Dissertations / Theses on the topic 'Omega-3 long-chain polyunsaturated fatty acid'
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Zhang, Ying. "Pancreatic islet function in long-chain polyunsaturated [omega-3] fatty acid-depleted rats." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/241307.
Full textNeijat, Mohamed. "Omega-3 fatty acid enrichment of chicken eggs: Regulation of long chain polyunsaturated fatty acid metabolism in laying hens." Poultry Science, 2014. http://hdl.handle.net/1993/32076.
Full textFebruary 2017
Alvarado-Gilis, Christian A. "Dietary factors affecting tissue profiles of long chain polyunsaturated fatty acids in cattle." Diss., Kansas State University, 2014. http://hdl.handle.net/2097/20416.
Full textDepartment of Animal Sciences and Industry
J. S. Drouillard
The main goal of this dissertation was to evaluate different methods to protect polyunsaturated fatty acids (PUFA) against biohydrogenation by ruminal microorganisms. The first chapter is a review of literature pertaining to fat and fatty acid metabolism by ruminants and why these fats are relevant in human nutrition. The second chapter discusses effects of supplementing high concentrations of dietary copper to feedlot cattle to assess impact on PUFA profiles in tissues. Two levels of copper (10 or 100 mg/kg) were supplemented to diets with or without flaxseed during the finishing period for beef heifers. Added copper did not affect performance (P > 0.15). Final body weights were similar for cattle fed with or without flaxseed (P > 0.05), but cattle fed diets with flaxseed consumed less feed (P < 0.05), and therefore were more efficient (P < 0.01). Carcass traits were unaffected by treatment. Feeding elevated levels of copper did not appreciably alter proportions of PUFA in plasma, but plasma concentrations of omega-3 fatty acids were greater for heifers fed flaxseed (P < 0.05). Chapter 3 describes the evaluation of 3 novel methods to protect PUFA from microbial biohydrogenation activity within the rumen, including a) coextrusion of flaxseed with molasses; b) mixing with soybean meal followed by induction of a non-enzymatic browning reaction; and c) encapsulation of ground flaxseed within a matrix consisting of dolomitic lime hydrate (L-Flaxseed). The resulting products were evaluated using in vitro methods to estimate resistance to biohydrogenation or in 12- to 14-d feeding studies in which plasma concentrations of [alpha]-linolenic acid (ALA) were measured. Our processing strategies a) and b) did not improve efficiency of omega-3 fatty acid utilization (P > 0.1). The in situ study of L-flaxseed revealed a 2-fold increase in resistance of ALA to ruminal biohydrogenation, and the concentration in plasma after 14 d on feed was more than 4 times that observed in cattle fed ground flaxseed, suggesting the dolomitic lime hydrate was effective as a protective matrix. Chapter 4 evaluated performance, carcass traits, and meat quality of finishing beef heifers in response to feeding diets containing L-Flaxseed. Animals were blocked by weight, randomly assigned to individual pens, and pens to 6 dietary treatments: Control (high concentrate finishing diet), ground flaxseed fed at 3 or 6% of diet DM, L-Flaxseed fed at 2, 4, or 6%. Concentration of ALA in meat increased linearly in response to the level of flaxseed fed (P < 0.05); Moreover, transfer of dietary ALA to tissues increased by 47% when flaxseed was encapsulated within the dolomitic lime matrix. Cattle that were fed diets with 4 or 6% L-Flaxseed consumed less feed than other treatments (P < 0.05), which adversely affected feedlot performance and carcass traits.
Sandford, Fiona Margaret. "The role of long-chain omega-3 polyunsaturated fatty acids in the management of rotator cuff tendinopathy." Thesis, King's College London (University of London), 2015. https://kclpure.kcl.ac.uk/portal/en/theses/the-role-of-longchain-omega3-polyunsaturated-fatty-acids-in-the-management-of-rotator-cuff-tendinopathy(73f89ba5-022f-4bb0-a42b-f44949df7a83).html.
Full textBijoux, Amandine. "Optimization of the production of omega-3 long-chain polyunsaturated fatty acids and their oxygenated metabolites in Ostreococcus tauri." Electronic Thesis or Diss., Paris 6, 2017. http://www.theses.fr/2017PA066743.
Full textOmega-3 long-chain polyunsaturated fatty acids (LC-PUFAs) that are essential to human health and development are precursors of lipid mediators that play important roles for tissue homeostasis. These metabolites derived from lipid oxidation processes and collectively named oxylipins, are involved in the regulation of various physiopathological processes including inflammation and cancer. As the global consumer needs for n-3 LC-PUFAs is increasing the fishes market will likely not be sufficient and new alternative sources of n-3 LC-PUFAs are needed. Microalgae are an interesting natural source as primary producers of n-3 LC-PUFAs and therefore, a possible source of these high-values added macromolecules. In this context, the present work aimed to evaluate the potential of the green picoeukaryote Ostreococcus as a source of n-3 PUFAs and derived oxylipins. This study clearly revealed microalgae of the genus Ostreococcus contain high levels of PUFAs, the omega-3 being predominant over the omega-6. Particularly, Ostreococcus cells showed high docosahexaenoic acid (DHA, C22:6 n-3) levels that remained fairly stable throughout the growth cycle and under various temperature, light intensity and salinity stress conditions. The biomass of Ostreococcus showed an array of oxylipins derived from PUFAs from the n-3 and n-6 series. In particular, two monohydroxy acids derived from DHA, 17-HDoHE and 14-HDoHE, were found to be predominant in Ostreococcus cells regardless the strain or the culture conditions tested. Furthermore, genetic engineering approach was successfully used to increase oxylipins content
Van, der Merwe Liandre Frances. "Long-chain omega-3 polyunsaturated fatty acids in relation to gut integrity, growth and cognitive development of rural African children." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2010. http://researchonline.lshtm.ac.uk/1440242/.
Full textStreet, Steven John. "The individual and interactive relationship between long chain omega-3 polyunsaturated fatty acids and physical activity as predictors of cognition in cognitively impaired and non-impaired older adults." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/60968/1/Steven_Street_Thesis.pdf.
Full textChen, Xi. "Functional food-related bioactive compounds: effect of sorghum phenolics on cancer cells in vivo and conversion of short- to long-chain omega-3 polyunsaturated fatty acids in duck liver in vivo." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38244.
