Дисертації з теми "Macronutrient composition"

Genome size (GS) is a fundamental trait influencing cellular, developmental and ecological parameters, and varies c. 2400- fold in angiosperms. This astonishing range has the potential to influence a plant's nutrient demands, since nucleic acids are amongst the most phosphate and nitrogen demanding cellular biomolecules, and hence its ability to grow and compete in environments where macronutrients are limited. Angiosperm GS are strongly skewed towards small genomes, despite the prevalence of polyploidy in the ancestry of most if not all angiosperm lineages. This thesis examines the hypothesis that large genome sizes are costly to build and maintain and that angiosperm species with large GS are constrained by nitrogen and phosphate limitation. It untangles the interactions between GS, polyploidy and competition in plant communities, and examines how herbivory and GS play a role in plant productivity, measured as above-ground biomass. The hypothesis that large GS are costly was approached by analysing: 1) plant communities growing under different macronutrient conditions at the Park Grass Experiment (Rothamsted, UK); 2) plant communities under different conditions of macronutrient limitation and insect, mollusc, and rabbit herbivory at Nash's Field in Silwood Park (UK); and, 3) Ellenberg's indicator values which represent the realised niche of a species in terms light, water, and soil fertility. Support for the hypothesis was found in all experiments. The range of analyses show that angiosperm plants with large genomes (e.g. 1C-value > 5 pg) are indeed under greater macronutrient limitation in comparison to plants with small genomes, and that it is polyploid plants with large GS which are the most competitive when macronutrient resources are plentiful. In terms of herbivory, the key finding is a highly significant negative association between GS and rabbit herbivory. A species' realised niche for soil fertility was found to show a positive association with its GS. Overall the thesis shows that angiosperm GS plays a central role in plant community composition and responses to macronutrient conditions, and potentially on higher ecosystem processes through associations at different trophic levels.

Understanding the central nervous systems role in appetite regulation is crucial to cure the obesity epidemic, which is more prevalent than any disease in the United States. Central appetite regulators, known as neuropeptides, are pivotal in understanding appetite regulation. Neuropeptide Y (NPY), a 36 amino acid peptide, plays a major role in regulating the hunger signals from the brain. In all vertebrates studied, it is a strong orexigenic neurotransmitter located throughout multiple nuclei of the hypothalamus. Peripheral hormones associated with hunger are able to activate NPY neurons in the arcuate nucleus, which leads to a cascade of events that activate orexigenic neurons throughout the hypothalamus. Although extensive research has gone into understanding the role of NPY in appetite regulation, the effects of macronutrient composition of diets on NPY function have not been elucidated in non-mammalian species. This research investigates how food intake is affected by dietary macronutrient composition in broiler type chickens that are fed three varying macronutrient diets: high carbohydrate (22% CP, 3000kcal/kg) a broiler starter diet, high fat (60% ME from lard), high protein 30%CP). All diets were formulated to be isocaloric. When chicks are fed the high fat diet central NPY administration has a greater effect on feed intake compared to both the basal and high protein diet. Regardless of what diet the chick is fed from hatch, if they are switched to one of the other two diets post central administration of NPY the high fat diet stimulated feed intake for the longest duration. Although, NPY had the strongest orexigenic effect on chicks fed the high fat diet, in a choice diet situation broiler chicks chose the high protein diet, independent of central NPY administration.
Master of Science

We studied the consequences of providing rat dams with elevated levels of dietary fat during lactation on stress responses in the offspring at different stages of development. High-fat feeding increased total milk lipid levels, and led to increased lipid deposition and plasma leptin levels in pups. Ten-day-old neonates from high-fat fed mothers had reduced stress responsiveness compared to controls. In contrast, 35-day-old pups from mothers fed high-fat diets showed greater stress-induced ACTH secretion. These findings indicate that maternal diet has effects on hypothalamic-pituitary-adrenal (HPA) responsiveness, which can persist after weaning to a normal rat chow diet. We also investigated macronutrient selection in the offspring, since differences in nutrient preferences may produce long-lasting consequences of lactational diet. However, our results did not support an involvement of maternal diet in postweaning nutrient selection. Furthermore, HPA stress responses were no longer related to maternal diet once offspring reached maturity.

The objective of this dissertation research was to investigate the effect of dietary macronutrient composition on neuropeptide Y (NPY)-mediated regulation of adipose tissue physiology in broiler chickens during the early post-hatch period. A high-carbohydrate (HC), high-fat (HF) or high-protein (HP) diet was fed to broiler chicks in all experiments and various facets of physiology were evaluated at day 4 post-hatch, including diet-, fasting-, and neuropeptide Y-induced effects on gene expression, cellular morphology, and lipid metabolism. Experiment 1 was designed to study the effects of diet on molecular changes in different adipose tissue depots (subcutaneous, clavicular and abdominal) after 3 hours of fasting and 1 hour of refeeding. Adipose tissue weights were decreased in chicks that consumed the HP diet, whereas adipocyte diameter was increased in response to the HF diet. There was greater expression of mRNAs encoding fatty acid binding protein 4 (FABP4) and monoglyceride lipase in chicks fed the HC and HF diets than the HP diet in all three adipose tissue depots. Fasting increased plasma non-esterified fatty acid concentrations in chicks fed the HC and HP diets. Results suggest that the heavier fat depots and larger adipocytes in chicks fed the HF diet are explained by greater rates of hypertrophy, whereas the HP diet led to a decrease in adipose tissue deposition, likely as a result of decreased rates of adipogenesis. Experiments 2 and 3 were designed to investigate how dietary macronutrient composition affects the effect of centrally or peripherally administered NPY, respectively, on lipid metabolism-associated factor mRNAs in adipose tissue. In experiment 2, vehicle or 0.2 nmol of NPY was injected intracerebroventricularly (ICV) and abdominal and subcutaneous fat samples were collected at 1 hour post-injection. In the subcutaneous fat, ICV NPY injection decreased peroxisome proliferator-activated receptor gamma (PPAR gamma) and sterol regulatory element-binding transcription factor 1 (SREBP1) mRNAs in chicks fed the HF diet, whereas there was an increase in SREBP1 expression in chicks fed the HF diet after NPY injection. Expression of PPAR gamma and FABP4 mRNAs increased in the abdominal fat of HF diet-fed chicks after NPY injection. Thus, HF diet consumption may have enhanced the sensitivity of chick adipose tissue to the effect of centrally-injected NPY on gene expression of adipogenesis-associated factors. In experiment 3, vehicle, 60, or 120 micrograms/kg BW of NPY was injected intraperitoneally (IP), and subcutaneous, clavicular, and abdominal fat was collected at 1 and 3 hours post-injection. Food intake and plasma NEFA concentrations were not different among chicks fed the HC, HF or HP diet after IP NPY injection, indicating that the effects of NPY on adipogenesis were independent of secondary effects due to altered energy intake. In response to the lower dose of NPY, the expression of NPY receptor sub-type 2 mRNA was increased at 1 hour post-injection in the subcutaneous fat of chicks fed the HP diet, whereas there was less 1-acylglycerol-3-phosphate O-acyltransferase 2 mRNA in the subcutaneous fat of chicks fed the HC diet. The higher dose of NPY was associated with greater AGPAT2 mRNA in the clavicular fat of chicks that consumed the HP diet and less CCAAT/enhancer-binding protein alpha in the abdominal fat of chicks that were provided the HF diet. However, there was also a decrease in the expression of some of these factors, although mechanisms are unclear. In conclusion, dietary macronutrient composition influenced the response of adipose tissue to the adipogenic effects of NPY and metabolic effects of short-term fasting and refeeding during the first week post-hatch. Collectively, this research may provide insights on understanding NPY's effects on the development of adipose tissue during the early life period and mechanisms underlying diet-dependent and depot-dependent differences in adipose tissue physiology across species.
Ph. D.

