 0.4kg, -3.6 ± 0.7kg respectively, p=0.007). Total and LDL-cholesterol increased on DIET 3 (high protein) compared to a fall on diet 2 (high carbohydrate/low-GI, p=0.013). TAG, HDL-cholesterol and glucose homeostasis improved on all four diets, with no effect of diet composition. Goals for energy distribution were not achieved exactly: both carbohydrate groups ate less fat and the diet 2 group ate more fibre. Conclusions: Reducing GL, through either substituting low-GI foods or replacing some carbohydrate with protein, improved the efficacy of a reduced-fat diet in women and in those with high TAG. Combining both approaches to produce the lowest GL did not promote further weight or body fat loss. Although weight loss was similar in all four diets for the group as a whole, overall clinical outcomes were superior on the high carbohydrate, low-GI diet.

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Davies, Ben Rhys. "Dietary glycaemic carbohydrate, physical activity and cardiometabolic health in postpubertal adolescents." Thesis, University of Bedfordshire, 2013. http://hdl.handle.net/10547/316091.

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The principle aims of this work were two fold; firstly to identify the current dietary intakes (specifically dietary glycaemic carbohydrate (CHO)) and physical activity (PA) and cardiorespiratory fitness (CRF) levels of a UK, postpubertal, adolescent population (n = 105) and assess the relationship between these factors, adiposity and cardiometabolic health. Diet and health relationships were assessed whilst accounting for energy misreporting and controlling for levels of PA and CRF. The effect of excluding dietary misreporters on the associations between glycaemic CHO and health was assessed whilst comparing an established technique (the Goldberg equation) to a novel approach (the ratio of energy intake (EI) to energy expenditure (EE)), which utilised RT3 accelerometry data (EI:EE(RT3)). Associations of PA and metabolic risk factors were also assessed whilst comparing two child specific PA thresholds for the assessment of PA subcomponents. Secondly, the impact of a flexible, ad libitum, low GI dietary intervention on cardiometabolic health was examined in an „at risk‟, overweight, postpubertal, adolescent population. Glycaemic index (GI) but not glycaemic load (GL) was shown to be associated significantly with anthropometric measures (body mass index (BMI), waist circumference (WC)) and adiposity (body fat percentage (BF%)) in this general group of post-pubertal adolescents from Bedfordshire. When adjusting for dietary intake, CRF was also associated with adiposity but PA was not. The prevalence of misreporting varied depending on the method used to assess the validity of dietary intakes; between 23% and 31% increasing to 62.1% (in overweight) of adolescents under reported energy intakes and up to 11.1% over reported. The novel application of a triaxial accelerometer to measure EE resulted in more under and over reporters being identified than when compared to the widely used Goldberg equation. Increased dietary GI was associated with increased odds of having a high WC; however, associations between GL and other risk factors were less clear; no associations with risk were observed. Excluding dietary misreporters from analysis had important implications for these associations. Only after removal of misreporters by EI:EE(RT3) was a borderline significant positive association between GL and blood glucose (BG) revealed using multiple analysis of covariance (MANCOVA), that was not present in prior analyses. Increased GI (moderate vs low GI intake) was significantly associated with reduced high density lipoprotein cholesterol (HDL) and increased triglyceride (TG) levels (borderline significant) after removal of misreporters. In addition, using different PA thresholds to assess PA intensity resulted in different relationships between PA subcomponents and metabolic risk factors. Regardless of the threshold used, evidence suggested that limiting sedentary (SED) behaviour and engaging in moderate to vigorous PA (MVPA) is beneficial for blood pressure (BP) in this adolescent population. Additionally, irrespective of the threshold utilised, higher levels of vigorous PA (VPA) were associated with reduced odds of having a high clustered risk score and the associations observed between CRF and risk factors were stronger than those observed with PA. Despite a lack of significant improvement in individual metabolic risk factors as a result of the low GI (LGI) dietary intervention, there was a significant reduction in clustered risk score for the LGI group at week 12. A borderline significant improvement in glycated haemoglobin (HbA1c) was also observed as a result of the LGI intervention compared to those in the control group. Conversely, there appeared to be an unfavourable effect of the LGI diet on fasting insulin levels and thus the diet‟s impact on health overall is unclear. The small sample size of this randomised controlled trial (RCT) means that caution is required when interpreting the results. These data suggest that future research in this age group should target improvements in CRF and a lower dietary GI to reduce adiposity. Controlling for dietary misreporting appears to have a significant impact on associations of glycaemic CHO and cardiometabolic health and should be an important consideration of future research. The low GI intervention may be an effective approach for reducing glycaemic CHO, whilst maintaining a healthy macronutrient intake, in comparison to more restricted dietary regimens published in the literature. However, the impact of this regime needs to be confirmed utilising a larger sample of adolescents. This may provide a useful approach for future research aiming to assess the impact of reduced GI and GL.

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Jordaan, Michelle Bernitta. "Effect of processing on the starch and glycemic properties of Digitaria spp." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/2024.

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Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2013.
Acha starch was isolated and purified from clean and milled acha grain. Functional, thermal and physicochemical properties of acha starch were analysed using appropriate methods. Wheat starch was used as the reference standard. Acha bread from acha grain was baked and the consumer sensory acceptability was evaluated and white wheat bread was used as the reference standard. The effect of baking, boiling, steaming and microwaving on the starch and glycemic properties of the acha starch was evaluated. With regard to thermal properties, gelatinisation temperature of acha and iburu starches typifies that of waxy starch. Acha starch has similar retrogradation temperature profiles as that of wheat. There were however significant differences in some of the functional properties (pasting and turbidity) and physico-chemical properties (in vitro starch digestibility), but no significant difference in the texture profile analysis (TPA) and water binding capacity (WBC). WBC of both acha varieties was higher than that for wheat starch. Due to its high break down viscosity, white acha starch can be included in foods that are subjected to high temperature processing. This indicates that both acha starch varieties can be used for hot and cold desserts as well as for soft jelly like sweets and confectionery toppings. A prescreening exercise using carboxymethyl cellulose (CMC), Xanthan gum, yeast and acha starch as the variables was successful in concluding a recipe which rendered acha bread with the optimum specific loaf volume for both white and black acha bread. The optimum recipe consisted 8.0 % acha starch, 2.0 % xanthan gum, 2.0 % CMC and 1.0 % yeast. The majority of the consumer panellists found the crust colour, taste and aroma to be moderately desirable. This implies that most consumers find acha bread to have the potential to be marketed as wheat free bread. The different processing methods baking, boiling, microwaving and steaming, affected the black and white acha starch hydrolysis. The amount of starch hydrolysed for the different processing methods was in the following order: baking > boiling > microwaving > steaming. It can thus be concluded that different processing methods affects the micro structure and physical properties of the acha and wheat samples which thus influence their starch hydrolysis. The equilibrium percentage of starch hydrolysed after 180 min incubation was affected differently for the various starches, black acha, white acha and wheat starch by the different processing methods and times. In the case of baking black acha starch and wheat bread were affected similarly. However, this was not the case for microwaving, steaming and boiling, where both acha starch varieties and wheat starch were affected in the same way. The rate of starch hydrolysis for both acha varieties and wheat grain for the different processing methods, steaming, boiling, microwaving and baking was affected to the same degree respectively.

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Stevenson, Emma Jane. "Influence of the glycaemic index of mixed meals on postprandial and exercise metabolism in men and women." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/33805.

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The benefits of carbohydrate ingestion before and after prolonged exercise are well known to scientists, coaches and athletes alike. However, the type of carbohydrate consumed can have a significant effect on substrate metabolism both at rest and during exercise. The glycaemic index (GI) is a method of classifying carbohydrate-containing foods according to their postprandial glycaemic responses. This is a useful tool to aid the selection of appropriate carbohydrates for both pre- and post-exercise meals. This thesis examined the influence of ingesting mixed meals with different glycaemic indices both before exercise and during the post-exercise recovery period in male and female subjects.

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Wu, Ching-Lin. "Influence of high and low glycaemic index carbohydrate meals on exercise capacity and substrate metabolism in men." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/34154.

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Ingestion of carbohydrate (CHO) before exercise and after exercise enhances subsequent endurance exercise capacity when compared to a fasting state. However, the optimal type of CHO meal to be consumed is still unclear. Glycaemic and insulinaemic responses to a meal during the postprandial period may play an important role in subsequent exercise metabolism and performance. This thesis examined the influence of ingesting high and low glycaemic index (GI) CHO meals three hours before exercise and during four-hour recovery on substrate metabolism and exercise capacity in men.

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Arefhosseini, Seyed Rafie. "The influence of high carbohydrate diets and glycaemic index on metabolic risk parameters for coronary heart disease." Thesis, University of Glasgow, 2005. http://theses.gla.ac.uk/31019/.

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This thesis describes a series of studies investigating the relationship between diet, and in particular carbohydrate intake, and risk factors for type 2 diabetes and coronary heart disease (CHD). The first study investigated the effect of advice to increase carbohydrate intake as part of dietary advice to follow the dietary guidelines on metabolic risk factors for CHD in postmenopausal women (Chapter 3). The results showed that subjects appeared to have followed the dietary advice given as they reported significantly reducing their total daily energy (P = 0.011), fat {P ~ 0.008) and non-milk extrinsic sugar (NMES) intake (P = 0.015), and significantly increasing their total carbohydrate (P = 0.026), starch (P = 0.013j and non-starch polysaccharide (NSP) intake (P = 0.050). Subjects also significantly increased their dietary glycaemic index (GI) (P = 0.011). There was a significant reduction in body mass index (BMI) (P = 0.014), and an adverse effect on fasting plasma lipids including an increase in fasting TAG (P = 0.014), and a decrease in HDL cholesterol concentrations (P = 0.021). Subjects reported increasing their consumption of fruit and vegetables, and there was a significant increase in the 'antioxidant power' of plasma (P = 0.007). This appears to have mostly been associated with an increase in fruit intake. Conelation analyses showed that simple sugars appeared to have a more adverse effect on plasma lipids than starch. From this a decision was made to study the relationships between GI and plasma lipids and other metabolic risk factors in data that had already been collected. The mam findings of this case control study on offspring of patients of type 2 diabetes (offspring) and control subjects (Chapter 4) showed that there were no differences in habitual dietary intake, GI or GL between the groups. Offspring were found to demonstrate many of the features of the metabolic syndrome as they had greater levels of adiposity and female offspring had significantly higher waist to hip ratio (P = 0.036), waist circumference (P = 0.063) and BMI (P = 0.083) compared with female control subjects. Offspring were significantly more insulin resistant compared with control subjects with significantly higher fasting insulin (P = 0.049) and higher HOMAIR (P = 0.052) and significantly lower HDL cholesterol concentrations (P = 0.011). However, dietary GI and GL were not found to be directly associated with any of the metabolic parameters measured in the study, but GI was positively coirelated with waist circumference (P = 0.039) and waist to hip ratio (P = 0.043), and measures of adiposity were significantly correlated with many of the metabolic parameters measured in the study. Thus, while the glycaemic quality of the diet did not appear to directly influence metabolic risk factors, the results do support the idea that they influence metabolic risk factors through their effect on adiposity, and in particular central adiposity. TFor this reason it may be safer to advise the public to consume more slowly digestible carbohydrates (such as wholegrain cereals, pulses) rather than low GI foods which could still contain a high proportion of sugar which could mask the positive effects of the low GI diet on lipids. Overall, the results from this thesis highlight the need for more research to develop safer and more appropriate dietary guidelines which can be easily and clearly communicated to the general public.

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Cooper, Simon B. "Breakfast consumption, breakfast composition and exercise : the effects on adolescents' cognitive function." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9336.