Full textDepartment of Human Nutrition
Weiqun Wang
Many functional food related bioactive compounds have been discovered and draw the attention of scientists. This dissertation focused on sorghum phenolic compounds and omega-3 polyunsaturated fatty acids. Study 1: phenolic agents in plant foods have been associated with chronic disease prevention, especially cancer. However, a direct evidence and the underlying mechanisms are mostly unknown. This study selected 13 sorghum accessions and was aim to investigate: (1) the effect of extracted sorghum phenolics on inhibiting cancer cell growth using hepatocarcinoma HepG2 and colorectal adenocarcinoma Caco-2 cell lines; (2) and the underlying mechanisms regarding cytotoxicity, cell cycle interruption, and apoptosis induction. Treatment of HepG2 and Caco-2 cells with the extracted phenolics at 0-200 M GAE (Gallic acid equivalent) up to 72 hrs resulted in a dose- and time-dependent reduction in cell number. The underlying mechanism of cell growth inhibition was examined by flow cytometry, significant inverse correlations were observed between the decreased cell number and increased cell cycle arrest at G2/M or induced apoptosis cells in both HepG2 and Caco-2 cells. The cytotoxic assay showed that the sorghum phenolic extracts were non-toxic. Although it was less sensitive, a similar inhibitory impact and underlying mechanisms were found in Caco-2 cells. These results indicated for the 1st time that a direct inhibition of either HepG2 or Caco-2 cell growth by phenolic extracts from13 selected sorghum accessions was due to cytostatic and apoptotic but not cytotoxic mechanisms. In addition, these findings suggested that sorghum be a valuable functional food by providing sustainable phenolics for potential cancer prevention. Study 2: omega-3 polyunsaturated fatty acids (ω-3 PUFAs) especially long-chain ω-3 PUFAs, have been associated with potential health benefits in chronic disease prevention. However, the conversion rate from short- to long-chain ω-3 PUFAs is limited in human body. This study was aim to assess the modification of fatty acid profiles as well as investigate the conversion of short- to long-chain ω-3 PUFAs in the liver of Shan Partridge duck after feeding various dietary fats. The experimental diets substituted the basal diet by 2% of flaxseed oil, rapeseed oil, beef tallow, or fish oil, respectively. As expected, the total ω-3 fatty acids and the ratio of total ω-3/ ω-6 significantly increased in both flaxseed and fish oil groups when compared with the control diet. No significant change of total saturated fatty acids or ω-3 fatty acids was found in both rapeseed and beef tallow groups. Short-chain ω-3 α-linolenic acid (ALA) in flaxseed oil-fed group was efficiently converted to long-chain ω-3 docosahexaenoic acid (DHA) in the duck liver. This study showed the fatty acid profiling in the duck liver after various dietary fat consumption, provided insight into a dose response change of ω-3 fatty acids, indicated an efficient conversion of short- to long-chain ω-3 fatty acid, and suggested alternative long-chain ω-3 fatty acid-enriched duck products for human health benefits. In conclusion, the two studies in this dissertation provided a fundamental understanding of anti-cancer activity by sorghum phenolic extracts and the conversion of short- to long-chain ω-3 PUFAs in duck liver, contribute to a long term goal of promoting sorghum and duck as sustainable phenolic and ω-3 PUFAs sources as well as healthy food products for human beings.
Mariniello, Katia. "Comparative study of synthesis and incorporation of omega-3 and 6- long chain polyunsaturated fatty acids by THP-1 and HT29 cells with a specifc focus on the influence of retinoids." Thesis, London Metropolitan University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540612.
Full textChauvin, Lucie. "Voies de signalisation impliquées dans la sensibilisation des tumeurs mammaires au docétaxel par les acides gras polyinsaturés n-3." Thesis, Tours, 2015. http://www.theses.fr/2015TOUR3309/document.
Full textChemotherapy-resistant tumor cells are a major cause of cancer treatment failure. Preclinical studies show that polyunsaturated omega-3 long chain fatty acids (AGPIn-3LC), provided by food, improve the efficacy of chemotherapy without increasing side effects. AGPIn-3LCs are incorporated in cancer and stromal cells. This thesis aimed to identify molecular mechanisms involved in the increased sensitivity of mammary tumor cells to docetaxel. We have shown that docetaxel induces a resistance mechanism via activation of PKC/ERK and Akt pathways involved in cell proliferation and survival. Modification of the membrane lipid environment by AGPIn-3LCs supplementation inhibits these signaling pathways and increases the efficacy of docetaxel in mammary tumor cell lines and in a preclinical rodent model of native mammary tumors. Moreover, in this mammary tumor model we have found another molecular target regulated by AGPIn-3LCs: epiregulin, a member of the EGF family. AGPIn-3LCs inhibit epiregulin-VEGF induced in endothelial cells and induce a remodeling of tumor vasculature. Furthermore, AGPIn-3LCs act on the tumor microenvironment directly. This thesis work provides additional arguments for the use of AGPIn-3LCs as adjuvant molecules to reduce the resistance of breast tumors to anticancer agents
Commere, Oustric Julie. "Apports nutritionnels en acides gras polyinsaturés n-3 et action cellulaire de la vitamine A : effets sur la plasticité cérébrale et la mémoire spatiale chez le rat agé." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14211/document.
Full textLong chain polyunsaturated fatty acids (LC-PUFA) of the n-3 series play essential roles in brain functions, including brain plasticity and memory processes which are altered during aging. It is now well accepted that these PUFA regulate gene transcription through binding and activating specific nuclear receptors such as PPAR (peroxisome proliferator-activated receptors) and RXR (retinoid X receptors, which also bind 9-cis retinoic acid). As a common heterodimeric partner of both PPAR and RAR (all-trans retinoic acid receptors), RXR is a key factor in the modulation of gene expression by fatty acids and retinoids. In this context, the purpose of this work was to study the effects of a n-3 LC-PUFA supplementation on fatty acid and retinoid signalling pathways and on cerebral plasticity and spatial memory processes. Our main results show that n-3 LC-PUFA supplementation for 21 weeks in mid-life rats, maintains the mRNA levels of RXRγ and GAP-43 (synaptic protein) which were altered in aged rat hippocampus. Besides, supplemented aged rats exhibited increased numbers of newly generated neurons and improved spatial working memory, when compared with control aged rats. To summarize, our results support the neuroprotective effects of n-3 LC-PUFA during aging, in particular on cerebral plasticity and working memory. Furthermore, our works suggest the implication of RXR in the set up of these effects through notably the regulation of some target genes involved in synaptic plasticity and hippocampal neurogenesis processes
Roy, Jérôme. "Évaluation des propriétés antiarythmiques de dérives oxygénés des acides gras polyinsaturés à longue chaîne." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTT028.
Full textSince 40 years, ω3 poly-unsaturated fatty acids (n-3 PUFA) are known to have cardioprotective properties in ischemic disease such as cardiac infarction following ischemia/reperfusion period. Many studies in isolated cells or in animals confirmed these effects and it has been suggested that n-3 PUFA have direct effects on targeted proteins such as ionic channels. However, due to the abundance of double carbone bounds, the main n-3 PUFA; eicosapentaenoic acid (C20: 5 n-3, EPA) and docosahexaenoic acid (C22: 6 n-3, DHA) are very sensitive to free radical oxidation and can undergo non-enzymatic spontaneous peroxidation under oxidative stress conditions as it occurs in ischemia/reperfusion. In the present work, we addressed the question of the form of DHA having cardioprotective properties: reduced or oxidized. Indeed, the effects of n-3 PUFA on cardiac function are controversial, notably due to the lack of information on the mechanisms involved. Particularly, it is not well understood which is the active lipid: the PUFA or one of its oxygenated metabolites. In the context of oxidative stress, during ischemia/reperfusion and in month following cardiac infarction, a lot of oxygenated metabolites of PUFA like Neuroprostane; 4(RS)-4F4t-NeuroP are produced and used as biomarkers of oxidative stress. This metabolite is associated to a lower atherosclerosis risk suggesting a beneficial role in cardiovascular diseases. In this context we speculate that Neuroprostane are not just a markers of stress conditions but have biological activities.The aim of this thesis was in first time to investigate the influence of DHA peroxidation on its potentially anti-arrhythmic properties in isolated ventricular cardiomyocytes and in vivo in post-myocardial infarcted (PMI) mice. In same way, we investigated in cellulo and in vivo anti-arrhythmic properties of oxygenated metabolites of n-3 PUFA such as 4(RS)-4F4t-NeuroP. In second time we investigated if the pericardial delivery 20 minutes before occlusion of 4F4t-NeuroP protects in prevention the myocardium from ischemic damages and arrhythmias during and following an I/R episode in rats.In this study, we challenged the paradigm that spontaneously formed oxygenated metabolites of lipids are undesirable as they are unconditionally toxic. This study reveals that the lipid mediator 4(RS)-4-F4t-NeuroP derived from non-enzymatic peroxidation of DHA, can counteract such deleterious effects through cardiac anti-arrhythmic properties in month following cardiac infarction by preventing deleterious post-translational modification of RyR2 and thus regulating calcium homeostasis. More early, during ischemia/reperfusion, our results show that pericardial delivery of 4(RS)-4-F4t-NeuroP reduced ischemia-induced ventricular arrhythmias, infarct sizes, and cardiac dysfonction ; cardioprotective effects involving mitchondria mecanisms.This thesis demonstrate for the first time that DHA per se has no anti-arrhythmic effects and 4(RS)-4-F4t-NeuroP as a mediator of the cardioprotection characteristics of DHA. This discovery opens new perspectives for products of non-enzymatic oxidized n-3 PUFA as potent mediators in oxidative stress diseases like during a cardiac infarction, where oxidative stress generated play fundamental role in pathophysiological alterations
Harden, Charlotte Jane. "n-3 long-chain polyunsaturated fatty acids, appetite control and weight management." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/3814/.