Two thirds of American adults are overweight and almost half of those qualify as obese. Obesity independently increases risk for cardiovascular disease (CVD), type II diabetes (T2D), and hypertension; thus, strategies to reduce risk in this population are desperately needed. Oxidative stress and inflammation are two perpetuators of these chronic diseases that are often elevated in obesity. Interventions that target reductions in oxidative stress and inflammation may help to reduce co-morbidities associated with obesity. Weight loss is shown to reduce oxidative stress and inflammation. However, the composition of and food choices within the weight loss diet may influence the response of these factors to weight loss, and has not been adequately assessed. We first tested whether there were differential effects of a conventional low-fat, high carbohydrate weight loss diet (LF) and the Atkins diet (a popular low carbohydrate, high fat diet (HF)) on oxidative stress and inflammation. We demonstrated that HF raised C-reactive protein (CRP) levels relative to LF in overweight and obese women over four weeks. This finding raises questions as to the long term safety of the HF eating plan in terms of CVD risk. We next examined the role of oxidative stress in the HF diet-induced increase in inflammation by evaluating the effects of an antioxidant supplement versus a placebo in conjunction with HF in overweight and obese men and women. Although our full hypothesis was not supported, as oxidative stress did not increase with HF, the trend for a differential effect on CRP when antioxidants were consumed is provocative. It suggests that future research on the connection between oxidative stress, the macronutrient content of the diet, and inflammation in obesity is warranted. Regarding the effects of specific fats, epidemiological research shows that diets high in saturated fat (SFA) are associated with higher CVD risk while diets higher in omega 3 fats (n-3FA) with lower CVD risk. However, the acute effects of these fats on indices of inflammation and oxidative stress are less understood, particularly in the overweight/obese population. As the majority of the time is spent in the postprandial state, the acute responses to high fat meals are gaining attention for their contribution to endothelial dysfunction and CVD. We showed that acute meals high in SFA increased a marker of endothelial activation (ICAM-1) which could contribute to the atherogenic associations with SFA. Conversely, including n-3FA in a high fat meal acutely enhanced NF-κB activation in circulating mononuclear cells; however, there were no increases in any inflammatory proteins measured over the 6 h postprandial period. It is apparent that dietary macronutrients can influence factors associated with chronic disease in overweight and obese individuals. The evidence presented here may help to refine dietary recommendations for this population.
Ph. D.

The effect of the dietary macronutrient composition on weight loss has been a controversial issue for decades. During that time, a high-protein, high-fat, and low-carbohydrate diet has been one of the more popular weight loss diets with the public. We hypothesized that a computer simulation model using STELLA software could help to better understanding the effect of the dietary macronutrient composition on weight loss. We calculated daily total oxidation instead of total energy expenditure as others have done based on the facts that carbohydrate, fat, and protein intake influence carbohydrate, fat, and protein oxidation. In order to create a simple and accurate model comparing dietary macronutrient composition effects, we eliminated exercise as a factor and focused on a sedentary population. The model was validated by five sets of published human data. Following model validation, simulations were carried out to compare the traditional high-carbohydrate diet recommended by the American Dietetic Association and two well-known high-protein diets (Atkins and the Zone diet). The results of computer simulation suggested that the lean tissue retention effect of a high-protein diet, especially with a lower-fat diet, compared with a traditional high carbohydrate diet over 6 months.