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The studies described in this thesis were undertaken to examine the factors affecting adolescents cognitive function across the school morning. Specifically, the effects of breakfast consumption, breakfast glycaemic index (GI) and a mid-morning bout of exercise were examined, whilst the final experimental chapter examined their combined effects. The battery of cognitive function tests used in the present study was administered via a laptop computer and took approximately 15 min to complete. Across all experimental chapters, the visual search test (assessing visual perception), the Stroop test (assessing attention) and the Sternberg paradigm (assessing working memory) were used. Furthermore, in chapter V the Flanker task (also assessing attention) was added to the testing battery. The first experimental study (chapter IV) examined the effects of consuming a self-selected breakfast on cognitive function, compared to breakfast omission. Ninety-six adolescents (12 to 15 years old) completed two experimental trials (breakfast consumption and breakfast omission), scheduled seven days apart, in a randomised crossover design. Following breakfast consumption, accuracy on the more complex level of the visual search test was higher than following breakfast omission (p = 0.021). Similarly, accuracy on the Stroop test was better maintained across the morning following breakfast consumption when compared with breakfast omission (p = 0.022). Furthermore, responses on the Sternberg paradigm were quicker later in the morning following breakfast consumption, on the more complex levels (p = 0.012). Breakfast consumption also produced higher self-report energy and fullness, lower self-report tiredness and hunger, and higher blood glucose concentrations, compared with breakfast omission (all p < 0.001). Overall, the findings suggested that breakfast consumption enhanced adolescents cognitive function, when compared with breakfast omission. The second experimental study (chapter V) examined the effects of consuming a high GI breakfast, a low GI breakfast and breakfast omission on cognitive function. Forty-one adolescents (12 to 14 years old) completed three experimental trials, each scheduled seven days apart, in a randomised crossover design. There was a greater improvement in response times across the morning following a low GI breakfast, compared to breakfast omission on the complex level of the Stroop test (p = 0.009) and both levels of the Flanker task (p = 0.041), and compared to following a high GI breakfast on the complex level of the visual search test (p = 0.025) and all levels of the Sternberg paradigm (p = 0.013). Furthermore, accuracy was enhanced following a low GI breakfast, compared to breakfast omission on the more complex levels of the visual search test (p = 0.032), Sternberg paradigm (p = 0.051) and Flanker task (p = 0.001), and compared to following a high GI breakfast on both levels of the Stroop test (p = 0.033) and the more complex levels of the Sternberg paradigm (p = 0.002) and Flanker task (p = 0.014). Furthermore, participants exhibited a lower glycaemic response following the low GI breakfast (p < 0.001), though there was no difference in the insulinaemic response (p = 0.063), compared to following the high GI breakfast. Overall, the findings suggest that a low GI breakfast is the most beneficial for adolescents cognitive function, compared with a high GI breakfast and breakfast omission. The third experimental study (chapter VI) examined the effects of a mid-morning bout of exercise, following a self-selected breakfast, on cognitive function. Forty-five adolescents (12 to 13 years old) completed two experimental trials (exercise and resting), scheduled seven days apart, in a randomised crossover design. There was a greater improvement in response times across the morning following the mid-morning bout of exercise on all levels of the Sternberg paradigm (p = 0.010). There was also a greater improvement in response times across the morning on the visual search test following the exercise (p = 0.009), but this improved speed was combined with a greater decrease in accuracy following the exercise (p = 0.044). This suggests that following exercise, the adolescents exhibited a speed-accuracy trade-off, whereby they responded quicker, but this was to the detriment of accuracy. Overall, the findings suggest that whilst the mid-morning bout of exercise improved some components of cognitive function (e.g. response times on the Sternberg paradigm), it did not affect other components (e.g. Stroop test performance). The final experimental study (chapter VII) examined the combined effects of breakfast GI and a mid-morning bout of exercise on adolescents cognitive function. Forty-two adolescents (11 to 13 years old) were allocated to matched high GI (n = 22) and low GI (n = 20) breakfast groups. Within the matched groups, participants completed two experimental trials (exercise and resting) in a randomised, crossover design. The findings indicate that, for the complex level of the Stroop test, following the high GI breakfast there was a greater improvement in response times across the morning on the resting trial, whereas following the low GI breakfast response times improved across the morning on both the exercise and resting trials, though the magnitude of the improvement was greatest on the exercise trial (p = 0.012). On the Sternberg paradigm, response times improved across the morning following the low GI breakfast regardless of exercise, whereas following the high GI breakfast response times improved across the morning on the exercise trial, though remained similar across the morning on the resting trial (p = 0.019). Overall, the findings suggest that the effects of the mid-morning bout of exercise were dependent upon the breakfast GI and the component of cognitive function being examined and that, for the Stroop test, the beneficial effects of the low GI breakfast and mid-morning bout of exercise were additive. Overall, the results from this thesis suggest that breakfast consumption is more beneficial than breakfast omission and more specifically, that a low GI breakfast is more beneficial than both a high GI breakfast and breakfast omission, for adolescents cognitive function across the school morning. However, the effects of exercise appear to be more variable, with the effect of exercise depending upon the component of cognitive function examined and the GI of the breakfast consumed. Overall, the findings presented in this thesis suggest that the nutritional effects on adolescents cognitive function (i.e. the effects of breakfast consumption and GI) were stronger and more consistent than the exercise induced effects.

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Gouws, Jacqueline. "The glycaemic index of muffins baked with extruded dried bean flour compared to muffins baked with whole wheat flour / Jacqueline Gouws." Thesis, North-West University, 2004. http://hdl.handle.net/10394/347.

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Emphasis on using the glycaemic index (GI) in addition to carbohydrate exchange lists has led to a greater variety of foods from which to choose for the diabetic population. Breakfast is regarded as the most important meal of the day and the glycaemic response to lunch can be improved by decreasing the GI of breakfast. However, most conventional breakfast cereals and bread exhibit a high GI. Dried beans have a low GI and various processes such as cooking and canning increase GI values, but still in the low GI range. In recent years, extrusion cooking has become one of the popular new processes developed by the food industry. Extrusion provides a convenient alternative for the ingestion of dry beans in the diet. Muffins are eaten by many South Africans and may be an ideal alternative for breakfast cereals and bread, especially if the GI of the muffins is low. The aim of this study was to determine the GI of a muffin baked with extruded bean flour and compare it to the GI of a muffin baked with whole wheat flour. Subjects and methodology: The study cohort consisted of ten healthy males and ten healthy females. Subjects randomly consumed test meals of glucose (the reference), bean muffins and whole wheat muffins on different days. Each test meal provided 509 available carbohydrate as analysed by the Englyst method. Results: The GI of the muffin baked with extruded bean flour (mean 53.0%, Confidence intervals (CI): 41.7; 64.2) was not significantly different from that of the whole wheat muffin (mean 55.5%, CI: 41.8; 69.2) but still in the low to intermediate GI category. Conclusion: Extrusion of dried beans results in a fine flour with relatively no intact starch which may explain the very low resistant starch content (1.6I100g) of the muffins. The small particle size of the fine flour could further have contributed to the higher than expected GI of the bean muffin because the size of the particle is inversely related to glycaemic response. Muffins baked with extruded dried bean meal are nevertheless regarded as an excellent choice for breakfast and as part of the prudent diet. Beans have additional health benefits and are included in the South African Food Based Dietary Guidelines.
Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2004.

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Negrini, Juliana de Almeida Egas. "Impacto do consumo de pães integrais na resposta glicêmica de voluntários saudáveis." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/9/9132/tde-28052015-090407/.

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Pães integrais são alimentos de consumo habitual da população brasileira, porém há poucas informações a respeito da resposta glicêmica pós-prandial, O presente trabalho teve como objetivo avaliar a resposta glicêmica produzida, em indivíduos saudáveis, após o consumo de pães de fôrma rotulados como integrais. Oito pães de fôrma integrais de três categorias (clássico, light e com grãos) foram avaliados, após o consumo de porcão equivalente a 25 g de carboidratos disponíveis, através do índice glicêmico (IG) e carga glicêmica (CG). Os voluntários (n=15) compareceram ao laboratório em jejum (10 a 12 horas), pela manhã, em onze ocasiões (três dias para o consumo do pão controle e um dia para cada tipo de pão de fôrma integral). A glicemia foi determinada em jejum (t=0) e após o consumo de cada pão nos tempos: 15; 30; 45; 60; 90 e 120 minutos. A curva de resposta glicêmica, a área sob a curva (ASC) e o cálculo do IG e CG para cada um dos pães foram realizados. Considerando a glicose como referência, os pães integrais clássicos (n=2) apresentaram alto IG (71 %); os light (n=2), IG baixo (50 %) e médio (58 %) e; os com grãos (n=4), IG baixo (44 e 49 %) e médio (57 e 60 %). Os pães de fôrma light e com grãos apresentaram IG menor que os do tipo clássico (p<0,05), os quais apresentaram IG igual ao pão francês (controle). Como foi consumida a mesma quantidade de carboidratos disponíveis, a menor proporção de açúcar solúvel na categoria light parece ter sido o fator que induziu ao menor IG observado. Em relação à CG, um pão de fôrma integral light (CG=10) e outro com grãos (CG=7) foram classificados como baixa CG; os demais pães integrais (n=6) foram classificados como média CG (11 a 16). Todos os pães integrais apresentaram CG inferior a do pão controle (CG=18) (p<0,05) e entre os integrais novamente os da categoria light e com grãos foram os que apresentaram menor CG. Assim, foi observada variação na resposta glicêmica após o consumo de pães de fôrma integrais, sendo que a redução no conteúdo de açúcares solúveis, para os pães light, e a adição de grãos integrais, nos pães com grãos, favoreceram menor elevação da resposta glicêmica pós-prandial.
Whole meal breads are part of the habitual daily diet of the Brazilian population, but there is little information on the postprandial glycaemic response. The aim of this work was to evaluate the glycaemic response produced, in healthy volunteers, following the consumption of breads labeled as whole meal. Eight whole meal breads of three different categories (classic, light and grains) were evaluated, after the consumption of a portion containing approximately 25 g of available carbohydrates, using the glycaemic index (GI) and glycaemic load (GL). The subjects (n=15) attended to the laboratory after an overnight fasting (10 to 12 hours), in eleven different occasions (three days for the consumption of the control bread and a day for each whole meal bread). In every occasion, a portion of bread containing 25 g of available carbohydrate was consumed. Capillary blood samples were taken immediately before (t=0) and 15, 30, 45, 60, 90 and 120 minutes after the consumption of test breads. The glycaemic response curve, area under the curve (AUC), GI and GL for each bread were obtained. Considering glucose as reference, the classic breads (n=2) had high GI (71 %); the light (n=2), low (50 %) and medium (58 %) GI; and grains (n=4), low (44 and 49 %) and medium (57 and 60 %) GI. The light and grain breads had lower GI than the classic (p<0,05), which presented GI similar to white bread (control). As the same amount of available carbohydrates was consumed, the reduced proportion of soluble sugars in the light category breads seems to be a factor that induced the lower GI observed. In relation to the GL, one light bread (GL=10) and a grain bread (GL=7) were classified as low GL; the other whole meal breads (n=6) were classified as medium GL (11 to 16). All whole meal breads had lower GL than the control bread (GL=18) (p<0,05), and among the whole meal breads the ones in both light and grain categories presented the lower GL. Therefore, it was possible to observe variation on the glycaemic responses following the consumption of whole meal breads, the reduction in soluble sugar content, in the light breads, and the addition of whole grains, in the grain breads, favored lower elevation in the postprandial glycaemic response.

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Nute, Maria L. G. "Influence of high and low glycaemic index carbohydrate pre-exercise meal on fat metabolism in men and women." Thesis, Loughborough University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506210.

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Wu, Mei Yi. "The effects of glycaemic index of mixed meals on postprandial appetite sensation, cognitive function, and metabolic responses during intermittent exercise." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/14403.