Full textNolte, Noreen Kathleen. "Protection of the long chain N-3 polyunsaturated fatty acids in hake head flour against oxidation." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/49781.
Full textGeppert, Julia. "Evaluation of two supplementation strategies to improve long-chain omega-3 fatty acid status in healthy subjects." Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-68271.
Full textTeodorescu, Carmen Aurora Craig-Schmidt Margaret C. "The interactive effects of N-3 long-chain polyunsaturated fatty acids and methylmercury on the cardiovascular system." Auburn, Ala., 2007. http://hdl.handle.net/10415/1351.
Full textMcCartan, Sheila. "The effects of n-3 long chain polyunsaturated fatty acids on THP-1 and endothelial cell function." Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.579794.
Full textLewis, Amanda Gloria. "Treatment of Hypertriglyceridemia with Omega-3 Fatty Acids: A Systematic Review." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd458.pdf.
Full textGibbs, Rachael Ann. "Very long chain N-3 polyunsaturated fatty acids in the diet and opportunities to increase intake of them." Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515778.
Full textMavrommatis, Ioannis. "The effects of dietary long chain n-3 polyunsaturated fatty acids on soluble epoxide hydrolase and related markers of cardiovascular health." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=56261.
Full textChu, Hyun Sik Stephano. "Long Chain n-3 PUFA and Oleic Acid Modification Strategies to Enhance Fillet Quality in Tilapia, Oreochromis species." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/85868.
Full textPh. D.
Kwaw, Armah Christopher. "Physiological responsiveness of cardiovascular risk factors to long chain N-3 polyunsaturated fatty acids : Impact of genotype, gender and age." Thesis, University of Reading, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515723.
Full textMcAfee, Alison J. "Contribution of meat (beef and lamb) from grass-fed ruminants to total dietary intake of long chain n-3 polyunsaturated fatty acids." Thesis, University of Ulster, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.554230.
Full textCherfaoui, Maya. "La synthèse et/ou la lipoperoxydation des acides gras polyinsaturés à très longue chaîne n-3 sont-elles les étapes limitantes de leur dépôt musculaire chez le bovin ?" Thesis, Clermont-Ferrand 1, 2012. http://www.theses.fr/2012CLF1MM15.
Full textN-3 very long chain polyunsaturated fatty acids (n-3 VLC PUFA) are essential for human health but are almost exclusively present in seafood. Thus, in a strategy of diversification of n-3 VLC PUFA sources for human, the aim of this thesis was to better understand the cellular mechanisms that may explain the low n-3 VLC PUFA content in bovine muscle, by exploring three potentially limiting metabolic pathways of these fatty acids (biosynthesis, facilited uptake and non-enzymatic peroxidation) by qPCR or transcriptomic approaches. The main results indicate that the liver and muscles of cattle possess all the genetic material necessary for the synthesis of n-3 VLC PUFA and may therefore ensure their synthesis, except in entire males where gene expression of the elongase 5 is suppressed by the presence of male sex hormones. On the other hand, the higher n-3 VLC PUFA content in muscle of cattle with a grass based diet compard to corn silage and in glycolytic muscle compared to oxidative muscle do not seem to be explained by a modulation of gene expression of proteins involved in their biosynthesis or in their facilited uptake or in the endogenous regulation of their lipoperoxidation. In conclusion, this thesis has greatly advance our understanding of mechanisms involved in the regulation of n-3 VLC PUFA deposits in muscles of cattle. However, these regulations are certainly more complex and probably multifactorial. Many tracks remain to be explored before considering increasing n-3 VLC PUFA content in beef
Almeida, Bianca Bellizzi de. "Ações do óleo de peixe e triglicerídeos de cadeia média na esteatose hepática e estresse oxidativo induzidos pela dieta hiperlipídica em ratos." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/17/17138/tde-22112011-102759/.
Full textIntroduction: The Non-alcoholic Fatty liver disease is characterized by hepatic accumulation of lipids, mainly in the form of triglycerides. The disease may progress to a more severe form, the Non-alcoholic steatohepatitis, due to progressive inflammatory activity. Many authors have shown positive metabolic effects associated with the use of polyunsaturated omega-3 fatty acids and reduction in hepatic steatosis. However, these fatty acids are more susceptible to lipid peroxidation. The medium chain triglycerides (MCTs) are able to block beta-oxidation of fatty acids and reduce lipid peroxidation, but the MCT effects in steatosis are still controversial. Objective: The aim of this study was to assess the implications of high-fat diet (HF+) with fish oil or with MCT oil in the development of hepatic steatosis, liver fatty acid profile and oxidative stress markers in rats. Methodology: Fifty wistar male rats were divided into 5 groups. The animals had free access to food and water for 45 days. The first 15 days was dedicated for adaptation to high-fat diet. The HF+AF group received high-fat diet with 50% of animal fat and the other high-fat diets were made with 35% of animal fat plus 15% of other types of fat: soybean oil (HF+SO), MCT oil (HF+MCT) and fish oil (HF+FO). Results: The high-fat groups had higher hepatic total fat and triglycerides accumulation and only the groups HF+AF and HF+MCT had higher accumulation of hepatic cholesterol compared to control. The HF+MCT group had the highest percentage of hepatic fat accumulation and an exacerbated triglyceride accumulation in the liver among HF+ groups. The serum total cholesterol decreased in groups HF+MCT and HF+FO compared with the control group. The highest incorporation of hepatic fatty acids EPA and DHA in the HF+FO group contributed to the increased fatty acids peroxidizability index and total and free hepatic TBARS and depletion of hepatic vitamin E. The biggest ratio SFA/PUFA of liver fatty acids observed in the HF+MCT group contributed to the preservation of hepatic antioxidants. The alanine aminotransferase is a liver damage marker and was increased in all high-fat groups. Conclusions: The high-fat diet was effective to increase the hepatic fat concentration. The consumption of MCT oil can increase the hepatic lipid concentration and hepatic antioxidants. There was a significant increase in hepatic lipid peroxidation in the HF+FO group, although hepatic cholesterol and triglycerides were decreased.
Abbott, Kylie Anne. "Long-chain omega-3 polyunsaturated fatty acids, sex hormones, and insulin resistance." Thesis, 2019. http://hdl.handle.net/1959.13/1416221.