Dietary restriction (DR), is a reduction in food intake, either through overall calorie or specific macronutrient intake, while avoiding malnutrition. DR has been consistently shown to increase longevity and protect against age related diseases. Although originally thought to be the result of a reduction in caloric intake, recent evidence suggests that the ratio of macronutrients, particularly that of protein : non-protein energy, also plays a role. The broad range of species in which DR is known to be effective, suggests an evolutionary conserved mechanism. However, the suggestion of a strong model species bias and a potential sex bias have led some to question the ubiquity of responses to DR. Here, I address the following questions: (i) How consistent is the effect of DR on reproduction? (ii) How does varying macronutrient intake effect both growth and body composition in three-spine sticklebacks (Gasterosteus aculeatus)? (iii) What is the effect of dietary macronutrient intake on lifespan and reproduction in the three-spine stickleback? and (iv) How does changing macronutrient intake impact fitness related traits, such as condition and performance in three-spine sticklebacks? Through use of a systematic review and meta-analysis, I show that the effect of DR on reproduction is evolutionarily conserved, though the effect is stronger in model species. However, when accounting for all significant moderators there is no evidence of the suggested sex differences in the effect of DR. I show that body composition is predicted by dietary lipid intake, with sticklebacks targeting a lower ratio of protein : fat within the body, potentially via metabolism and excretion of protein. These results hint at a link between conversion and excretion of protein and survival costs associated with high protein diets. I show that mortality risk is reduced at balanced protein : lipid intakes in males and generally at low protein : lipid intakes for females. However, the effect in females is not consistent throughout life. I further show that reproduction is maximised on high protein : lipid intakes for both sexes. These results suggest a macronutrient mediated trade-off between lifespan and reproduction in male three-spine sticklebacks. Finally I show a positive effect of lipid intake on male condition (a possible indicator of overall health) hinting at a relationship between lipid intake, adiposity, health and lifespan in male three-spine sticklebacks.

Thesis (Ph. D.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Entomology. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Background/Objective: Several studies have shown that a low carbohydrate diet (LCHOD) can improve glycaemic control in type 2 diabetes (T2DM). The objective of the current study was to compare two ways of administration of a LCHOD: self-prepared meals versus ready-made meals, and their effects on weight loss, glycaemic control, body composition, cardiovascular risk and resting metabolic rate over 12 months. Research design and methods: Forty-one volunteers with the mean body mass index of 38.8 kg/m2 and poorly controlled T2DM (glycosylated haemoglobin, HbA1c > 7.5%) were randomized to either protein sparing modified fast (< 40g of carbohydrate daily, self-cooked; PSMF) or Go Lower (readymade meals; GL) diet. Both groups received multivitamin supplementation and attended monthly visits. The main outcome was weight loss and its composition. Results: Fourteen (34 %) participants completed 12 months of the intervention. There were no differences in the weight or any other changes between the diet groups at 12 months. Overall, body mass and fat mass decreased (-5.5 ± 7.3 kg, P < 0.001 and -5.1 ± 6.7 kg, P < 0.001 respectively) but fat free mass did not change. There was an overall reduction in HbA1c (-0.4 ± 1.1 %, P < 0.001), increase in HDL-cholesterol (+0.07 ± 0.18 mmol/L, P < 0.001) and decrease in triacylglycerol (-0.6 ± 2.4 mmol/L, P = 0.014). Resting metabolic rate significantly decreased (-137 ± 265 kcal/d, P < 0.001). Conclusion: LCHOD, independently of the approach taken, led to weight loss and improvements in glycaemic control in obese volunteers with poorly controlled T2DM. The results confirm that lifestyle modification using LCHOD is effective for improving T2DM and suggest that the type of approach to the diet can be matched to an individual’s preferences.

Très peu de données sont aujourd’hui disponibles sur le rôle des nutriments et de leurs interactions in vivo dans la régulation de l’autophagie. L'objectif principal de cette thèse était donc d’étudier l’effet de la qualité nutritionnelle de l’aliment sur le contrôle de cette fonction cellulaire. Une première étude a permis de montrer que les différents ratios en protéines et en glucides influencent significativement les mécanismes de contrôle de l’autophagie dans le muscle de truite arc-en-ciel (Oncorhynchus mykiss). Ces résultats ont été renforcés par une étude sur culture primaire de myoblaste de truite montrant que l’addition d’acides aminés dans le milieu de culture inhibe l’autophagie alors que le glucose à un effet inverse (article 1). Une seconde étude a porté sur la fraction protéique de l’aliment et notamment sur la teneur en méthionine, dont le niveau est trop faible dans les aliments pour poissons à base de végétaux. Les résultats obtenus indiquent que la machinerie autophagosomale mais également les principaux facteurs du renouvellement des protéines musculaires sont sensible aux variations de la teneur en méthionine de l’aliment et que la réponse qui en résulte peut fortement affecter la croissance (article 2). L’ensemble des données obtenues dans les deux premières études reposaient sur la mesure du taux d’un marqueur de l’autophagie (LC3-II) qui est à la fois produite et dégradée au cours du processus (flux) autophagique. Ainsi, dans l’optique de préciser les résultats obtenus dans les deux premiers articles, une troisième étude a été effectuée afin de déterminer s’il est possible de bloquer le flux autophagique dans le muscle de truite par l’emploi de différents agents pharmacologiques (inhibiteurs du flux autophagique). Il s’agissait également de déterminer les limites de l’utilisation de tels inhibiteurs chez cette espèce. Les essais effectués n’ont pas permis de mesurer le flux autophagique dans le muscle. En revanche, l’injection intrapéritonéale de colchicine a bien bloqué le flux autophagique dans le foie, ouvrant ainsi un nouveau champ d’investigations sur le rôle de l’autophagie dans le métabolisme intermédiaire. En conclusion, l’ensemble de ces travaux montre que l’autophagie n’est pas uniquement sensible à l’état nutritionnel (jeûne/nourris) mais également à la nature des aliments consommés. Outre leurs intérêts agronomique et thérapeutique, ces résultats ouvrent de nouvelles perspectives pour une meilleure compréhension des mécanismes d’action de l’autophagie au niveau cellulaire et métabolique mais également de son rôle dans l’adaptation des espèces au cours l’évolution
Few data has been published on the role of nutrients and their interactions in vivo in the regulation of autophagy. The main objective of this thesis was therefore to characterize the response of the autophagic/lysosomal pathway to the macronutrients composition of the diets. The first study showed that different ratio of proteins and carbohydrates in the diet significantly affect the controls of autophagy in the muscle of rainbow trout (Oncorhynchus mykiss). These results were strengthened by study on primary culture of trout myoblasts showing that the addition of amino acids in cell culture medium inhibited the formation of autophagosomes, whereas the addition of glucose had an opposite effect (paper 1). A second study focused on the protein fraction of the diet and specifically on the content of methionine, whose the levels are low in fish feed plant-based diets. The obtained results showed that both autophagy machinery and the main factors of muscle protein turnover are significantly sensitive to change in dietary methionine levels and the resulting response may strongly affect growth and feed utilization (paper 2). The data obtained in these two first studies were based on measuring the level of autophagy marker (LC3-II), which is both produced and degraded during autophagic (flux) process. Thus, in view to clarify the results obtained in the two first studies, we conducted a third study to determine whether it is possible to block the autophagic flux in trout muscle by using different lysosomotropic agents (autophagic flux inhibitors). The objective was also to determine the limits of autophagic flux inhibitors utilisation in vivo. Different tests failed to measure autophagic flux in the muscle of rainbow trout. In contrast, intraperitoneal injection of colchicine blocked the autophagic flux in the liver. This study allowed us to investigate the function of autophagy in the intermediary metabolism. In conclusion, these studies show that autophagy is not only sensitive to the nutritional status (fasting/fed) but also to the nature of the consumed diets. In addition to their therapeutic and agricultural interests, these results open new perspectives to better understand the mechanisms of autophagy at metabolic and cellular level but also its role in the adaptation of species during evolution