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Glucose is the primary fuel for the brain and also important for exercising muscle. The purpose of the thesis was to investigate the effects of the glycaemic index (GI) of mixed meals on appetite, cognitive performances and metabolic responses during intermittent exercise in recreationally active adults. Study one investigated whether a low GI (LGI) breakfast (GI = 42.5) could suppress appetite and reduce energy intake (EI) of 12 recreationally active females (28.2 ± 8.0 years) more than a high GI (HGI) breakfast (GI = 73.5). Area under the curve of the appetite score (AS AUC) following LGI breakfast was significantly greater than the HGI trial during the 60-min postprandial (pp) period (2568 ± 1027 vs. 2198 ± 821 mm∙min, p = 0.025). The HGI breakfast facilitated a stronger appetite suppressing effect up to eight hours post breakfast than the LGI trial (18834 ± 3906 vs. 21278 ± 3610 mm∙min, p = 0.028). The EI on the LGI trial day was significantly higher than on the pre-trial day (2,215 ± 576 vs. 1,748 ± 464 kcal, corrected p = 0.008). Fourteen recreationally active males (34.5 ± 8.9 years) in study two consumed the LGI (GI = 41.3) and HGI (GI = 74.3) breakfasts in the laboratory and then prescribed LGI and HGI meals in the free living environment. In line with study one, the AS AUC was significantly smaller following HGI than LGI breakfast over the 60-min pp period (2,989 ± 1,390 vs. 3,758 ± 1,290 mm∙min, p = 0.027). The HGI meals (GI = 76.9) suppressed appetite more than the LGI meals (GI = 39.6) over 12 hours on the trial day (35,454 ± 9,730 vs. 41,244 ± 8,829 mm∙min, p = 0.009) although energy balance was not different between trials. Study three investigated whether following a LGI breakfast (GI = 42.2) providing 1 g CHO kg-1 BM could result in a better vigilance and attention than a HGI breakfast (GI = 72.4), and reduced lunch EI in 16 recreationally active males (24.4 ± 3.6 years). A significant trial x time effect in the interference time of the Stroop Colour Word Task (SCWT) (p = 0.039) showed that the LGI breakfast maintained the attentional performance up to 90-min pp. Both high pre-task glucose concentration ([Glucose]) at 15-min pp and low pre-task [Glucose] at 105-min pp in the HGI trial were associated with unfavourable outcomes in vigilance in the Rapid Information Processing Task (RIPT). The LGI pre-task [Glucose] returning back to fasting level at 60-min pp was associated positively with the response time. The pre-lunch AS was a significant predictor of the lunch EI per fat free mass which explained 21% and 26% of variance in the LGI and HGI trials respectively. No significant difference was found in the ad libitum lunch EI between trials. Sixteen recreationally active males (27.8 ± 7.7 years) in study four consumed a LGI (GI = 42) and a HGI breakfast (GI = 72.8) providing 1.2 g CHO kg-1 BM consumed 60 minutes prior to intermittent running on two separate mornings. Better attentional performance at 150-min pp was found following LGI than HGI breakfast. The significant trial x time interaction in the SCWT (p = 0.045) showed the shortest interference time performed after the last exercise session in the LGI trial. The amounts of CHO and fat being oxidized were comparable between trials during three sessions of 16-min intermittent running with an average intensity of 65% V̇O2max. In conclusion, the pre-meal appetite sensation is more predictive of the subsequent meal EI than the pre-meal [Glucose]. The meal strategy for weight management in recreationally active adults may focus on greater appetite suppression by selecting HGI foods whilst maintaining healthy eating guidelines. Recreationally active males performing sports requiring high levels of vigilance and selective attention with low physical activity levels can benefit up to 60–90 min pp from the LGI breakfast. Their attentional performance can benefit from the LGI breakfast with moderate to high intermittent intensities in the late exercise period at 150–min pp. Recreationally active adults should consider the timing of meal consumption in relation to performing intermittent exercise, in order to maximize the advantages from the LGI or HGI breakfasts for cognitive performance or appetite suppression. They may be more liberal in pre-exercise food choices if substrate oxidation during intermittent running is only of their concern.

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CILIBERTI, CATERINA. "Effects on glycometabolic and functional parameters of low-glycaemic-index pasta intake in patients with type 2 diabetes mellitus." Doctoral thesis, Università di Foggia, 2016. http://hdl.handle.net/11369/363161.

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Il diabete mellito tipo 2 è una patologia in allarmante crescita ed è una delle principali cause di malattia cardio-renale. Nel diabete mellito tipo 2, l’eccessiva esposizione dell’organismo al glucosio circolante, determina l’attivazione di processi di glicazione che conducono ad alterazioni morfo-funzionali di vari organi ed apparati. Già numerose osservazioni in questo ambito hanno dimostrato che tali modifiche dieto-terapeutiche si associno ad un miglior controllo glico-lipidico e ad una riduzione degli eventi renali e cardiovascolari. L’obiettivo principale dello studio è stato duplice: 1) Ottimizzazione delle condizioni di formulazione e di processo per l’ottenimento di paste funzionali e 2) Valutazione clinica delle paste oggetto della ricerca attraverso una valutazione degli effetti nutraceutici dei prodotti funzionali sullo stato di salute e sullo stato di malattia attraverso la verifica della modificazione di indici clinici e bioumorali. Sono state preparate diverse tipologie di pasta: utilizzando sfarinati non convenzionali ricchi in fibra (Triticum monococccum), e con un elevato contenuto in amilosio (sfarinati di fava) e sfarinati convenzionali prodotti con farina e acqua utilizzando diverse tecnologie di produzione, al fine di valutare come riportato in letteratura, se la maggior quota in amido resistente osservata in vitro potesse derivare dall’utilizzo di alte temperature e/o dei processi di refrigerazione o di essiccazione della pasta. È stata selezionata la pasta fresca sterilizzata, e per controllo la pasta fresca convenzionale, per la somministrazione in cronico ai pazienti diabetici, al fine di valutare i suoi effetti nutraceutici sulla stato di malattia mediante la misurazione di indici clinici e bioumorali. Per lo studio di valutazione tecnologica della pasta, sono stati condotti test in vitro sulla digeribilità dell’amido e sulle proprietà funzionali. Lo studio in vivo includeva una fase iniziale di follow-up e randomizzazione di soggetti sani e diabetici, rispettivamente per la valutazione in acuto ed in cronico ed una seconda fase durante la quale sono stati valutati i cambiamenti dal baseline dei parametri clinici, antropometrici, nutrizionali e biochimici, mediante l’utilizzo di un protocollo cross-over. Nei soggetti sani la pasta fresca sterilizzata non ha mostrato superiorità in termini di indice glicemico rispetto alla pasta fresca di controllo nonostante dai risultati in vitro la pasta fresca sterilizzata era caratterizzata da una più elevata quota in amido resistente rispetto alla pasta fresca di controllo. Nei pazienti diabetici sottoposti alla valutazione in cronico, la pasta fresca sterilizzata non ha dimostrato altrettanta superiorità in termini di miglioramento di parametri antropometrici ed ematochimici rispetto alla pasta fresca di controllo. Una casistica caratterizzata da pazienti con compenso mediocre dovuto in gran parte alle fluttuazioni glicemiche post-prandiali avrebbe potuto rappresentare un modello migliore per verificare l’eventuale superiorità della pasta funzionale. E’ ovvio che innumerevoli fattori possono influenzare l’andamento di uno studio clinico rispetto agli studi condotti in vitro, in questi ultimi gli errori sono facilmente rilevabili dall’operatore in qualsiasi metodica di laboratorio applicata, risulta invece di difficile misurazione l’errore nell’analisi clinica su soggetti umani che, pur se monitorati periodicamente, erano caratterizzati da innumerevoli influenze esterne. Sicuramente le modifiche apportate mediante uno stile di vita alimentare controllato dimostrano risultati positivi in termini di compenso metabolico e miglioramento della composizione corporea, quest’ultima annoverata tra i fattori di rischio più importanti nella gestione del paziente diabetico e nella prevenzione delle complicanze cardiovascolari. Più critico invece risulta il monitoraggio in vivo effettuabile sul singolo alimento. Il punto di forza della nostra ricerca è stata sicuramente l’innovazione della metodica clinica messa a punto per lo studio in vivo e, data la carenza in letteratura di test condotti in vivo riguardo l’indice glicemico, sicuramente è stato condotto un grande passo in avanti nella ricerca rispetto alle sperimentazioni passate
Type 2 diabetes mellitus is one of the principal causes of cardio-renal disease. In type 2 diabetes melllitus, excessive exposure to the circulating glucose excess is responsible for enhanced glycation processes which in turn eventually lead to morpho-functional alterations of many organs. Recent observations proved that adhesion to specific dietotherapeutic recommendations is associated with a better glico-lipidic control with a consequent significative reduction of cardio-renal complications. The objective of the study were twofold: 1) Optimization of formulation and process conditions for the creation of functional pasta and 2) Clinical assessment of functional pasta through an evaluation of the nutraceutical effects of functional products consumption on health and disease status by assessing changes in their clinical and biohumoral indices. Different types of pasta have been analyzed: using both fiber rich non conventional flours (Triticum monococcum), non conventional flours with a high amylose content (faba bean) and conventional fresh pasta made with flours and water using some technological changes in order to assess whether, as reported in the literature, the higher proportion of resistant starch as observed in vitro might reflect the use of high temperatures and/or refrigeration or drying of the pasta. In healthy subjects, fresh sterilized pasta was no better in terms of glycaemic index than control pasta fresh was, even though in vitro results for sterilized fresh pasta showed it has a higher proportion of resistant starch than control fresh pasta. In diabetic patients assessed under chronic conditions, sterilized fresh pasta failed to demonstrate the same superiority in terms of improvement in anthropometric parameters and blood chemistry compared to the control fresh pasta. A case study characterized by patients with poor compensation due mainly to post-prandial glycaemic fluctuations could have been a better model for testing the potential superiority of functional pasta. Naturally, many external influences can affect the course of a clinical trial on human subjects compared to in vitro studies, in which errors can easily be detected by the operator in any laboratory method applied. Clearly the changes which occurred owing to a well-controlled dietary lifestyle show positive results in terms of improvements in metabolic and body composition, the latter being among the most important risk factors in the management of the diabetic patient and in the prevention of cardiovascular complications. In vivo monitoring on single foodstuffs, though, is even more critical. The strength of our research was definitely the innovation of a clinical method for the in vivo study and, given the lack in the literature of tests conducted in vivo regarding the glycaemic index, this was a big step forward in research terms compared with previous experiments.

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Van, Heerden Yvonne. "Evaluation of the methodology for determining the glycaemic index of foods with special reference to blood sampling / Y. van Heerden." Thesis, North-West University, 2003. http://hdl.handle.net/10394/269.