Full textType 2 diabetes (T2D) is the fastest growing chronic health condition, driven by obesity-related insulin resistance (IR). Obesity accounts for 50% of the total diabetes burden in Australia and worldwide. As the global prevalence of obesity increases, diabetes-related health care costs will continue to rise. Interventions that prevent or delay the onset of diabetes can potentially reduce the overall diabetes burden and associated health care costs. Weight loss is clinically effective in ameliorating IR and reducing T2D risk, however long-term weight loss remains difficult to achieve and maintain, and research into adjunct therapies are warranted. Previous studies reported a sex-dependent association between long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) eicosapentaenoic acid (EPA; c20:5n-3) and docosahexaenoic acid (DHA; c22:6n-3) and T2D. Sex hormones are known to regulate synthesis of DHA from α-linolenic acid (ALA; c18:3n-3), though precise mechanisms through which they do so are not well understood. Sex hormones also affect T2D risk differentially in men and women. Interactions between sex hormones and LCn-3PUFA may in part explain some of the differential T2D risk in men and women. Therefore, this thesis aimed to investigate the interactions between sex hormones and LCn-3PUFA for the prevention of obesity-associated IR and subsequent development of T2D. A systematic review and meta-analysis was undertaken to review the existing evidence to determine whether currently available literature supported the prevailing hypothesis, that LCn-3PUFA reduce IR in a sex-dependent manner. The literature was searched to identify randomised controlled trials (RCT) which used a dietary or supplemental n3-PUFA intervention and included measures of IR or insulin sensitivity as an outcome. Thirty-two studies including n=1848 participants were included, with two studies conducted in men, seven in women and the rest in mixed population. Meta-analysis showed that interventions with LCn-3PUFA in females ≥6 weeks duration displayed a reduction in IR, with no change in IR in studies in male populations. However, few intervention studies were conducted in males and significant heterogeneity was present that could not be explained in our analysis, limiting conclusions that could be drawn. Furthermore, there were no studies in which men and women were exposed to an identical intervention protocol, necessitating development of a double-blind RCT. A cross-sectional study of n=2,092 older (55-85 years) Australians assessed relationships between LCn-3PUFA status and diabetes, with sub-group analyses used to investigate sex- and weight- related interactions. There was a significant three-way interaction between sex, weight status and LCn-3PUFA status in the prediction of T2D, therefore sub-group analysis was performed based on this. This demonstrated an inverse association between LCn-3PUFA and diabetes in overweight and obese women, which is consistent with previously reported findings. LCn-3PUFA was inversely correlated with HOMA-IR in men and women. However, this was attenuated when adjusted for BMI. A mediation analysis explored whether the observed association between LCn-3PUFA and T2D was mediated through inflammatory pathways, which demonstrated that interleukin-6, but not C-reactive protein, fibrinogen, or neutrophil-leukocyte ratio, was a partial mediator of the association in overweight and obese women. A double-blind RCT was designed and conducted to investigate the effects of a 12-week DHA-enriched fish oil supplementation on IR in men and women with abdominal obesity and no history of diabetes. This study found a significant reduction in IR in men and women with hyperinsulinaemia at baseline, with no significant interaction between sex and treatment. There was no change in fasting glucose or beta-cell function in any groups across the course of the study. Contrary to the hypothesis, there was a similar magnitude of change in both the males and females. Secondary analysis showed that there was a significant interaction between sex and treatment on testosterone across the course of the study, with fish oil increasing circulating testosterone levels in males compared with control, whilst no change was evident amongst females (p-interactionsex*treatment=p<0.001). Changes in testosterone in males were inversely associated with changes in omega-6 PUFA dihomo-γ-linolenic acid content in erythrocyte membranes, and change in testosterone was a significant predictor of changes to insulin and HOMA-IR in men across the 12 week intervention. Finally, an observational study in n=20 transgender individuals undergoing cross-sex hormone treatment (feminising therapy: n=10; masculinising therapy: n=10) investigated effects of testosterone, androgen blockers and oestradiol on erythrocyte DHA levels and body composition. This suggested that exogenous testosterone administration in trans-men acutely downregulates DHA concentrations, but inhibiting the action of testosterone with androgen receptor antagonists does not increase erythrocyte DHA, suggesting an indirect effect; however, these did not reach statistical significance. Masculinising therapy was associated with significant increases in skeletal muscle mass at 3- and 6- months; feminising therapy was associated with decreases in skeletal muscle mass at 3- and 6- months, and increases in % body fat after 6 months treatment. Observational studies with larger sample sizes are required to determine whether change to erythrocyte DHA composition modulates any change in metabolic functioning. This thesis provides further evidence of an inverse association between LCn-3PUFA and T2D in overweight and obese women. However, the sex-dependency of the association appears to be independent of a direct effect on IR, and may represent differences in the pathogenesis of T2D in men and women. Investigations between DHA and testosterone in obese men is deserving of further research, and if substantiated, may have clinical applications for men with mild hypogonadism for whom testosterone is not clinically indicated. The inverse association between DHA and diabetes in women may have biological significance for the development of gestational diabetes. Future research should focus on associations between DHA, inflammation and IR in pregnancy.
Munro, Irene A. "Role of long chain omega-3 polyunsaturated fatty acids on weight management." Thesis, 2013. http://hdl.handle.net/1959.13/937489.
Full textDespite an ever-growing body of research on obesity, investigating causes and possible solutions to address the problem, the prevalence of obesity continues to escalate. A major cause of obesity is attributed to poor eating behaviours driven by food advertising, lack of nutrition knowledge, lack of physical activity, lack of time and lack of will power to control food intake, and there is a plethora of research with a focus on changing dietary behaviour for weight management. In part, this research also addressed dietary change, employing a reduced energy intake for weight loss supported with nutrition education and counselling to enable maintenance of the weight lost. However, consideration was also given to the internal interactions and changes that occur in the body when energy intake exceeds energy output resulting in weight gain and obesity, and whether these mechanisms could be manipulated to reduce weight gain through the inclusion of long chain omega-3 polyunsaturated fatty acids (LCω-3PUFA) in the diet. Prospective studies in humans have reported that high levels of LCω-3PUFA were associated with low levels of obesity in males while higher intakes of LCω-3PUFA were associated with higher rates of obesity in females. The data on LCω-3PUFA concentrations in males and females had been sourced from dietary records with questionable reliability. Thus the first aim of this research was to investigate whether there was a relationship between plasma LCω-3PUFA and weight status in humans. The first research chapter (Chapter 3) reports on the relationship observed between plasma LCω-3PUFA composition and weight status in free living adults. Obese individuals, both males and females, had significantly lower levels of LCω-3PUFA compared to healthy-weight individuals. Thus the aim of the first clinical trial (Chapter 4) was to investigate whether LCω-3PUFA supplementation, combined with a healthful diet with portion control and energy restriction would facilitate weight loss, improve blood lipids and inflammatory mediators. This was a double-blinded randomised controlled trial with two parallel groups. Both groups were instructed to follow the same diet for 12 weeks, one group consumed fish oil capsules and the other group consumed placebo capsules (monounsaturated oil). Despite a two-fold increase of EPA and DHA in the treatment group, there were no significant differences in outcome measures between the two groups. Both the placebo and the fish oil supplemented groups lost similar amounts of weight, fat mass and fat free mass. Overall dietary compliance was poor representing a possible confounding factor on the outcomes. The aim of the next clinical trial (Chapter 5) was to investigate whether LCω-3PUFA supplementation would facilitate weight loss, but this time in combination with a very-low-energy-diet (VLED), using meal replacements (MRs), to improve dietary compliance. The protocol for this trial was the same as the previous one apart from the change to the diet and with a shortened intervention of 4 weeks. Also, because of the anticipated rapid weight loss, a 10 week weight maintenance phase with continued supplementation was included. Although there was a greater than two-fold increase of EPA and DHA in the treatment group, there were no significant differences in outcome measures between the two groups after 4 weeks of weight loss. However, after a further 10 weeks of supplementation during weight maintenance, there was a significant reduction in anthropometric measurements, apart from fat free mass, in the treatment group but not the placebo group. The differences between the two groups were not significant. The final clinical trial (Chapter 6) investigated potential benefits of loading the body cells/membranes with LCω-3PUFA prior to following a weight loss program. The protocol for the trial was similar to the previous two, but commenced with 4 weeks of prior-supplementation with fish oil or placebo in the treatment and placebo groups, respectively, while consuming their usual diet. This was followed by 4 weeks of dietary intervention where both groups again consumed a VLED with MRs plus continued supplementation. The same measurements were taken as for the previous trials. After 4 weeks of prior-supplementation there were no significant differences in outcome measures for either group. However, at 8 weeks a significant 3-way interaction between time, group and gender was observed for percentage reduction in weight and BMI, suggesting a significant effect of LCω- 3PUFA for the fish oil group. There was also a significant reduction in percentage weight loss for females in the fish oil group. These results suggest that priorsupplementation with LCω-3PUFA, followed by supplementation with LCω-3PUFA and a VLED regimen may assist weight loss.