Traditional treatments for weight management have focussed on prescribed dietary restriction or regular exercise, or a combination of both. However recidivism for such prescribed treatments remains high, particularly among the overweight and obese. The aim of this thesis was to investigate voluntary dietary changes in the presence of prescribed mixed-mode exercise, conducted over 16 weeks. With the implementation of a single lifestyle change (exercise) it was postulated that the onerous burden of concomitant dietary and exercise compliance would be reduced, leading to voluntary lifestyle changes in such areas as diet. In addition, the failure of exercise as a single weight loss treatment has been reported to be due to compensatory energy intakes, although much of the evidence is from acute exercise studies, necessitating investigation of compensatory intakes during a long-term exercise intervention. Following 16 weeks of moderate intensity exercise, 30 overweight and obese (BMI≥25.00 kg.m-2) men and women showed small but statistically significant decreases in mean dietary fat intakes, without compensatory increases in other macronutrient or total energy intakes. Indeed total energy intakes were significantly lower for men and women following the exercise intervention, due to the decreases in dietary fat intakes. There was a risk that acceptance of the statistical validity of the small changes to dietary fat intakes may have constituted a Type 1 error, with false rejection of the Null hypothesis. Oro-sensory perceptions to changes in fat loads were therefore investigated to determine whether the measured dietary fat changes were detectable by the human palate. The ability to detect small changes in dietary fat provides sensory feedback for self-initiated dietary changes, but lean and overweight participants were unable to distinguish changes to fat loads of similar magnitudes to that measured in the exercise intervention study. Accuracy of the dietary measurement instrument was improved with the effects of random error (day-to-day variability) minimised with the use of a statistically validated 8-day, multiple-pass, 24 hour dietary recall instrument. However systematic error (underreporting) may have masked the magnitude of dietary change, particularly the reduction in dietary fat intakes. A purported biomarker (plasma Apolipoprotein A-IV) (apoA-IV) was subsequently investigated, to monitor systematic error in self-reported dietary intakes. Changes in plasma apoA-IV concentrations were directly correlated with increased and decreased changes to dietary fat intakes, suggesting that this objective marker may be a useful tool to improve the accuracy of dietary measurement in overweight and obese populations, who are susceptible to dietary underreporting.

L’étude du microbiote intestinal et de ses produits de sécrétion est un domaine de recherche en expansion en raison des perspectives thérapeutiques que cela peut ouvrir pour les maladies nutritionnelles telles que l’obésité ou les TCA. La Caseinolytic peptidase B (ClpB) est une protéine bactérienne produite par les entérobactéries qui présente un mimétisme moléculaire avec l’α-MSH, un neuropeptide anorexigène signalant la satiété au niveau de l’hypothalamus. Des études récentes ont cherché à évaluer si la protéine ClpB pouvait induire des effets anorexigènes similaires à ceux de l’α-MSH, en situation physiopathologique et dans des modèles de troubles nutritionnels. Dans ce contexte, l’objectif de cette thèse a été d’étudier les potentiels effets pharmacologiques de la protéine ClpB, intacte ou fragmentée sur les différents mécanismes de régulation de la prise alimentaire impliquant l’axe microbiote-intestin-cerveau et l’influence des nutriments. La première étude a évalué in vitro l’impact de trois macronutriments sur la production et l’expression de la protéine ClpB par les bactéries E. coli : seul l’apport protéique augmentait significativement la production de ClpB. Nous avons montré que la ClpB augmentait la sécrétion de PYY par les cellules entéro-endocrines intestinales de rat en culture. La deuxième d’étude a été réalisée chez des souris dans un modèle d’anorexie (ABA). La restriction alimentaire, avec ou sans activité physique, augmentait la concentration plasmatique de ClpB, qui était associée à une augmentation de la proportion d’entérobactéries dans le microbiote, ce qui suggère son implication possible dans la physiopathologie de l’anorexie mentale. Enfin, la troisième étude a évalué in vivo chez le Rongeur, les effets pharmacologiques de la protéine ClpB sur la prise alimentaire. La prise alimentaire était réduite par l’injection de ClpB intacte ou fragmentée, mais pas par son fragment de 25 kDa. Ces résultats confortent le rôle de la protéine ClpB, produite par les entérobactéries, dans la régulation physiologique de la prise alimentaire et incitent à poursuivre l’étude de son implication dans les troubles anorexiques et son application thérapeutique dans les situations d’excès de poids
The study of the gut microbiota and especially the effect of its secretory products is an expanding field of research in order to open therapeutic perspectives for nutritional diseases such as obesity or TCA. Among these molecules, the Caseinolytic peptidase B (ClpB) is a bacterial protein having a molecular mimicry in common with α-MSH, a neuropeptide whose anorectic actions are peripheral and central and possible via a microbiota-intestinal-brain communication. Current studies attempt to demonstrate whether this molecular mimicry can confer similar anorectic effects at the ClpB protein. The aim of this thesis was studied the potential pharmacological effects of ClpB protein the regulation of eating behavior. Given that the composition of the gut microbiota is dependent on the food present, the first study was evaluated in vitro the impact of three types of macronutrients on the production and expression of the ClpB protein by E. coli bacteria. Then, it was evaluated whether this protein could influence the secretion of satietogenic peptides like PYY by intestinal enteroendocrine cells using a primary culture of rat intestinal cells. Previous studies of U 1073 laboratory have shown that this protein has been found at the plasma level, the second study was performed in mice submitted to an anorexia model (ABA) to clarify the impact of dietary restriction on the ClpB protein, to better understand its possible involvement in the physiopathology of anorexia nervosa. Finally, the third study was evaluated the pharmacological effects of ClpB protein on food intake in vivo in rodents. The impact of the natural fragmentation of this protein and particularly of one of its fragments on food intake was also evaluated