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Different types of carbohydrates from different food sources affect blood glucose differently. This physiological effect of carbohydrate containing foods has been quantified and expressed as the glycaemic index (GI) of the food. The GI is defined as the ratio of the incremental area under the blood glucose response curve for a test food containing 509 available carbohydrate to the corresponding area after an equal carbohydrate portion of a standard food is taken by the same subject. The GI of a food can, therefore, be used to guide consumers in choosing a particular food with a predicted known effect on blood glucose levels and homeostasis. Numerous methodological factors may influence the interpretation of glycaemic response data. One of the major problems regarding labelling foods with GI values is the lack of standardised methodology amongst different researchers in determining the GI. Furthermore, clear directions are needed regarding standardised methodology in accredited laboratories, including clarity on issues such as the reference (standard), total (available) carbohydrate of the test food, number and characteristics of experimental subjects, capillary versus venous blood samples, analytical method for determination of blood glucose value and the method for calculation of the area under the glucose curve. A food company commissioned an independent assessment of the GIs of Jungle Oats, Bokomo Oats and Oatso-Easy using methods complying with the most recent internationally accepted methodology and carried out under strictly standardised conditions. Thus, the area under the curve (AUC) and GI of Jungle Oats, Bokomo Oats and Oatso-Easy was determined using both capillary whole blood and venous plasma. Another objective of the study was to determine if there were significant differences between the GI of the three oats porridges. Methods Twenty healthy, non-smoking fasting male students, aged 21-27 years, each consumed 509 available carbohydrate from Jungle Oats, Bokomo Oats, Oatso-Easy and the standard food (glucose) on four different occasions. Finger-prick capillary blood and venous whole blood were collected simultaneously before and at 15 and 30 minute intervals for the first and second hour after ingestion respectively. The capillary whole blood glucose values were determined by using SureStep test strips and SureStep glucometres (Lifescan) and the venous plasma glucose was determined with an enzymatic colorimetric method. The AUC and the GI for the three different oats porridges, taken at four different occasions randomly by the same subjects was calculated using one glucose response as standard. Results Statistically significant differences (p<0.05) were found between the AUCs of the three different oats porridges for capillary blood and venous plasma. However, no statistically significant differences (p>0.05) were found between the mean GIs of the three different oats porridges both for capillary blood and venous plasma (77.1, 67.7 and 78.0 for Oatso-Easy, Jungle Oats and Bokomo Oats, respectively using capillary sampling and 112.4, 112.4 and 113.8 respectively, using venous sampling). The 95% confidence interval (CI) and standard deviation (SD) of the mean capillary blood glucose were notably smaller than those of the venous plasma. Conclusions It can be concluded from the study that the three different oats porridges fell between the intermediate to high categories and that glycaemic responses measured in venous plasma are lower and more variable than those simultaneously obtained in capillary blood. Recommendations It is recommended that the methodological guidelines determined by the GI Task Force should be followed. Capillary blood glucose samples are preferred to determine the GI. The last recommendation is that in using the GI to choose carbohydrate foods, patients and consumers should be made aware of the fact that physiological responses to a food may vary between individuals. For example, when advising on the GI, it should be mentioned that the GI of a particular food is & low, medium or high, but that exceptions can be expected and that these exceptions are normal. Therefore, the label indicating the GI of foods, food products and beverages should be accompanied by clear instructions.
Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2004.

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Opperman, Anna Margaretha. "Meta-analysis and systematic review of the benefits expected when the glycaemic index is used in planning diets / Anna Margaretha Opperman." Thesis, North-West University, 2004. http://hdl.handle.net/10394/557.

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Motivation: The prevalence of non-communicable diseases such as diabetes mellitus (DM) and cardiovascular disease (CVD) is rapidly increasing in industrialized societies. Experts believe that lifestyle, and in particular its nutritional aspects, plays a decisive role in increasing the burden of these chronic conditions. Dietary habits would, therefore, be modified to exert a positive impact on the prevention and treatment of chronic diseases of lifestyle. It is believed that the state of hyperglycaemia that is observed following food intake under certain dietary regimes contributes to the development of various metabolic conditions. This is not only true for individuals with poor glycaemic control such as some diabetics, but could also be true for healthy individuals. It would, therefore, be helpful to be able to reduce the amplitude and duration of postprandial hyperglycaemia. Selecting the correct type of carbohydrate (CHO) foods may produce less postprandial hyperglycaemia, representing a possible strategy in the prevention and treatment of chronic metabolic diseases. At the same time, a key focus of sport nutrition is the optimal amount of CHO that an athlete should consume and the optimal timing of consumption. The most important nutritional goals of the athlete are to prepare body CHO stores pre-exercise, provide energy during prolonged exercise and restore glycogen stores during the recovery period. The ultimate aim of these strategies is to maintain CHO availability to the muscle and central nervous system during prolonged moderate to high intensity exercise, since these are important factors in exercise capacity and performance. However, the type of CHO has been studied less often and with less attention to practical concerns than the amount of CHO. The glycaemic index (GI) refers to the blood glucose raising potential of CHO foods and, therefore, influences secretion of insulin. In several metabolic disorders, secretion of insulin is inadequate or impossible, leading to poor glycaemic control. It has been suggested that low GI diets could potentially contribute to a significant improvement of the conditions associated with poor glycaemic control. Insulin secretion is also important to athletes since the rate of glycogen synthesis depends on insulin due to it stimulatory effect on the activity of glycogen synthase. Objectives: Three main objectives were identified for this study. The first was to conduct a meta-analysis of the effects of the GI on markers for CHO and lipid metabolism with the emphasis on randomised controlled trials (RCT's). Secondly, a systematic review was performed to determine the strength of the body of scientific evidence from epidemiological studies combined with RCT's to encourage dieticians to incorporate the GI concept in meal planning. Finally, a systematic review of the effect of the GI in sport performance was conducted on all available literature up to date to investigate whether the application of the GI in an athlete's diet can enhance physical performance. Methodology: For the meta-analysis, the search was for randomised controlled trials with a cross-over or parallel design published in English between 1981 and 2003, investigating the effect of low GI vs high GI diets on markers of carbohydrate and lipid metabolism. The main outcomes were serum fructosamine, glycosylated haemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC) and triacylglycerols (TG). For the systematic review, epidemiological studies as well as RCT's investigating the effect of LGI vs HGI diets on markers for carbohydrate and lipid metabolism were used. For the systematic review on the effect of the GI on sport performance, RCT's with either a cross-over or parallel design that were published in English between January 1981 and September 2004 were used. All relevant manuscripts for the systematic reviews as well as meta-analysis were obtained through a literature search on relevant databases such as the Cochrane Central Register of Controlled Trials, MEDLINE (1981 to present), EMBASE, LILACS, SPORTDiscus, ScienceDirect and PubMed. This thesis is presented in the article format. Results and conclusions of the individual manuscripts: For the meta-analysis, literature searches identified 16 studies that met the strict inclusion criteria. Low GI diets significantly reduced fructosamine (p<0.05), HbA1c, (p<0.03), TC(p<0.0001) and tended to reduce LDL-c (p=0.06) compared to high GI diets. No changes were observed in HDL-c and TG concentrations. Results from this meta analysis, therefore, support the use of the GI concept in choosing CHO-containing foods to reduce TC and improve blood glucose control in diabetics. The systematic review combined the results of the preceding meta-analysis and results from epidemiological studies. Prospective epidemiological studies showed improvements in HDL-c concentrations over longer time periods with low GI diets vs. high GI diets, while the RCT's failed to show an improvement in HDL-c over the short-term. This could be attributed to the short intervention period during which the RCT's were conducted. Furthermore, epidemiological studies failed to show positive relationships between LDL-c and TC and low GI diets, while RCT's reported positive results on both these lipids with low GI diets. However, the epidemiological studies, as well as the RCT's showed positive results with low GI diets on markers of CHO metabolism. Taken together, convincing evidence from RCT's as well as epidemiological studies exists to recommend the use of low GI diets to improve markers of CHO as well as of lipid metabolism. 3 From the systematic review regarding the GI and sport performance it does not seem that low GI pre-exercise meals provide any advantages over high GI pre-exercise meals. Although low GI pre-exercise meals may better maintain CHO availability during exercise, low GI pre-exercise meals offer no added advantage over high GI meals regarding performance. Furthermore, the exaggerated metabolic responses from high GI compared to low GI CHO seems not be detrimental to exercise performance. However, athletes who experience hypoglycaemia when consuming CHO-rich feedings in the hour prior to exercise are advised to rather consume low GI pre-exercise meals. No studies have been reported on the GI during exercise. Current evidence suggests a combination of CHO with differing Gl's such as glucose (high GI), sucrose (moderate GI) and fructose (low GI) will deliver the best results in terms of exogenous CHO oxidation due to different transport mechanisms. Although no studies are conducted on the effect of the GI on short-term recovery it is speculated that high GI CHO is most effective when the recovery period is between 0-8 hours, however, evidence suggests that when the recovery period is longer (20-24 hours), the total amount of CHO is more important than the type of CHO. Conclusion: There is an important body of evidence in support of a therapeutic and preventative potential of low GI diets to improve markers for CHO and lipid metabolism. By substituting high GI CHO-rich with low GI CHO-rich foods improved overall metabolic control. In addition, these diets reduced TC, tended to improve LDL-c and might have a positive effect over the long term on HDL-c. This confirms the place for low GI diets in disease prevention and management, particularly in populations characterised by already high incidences of insulin resistance, glucose intolerance and abnormal lipid levels. For athletes it seems that low GI pre-exercise meals do not provide any advantage regarding performance over high GI pre-exercise meals. However, low GI meals can be recommended to athletes who are prone to develop hypoglycaemia after a CHO-rich meal in the hour prior to exercise. No studies have been reported on the effect of the GI during exercise. However, it has been speculated that a combination of CHO with varying Gl's deliver the best results in terms of exogenous CHO oxidation. No studies exist investigating the effect of the GI on short-term recovery, however, it is speculated that high GI CHO-rich foods are suitable when the recovery period is short (0-8 h), while the total amount rather than the type of CHO is important when the recovery period is longer (20-24 h). Therefore, the GI is a scientifically based tool to enable the selection of CHO-containing foods to improve markers for CHO and lipid metabolism as well as to help athletes to prepare optimally for competitions. Recommendations: Although a step nearer has been taken to confirm a place for the GI in human health, additional randomised, controlled, medium and long-term studies as well as more epidemiological studies are needed to investigate further the effect of low GI diets on LDL-c. HDL-c and TG. These studies are essential to investigate the effect of low GI diets on endpoints such as CVD and DM. This will also show whether low GI diets can reduce the risk of diabetic complications such as neuropathy and nephropathy. Furthermore, the public at large must be educated about the usefulness and application of the GI in meal planning. For sport nutrition, randomised controlled trials should be performed to investigate the role of the GI during exercise as well as in sports of longer duration such as cricket and tennis. More studies are needed to elucidate the short-term effect of the GI post-exercise as well as to determine the mechanism of lower glycogen storage with LGI meals post-exercise.
Thesis (Ph.D. (Dietetics))--North-West University, Potchefstroom Campus, 2005.

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Erith, Samuel. "Fitness assessment and recovery strategies for soccer." Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/12653.

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In recent years our understanding of the physical demands of soccer has improved. We know that the intensity at which the game is played has increased and that the fixture schedules for professional teams can often be very congested. These factors are likely to have increased the importance placed on the physical condition of players. Therefore, the process of monitoring the fitness levels of players is likely to be an important task within clubs. Any fitness assessments that are employed need to be sensitive enough to detect changes that may result from different training stimuli. A further critical consideration for clubs is what are the best practices to implement in order to maximise recover between matches? The two areas that are central to successful recovery of performance are the restoration of muscle and liver glycogen stores and the rapid reduction of muscle soreness. We have a good understanding of the importance of carbohydrate feeding in the immediate hours following the completion of exercise, furthermore that high levels of carbohydrate consumed during short recovery periods can improve subsequent endurance running capacity in both continuous and intermittent exercise. However, there is dearth of literature investigating the effects that different types (glycemic index) of carbohydrates have on subsequent performance of high intensity intermittent exercise. Furthermore, we know that the movement patterns experienced in soccer commonly induce symptoms of muscle damage. Despite this there is little research based information on modalities that reduce these potentially detrimental side-effects (Bamett, 2006). For these reasons the series of investigations that have been conducted in this thesis were designed with the intent to examine areas that are critical to the preparation and recovery of soccer players. The first of five experimental chapters collated information on the use of fitness testing within English professional football. It was concluded that the practise of fitness testing players is extremely commonplace and that field-based testing protocols were far more popular an assessment method. The second experimental chapter went on to demonstrate that the most commonly used fitness test within professional football (MSFT) was sensitive enough to detect performance changes that occur as a result of training. A further finding within the context of the question was that it is possible for female players to significantly improve aerobic capabilities with additional high intensity aerobic training. The third experimental chapter investigated the effect different glycemic index high CHO diets could have on recovery of performance following 90 min of intermittent soccer type exercise. This study concluded that consuming either predominately high or low GI CHO mixed meals in the 24h recovery period between bouts of high intensity prolonged intermittent exercise had no difference on measures of performance. The final two experimental chapters went on to investigate the effects of cold water immersion on indices of muscle damage following intermittent exercise. Results from these investigations suggest that submerging individuals in 10°C water immediately following high intensity intermittent exercise reduces some but not all indices of muscle damage. In summary, fitness assessments of players are commonly made within professional football clubs. The most common test used was the MSFT and this appears to be sensitive to changes that result as a consequence of training. During recovery from high intensity intermittent exercise the importance of carbohydrates is apparent although the type of carbohydrate appears to be less important, furthermore, cold-water immersion may be effective in reducing some but not all indices of muscle damage.