Debicki, Donna Monica. "Electrophysiological effects of long chain omega-3 polyunsaturated fatty acids in rabbits in vivo." 2005. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=370422&T=F.
Full textSenanayake, S. P. J. Namal. "Enzyme-assisted synthesis of structured lipids containing long-chain omega-3 and omega-6 polyunsaturated fatty acids /." 2000.
Find full textKartikasari, Lilik Retna. "Assessment of omega-3 long chain polyunsaturated fatty acid incorporation in broiler chicken meat following the consumption of omega-3 rich vegetable oils." 2009. http://hdl.handle.net/2440/56829.
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Thesis (M.Ag.Sc.) - University of Adelaide, School of Agriculture, Food and Wine, 2009
Kartikasari, Lilik Retna. "Assessment of omega-3 long chain polyunsaturated fatty acid incorporation in broiler chicken meat following the consumption of omega-3 rich vegetable oils." Thesis, 2009. http://hdl.handle.net/2440/56829.
Full textThesis (M.Ag.Sc.) - University of Adelaide, School of Agriculture, Food and Wine, 2009
Kartikasari, Lilik Retna. "Omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) levels in chicken products following consumption of alpha-linolenic acid enriched diets." Thesis, 2013. http://hdl.handle.net/2440/82468.
Full textThesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2013
Smits, Robert J. C. "The functional role and requirement for long-chain omega-3 polyunsaturated fatty acids in breeding gilts and sows." Thesis, 2012. http://hdl.handle.net/2440/83610.
Full textThesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2012
Thota, Rohith N. "Curcumin and long-chain omega-3 polyunsaturated fatty acids: effects on glycaemic control and blood lipids." Thesis, 2018. http://hdl.handle.net/1959.13/1389618.
Full textType 2 diabetes (T2D) is the most common chronic metabolic disorder resulting from either deficit of insulin secretion and/or action. The transition of normal glucose tolerance to T2D is usually accompanied by a cluster of metabolic risk factors such as low-grade inflammation, oxidative stress, insulin resistance (IR) and dyslipidaemia. IR is one of the marked independent predictors among these cluster of metabolic abnormalities that mediates the transition in high risk states such as obesity, impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) to overt T2D. IR also is often associated with decreased clearance of lipids and lipoprotein abnormalities, together representing a greater risk of cardiovascular disease (CVD) in both high risk and individuals with T2D. Several studies have employed lipid ratios, homeostatic models, and anthropometric measures as surrogate markers for predicting IR. However, none of these accounted for both insulin and lipid availability in a single model to predict IR or metabolic syndrome (MetS). Therefore, the first aim of my PhD project, presented in the chapter 3, was to develop a novel marker for IR and MetS that accounts for both insulin and lipid availability in a single model. We proposed and evaluated a novel physiologically relevant marker, InsuTAG (product of fasting insulin and fasting triglycerides) as a predictor of IR and MetS. Cross-sectional analysis of data from the Retirement Health and Life-style Study (RHLS, n=618) showed that InsuTAG is a strong predictor of IR over existing lipid based surrogate markers and anthropometric measures. Receiver operating curve analysis indicated InsuTAG (93%) as the favourable marker for IR over other lipid based surrogate markers and anthropometry measures. Prevalence of MetS was significantly higher in individuals with InsuTAG values above the optimal cut-off value of 11.2. InsuTAG exhibited a greater area under than curve than HOMA-IR for identifying MetS. Together these observations indicate the potential of InsuTAG for predicting IR and MetS. Despite effective lifestyle and pharmacological interventions, the prevalence of T2D is growing at an alarming rate in Australia, in line with global prevalence. Failure of long term compliance to these interventions is a major barrier for their effectiveness in halting the transition to T2D in high risk state individuals, indicating a necessity for alternative effective approach. Given the fact that pathogenesis of T2D is chronic, complex and often involving multiple pathological pathways, use of well tolerated dietary bio-active compounds appears to be a potential strategy for delaying the onset of T2D. Several pre-clinical and in-vitro studies have reported the ability of dietary bio-actives to down regulate multiple pathological mechanisms (chronic low-grade inflammation, IR, oxidative stress and β-cell dysfunction) that are involved in the pathogenesis of T2D. We hypothesised that a combination of two lipid-lowering and anti-inflammatory dietary bio-active compounds, curcumin and long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA), could potentially act in multiple pathways to improve the glycaemic control in individuals at high risk of developing T2D. My second aim, presented in chapter 4, was to evaluate the acute effects of curcumin and/or LCn-3PUFA on glycaemic responses. Therefore, in a randomised, cross over trial we investigated the postprandial glucose and insulin response to a single dose of curcumin and/or LCn-3PUFA in healthy individuals. The glucose levels were reduced by curcumin at as early as 30 min, and the maximum effect was observed at 60 min post meal consumption. Curcumin was found to be effective for lowering the insulin demand to control postprandial glucose levels. Similar results were observed following dietary supplementation with curcumin plus LCn-3PUFA. It was apparent that the postprandial effects on glycaemic control were primarily due to curcumin even in the combined treatment group. Thus, providing basis for long-term supplementation study with curcumin for glycaemic control. In chapter 5, a detailed study protocol for 2x2 factorial placebo controlled, double blinded randomised trial with long term (12 weeks) curcumin and LCn-3PUFA supplementation (COP-D trial) was presented. In chapter 6, we examined the effects of curcumin with or without LCn-3PUFA on glycaemic control and blood lipid levels in people at high risk of T2D. 12 weeks of supplementation with curcumin has effectively reduced the fasting insulin levels and IR in individuals with high risk of T2D. Parallel to these results, both curcumin and LCn-3PUFA were able to reduce the fasting triglycerides and atherogenic index of plasma, however the magnitude of reduction was greater with LCn-3PUFA supplementation. InsuTAG levels were also reduced with curcumin and LCn-3PUFA supplementation. However, this study failed to show any complimentary effects with concurrent administration of curcumin and LCn-3PUFA. Though IR and fasting triglycerides, were effectively reduced by these two bio-actives, we did not find any beneficial effects of curcumin and LCn-3PUFA supplementation on fasting glucose and glycosylated haemoglobin levels. In chapter 7, we designed a study to target commonly prevalent dyslipidaemia with curcumin and/or LCn-3PUFA in individuals with T2D (CALFOR-CVD trial). Participants were randomised to either placebo or curcumin or LCn-3PUFA, or curcumin plus LCn-3PUFA for six weeks. This pilot study has demonstrated that supplementation of curcumin can effectively reduce the TG. Contrasting to the results from chapter 6, magnitude of reduction in triglycerides in this study was higher with curcumin than LCn-3PUFA. Preliminary observations also presented a non-significant, but a noteworthy reduction of 0.5 mmol/L in total cholesterol and LDL-Cholesterol with curcumin supplementation. In line with observations from the COP-D trial, curcumin and LCn-3PUFA did not have any complimentary and/or added benefits. In conclusion, the results presented in this thesis demonstrate that InsuTAG has the potential to predict IR and MetS. This provides a basis for further research to validate InsuTAG with gold standard technique for IR and a longitudinal data analysis to determine the ability of InsuTAG to predict T2D in general population. With regards to the intervention trials, our hypothesis of targeting multiple pathways (IR and dyslipidaemia) in high risk and T2D patients with curcumin and LCn-3PUFA supplementation was successful. However, this thesis failed to provide any evidence on beneficial effects of combining curcumin and LCn-3PUFA for better glycaemic control to delay the onset of T2D. This could partly be due to presence of any unknown interactions between the two bio-actives or may be due to uncertainties in co-administration of curcumin and LCn-3PUFA. Thus, paving a way for further research to investigate beneficial effects with single formulation (curcumin and LCn-3PUFA) for achieving glycaemic control. This thesis constitutes a noted contribution to the research area of bio-markers and novel intervention strategies for T2D, and also presents a set of riddles that provides an extensive scope for future research.