The thesis reports on 6 studies (2 of which were part of a multi-centre trial) examining hydration and fluid balance. The first study described in this thesis investigated the impact of hydration status on Dual energy x-ray absorptiometry (DXA) and other methods that are popular tools to determine body composition in athletes. We observed that it is important to ensure a euhydration when assessing body composition, particularly when considering changes associated with nutritional or exercise interventions. The second and third studies reported identified beverages that promote longer term fluid retention and maintenance of fluid balance in adults. We investigated the effects of 13 different commonly consumed drinks on urine output and fluid balance when ingested in a euhydrated state, with a view to establishing a beverage hydration index (BHI), i.e., the volume of urine produced after drinking expressed relative to a standard treatment (still water) for each beverage. The beverages with the highest BHI were oral rehydration solution, full fat milk and skimmed milk. BHI may be a useful measure to identify the short term hydration potential of different beverages when ingested in a euhydrated state. The fourth study aimed to systematically examine the influence of carbohydrate, sodium and caffeine content of beverages on the BHI. The BHI was greater in beverages with higher carbohydrate or higher sodium content, but not influenced by caffeine. The carbohydrate content of beverages has no effect on BHI at concentration up to 10% carbohydrate. Sodium content of beverages in concentrations of 27mmol/L and higher can improve the hydration potential of beverages. Caffeine doses in beverages up to 400mg/L do not have an impact upon diuresis when ingested in a euhydrated state. The fifth study compared net fluid balance (NFB) responses to the ingestion of commonly consumed drinks in young and older men. We observed that in young adults milk helps to maintain positive net fluid balance for longer than other drinks. In older adults this effect of milk is not observed despite similar net electrolyte balance responses. Future work should more fully explore these potential differences in fluid balance responses to drink ingestion between young and older adults. The final study investigated the hydration habits of Scottish young and older adults (+50 years old), identifying their fluid choices, volume, and preferences in relation to time of day. The results showed that 26.1% of the young females, 30.3% of the young males, 25.8% of the older females and 50.4% of the older males did not meet the European (EU) Food Safety Authority (EFSA) fluid intake recommendations. We also observed that the difference between those who met and those who did not meet the EFSA adequate intake could be attributed to differences in water ingestion, mainly during the mid-morning (after breakfast until 11 am) and during the early-afternoon (after lunch time up to 5 pm). It was concluded that these moments might be key when implementing interventions to improve hydration status especially in the older population.

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Os frutos do cerrado são atualmente estudados por apresentarem em sua composição substâncias com funções protetoras e preventivas de processos nocivos à saúde, além de fornecerem nutrientes essenciais ao adequado funcionamento do organismo. Dentre estes frutos está o Ananas ananassoides, planta da família Bromeliaceae, endêmica do Cerrado Brasileiro, popularmente conhecida como ananás, ananaí, ananás-de-raposa ou também abacaxizinho do cerrado. Seus frutos são resistentes à ação da natureza, além de pequenos e fibrosos. Apresentam elevado teor de açúcar, acidez e pequenas sementes. Estudos mostram que os frutos do cerrado apresentam boa capacidade antioxidante, porém investigações científicas que envolvem a caracterização físico-química, compostos bioativos, quantificação mineral e o efeito da incidência solar nos frutos de A. ananassoides não foram totalmente elucidados. Como a caracterização e uso deste fruto é pouco explorado o objetivo deste trabalho foi avaliar os compostos bioativos (carotenoides, compostos fenólicos, vitamina C e capacidade antioxidante), bem como as características físico-químicas e minerais do fruto em condições de luminosidade e sombreamento.
The fruits of the cerrado are currently studied because they present substances in its composition with protective and preventive functions against harmful processes to health, besides they provide essential nutrients to the appropriate organism functioning. Among this fruits is the Ananas ananassoides, plant of Bromeliaceae family, endemic of the brazilian cerrado, popularly known as ananás, ananaí, ananás-de-raposa or also abacaxizinho-do-cerrado. Its fruits are little and fibrous besides being resistant to the action of nature, They present high sugar content, acidity and small seeds. Studies show that the fruits of the cerrado present good antioxidant capacity, however scientific investigations that involve the physical-chemical caracterization, bioactive compounds, mineral quantification and the effect of solar incidence in fruits of A. ananassoides were not totally elucidated. As the caracterization and use of this fruit is poorly explored, the objective of this study was to avaliate the bioactive compounds (carotenoids, phenolic compounds, vitamin C and antioxidant capacity), as well as the physical-chemical and mineral characteristics of the fruit in conditions of luminosity and darkness.