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Strydom, Hildegard. "Determining the level of comprehension of registered dietitians in South Africa with regard to the glycemic index (GI) used in the treatment of Diabetes Mellitus." Thesis, Stellenbosch : University Stellenbosch, 2009. http://hdl.handle.net/10019.1/4609.

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Thesis (MNutr (Interdisciplinary Health Sciences. Human Nutrition))--University of Stellenbosch, 2009.
Thesis presented in partial fulfillment of the requirements for the degree of Master of Nutrition at Stellenbosch University.
ENGLISH ABSTRACT: The glycemic index (GI) has proven to be a valuable nutritional tool in the management and prevention of diabetes and other chronic diseases of lifestyle 1,3,4,5,6,79,12,14,15. In this quantitative, cross-sectional, observational and descriptive study, the aim was to determine the knowledge and level of comprehension of South African registered dietitians with regard to GI and glycemic load (GL) as well as to determine their ability to use/implement the GI in the treatment of diabetes / insulin resistance. A questionnaire was emailed to 388 registered dietitians for completion. The questionnaire was based on relevant scientific literature and divided into three parts. The first part gathered demographical information about the participants, with special emphasis on where they had acquired their knowledge of GI principles. The second and third parts contained closed-end questions to which the participants were required to answer ‘true’ or ‘false’ or were presented with a multiple choice. Twenty-five questions specifically focused on the GI and the other 12 focused on GL. One hundred and fourteen subjects took part in the study. The results showed that most dietitians (54 %) did not learn GI principles at university and that the year that they qualified did not affect test results. The University attended did not seem to affect test results either, with the exception of Medunsa (Medical University of South Africa), where graduates scored on average significantly lower than the rest of the group). The test scores varied between 43% and 97%. The average test score for the group was 71% with those dieticians in private practice scoring the highest average (76%) compared to those working in other practice areas. Although 84% percent of participants reportedly used GI principles in their daily practice with patients, compared to only 33% who reportedly used GL principles, results showed no significant difference between knowledge or comprehension levels of GI and GL or the ability to implement GI or GL principles. To conclude, South African dietitians seem to have a good general knowledge of GI, but there is still room for improvement in order to ensure that dietitians can become experts in the field. It is recommended that curricula be revised to give this subject more attention during formal university training.
AFRIKAANSE OPSOMMING: Navorsing het bewys dat die Glukemiese Indeks (GI) ‘n waardevolle wetenskaplike hulpmiddel is in die voorkoming en bestuur van diabetes en ander chroniese siektes van lewenstyl 1,3,4,5,6,79,12,14,15 . Die doelwit in hierdie kwantitatiewe, dwars-snit, beskrywende studie was om die kennis- en begripsvlak van Suid-Afrikaanse dieetkundiges te toets rakende die GI en glukemiese lading (GL) asook hul vermoëns om hierdie beginsels toe te pas en te gebruik in die behandeling van diabetes en insulienweerstandigheid. ‘n Vraelys is aan 388 dieetkundiges gepos. Die vraelys was gebasseer op relevante wetenskaplike literatuur en het uit drie afdelings beslaan. Die eerste afdeling was ten doel om demografiese inligting oor deelnemers te bekom met spesifieke belang by die afkoms van hul kennis oor die GI. Die tweede en derde afdelings het bestaan uit vrae waarop ‘waar’ of ‘vals’ gemerk moes word of uit veelvuldige keuse vrae. Vyfen-twintig vrae het gefokus op die GI en twaalf vrae het gefokus op die GL. Eenhonderd-en-veertien persone het deelgeneem aan die studie. Die resultate het getoon dat meerderheid van die deelnemers (54%) nie die beginsels aangaande die GI op universiteit geleer het nie. Die jaar waarop graduasie plaasgevind het, het blykbaar nie ‘n invloed op uitkoms gehad nie, en die universiteit waar graduasie plaasgevind het, het ook nie die uitslag beïnvloed nie, uitsluitend Medunsa (waar gegradueerdes aansienlik swakker gevaar het as die res van die groep). Toets uitslae het gewissel tussen 43% en 97%. Die gemiddelde toetspunt was 71%. Dieetkundiges werkend in privaat praktyk het die hoogste gemiddelde toetspunt van 76% behaal in vergelyking met dieetkundiges wat in ander velde praktiseer. Ten spyte daarvan dat 84% deelnemers aangetoon het dat hulle GI beginsels in hulle werksomstandighede toepas, in vergelyking met slegs 33% wat GL beginsels toepas, was daar geen noemenswaardige verskil in uitkomste rakende deelnemers se kennis of begripsvlak van GI of GL, of hul vermoë om verwante beginsels toe te pas nie. Ter opsomming wil dit voorkom of Suid- Afrikaanse dieetkundiges oor ‘n goeie vlak van algemene kennis betrekkende die GI beskik. Daar is wel steeds ruimte vir verbetering om te verseker dat dieetkundiges as ware kenners op die gebied kan optree. Dit word aanbeveel dat universiteite se kurrikulums aangepas word om sodoende voorsiening te maak vir verbeterde voor-graadse opleiding oor die onderwerp.

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Järvi, Anette. "Carbohydrate-Rich Foods in the Treatment of the Insulin Resistance Syndrome : Studies of the Importance of the Glycaemic Index and Dietary Fibre." Doctoral thesis, Uppsala University, Department of Public Health and Caring Sciences, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1507.

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The glycaemic responses to various carbohydrate-rich foods are partly dependent on the rate at which the carbohydrate is digested and absorbed. The glycaemic index (GI) is a way of ranking foods according to their glycaemic response and is recommended as a useful tool in identifying starch-rich foods that give the most favourable glycaemic response. This investigation was undertaken to determine whether carbohydrate-rich foods with a low GI and a high content of dietary fibre (DF) could have beneficial metabolic effects in the insulin resistance syndrome. This question was addressed both in single-meal studies and in randomised controlled clinical trials. Starch-rich foods with low GI values incorporated into composite meals resulted in lower postprandial responses of both glucose and insulin than foods with a high GI in meals with an identical macronutrient and DF composition, in subjects with type 2 diabetes. After three weeks on a diet including low GI starchy foods metabolic profile was improved in subjects with type 2 diabetes, compared with a corresponding high GI diet. The glucose and insulin responses throughout the day were lower, the total and low density lipoprotein cholesterol was decreased, and the fibrinolytic activity was normalised. In subjects with impaired insulin sensitivity and diabetes low GI foods rich in soluble DF for breakfast gave a more favourable metabolic profile, with smaller glucose fluctuations from baseline during the day, than a breakfast with high GI foods low in DF. A low GI breakfast high in DF also resulted in lower responses of insulin and C-peptide after breakfast and a lower triacylglycerol response after a standardised lunch. However, none of the tested breakfasts improved the glucose and insulin responses after lunch. Similar results were obtained in obese subjects after including a breakfast with a low GI high in soluble DF for a period of four weeks in comparison with a breakfast with a high GI and low content of DF.

These results support the therapeutic potential of a diet with a low GI in the treatment of diabetes and also in the treatment of several of the metabolic disturbances related to the insulin resistance syndrome.

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Järvi, Anette. "Carbohydrate-rich foods in the treatment of the insulin resistance syndrome : studies of the importance of the glycaemic index and dietary fibre /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5166-7/.

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Särnblad, Stefan. "Body composition in adolescents with type 1 diabetes : aspects of glycaemic control and insulin sensitivity /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4056.

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Hamzah, Sareena Hanim. "Impact of glycaemic index of high carbohydrate diets on exercise energy metabolism and capacity and fasting concentration of plasma lipids in healthy physically active individuals." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2632/.

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The present thesis describes the impact of glycaemic index of high carbohydrate diets consumed for 5 days on exercise energy metabolism and capacity and fasting plasma lipids in healthy physically active individuals. The thesis consists of a literature review (Chapter 1), general methods (Chapter 2), four experimental chapters (Chapter 3-Chapter 6) and general discussion and conclusion (Chapter 7). Chapter 3 presents a pilot study aimed to investigate whether high carbohydrate meals with high and low glycaemic index of foods present within meals developed by using the glycaemic index values from the published glycaemic index tables, produce significant differences in postprandial glucose response. Eight healthy active women consumed prescribed high carbohydrate diets with either high or low glycaemic index in a randomised counterbalanced order. The experimental meals which consisted of breakfast, morning snack and lunch were consumed after an overnight fast. Plasma glucose responses were measured at baseline and every 30 minutes for 300 minutes after baseline. We concluded that high carbohydrate meals with high and low glycaemic index prescribed using the glycaemic index values from the existing glycaemic index tables in the literature produced a significant difference in postprandial plasma glucose responses. Thus, for further studies high carbohydrate diets with high and low glycaemic index were developed using glycaemic index values from available glycaemic index tables. The aim of Chapter 4 and Chapter 5 was to investigate the extent to which the glycaemic index of high carbohydrate diets consumed for 5 days reduces the rate of fat oxidation during endurance exercise and exercise capacity during running conducted in the fasted state in men and women. To determine this, 9 healthy physically active men (Chapter 4) and 9 healthy physically active women (Chapter 5) performed three treadmill runs to exhaustion at 65% max after their habitual diet, after 5 days on a high carbohydrate high glycaemic index diet, and after 5 days on high carbohydrate low glycaemic index diet, in a randomised counterbalanced order. Blood samples for the measurements of glucose, insulin, glycerol and non-esterified fatty acids, and expired air samples for the measurements of the rates of fat and carbohydrate oxidation were obtained at 15, 30, 45, 60, 75, 90 minutes and at the point of exhaustion. Running capacity was measured as time to exhaustion and distance covered. It was found that in both men and women, the extent to which high carbohydrate diets consumed for 5 days reduced the rate of fat oxidation during running in the fasted state was not influenced by the glycaemic index of the diet, and that glycaemic index of high carbohydrate diets consumed for 5 days had no impact on running capacity. Chapter 6 aimed to investigate the impact of the consumption of high carbohydrate diets with high and low glycaemic index for 5 days on fasting plasma concentration of lipids, insulin sensitivity and biomarkers for endothelial function (i.e. intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) in physically active individuals. Fasting blood was collected from 17 healthy individuals on three occasions in a randomised counterbalanced order: after consuming habitual diet, after 5 days on high carbohydrate high glycaemic index diet and after 5 days on high carbohydrate low glycaemic index diet. It was found that the extent to which high carbohydrate diets consumed for 5 days increases fasting plasma concentration of triglyceride and reduces the concentration of high density lipoprotein cholesterol was not influenced by the glycaemic index of the diets. It was also found that glycaemic index of high carbohydrate diets consumed for 5 days had no impact on insulin sensitivity or on biomarkers of endothelial activation. In conclusion, consideration of the glycaemic index of high carbohydrate diets consumed by physically active healthy men and women for 5 days has no impact on insulin sensitivity and fasting concentration of plasma lipids, it does not influence the rate of fat oxidation induced by high carbohydrate diets during running conducted in the fasted state and has no influence on running capacity. Thus, when physically active individuals increase carbohydrate intake for the purposes of muscle glycogen accumulation, consideration of the glycaemic index is not important. Future studies are needed to determine whether the glycaemic index of high carbohydrate diets modify exercise energy metabolisms in top grade athletes.

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Adjei-Duodu, Thomas. "Physical, chemical and functional properties of tiger nuts (Cyperus esculentus) selected from Ghana, Cameroon and UK market (Spain)." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3313.