Dias, Cintia. "Do long chain omega-3 polyunsaturated fatty acids modulate dietary fat induced changes in plasma lipid and lipoprotein profiles?" Thesis, 2016. http://hdl.handle.net/1959.13/1313736.
Full textThe consumption of foods rich in saturated fats has been associated with elevated blood lipid levels and consequently with risk for numerous chronic diseases, such as coronary heart disease. However, understanding the effects of replacing saturated fat in the diet is complex, and the health effects of reducing saturated fat consumption clearly depend on what substitutions are made. Furthermore, studies using animal models have demonstrated that dietary saturated fats raise triglyceride levels only when the diet is deficient in omega-3 polyunsaturated fatty acids (n-3PUFA). The n-3PUFA are known for their potential to help in managing hyperlipidaemia for the prevention of coronary heart disease, as well as for their anti-inflammatory, anti-arrhythmic and anti-aggregatory potential. In addition, research in human and animal models has shown competition for important enzymes in the metabolism of omega-6 polyunsaturated fatty acids (n-6PUFA) and n-3PUFA, with high consumption of n-6PUFA leading to an increase in their metabolism at the expense of n-3PUFA. This leads to an increased production of n-6PUFA derived eicosanoids, which are pro-inflammatory and pro-aggregatory, in contrast with those derived from n-3PUFA, which are less inflammatory and aggregatory. Therefore, we hypothesised that consumption of saturated fats, would not adversely influence coronary heart disease risk factors (blood lipid levels, lipoprotein profiles, platelet aggregation and inflammation) when the diet was balanced with an adequate intake of n-3PUFA. Moreover, we hypothesized that the health benefits obtained with the consumption of n-3PUFA would be maximised by including foods rich in saturated fat and reducing the consumption of vegetable oils (rich in n-6PUFA) in the diet. Our first aim, addressed in chapter 3, was to establish the basis for our hypothesis, analysing the literature on saturated fatty acids to identify the contradictions in the literature to date and to highlight the gaps in knowledge gained from previous interventional and epidemiological studies. We have observed that although many studies have associated saturated fatty acids with hyperlipidaemia and cardiovascular disease risk factors, there is still much contradiction on the subject with not all studies finding the same association. The key studies relating saturated fat consumption and heart health made no mention about the presence or absence of n-3PUFA as a possible confounding factor. This may have been due to the lack of knowledge about the existence of n-3PUFA or an inability to determine n-3PUFA concentration in most of the early studies. Therefore the missing link in the research on cardiovascular disease risk and dietary fats could be an ignorance of the interactions between different dietary fats and the effect of this interaction. In Chapters 4a and 4b we aimed to determine if LCn-3PUFA and the other dietary fats interact during digestion, absorption, re-esterification into triglycerides and assembly into chylomicrons to modulate circulating lipid levels postprandially. In a randomised cross-over design, we investigated the effect of feeding meals rich in either saturated fatty acids or n-6PUFA in conjunction with LCn-3PUFA on plasma lipid (triglycerides and total, low density lipoprotein and high density lipoprotein cholesterol) and fatty acid levels. The postprandial lipemic response and fatty acid kinetics were similar after the consumption of both meals and suggest that the competition between n-3 and n-6PUFA may be a longer term phenomenon, not just a postprandial effect. The aim of Chapter 5 was then to determine if there were interactions between LCn-3PUFA and other dietary fats in the longer term (6 weeks). Therefore, in a randomized parallel design intervention we investigated the longer-term effects of LCn-3PUFA supplementation in subjects consuming diets enriched in either saturated fatty acids or n-6PUFA, on blood lipid profiles and on the incorporation of fatty acids into plasma and erythrocyte lipids. Long chain omega-3 polyunsaturated fatty acids were incorporated to a greater extent into the plasma and erythrocyte lipids of subjects consuming the saturated fat rich diet compared to the n-6PUFA rich diet, although total and low density lipoprotein (LDL) cholesterol were also increased. Plasma samples of the subjects who completed the intervention in chapter 5 were then further analysed in chapter 6 for lipoprotein profiles, with the aim of determining if the increase in plasma cholesterol levels was due to changes in the lipoprotein particle concentration or size. The increase in LDL cholesterol was due to an increase in the less atherogenic, large, buoyant LDL particles rather than the small, dense LDL particles. In chapter 7, the aim was to determine if pre-supplementation rather than co-supplementation with LCn-3PUFA would improve the effect of the major dietary fat groups on plasma lipids and lipoprotein profiles. Therefore, in a randomized parallel design clinical intervention, we examined the effect of increasing the omega-3 index of subjects before randomizing them to a diet rich in either saturated fatty acids or n-6PUFA. The diet rich in saturated fatty acids increased, while the diet rich in n-6PUFA decreased, total and LDL cholesterol, independently of LCn-3PUFA supplementation. However, the saturated fatty acid rich diet caused a further increase in plasma and erythrocyte LCn-3PUFA compared to the n-6PUFA rich diet. In conclusion, the results presented in this thesis demonstrate that the background dietary fat is a determinant of the degree of incorporation of LCn-3PUFA into plasma and tissue lipids. The consumption of a saturated fat rich diet did indeed cause an increase in plasma cholesterol levels. However, the rise in circulating cholesterol levels following saturated fat consumption is accompanied by an increase in the less atherogenic LDL particle size, when the LCn-3PUFA status is adequate, which is likely to reduce the detrimental effects. In addition, there was a concurrent increase in incorporation of LCn-3PUFA into plasma and erythrocytes, which may have benefits, independent of cholesterol or blood lipids. Hence, this thesis paves the way for further research to examine the impact of increased plasma and tissue LCn-3PUFA levels as a result of saturated fat consumption with adequate LCn-3PUFA intakes, on cardiovascular health risk indicators, such as inflammation, hypertension, platelet aggregation and endothelial function.
Saedi, Some Olia Ahmad. "Role of lycopene and long chain n-3 polyunsaturated fatty acid supplements in airway inflammation." Thesis, 2008. http://hdl.handle.net/1959.13/31535.
Full textIn Western society, increased asthma prevalence over recent years has coincided with changes in dietary patterns, leading to the hypothesis that a Western diet increases susceptibility to asthma. Components of the diet that may be important are antioxidants (e.g. lycopene) and fatty acids. Lycopene and long chain n-3 polyunsaturated fatty acids (LCn-3PUFA) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have anti-inflammatory effects. As asthma is a disease linked to oxidative stress and inflammation, it was hypothesised that these nutrients may have a beneficial effect individually, and may have a synergistic anti-inflammatory effect when used in combination. The aim was to examine the ability of lycopene and/or LCn-3PUFAs to protect against virus-induced inflammation, as rhinovirus infection is the primary cause of asthma exacerbation. The results presented demonstrate that both lycopene and DHA (but not EPA) individually decreased the inflammatory response of airway epithelial cells infected with rhinovirus. The results also showed that DHA supplementation increased the utilization of lycopene by cells. Furthermore, lycopene reduced rhinovirus replication. A combination of lycopene and DHA also reduced the inflammatory response of cells to rhinovirus infection, however, no synergistic anti-inflammatory effect was apparent. It is concluded that consumption of foods containing lycopene and DHA may exhibit a beneficial effect on the inflammatory response to rhinovirus infection. This may have important clinical implications, as increased dietary intake of foods rich in these nutrients may lead to a reduction in the frequency and severity of asthma exacerbations.