Research Doctorate - Doctor of Philosophy (PhD)
Early life environmental factors, including maternal dietary intake and nutritional status during pregnancy, can program offspring health outcomes in later life. Given the rapid worldwide burden of non-communicable conditions (e.g. obesity, type 2 Diabetes Mellitus (T2DM) and cardiovascular disease), early prevention by optimising maternal, foetal and infant nutrition has been identified as a strategy that is likely to be beneficial and cost effective. The primary purpose of this thesis is to evaluate the dietary intakes of women during pregnancy, and to investigate the relationship between maternal intake and foetal body composition. Three research studies were undertaken to meet these aims. A systematic review of the available literature determined the energy, macronutrient and micronutrient intakes of pregnant women in developed countries, and appraised the nutritional adequacy of intakes compared to current recommendations. Meta-analyses provided evidence that the dietary intakes of pregnant women do not match with international recommendations. Energy and carbohydrate intakes were generally below recommendations, total fat and saturated fat intakes were generally above recommendations, while protein intakes were within the recommendations. Secondly, pregnant women reported suboptimal micronutrient intakes with folate, iron and vitamin D intakes consistently below nutrient recommendations in all geographical regions. A cross-sectional study evaluated the dietary intakes of Australian women of reproductive age by pregnancy status, in comparison to national food group recommendations. This determined whether their eating patterns achieved the recommended intakes of nutrients important for pregnancy. Data were obtained from the Australian Longitudinal Study on Women‟s Health (ALSWH), young cohort aged 25 – 30 years in 2003 (n 9076). Pregnancy status was self-reported as pregnant (n 606), trying to conceive (n 454), given birth in the last 12 months (n 829) or other (n 5597). Diet was assessed using a validated 74-item food frequency questionnaire (FFQ). Daily food group servings and nutrient intakes were compared to the Australian Guide to Healthy Eating (AGHE) and Australian Nutrient Reference Values (NRVs). The study found that the AGHE does not enable pregnant women to meet all the NRVs and further the contemporary eating pattern of Australian women that do achieve nutrient intake targets does not align with the AGHE recommendations for daily servings of food groups. Longitudinal data, collected prospectively as part of the Women and Their Children‟s Health (WATCH) study from a cohort of 179 pregnant women, was used to evaluate whether maternal macronutrient intakes are associated with foetal body composition and secondly, whether the macronutrient content of maternal diet is associated with the adequacy of micronutrient intakes, compared to Australian dietary recommendations. Linear mixed-model regression analyses and parametric response surfaces provided evidence that there may be a target maternal macronutrient profile associated with optimal foetal body composition. The development of foetal abdominal visceral area throughout gestation was positively associated with higher maternal protein intakes, decreased starch intakes and a higher protein to carbohydrate (P:C) ratio. Foetal midthigh lean area was positively associated with increased maternal PUFA intakes and decreased SFA intakes. Response surfaces for micronutrient intakes were optimized when the percentage energy was within intermediate protein (18-20%E), intermediate fat (28-30%E) and intermediate carbohydrate (50-54%E) intakes. Results suggest a moderate protein intake may support pregnant women to consume the largest variety of nutrients across all food groups. In conclusion, the study findings presented in this thesis provide evidence that dietary intakes during pregnancy commonly fail to achieve target NRVs and that current dietary selection models to guide the food consumption of pregnant women in Australia may require revision. Findings also suggest that foetal body composition and maternal micronutrient adequacy may be modifiable by nutritional interventions in the mother, with a particular emphasis on protein as a key driver of these relationships. These results are likely to have important implications for the offspring‟s risk of non-communicable disease, and key recommendations for future research to support optimal health outcomes are provided.