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The tiger nut (Cyperus esculentus) has attracted a lot of unsubstantiated health claims, yet there is a dearth of research investigation within Ghana specifically in the area of food product development. This study addresses the development of ‘functional bread and biscuit’ from tiger nuts obtained from UK market (Spain). The chemical constituents; carbohydrate, lipid, protein, dietary minerals and antioxidants, the functional properties of three varieties of tiger nuts obtained from Ghana (black and brown), Cameroon (yellow) and UK market (Spain) (brown) were investigated using standard analytical methods as well as the blood glucose response of healthy adults who consumed the developed bread. Tiger nuts were found to be good sources of carbohydrate (51-82g/100g) and lipids (21-37g/100g). The dietary fibre components ranged between 18, 1, 19 and 19g/100g for IDF, SDFP, HMWDF, and ITDF respectively, while the available carbohydrate as sugars were 45, 0.5 and 5g/100g for glucose, maltose and xylose respectively. Minerals that were found to be inherent to the crop were; potassium, phosphorus, magnesium, copper, iron, zinc and selenium and do not depend on place of origin. The following ratios for Sodium/Potassium 0.04, Calcium/Phosphorus 0.13 and Calcium/Magnesium 0.28 were obtained. Tiger nuts had TPC ≥ 134GAE per g, DPPH and stability index of 0.9-8.7mmol/litre and 3- 4 respectively. In conclusion the tiger nuts originating from different geographical locations were good sources of health giving minerals and had diversity of physical properties and chemical constituents which could inform future research in the functional food industry. Tiger nut could be added to the Ghana food basket and the product developed from it could be a potential functional food because of its effect on glucose response and phytochemical contents. It could again be used to replace artificial antioxidants (BHA or BHT) which are used in the food industry to inhibit lipid and protein oxidation especially the black variety.

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38

O'Sullivan, Therese Anne. "The relationship between glycemic intake and insulin resistance in older women." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/17814/1/Therese_Anne_O%27Sullivan_Thesis.pdf.

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Glycemic intake influences the rise in blood glucose concentration following consumption of a carbohydrate containing meal, known as the postprandial glycemic response. The glycemic response is a result of both the type and amount of carbohydrate foods consumed and is commonly measured as the glycemic index (GI) or glycemic load (GL), where the GI is a ranking in comparison to glucose and the GL is an absolute value encompassing both the GI and amount of carbohydrate consumed. Evidence from controlled trials in rat models suggests that glycemic intake has a role in development of insulin resistance, however trials and observational studies of humans have produced conflicting results. As insulin resistance is a precursor to type 2 diabetes mellitus, lifestyle factors that could prevent development of this condition have important public health implications. Previous observational studies have used food frequency questionnaires to assess usual diet, which could have resulted in a lack of precision in assessment of individual serve sizes, and have been limited to daily measures of glycemic intake. Daily measures do not take fluctuations in glycemic intake on a per meal basis into account, which may be a more relevant measure for investigation in relation to disease outcomes. This PhD research was conducted in a group of Brisbane women aged 42 to 81 years participating in the multidisciplinary Brisbane Longitudinal Assessment of Ageing in Women (LAW study). Older women may be at particular risk of insulin resistance due to age, hormonal changes, and increases in abdominal obesity associated with menopause, and the LAW study provided an ideal opportunity to study the relationship between diet and insulin resistance. Using the diet history tool, we aimed to assess the glycemic intake of the population and hypothesised that daily GI and daily GL would be significantly positively associated with increased odds of insulin resistant status. We also hypothesised that a new glycemic measure representing peaks in GL at different meals would be a stronger predictor of insulin resistant status than daily measures, and that a specially designed questionnaire would be an accurate and repeatable dietary tool for assessment of glycemic intake. To address these hypotheses, we conducted a series of studies. To assess glycemic intake, information on usual diet was obtained by detailed diet history interview and analysed using Foodworks and the Australian Food and Nutrient (AUSNUT) database, combined with a customised GI database. Mean ± SD intakes were 55.6 ± 4.4% for daily GI and 115 ± 25 for daily GL (n=470), with intake higher amoung younger participants. Bread was the largest contributor to intakes of daily GI and GL (17.1% and 20.8%, respectively), followed by fruit (15.5% and 14.2%, respectively). To determine whether daily GI and GL were significantly associated with insulin resistance, the homeostasis model assessment of insulin resistance (HOMA) was used to assess insulin resistant status. Daily GL was significantly higher in subjects who were insulin resistant compared to those who were not (134 ± 33 versus 114 ± 24 respectively, P<0.001) (n=329); the odds of subjects in the highest tertile of GL intake being insulin resistant were 12.7 times higher when compared with the lowest tertile of GL (95% CI 1.6-100.1, P=0.02). Daily GI was not significantly different in subjects who were insulin resistant compared to those who were not (56.0 ± 3.3% versus 55.7 ± 4.5%, P=0.69). To evaluate whether a new glycemic measure representing fluctuations in daily glycemic intake would be a stronger predictor of insulin resistant status than other glycemic intake measures, the GL peak score was developed to express in a single value the magnitude of GL peaks during an average day. Although a significant relationship was seen between insulin resistant status and GL peak score (Nagelkerke’s R2=0.568, P=0.039), other glycemic intake measures of daily GL (R2=0.671, P<0.001) and daily GL per megajoule (R2=0.674, P<0.001) were stronger predictors of insulin resistant status. To develop an accurate and repeatable self-administered tool for assessment of glycemic intake, two sub-samples of women (n=44 for the validation study and n=52 for the reproducibility study) completed a semi-quantitative questionnaire that contained 23 food groupings selected to include the top 100 carbohydrate foods consumed by the study population. While there were significant correlations between the glycemic intake questionnaire and the diet history for GL (r=0.54, P<0.01), carbohydrate (r=0.57, P<0.01) and GI (r=0.40, P<0.01), Bland-Altman plots showed an unacceptable difference between individual intakes in 34% of subjects for daily GL and carbohydrate, and 41% for daily GI. Reproducibility results showed significant correlations for daily GL (r=0.73, P<0.001), carbohydrate (r=0.76, P<0.001) and daily GI (r=0.64, P<0.001), but an unacceptable difference between individual intakes in 25% of subjects for daily GL and carbohydrate, and 27% for daily GI. In summary, our findings show that a significant association was observed between daily glycemic load and insulin resistant status in a group of older women, using a diet history interview to obtain precise estimation of individual carbohydrate intake. Both the type and quantity of carbohydrate are important to consider when investigating relationships between diet and insulin resistance, although our results suggest the association is more closely related to overall daily glycemic intake than individual meal intake variations. A dietary tool that permits precise estimation of carbohydrate intake is essential when evaluating possible associations between glycemic intake and individual risk of chronic diseases such as insulin resistance. Our results also suggest that studies using questionnaires to estimate glycemic intake should state degree of agreement as well as correlation coefficients when evaluating validity, as imprecise estimates of carbohydrate at an individual level may have contributed to the conflicting findings reported in previous studies.

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39

O'Sullivan, Therese Anne. "The relationship between glycemic intake and insulin resistance in older women." Queensland University of Technology, 2008. http://eprints.qut.edu.au/17814/.

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Abstract:

Glycemic intake influences the rise in blood glucose concentration following consumption of a carbohydrate containing meal, known as the postprandial glycemic response. The glycemic response is a result of both the type and amount of carbohydrate foods consumed and is commonly measured as the glycemic index (GI) or glycemic load (GL), where the GI is a ranking in comparison to glucose and the GL is an absolute value encompassing both the GI and amount of carbohydrate consumed. Evidence from controlled trials in rat models suggests that glycemic intake has a role in development of insulin resistance, however trials and observational studies of humans have produced conflicting results. As insulin resistance is a precursor to type 2 diabetes mellitus, lifestyle factors that could prevent development of this condition have important public health implications. Previous observational studies have used food frequency questionnaires to assess usual diet, which could have resulted in a lack of precision in assessment of individual serve sizes, and have been limited to daily measures of glycemic intake. Daily measures do not take fluctuations in glycemic intake on a per meal basis into account, which may be a more relevant measure for investigation in relation to disease outcomes. This PhD research was conducted in a group of Brisbane women aged 42 to 81 years participating in the multidisciplinary Brisbane Longitudinal Assessment of Ageing in Women (LAW study). Older women may be at particular risk of insulin resistance due to age, hormonal changes, and increases in abdominal obesity associated with menopause, and the LAW study provided an ideal opportunity to study the relationship between diet and insulin resistance. Using the diet history tool, we aimed to assess the glycemic intake of the population and hypothesised that daily GI and daily GL would be significantly positively associated with increased odds of insulin resistant status. We also hypothesised that a new glycemic measure representing peaks in GL at different meals would be a stronger predictor of insulin resistant status than daily measures, and that a specially designed questionnaire would be an accurate and repeatable dietary tool for assessment of glycemic intake. To address these hypotheses, we conducted a series of studies. To assess glycemic intake, information on usual diet was obtained by detailed diet history interview and analysed using Foodworks and the Australian Food and Nutrient (AUSNUT) database, combined with a customised GI database. Mean ± SD intakes were 55.6 ± 4.4% for daily GI and 115 ± 25 for daily GL (n=470), with intake higher amoung younger participants. Bread was the largest contributor to intakes of daily GI and GL (17.1% and 20.8%, respectively), followed by fruit (15.5% and 14.2%, respectively). To determine whether daily GI and GL were significantly associated with insulin resistance, the homeostasis model assessment of insulin resistance (HOMA) was used to assess insulin resistant status. Daily GL was significantly higher in subjects who were insulin resistant compared to those who were not (134 ± 33 versus 114 ± 24 respectively, P<0.001) (n=329); the odds of subjects in the highest tertile of GL intake being insulin resistant were 12.7 times higher when compared with the lowest tertile of GL (95% CI 1.6-100.1, P=0.02). Daily GI was not significantly different in subjects who were insulin resistant compared to those who were not (56.0 ± 3.3% versus 55.7 ± 4.5%, P=0.69). To evaluate whether a new glycemic measure representing fluctuations in daily glycemic intake would be a stronger predictor of insulin resistant status than other glycemic intake measures, the GL peak score was developed to express in a single value the magnitude of GL peaks during an average day. Although a significant relationship was seen between insulin resistant status and GL peak score (Nagelkerke’s R2=0.568, P=0.039), other glycemic intake measures of daily GL (R2=0.671, P<0.001) and daily GL per megajoule (R2=0.674, P<0.001) were stronger predictors of insulin resistant status. To develop an accurate and repeatable self-administered tool for assessment of glycemic intake, two sub-samples of women (n=44 for the validation study and n=52 for the reproducibility study) completed a semi-quantitative questionnaire that contained 23 food groupings selected to include the top 100 carbohydrate foods consumed by the study population. While there were significant correlations between the glycemic intake questionnaire and the diet history for GL (r=0.54, P<0.01), carbohydrate (r=0.57, P<0.01) and GI (r=0.40, P<0.01), Bland-Altman plots showed an unacceptable difference between individual intakes in 34% of subjects for daily GL and carbohydrate, and 41% for daily GI. Reproducibility results showed significant correlations for daily GL (r=0.73, P<0.001), carbohydrate (r=0.76, P<0.001) and daily GI (r=0.64, P<0.001), but an unacceptable difference between individual intakes in 25% of subjects for daily GL and carbohydrate, and 27% for daily GI. In summary, our findings show that a significant association was observed between daily glycemic load and insulin resistant status in a group of older women, using a diet history interview to obtain precise estimation of individual carbohydrate intake. Both the type and quantity of carbohydrate are important to consider when investigating relationships between diet and insulin resistance, although our results suggest the association is more closely related to overall daily glycemic intake than individual meal intake variations. A dietary tool that permits precise estimation of carbohydrate intake is essential when evaluating possible associations between glycemic intake and individual risk of chronic diseases such as insulin resistance. Our results also suggest that studies using questionnaires to estimate glycemic intake should state degree of agreement as well as correlation coefficients when evaluating validity, as imprecise estimates of carbohydrate at an individual level may have contributed to the conflicting findings reported in previous studies.