Saedi, Some Olia Ahmad. "Role of lycopene and long chain n-3 polyunsaturated fatty acid supplements in airway inflammation." 2008. http://hdl.handle.net/1959.13/31535.
Full textIn Western society, increased asthma prevalence over recent years has coincided with changes in dietary patterns, leading to the hypothesis that a Western diet increases susceptibility to asthma. Components of the diet that may be important are antioxidants (e.g. lycopene) and fatty acids. Lycopene and long chain n-3 polyunsaturated fatty acids (LCn-3PUFA) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have anti-inflammatory effects. As asthma is a disease linked to oxidative stress and inflammation, it was hypothesised that these nutrients may have a beneficial effect individually, and may have a synergistic anti-inflammatory effect when used in combination. The aim was to examine the ability of lycopene and/or LCn-3PUFAs to protect against virus-induced inflammation, as rhinovirus infection is the primary cause of asthma exacerbation. The results presented demonstrate that both lycopene and DHA (but not EPA) individually decreased the inflammatory response of airway epithelial cells infected with rhinovirus. The results also showed that DHA supplementation increased the utilization of lycopene by cells. Furthermore, lycopene reduced rhinovirus replication. A combination of lycopene and DHA also reduced the inflammatory response of cells to rhinovirus infection, however, no synergistic anti-inflammatory effect was apparent. It is concluded that consumption of foods containing lycopene and DHA may exhibit a beneficial effect on the inflammatory response to rhinovirus infection. This may have important clinical implications, as increased dietary intake of foods rich in these nutrients may lead to a reduction in the frequency and severity of asthma exacerbations.
Fink, Naomi Hayden. "Enteral docosahexaenoic acid supplementation to attenuate inflammation in the preterm infant." Thesis, 2017. http://hdl.handle.net/2440/105284.
Full textThesis (Ph.D.) (Research by Publication) -- University of Adelaide, Adelaide Medical School, 2017.
Tu, Wei-Chun. "Effects of dietary alpha linolenic acid on biosynthesis of N-3 long chain polyunsaturated fatty acids in animals." Thesis, 2011. http://hdl.handle.net/2440/71107.
Full textThesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2011
Phang, Melinda. "Differential effects of long chain omega-3 polyunsaturated fatty acids on platelet aggregation and hemostatic variables in healthy male versus female subjects." Thesis, 2013. http://hdl.handle.net/1959.13/938766.
Full textThrombosis is a critical event that accounts for considerable morbidity and mortality in the Western world. Thrombosis is associated with arterial diseases including, myocardial infarction, stroke, and peripheral occlusive disease as well as with venous thromboembolic disorders. Consequently, the primary goal for the prevention of arterial and venous thrombosis to combat disease progression is to limit thrombus extension. Platelet activation and aggregation is considered to be central to thrombus production; thus anti-thrombotic treatments to inhibit platelet activity have been a major drug target to retard the thrombotic and atherosclerotic processes. Despite extensive resource investment in cardiovascular research and treatment, the current pharmacological strategies for the inhibition of platelet aggregation, although effective, may present limitations and adverse health effects have been reported. Given the toll taken by thrombotic complications, a safe and efficacious non-pharmacological approach may be paramount for the prevention and management of thrombotic disease. While a wealth of evidence supports that fish oil provides preventative or ameliorative effects against thrombotic disease, the mechanisms responsible for this association are not understood and are further complicated by contrasting reports. Fish oils are a rich source long chain omega-3 polyunsaturated fatty acids including eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), however it is not clear whether the anti-thrombotic effects are due to EPA or DHA or whether both are equally effective. In the available literature relating fish oil and platelet aggregation, wide variability in terms of dosage, concentration ratios, study design, subject characteristics and gender inequality are apparent, hence there is discrepancy regarding the effect of fish oils on platelet activity. Consequently, the anti-thrombotic potential of fish oil supplementation is controversial and largely disregarded by the medical community. This dissertation investigated the independent effects of EPA and DHA on platelet and coagulant activity. A series of three controlled studies were undertaken to elucidate the mechanisms by which EPA and DHA influence hemostatic parameters with the hope to resolve the existing controversy. The ultimate and unifying theme of these studies was to provide a safe and efficacious approach to optimise cardio-protection via anti-thrombotic potential of EPA versus DHA. Firstly, an in vitro investigation was carried out that compared the effects of EPA with DHA on platelet aggregation in healthy male and female subjects. The inhibition of platelet aggregation by EPA/DPA/DHA was equally effective and correlated with lag time; however most strikingly the results were influenced in a gender-specific manner. These observations suggest that interactions between sex hormones and fish oils exist to influence platelet response differentially. With a new perspective of gender bias effects, an acute supplementation study monitored the platelet responses up to 24 hours after consumption of a single dose of an EPA versus DHA-rich oil capsule in thirty male and female subjects. The kinetics of the EPA and DHA supplement on platelet activity was examined according to gender stratified treatment. Subgroup gender analysis showed that the anti-aggregatory effects of EPA were predominately evident in males while female platelets were more responsive to DHA. The marked decrease in platelet aggregation with EPA supplementation was paralleled with a reduction in platelet microparticle activity in the male subjects only, and an inverse relationship between testosterone levels and platelet responses were observed. Findings from this study reflected the in vitro observations and suggest that EPA and DHA inhibit platelet aggregation via independent pathways compounded by sex hormonal influences. Confirmation of gender-specific platelet responses with omega-3 fatty acid supplementation was achieved in a chronic supplementation study involving ninety-four healthy male and female subjects. Subsequently, this four week dietary intervention trial demonstrated that the anti-thrombotic potential is apparent with longer term exposure to EPA/DHA and explored the mechanistic pathways. Significant interactions between gender and treatment were observed; the effects of EPA were specific in reducing platelet aggregation and specific coagulation factors in males, whereas no effects were observed in the female cohort. Conversely, the effects of DHA were unique to females with a similar decrease in platelet aggregability. Interactions between sex hormones with coagulation factors and retention of EPA and DHA in plasma were also observed.In conclusion, the study findings presented in this thesis provide evidence that the effects of EPA and DHA on platelet aggregation are apparent; the effects are neither shared nor complementary, rather they are gender-specific. Furthermore, the results herein may explain the existing controversy between fish oils, platelets and thrombosis that have intrigued clinical investigators for several decades. With respect to thrombotic disease risk, males would likely benefit more from supplementation with EPA while females are more responsive to DHA. The significance of these findings allows optimal cardio-protection tailored for both gender groups offering a safe and efficacious non-pharmacological approach.
Vollhardt, Christiane [Verfasser]. "The effect of lowering the ω-6/ω-3 [omega-6/omega-3] long-chain polyunsaturated fatty acid ratio in the diet of pregnant and lactating women on fatty acid levels and body composition of the women and their newborns / Christiane Vollhardt." 2010. http://d-nb.info/1004942060/34.
Full textSung, Hyunsin. "The effect of krill oil supplementation focusing on the incorporation of plasma omega-3 polyunsaturated fatty acids, clinical biomarkers and lipidomic profiles in women." Thesis, 2017. https://vuir.vu.edu.au/36975/.
Full textChown, Samantha Naomi. "Understanding lipid utilisation in large (> 2 kg) Yellowtail Kingfish (Seriola lalandi)." Thesis, 2019. http://hdl.handle.net/2440/122337.
Full textThesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2019
Martinho, Joana Paiva. "Neurobiological effects of long chain n-3 polyunsaturated fatty acids." Master's thesis, 2016. http://hdl.handle.net/10451/26249.