Tese de mestrado. Biologia (Biologia Evolutiva e do Desenvolvimento). Universidade de Lisboa, Faculdade de Ciências, 2014
One of the main contributions for an animal’s life success is an optimal nutrition. Macronutrients, such as proteins and carbohydrates, are essential for organism development, determining for example, the size of the body and or reproductive capacity. Different animals use macronutrients differently. To achieve the necessary requirements, generalist species use a wide range of substrates, whereas specialist species are specialised in one type of substrate. In general, animals balance their food intake to achieve nutritional optima, referred as intake target. Uncovering an animal’s intake target requires solving the problem of balancing multiple and changing nutrient needs in a variable nutritional environment. To address this we can study the nutritional geometry framework of an animal. Foraging decisions can then be described within this nutrient space, however these decisions may bring consequences for the animals’ development. In this thesis, we measured the influence of unbalanced larval diets on life history traits, such as survival, developmental time, body size, ovariole number and pupal case pigmentation. We also addressed this by analysing the consequences on foraging behaviour. We found that Drosophila virilis maximises life history traits at a high protein to carbohydrate ratio and pupal pigmentation changes by increasing the content of protein on larval diet. However, larvae do not regulate their intake to maximise any trait responses. Since intake target changes over developmental time and evolutionary time, we expected to see differences between generalists and specialists species. We used our previous data from Drosophila melanogaster, a generalist species, to compare with the results from this thesis. We saw differences, whereas D. virilis seem to be more tolerant to high proteins than D. melanogaster but less tolerant to high carbohydrates content. Depending on their feeding strategies, species will always differ in nutritional requirements and foraging strategies in unbalance nutritional environments.
A qualidade nutricional da comida é essencial ao desenvolvimento dos organismos. Sabemos que os macronutrientes, entre eles as proteínas e os hidratos de carbono, são importantes para formação e manutenção de tecidos ou fornece uma das principais fontes de energia aos processos metabólicos, respectivamente. A alimentação é o único meio pelo qual os organismos conseguem adquirir os nutrientes de que necessitam, sendo que as suas necessidades não são sempre as mesmas. Dependendo da espécie, cada nutriente é necessário em quantidades distintas, assim como a relação entre nutrientes é variável. Os animais regulam e tomam decisões relativamente à comida ingerida. Estratégias de comportamento relativas à alimentação foram desenvolvidas consoante as necessidades de cada espécie. Dois grupos podem ser definidos, relativamente a estas estratégias: espécies generalistas, que são espécies que usam uma gama variada de substratos para satisfazer as suas necessidades nutricionais; e espécies especialistas que satisfazem as suas necessidades nutricionais utilizando um número muito restrito de substratos. Os substratos sofrem alterações nutricionais ao longo do tempo. Embora o ambiente seja responsável por parte dessas alterações, microrganismos desempenham um papel fundamental e, por isso, nem sempre existe um substrato com a composição nutricional ideal que se mantenha por muito tempo. Devido ao carácter nutricional instável de cada substrato, os animais ponderam quais as escolhas possíveis de forma a atingir os valores nutricionais ótimos para o seu desenvolvimento, que se define como alvo nutricional. O alvo nutricional pode ser encontrado usando o método desenvolvido por Steve J. Simpson e David Raubenheimer em 1990, o modelo de geometria nutricional. Este método permite criar um espaço nutricional com base num gradiente de concentrações de dois nutrientes e avaliar as decisões dos animais nesse espaço. Este método permite-nos descrever como os animais se comportam em três cenários diferentes. Primeiro, têm à sua disposição uma dieta equilibrada, e comem até atingirem os níveis nutricionais ótimos. Segundo, podem ter à disposição duas dietas, ambas desequilibradas, o que resulta numa ingestão alternada de ambas as dietas para que se possa atingir os níveis nutricionais ideias. Terceiro, apenas está disponível uma única dieta, que é desequilibrada. Neste caso, existem duas decisões possíveis para que os animais atingirem os níveis ótimos. Uma alternativa é que um dos nutrientes se revela mais importante, e a quantidade ingerida é regulada de forma e atingir os níveis ótimos apenas para essa nutriente, ingerindo o segundo em excesso ou em défice. A outra alternativa é a ingestão de níveis intermédios para ambos os nutrientes. Para descobrir o alvo nutricional é necessário explorar como é que os animais tomam estas decisões, como é que preenchem as suas necessidades nutricionais num ambiente nutricionalmente variável. Este método já deu provas do seu potencial, desde de mamíferos, como humanos e ratos, a invertebrados, como gafanhotos, escaravelhos, aranhas e moscas, onde foi verificado que todos estes animais regulam a ingestão de nutrientes (Simpson and Raubenheimer, 2005; Mayntx et al., 2005). O mesmo alvo nutricional pode não ser mantido ao longo da vida do animal, sofrendo mudanças dependendo da espécie. No entanto, também se altera consoante o estado fisiológico e estadio do ciclo de vida. Por exemplo, quando a mosca da fruta, Ceratitis capitata está perto da metamorfose, o seu alvo nutricional deixa de ser maioritariamente proteico e passa a conter alto teor de hidratos de carbono, que irão providenciar energia para a fase que precede a metamorfose (Zucoloto, 1987). O alvo nutricional também se altera quando as fêmeas de Drosophila melanogaster acasalam (Ribeiro and Dickson, 2010). Após acasalarem, a produção de ovos é estimulada e as fêmeas passam a consumir uma dieta mais rica em proteínas do que as que ainda são virgens. O consumo de dietas proteínas em gafanhotos é alterado para um menor consumo de proteína quando deixa de haver crescimento de tecidos (Raubenheimer and Simpson 1999). As espécies generalistas e as especialistas podem ter o mesmo alvo nutricional mas desenvolveram diferentes estratégias para o atingir. As suas necessidades nutricionais podem ser diferentes, como é o caso da Schistocerca gergaria, uma espécie generalistas, que mostra maior tolerância a elevados níveis de proteína do que a espécie especialista, Locusta migratoria (Raubenheimer and Simpson, 2003). A mesma situação foi encontrada em espécies de Lepidoptera generalistas e especialistas (Lee et al., 2002 and 2003). Nesta tese, decidimos primeiro avaliar com este método como as características que têm um papel na fitness dos animais é afetada pelos macronutrientes, proteínas e hidratos de carbono, na espécie especialista, Drosophila virilis. Esta espécie tem como principal fonte de alimento a seiva das árvores. Por fim, comparamos a resposta de uma espécie generalista (D. melanogaster), descrita anteriormente e da espécie especialista (D. virilis) descrita nesta tese. As características avaliadas são conhecidas por serem influenciadas por diferentes ambientes nutricionais. O tempo de desenvolvimento da fase larval é afectado pela nutrição, tal como a sobrevivência. Também estudámos a influência de dietas desequilibradas no tamanho do corpo de adulto, pesando as pupas antes do adulto emergir. Observámos que quanto mais pobre em proteína é a dieta mais pequenos são os indivíduos. O número de filamentos que constituem os ovários, chamados de ovaríolos, está diretamente relacionado com o número de ovos que uma fêmea irá pôr, ao longo da vida, e varia com a qualidade da dieta. Sendo Drosophila um organismo holometábolo, ou seja, sofre uma total metamorfose antes da fase adulta. Uma vez que é nesta fase que todos os tecidos e órgão se preparam para dar origem às estruturas e órgãos do adulto, todas as características descritas neste estudo são analisadas na fase larval. Depois da metamorfose os indivíduos param o seu crescimento, ou seja o tamanho do adulto é definido na fase de larva. Também o número de ovaríolos é determinado na fase de larva. Para conseguirmos desvendar a influência dos macronutrientes, fornecemos aos indivíduos, várias dietas que diferiam entre si pelo rácio entre proteínas e hidratos de carbono (rácio P:C) e também no seu teor calórico. Com o nosso espaço nutricional definido, analisámos quando indivíduos formaram pupa, quando tempo demoraram até formarem pupa, qual o seu peso antes do adulto emergir e o no caso das fêmeas quantos ovaríolos têm em ambos os ovários. Os nossos resultados mostraram que é nas dietas com um rácio entre proteínas e hidratos de carbono elevado que os indivíduos maximizaram a sua sobrevivência, tamanho do corpo e número de ovaríolos, e minimizam o tempo de desenvolvimento. Enquanto que no caso de D. melanogaster, as diferentes características foram maximizadas por diferentes dietas. Decidimos em seguida analisar o como as larvas de D. virilis reagem quando confrontadas com um ambiente de duas dietas desequilibradas. Que decisões irão tomar? Esta parte do processo baseou-se em analisarmos o comportamentos tanto das larvas como das fêmeas adultas. No caso das larvas, analisámos as decisões que estes indivíduos tomaram para satisfazerem os seus requisitos nutricionais. O nosso procedimento passou por usar larvas no terceiro estádio larvar e dar-lhes duas opções de dietas. Verificámos que, de facto, as larvas regulam a quantidade de ambas as dietas ingeridas de modo a alcançar valores específicos de proteína e hidratos de carbono, no entanto estes não correspondem aos valores que optimizam as características acima referidas. Quando comparado com os dados de D. Melanogaster, as larvas regularam a ingestão dos nutrientes de forma a minimizar o tempo de desenvolvimento. Relativamente ás fêmeas adultas, analisámos tanto o seu comportamento de alimentação, como na escolha de local para oviposição. Quando as fêmeas chegaram ao pico de fertilidade, fornecíamos a machos e fêmeas três dietas nutricionalmente desequilibradas. Fizemos contagem de quantas fêmeas comeram de cada dieta e do número de ovos postos em cada dieta. Os nosso resultados mostraram que as fêmeas não fizeram nenhuma escolha sobre qual das dietas ingerir. Adicionalmente, não encontramos nenhuma escolha de preferência para pôr os ovos. O oposto tinha sido visto em D. melanogaster, onde as fêmeas fizeram escolhas sob qual a dieta a ingerir, elevado teor de proteína, e em qual colocar os ovos, elevado teor de hidratos de carbono. Durante o protocolo do modelo de geometria nutricional, deparamo-nos com diferenças na pigmentação dos casulos de pupa. Fizemos, então, novamente este protocolo, de forma a quantificar as diferenças de pigmentação de acordo com as diferentes dietas. As larvas desenvolveram-se nas mesmas dietas usadas anteriormente, e após o adulto emergir as pupas vazia eram retiradas e fotografadas. Utilizando Mathematica, calculámos um valor RGB da coloração de cada pupa. Os nossos resultados mostram um gradiente de pigmentação que varia com a quantidade de proteína na dieta. Quanto mais proteína, mais escuras são as pupas. Podemos assim concluir que os macronutrientes, de facto, influenciam tanto o desenvolvimento dos animais como o seu comportamento. Também podemos observar que os macronutrientes afetam de forma variada cada espécie.