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40

TRETOLA, MARCO. "FORMER FOODSTUFFS PRODUCTS INTENDED FOR PIG NUTRITION: IN VITRO AND IN VIVO NUTRITIONAL EVALUATION, IMPACT ON GROWTH PERFORMANCES AND GUT HEALTH." Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/609808.

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La produzione animale riveste un ruolo chiave nel garantire la sicurezza alimentare. Tale ruolo viene esercitato soprattutto grazie all’approvvigionamento di prodotti di origine animale e prodotti dell’agricoltura. Tuttavia, a causa delle diminuite disponibilità di terreni destinati all’allevamento ed alla agricoltura, insieme ai cambiamenti climatici e alla riduzione delle risorse idriche, diventa sempre più importante aumentare la sostenibilità e l’efficienza del settore agroalimentare. Per fare ciò, diventa necessario soddisfare le crescenti esigenze utilizzando al tempo stesso una quantità ridotta di risorse. Questa tesi ha avuto come tema principale quello di esaminare a fondo il potenziale utilizzo di scarti della industria alimentare (chiamati “former foodstuffs products”, FFPs) come ingredienti alternativi e sostenibili per la nutrizione animale. I prodotti esaminati sono alimenti che vengono scartati dalla grande distribuzione per difetti relativi alla loro forma, al loro colore, al loro packaging ecc. Tali scarti solitamente sono destinati a diventare rifiuto, nonostante il loro elevato potenziale nel poter essere utilizzati come ingredienti sostenibili per mangimi. La prima parte della tesi si concentra sull’analisi della composizione chimica di sei diversi tipi di FFPs. Inoltre, di questi prodotti sono state anche stimate l’energia digeribile e metabolizzabile con riferimento ai suini, la digeribilità in vitro, l’indice glicemico e di idrolisi attraverso tecniche di digestione enzimatica. La seconda parte della tesi è stata dedicata agli aspetti legati alla sicurezza dei FFPs. Campioni di FFPs sono stati quindi analizzati per la loro carica microbica e la presenza di residui di materiale di imballaggio. Per questo ultimo aspetto, sono stati testati due metodi differenti: il primo, precedentemente validato, basato sull’uso dello stereomicroscopio; il secondo, basato sull’uso dello stereomicroscopio accoppiato ad un sistema digitale di acquisizione di immagine (Computer Vision System). L’ultima parte, invece, ha investigato gli effetti di una dieta in cui in cui i cereali comunemente utilizzati per la formulazione di diete per suini in post svezzamento, sono stati parzialmente sostituiti dagli FFPs. In particolare, una dieta di controllo e quella contenente FFPs sono state confrontate per quanto riguarda la digeribilità in vitro ed in vivo della sostanza secca, le performances di crescita di suini in post svezzamento, così come alcuni metaboliti ematici ed il microbiota fecale. I risultati della tesi hanno dimostrato che gli FFPs possono essere considerati una “versione fortificata” dei cereali tradizionali comunemente utilizzati nel settore suinicolo, con valori di digeribilità in vitro comparabili agli stessi, ma con valori di indice glicemico e di idrolisi maggiori, caratterizzandoli come una fonte eccellente di carboidrati. Tutti i campioni di FFP sono risultati sicuri dal punto di vista microbiologico e sempre privi di Salmonella. Per quanto concerne la presenza di residui di materiale da imballaggio, il livello di contaminazione è risultata sempre al di sotto delle soglie di tolleranza. Il Computer Vision System si è inoltre rivelato essere una rapida alternativa per rilevare la presenza di materiali di imballaggio nei FFPs se accoppiata allo seteromicroscopio. Lo studio in vivo ha rivelato che sia i valori di digeribilità in vitro che in vivo delle diete contenenti FFPs sono maggiori rispetto ai valori delle diete di controllo. Alla fine dell’esperimento, non sono state osservate differenze nelle performance di crescita, tuttavia nei suinetti alimentati con la dieta FFP c’è stato un aumento di glucosio plasmatico ed una riduzione nella concentrazione di urea. Il sequenziamento di nuova generazione delle regioni variabili V3 e V4 del gene che codifica per il 16S rRNA hanno evidenziato come l’utilizzo di FFPs nelle diete per suini in post svezzamento riduca sia la numerosità che la biodiversità dei batteri che costituiscono il microbiota nel largo intestino. L’analisi “unweighted beta diversity” ha anche dimostrato piccole differenze nella composizione dei taxa batterici tra il gruppo FFP e quello di controllo. Inoltre, l’analisi lineare delle discriminanti ha documentato un aumento del phylum Proteobacteria ed una diminuzione del genere Lactobacillales nel gruppo FFP rispetto al controllo. Questi risultati hanno messo in evidenza il potenziale di questi ingredienti alternativi ed il loro utilizzo sicuro nella nutrizione suinicola. Il loro aumentato utilizzo potrebbe quindi portare ad una riduzione dello spreco alimentare, una riduzione dei costi del mangime, e ad un ridotto impatto ambientale della catena alimentare.
Livestock play a key role in food security, through food provision, agricultural production, and by providing employment and income. However, with the diminishing availability of farmland, climate change and the threat of declining water resources, the goal is to meet the growing demand for food and feed by using fewer resources. Exploiting alternative ingredients for livestock, feed could be one way of increasing livestock sustainability. This thesis focused on processed and ready-to-eat food products that are no longer suitable for human consumption due to logistical, manufacturing or packaging defects. Such products would normally go to a landfill yet actually have a high potential of being used as sustainable feed ingredients. The first part of this thesis investigated the chemical composition of six different former foodstuff products (FFPs). Based on the FFP composition data, the digestible energy and metabolisable energy values for pigs were estimated. In addition, the in vitro digestibility values of FFPs were evaluated using a multi-step enzymatic technique. The in vitro predicted glycaemic index and hydrolysis index of the same samples were examined using a two-step in vitro digestion assay. In the second part, the safety issues linked to the use of FFPs were investigated. FFP samples were thus analysed in relation to the microbial load and the presence of presumed remnants of packaging materials. For this purpose, two different methods were used: stereomicroscopy, according to published methods; and stereomicroscopy coupled with a computer vision system. The final part addressed the effects of a diet in which common cereal grains were partially replaced by FFPs in post weaning piglet diets. Specifically, pig growth performance and selected plasma biochemical variables were evaluated in twelve post-weaning piglets. The apparent total tract digestibility of dry matter and the faecal microbiota were also characterized. When compared with common cereal grains used in pig feed formulations, FFPs can be considered a fortified version of cereals, with comparable in vitro digestibility values and with higher glycaemic and hydrolysis indexes, thus characterizing them as an excellent source of carbohydrates. All FFP samples were safe from a microbiological point of view, showing a limited microbial load and were always Salmonella free. Regarding the presumed remnants of packaging materials, the contamination level was always below the safety threshold set by German authorities, and the validated method demonstrated that packaging remnants were mainly from the 1-mm sieve mesh fraction. In order to find a more rapid and objective method for evaluating the packaging remnants, the innovative computer vision system was a rapid alternative for the detection of packaging remnants in ex-food samples when combined with a stereomicroscope. The in vivo study revealed that both in vitro and in vivo digestibility values were higher for the diet based on FFPs compared to the control diet. At the end of the experiment, no differences in growth performance were observed, however the plasma glucose increased in piglets fed FFPs compared to piglets fed the control diet, while the urea concentration decreased. The sequencing analysis of the variable regions V3 and V4 of the 16S rRNA gene showed that the use of FFPs in the post-weaning period decreased the bacterial richness and evenness in the large intestine. The unweighted beta diversity analysis also resulted in a statistically significant difference between the two groups in terms of the taxa composition. The linear discriminant analysis of effect size also demonstrated an increased amount of Proteobacteria phylum and a decreased amount of Lactobacillales genus in the FFP compared to the control group. The results highlighted the potential of these alternative feed ingredients and their safe use in pig nutrition. This is essential for establishing the best scientific practices for the use of FFPs in animal nutrition and feeding. Given the increasing need to obtain a more sustainable livestock sector, research in animal sciences should focus not only on increasing the efficiency of the animal production chain but also on the efficiency of the entire food system in ensuring sustainable nutrition. By recognizing that former foodstuffs that are not suitable for human consumption are a resource for animal nutrition and not a waste product, food and feed industries could reduce the amount of waste sent to landfill or deposed-off every year, thus saving costs, and reducing the environmental impact of the food production chain.

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41

Brennan, Margaret Anne. "Dietary fibres and their properties : the possibility of fibre lowering the glycaemic index of foods post extrusion : presented in partial fulfilment of the requirement for the degree of MPhil in Food Science and Technology at Massey University, Palmerston North campus, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/829.

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A series of experiments were devised in order to establish the relationship between fibre addition to an extruded breakfast cereal base recipe and the physical, chemical and nutritional qualities of the breakfast cereals. A twin screw extruder was used for all experiments. Preliminary investigations using, guar gum and inulin additions, illustrated that screw configuration was important in determining the physical properties (degree of expansion, firmness and crunchiness) of the extruded products. Thus a screw configuration featuring a reverse screw and mixing zone within the barrel was selected for the larger research study. In the extended experimental design guar gum, inulin, wheat bran, swede fibre, and hi-maize were added to a base recipe at; 5, 10 and 15 % of total dry ingredient content. A further experiment was completed to investigate the synergistic effects of adding differing fibres in combination. Results illustrated that soluble dietary fibres (for instance guar and inulin) created a porous, less firm, but crispier breakfast cereals than the insoluble fibres, which generally produced denser, harder products. The inclusion of fibre into the extruded breakfast cereals did not affect the chemical composition of the breakfast cereal significantly (P=0.05) when taking into account the diluting factor of adding the fibre into the base recipe. However moisture loss / retention on extrusion varied significantly (P=0.05) between fibre combinations. Thus the moisture loss of samples containing guar or inulin were greater than those samples containing wheat bran and swede fibre. The process of extrusion did not significantly effect the amount of protein, starch or fibre in the samples when the extruded samples were compared to the control samples. Pasting properties of samples were evaluated using the Rapid Visco Analyser. This was conducted to try to determine associations between starch pasting properties (gelatinisation events) of the raw and extruded samples and the physical or nutritional quality of the products. However, the results did not show clear associations. An in vitro analysis was conducted to determine the effect of fibre addition on starch breakdown and subsequent release of reducing sugars. Breakfast cereals which included wheat bran, guar and swede fibre all showed a reduced rate of starch degradation compared to the control (P=0.05). These fibres appeared to inhibit the rate of enzyme degradation of starch, in effect increasing the amount of slowly digestible starch in the breakfast cereals. Cereal samples containing inulin did not show this pattern. Generally the rate of inhibition was related to the amount of fibre added to the base recipe. When used in combinations, samples containing inulin and hi-maize were not significantly different to the control in terms of reducing sugar release, whereas inclusion of guar gum significantly reduced this release. In conclusion, the addition of selected fibres can be used effectively as a method of manipulating the starch degradation rates of extruded breakfast cereals. This has nutritional implications in terms of glycaemic index and loading of breakfast cereals. Further work is required to develop clearer associations between the events of starch gelatinisation during extrusion and the potential glycaemic response.

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42

Ayepola, Omolola Rebecca. "Effects of kolaviron–a Garcinia kola biflavonoid on biochemical and histological parameters in streptozotocin - induced diabetes and diabetic complications (nephrotoxicity and hepatotoxicity) in male Wistar rats." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/1512.

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Thesis submitted in fulfillment of the requirements for the Doctor of Technology: Biomedical Technology In the Faculty of Health and Wellness At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2014
Diabetes mellitus (DM) results in severe metabolic imbalances and pathological changes in many tissues. Chronic inflammation and oxidative stress have been implicated in the pathophysiology of diabetes mellitus. Garcinia kola (Family: Guttiferae) is a plant well known for its ample medicinal values. The seed of the plant also known as ‘bitter kola’ due to its bitter taste is used as a masticatory agent in traditional hospitality, cultural and social ceremonies in Africa. Kolaviron (KV) is a defatted ethanol extract from the seeds of Garcinia kola (GK). Kolaviron has been shown in experimental models of diseases to have numerous beneficial effects due to the presence of flavonoids (mainly Garcinia biflavonoid (GB)-1, GB-2 and kolaflavanone). However, there is paucity of information regarding the possible effect of kolaviron on inflammatory mediators and oxidative stress in diabetes mellitus. Therefore, this study was carried out to investigate the potential beneficial effects of kolaviron on antioxidant status, inflammatory mediators and apoptosis. Other biochemical and histological alterations in the blood, liver and kidney of streptozotocin-induced diabetic rats were also evaluated. A single intraperitoneal injection of freshly prepared solution of streptozotocin (50 mg/kg.b.wt.) in citrate buffer (0.1M, pH 4.5) was administered to overnight fasted rats for diabetes induction. Diabetes was confirmed by stable hyperglycemia (>18 mmol/l) in the tail blood glucose after 5 days of streptozotocin injection. Kolaviron (100 mg/kg b.wt.) was administered to diabetic rats (by gastric gavage) on the 6th day after the induction of diabetes and treatment continued for 6 weeks (5 times weekly). The effects on blood glucose, body weight, organ (liver and kidney) weight, serum biochemical parameters, oxidative status, inflammatory mediators and histology of the liver, kidney and pancreas were assessed. Kolaviron (KV) treatment lowered blood glucose in diabetic and normoglycemic rats and reduced glycated haemoglobin [HbA1C (%)]. Plasma insulin level was raised in diabetic rats treated with KV. Histomorphometric analysis of the pancreas revealed increased β-cell area of pancreatic islets of kolaviron-treated diabetic group. The indices of organ (liver and kidney) damage were increased in diabetic rats. However, KV treatment protected against liver and kidney damage. The characteristic features of diabetic dyslipidemia such as elevated serum triglyceride and cholesterol concentration which are major risk factors for cardiovascular disease were also significantly reduced in KV-treated diabetic rats. Alteration in antioxidant enzymes status was observed in the liver, kidney and blood (erythrocyte, plasma and serum) of diabetic rats. Lowered catalase (CAT) activity was observed in the liver and kidney of diabetic rats while KV treatment significantly (p < 0.05) elevated catalase activity in the liver and kidney. There was no significant change (p > 0.05) in erythrocyte catalase activity among all treatment groups. Erythrocyte of diabetic rats showed a marked reduction in the activity of superoxide dismutase (SOD) with no significant changes in liver and kidney SOD activity of diabetic rats compared to control whereas KV administration to rats markedly increased SOD activity. Glutathione peroxidase (GPX) activity was elevated in the erythrocyte and kidney of STZ-induced diabetic rats with no significant effect on liver GPX activity. KV treatment reversed the alteration in GPX activity in the kidney and erythrocyte. Level of reduced glutathione (GSH), a non-enzymatic antioxidant was decreased in the both liver and kidney of diabetic rats and treatment of diabetic rats with KV elevated GSH concentration in both tissues. Also, malondialdehyde (MDA), a marker of lipid peroxidation was elevated in the liver, kidney and plasma of diabetic rats and significantly (p < 0.05) lowered following KV treatment. Diabetes induction reduced the capacity of liver and kidney to absorb oxygen radicals as demonstrated by lowered oxygen radical absorbance capacity (ORAC) values. KV administration to normal and diabetic rats significantly increased ORAC values. Increased rate of apoptosis, a major cellular response to high glucose induced stress was observed in the renal and hepatic tissues of diabetic control rats. Kolaviron treatment of diabetic rats protected the liver and kidney against hyperglycemia-induced apoptosis and decreased the number of TUNEL positive cells A significant (p < 0.05) elevation of pro-inflammatory cytokines; monocyte chemoattractant protein (MCP-1), Interleukin-1β (IL-1β), IL-6 and tumor necrosis factor (TNF)-𝛂 was observed in the liver of diabetes rats. KV treatment lowered these inflammatory biomarkers. On the other hand, the kidney of diabetic rats showed elevated concentration of pro-inflammatory IL-1β with no significant effect on kidney TNF-𝛂. An increase in the serum concentration of MCP-1 and IL-1β was observed in the untreated diabetic rats while kolaviron treatment normalized the alteration in serum concentration of MCP-1, IL-1β and vascular endothelial growth factor (VEGF). In conclusion, persistent and chronic hyperglycemia promotes the generation of free radicals and inflammatory molecules which contributes to progressive development of micro- and macro vascular complications and multi-organ damage. Kolaviron demonstrated beneficial effects on markers of oxidative stress and inflammation in the diabetic rats and also promoted the survival and functional integrity of the liver and kidney.

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Saxena, Nishta. "Some determinants of the glycaemic index of bread." 2007. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=788829&T=F.

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Moreira, Tracy Sousa. "The Role of Starch Physicochemical Properties in Determining the Glycaemic Index of Novel Potato Varieties." Thesis, 2012. http://hdl.handle.net/1807/32609.

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Potatoes are often thought of as high GI. It is known that cooking and cooling affect GI and that these effects may be mediated through the physicochemical properties of their starch. As part of a Canadian initiative to develop low GI potatoes, novel potato varieties which differed in starch composition were tested in 2 separate studies. In study 1, we determined the GI of 8 varieties and found that cooling produced a wide range of effects (0-50% reduction in GI). In study 2, four previously tested varieties were re-examined. A significant variety-x-treatment interaction (p<0.01) was observed with cooling reducing GI in some potatoes. Examination of the starch properties and their role in determining GI showed that RDS was positively associated with GI (r2= 0.85, p= 0.001) and SDS (r2=-0.60, p= 0.02) and amylose (r2=-0.99, p=0.007) negatively associated with GI. No relationship between RS and phosphorous content and GI was observed.

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Sparks, Matthew James. "Pre-exercise carbohydrate ingestion : effect of the glycaemic index on metabolism and endurance performance." Thesis, 1995. https://vuir.vu.edu.au/17890/.

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Carbohydrates are a major substrate contributing to energy transduction during medium to high intensity exercise, and the body's levels of this substrate can be manipulated by dietary and exercise behaviours. Nutritional strategies employed before and during exercise affect endurance exercise performance by altering the metabolism of carbohydrate within the body. Carbohydrate feeding during endurance exercise has repeatedly been demonstrated to be beneficial to the athlete. Studies investigating preexercise carbohydrate feeding, particularly in the hour before exercise, have produced conflicting results and justify further investigation. The study reported in this dissertation aimed to further investigate the role of the meal, in particular, examine the effect of differing glycaemic indices of carbohydrate foods on metabolism and exercise performance. A total of eight, endurance trained subjects participated in this study which involved the ingestion of carbohydrate food with differing glycaemic indices 45 min before cycling at a submaximal workload corresponding to 70% VO2max for 50 min, followed by a self-paced 15 min performance ride. In all trials blood samples were taken from a forearm vein and analysed for metabolites and hormones. The results from this study demonstrate that the pre- exercise ingestion of carbohydrate foods with different glycaemic indices alter metabolism during rest and subsequent submaximal exercise. The data from this study demonstrated that pre-exercise ingestion of a high glycaemic index (HGI) food resulted in a hyperglycaemic response followed by an insulin-mediated hypoglycaemia at the onset of exercise. In addition, the elevated insulin during the HGI trial resulted in an attenuation in circulating FFA and higher rate of carbohydrate oxidation compared with the ingestion of a low glycaemic index food (LGI) or placebo (CON). Despite the changes in metabolism associated with pre-exercise CHO feeding, exercise performance following 50 min of submaximal exercise was not affected.

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Sehloho, Tohlang Solomon Aldrin. "Effect of insulin dose adjustment for glycaemic control on body mass index : a retrospective cohort study of type 1 diabetes patients at the Kalafong Diabetic Clinic between 2009 and 2014." Diss., 2016. http://hdl.handle.net/2263/56947.

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Type 1 diabetes mellitus (T1DM), an autoimmune disease in which the insulin-producing pancreatic ?-cells are destroyed, results in the inability of the pancreas to produce insulin to regulate blood glucose levels, an accumulation of glucose in the blood and cell starvation. Elevated glycated haemoglobin (HbA1c) levels, a metabolic marker of glucose control, are characteristic of T1DM. Chronic exposure to high blood glucose levels leads to microvascular and macrovascular complications. Disease management requires regular blood glucose monitoring and daily exogenous insulin administration to maintain fasting and post-prandial blood glucose levels within near to the normal range of 3.9 to 5.6 mmol/L. However, T1DM patients on daily insulin replacement therapy have been observed to experience weight-gain over time, regardless of the level of glycaemic control achieved. The study aimed to determine the effects of quarterly adjusted total daily doses of twice-daily biphasic insulin and basal NPH plus prandial regular insulin to achieve optimum glycaemic control, on body mass index (BMI) in T1DM patients. Secondarily, dosage regimens that achieved optimum glycaemic control, without increasing BMI, as well as gender differences in BMI and HbA1c outcomes, were also explored. All available clinic records of T1DM patients who attended the Kalafong Hospital Diabetes clinic between 2009 and 2014, and not on metformin and/or acarbose, were reviewed (n=493) and all eligible patients included in the study (n=211, mean±SD=43±14.4 years, 51% female, duration of T1DM ?2 years). Baseline and quarterly BMI levels were calculated from initial and quarterly height and weight measurements obtained from clinic records, respectively. Prescribed total daily insulin dosage and regimen at each visit and measurements of other clinically important covariates of interest were also recorded. Baseline characteristics stratified by gender indicated no significant differences in the mean age distribution, number of years with T1DM, number of years of observation in the study, proportions on the basal NPH plus prandial regular insulin regimen and number of clinic visits. However, females had a statistically significant higher baseline BMI than males and more males were current smokers than females. Although females had a statistically and clinically significant higher baseline HbA1c level than males, they were prescribed similar average twice-daily biphasic insulin doses. On multivariate multilevel mixed-effects linear regression analysis, time-varying BMI was significantly increased by exposure to any insulin regimen. Higher baseline HbA1c and BMI levels were predictive of an increase in BMI. However, males experienced significant comparative reductions in BMI on exposure to the adjusted twice-daily biphasic regimen, the regimen prescribed for 85% of patients and equally spread by gender. Poor glycaemic control during insulin therapy was associated with a reduction in BMI, and vice versa, regardless of regimen. The study concluded that exposure to adjusted doses of insulin to achieve optimum glycaemic control in T1DM patients resulted in a statistically significant increase in BMI. However, this relationship seemed to be more prominent in female patients and in patients at higher baseline HbA1c levels and BMI categories, respectively. In addition, increasing BMI was consistent with improvements in blood glucose control.
Dissertation (MSc)--University of Pretoria, 2016.
tm2016
School of Health Systems and Public Health (SHSPH)
MSc
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Monge, Ana Catarina. "Community pharmacy: Going beyond dispensing pharmaceuticals." Master's thesis, 2016. http://hdl.handle.net/10362/18653.

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The aim of this study is to understand if it is possible to predict health crisis based on biochemical and physiological measurements made at the pharmacy, and, if needed, refer patients to the doctor. This would avoid emergency services and increase pharmacies’ income. Three pharmaceutical consultations were made, where these parameters were measured and the therapeutics registered. The short duration of the study (three months) and the small sample (57 patients) did not allow to reach clear conclusions, as patients had little variation in their health. It was also addressed the issue of how important these consultations are for patients and results were positive: they considered consultations important and helpful and the majority of patients were willing to pay €5 or less for them.

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Dissertations / Theses on the topic 'Glycaemic index'

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