abstract: No studies have evaluated the impact of tracking resting energy expenditure (REE) and modifiable health behaviors on gestational weight gain (GWG). In this controlled trial, pregnant women aged >18 years (X=29.8±4.9 years) with a gestational age (GA) <17 weeks were randomized to Breezing™ (N=16) or control (N=12) for 13 weeks. The Breezing™ group used a real-time metabolism tracker to obtain REE. Anthropometrics, diet, and sleep data were collected every 2 weeks. Rate of GWG was calculated as weight gain divided by total duration. Early (GA weeks 14-21), late (GA weeks 21-28), and overall (GA week 14-28) changes in macronutrients, sleep, and GWG were calculated. Mediation models were constructed using SPSS PROCESS macro using a bootstrap estimation approach with 10,000 samples. The majority of women were non-Hispanic Caucasian (78.6%). A total of 35.7% (n=10), 35.7% (n=10), and 28.6% (n=8) were normal weight, overweight, and obese, respectively, with 83.3% (n=10) and 87.5% (n=14) of the Control and Breezing™ groups gaining above IOM GWG recommendations. At baseline, macronutrient consumption did not differ. Overall (Breezing™ vs. Control; M diff=-349.08±150.77, 95% CI: -660.26 to -37.90, p=0.029) and late (M diff=-379.90±143.89, 95% CI:-676.87 to -82.93, p=0.014) changes in energy consumption significantly differed between the groups. Overall (M diff=-22.45±11.03, 95% CI: -45.20 to 0.31, p=0.053), late (M diff=-23.16±11.23, 95% CI: -46.33 to 0.01, p=0.05), and early (M diff=20.3±10.19, 95% CI: -0.74 to 41.34, p=0.058) changes in protein differed by group. Nocturnal total sleep time differed by study group (Breezing vs. Control; M diff=-32.75, 95% CI: -68.34 to 2.84, p=0.069). There was a 11.5% increase in total REE throughout the study. Early changes in REE (72±211 kcals) were relatively small while late changes (128±294 kcals) nearly doubled. Interestingly, early changes in REE demonstrated a moderate, positive correlation with rates of GWG later in pregnancy (r=0.528, p=0.052), suggesting that REE assessment early in pregnancy may help predict changes in GWG. Changes in macronutrients did not mediate the relationship between the intervention and GWG, nor did sleep mediate relationships between dietary intake and GWG. Future research evaluating REE and dietary composition throughout pregnancy may provide insight for appropriate GWG recommendations.
Dissertation/Thesis
Doctoral Dissertation Nutrition 2019

The inexorable rise of type 2 diabetes (T2D) worldwide is a serious public health problem with significant health and socioeconomic costs. Diabetes- related complications are underpinned by poor glycaemic control that is greatly influenced by diet composition. Sustainable lifestyle modifications in diet and physical activity form the cornerstone of T2D prevention and management. Energy- restricted, high unrefined carbohydrate, low fat (HC) diets have traditionally been recommended for the dietary management of T2D. However, accumulating nutrition research indicate that carbohydrate restriction and higher intakes of protein and unsaturated fats, improve glycaemic control and reduce cardiovascular disease (CVD) risk markers. Based on this evidence, a novel dietary approach incorporating a very low carbohydrate, high unsaturated fat/ low saturated fat (LC) diet was designed. This LC diet was nutritionally adequate, with the potential to improve glycaemic control and mitigate CVD risk to a greater extent than the traditional HC diet. This thesis discusses the findings of a large, well- controlled, randomised, clinical trial that compared the long- term effects of consuming a traditional HC diet with an energy- matched LC diet, on a range of health outcomes including glycaemic control and CVD risk markers. Both diets were delivered as part of a holistic lifestyle intervention that included a structured exercise program. After one year, both diets achieved substantial weight loss, and reduced blood pressure, HbA1c, fasting glucose and LDL-C. However, the LC diet sustained greater reductions in diabetes medication and glycaemic variability, as well as triglycerides (TAG), and greater increases in HDL-C. Both diets had similar changes in renal and cognitive outcomes, suggesting that the LC diet did not adversely affect renal or cognitive function. These results have important implications for the lifestyle management of T2D with direct relevance to achieving better health outcomes and reducing healthcare costs.
Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Medicine, 2016.