Full textOs ácidos gordos polinsaturados, conhecidos por PUFA (do inglês, polyunsaturated fatty acids), contêm duas ou mais ligações duplas de carbono e incluem os ácidos gordos essenciais, ómega-6 (n-6) e ómega-3 (n-3). O ómega-6 deriva do ácido linoleico (LA, 18:2n-6) e origina o ácido araquidónico (AA) como metabolito final. O ómega-3 deriva do ácido linolénico (ALA, 18:3n-3) e tem como metabolitos principais o ácido eicosapentaenóico (EPA, 20:5n-3) e ácido docosahexaenóico (DHA, 22:6n-3), que são ácidos gordos de cadeia longa (LC-PUFA, do inglês, long-chain polyunsaturated fatty acids). Os metabolitos do n-6 e do n-3 são originados através de uma cascata de reacções de dessaturação, alongamento e oxidação, com enzimas específicas. O n-6 produz também alguns eicosanóides com propriedades pró-inflamatórias e pró-trombóticas: lipoxinas (LXs), prostaglandinas (PGs), thromboxanos (TXs) e leucotrienos (LTs), que são contrabalançados pelos eicosanóides anti-inflamatórios do n-3. Os PUFA são considerados ácidos gordos essenciais porque não conseguem ser sintetizados de novo pelo nosso organismo e precisam de ser obtidos através da dieta. As melhores fontes de ácidos gordos são o peixe gordo e os seus óleos, os óleos vegetais, como óleo nozes, chia, canola e linhaça e também óleo ou extracto de algas marinhas. Os PUFA podem também ser encontrados em suplementos alimentares e no leite materno. O rácio de ingestão n-6/n-3 é considerado um factor de promoção da saúde humana, sendo os níveis baixos deste rácio recomendados para se obterem os efeitos protectores destes ácidos gordos, nomeadamente ao nível das suas propriedades anti-inflamatórias, cardiovasculares e neurobiológicas. Na dieta ocidental moderna existe um consumo excessivo de n-6 relativamente ao n-3, o que origina uma desregulação do metabolismo normal destes ácidos gordos, onde o n-6 compete com o n-3 pelas mesmas enzimas e leva ao aumento dos eicosanóides pró-inflamatórias do n-6. Há, no entanto, estudos recentes que colocam em causa o papel do rácio n-6/n-3 e reforçam a ideia do consumo de EPA e DHA em maior quantidade, ao invés de n-3 sob a forma de ALA. Actualmente é recomendado o consumo de 1g/ dia de n-3 PUFa, sob a forma de EPA+DHA, para se obterem efeitos benéficos no sistema cardiovascular. O consumo de óleo de peixe, rico em EPA e DHA, tem sido associado a efeitos protectores no sistema nervoso central, promovendo o desenvolvimento dos circuitos corticais e afectando o funcionamento de neurotransmissores (serotonina, adrenalina, noradrenalina e dopamina), tendo consequentemente um impacto positivo na progressão de patologias neurológicas do foro inflamatório e também comportamental, como a depressão, ansiedade, stress e perturbações de humor. Condições como a depressão, a ansiedade e o stress têm um impacto negativo na sociedade, podendo levar a situações fatais. Assim, é necessário avaliar o impacto dos ácidos gordos de cadeia longa na prevenção destes distúrbios. A maior parte dos estudos sobre EPA e DHA foca-se na toma conjunta destes ácidos gordos e, por isso, não clarificam o papel individual de cada um destes compostos sobre a saúde. O objectivo principal deste trabalho é, portanto, explorar os efeitos benéficos da toma de EPA e DHA, comparando a sua acção isolada com a sua acção conjunta, na promoção de comportamentos activos, opostos aos encontrados em situações de depressão e outros distúrbios comportamentais. Para este trabalho foram usados 32 ratos Wistar como modelo de estudo, distribuídos aleatoriamente por 4 dietas diferentes (com 8 animais por grupo) e ricas em ácidos gordos de diferentes origens, de forma a avaliar qual destes compostos tem um efeito benéfico maior sobre o comportamento: óleo de peixe, rico em EPA+DHA (grupo Fish Oil), óleo de Nannochloropsis, uma microalga marinha rica em EPA (grupo Nanno) e óleo de Schizochytrium, uma alga marinha rica em DHA (grupo Schyzo). Uma dieta pobre em EPA e DHA (grupo Milk Fat) foi usada como controlo negativo. Os animais foram pesados duas vezes por semana durante dois meses, registando-se igualmente a quantidade de alimento ingerido nesse período. Para avaliar estado de actividade/passividade dos animais recorreu-se a um teste de natação forçada (Forced Swimming Test, FST, em inglês), em que os animais são colocados numa piscina com 30 cm água, num ambiente controlado e do qual não podem escapar. O teste foi realizado em duas fases, em dois dias consecutivos (pré-teste de 15 minutos + teste de 5 minutos), sendo o segundo teste gravado para análise dos movimentos natatórios, frequência de movimentos, tempo de latência e tempo de imobilidade dos animais. O maior tempo de imobilidade está associado a um estado menos activo e pode ser interpretado como uma maior tendência para um comportamento depressivo. Posteriormente, os animais foram sacrificados e procedeu-se à recolha dos seus órgãos e sangue, usados para análise do perfil de ácidos gordos, quantificação de parâmetros bioquímicos e análise dos níveis de serotonina e catecolaminas. As fezes (previamente recolhidas) foram também analisadas para determinar o perfil de ácidos gordos e a eventual absorção destes pelo organismo. Os resultados do teste comportamental revelam um maior poder benéfico no consumo conjunto de EPA+DHA, uma vez que o grupo Fish Oil revelou tempos de imobilidade menores e uma maior latência de imobilidade. O grupo Schyzo, rico em DHA, teve valores próximos, embora inferiores, aos encontrados no grupo Fish Oil, tendo os grupos Milk Fat e Nanno uma pior prestação global no teste comportamental. Os resultados nas fezes revelam um maior poder de absorção para o grupo Fish Oil e menor para o grupo Nanno. A análise ao plasma revelou valores mais baixos de lípidos totais, colesterol total, triglicéridos e glucose para o grupo rico em EPA+DHA, bem como níveis mais altos de dopamina e adrenalina, associados a um maior índice de actividade e motivação. O grupo Nanno, rico em EPA, apresentou bons resultados nos parâmetros ligados à saúde cardiovascular, o que pode indicar um papel mais benéfico deste ácido gordo, relativamente à toma de DHA. Os eritrócitos e o cérebro apresentaram também níveis elevados de EPA e DHA para o grupo Fish Oil, em comparação com os níveis encontrados nos outros grupos, revelando uma maior incorporação de ácidos gordos por parte da dieta rica em óleo de peixe. Pode concluir-se que a toma conjunta de EPA+DHA é mais benéfica para a saúde cardiovascular geral e para melhorar os níveis de actividade nos indivíduos do que a toma isolada destes compostos, uma vez que o grupo alimentado com EPA+DHA apresentou melhores resultados em todos os parâmetros analisados, comparativamente aos que apenas tomavam EPA ou DHA.
Polyunsaturated fatty acids include the essential omega-6 (n-6) and omega-3 (n-3) fatty acids, which are not synthesised by our body and must be obtained through diet. The most abundant sources of PUFA are fish, plant and algae oils. Omega-3 has an important anti-inflammatory power and is known for its benefit effect on the prevention of cardiovascular diseases. The main n-3 metabolites are eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6,n-3), the long-chain PUFA (LC-PUFA), mainly found in fish oil and known to have a protective role regulating brain development and neurotransmitter functioning. Therefore, LC-PUFA are implied for the prevention of neurodegenerative and neurological conditions, as well as behavioural disturbances like depression and anxiety-related disorders. However, there is a lack of information about the individual role of these fatty acids on these stated conditions. The purpose of this work was to test and compare the effects of EPA and DHA, in form of isolated and combined diet, on the promotion of active behaviours, favourable in neurologic disorders. An experimental design was made using 32 Wistar rats, divided into 4 different diets to assess the specific effects of each fatty acid: Milk Fat, the negative control diet without EPA or DHA added; Fish Oil, the positive control diet, rich in EPA+DHA; Nanno group, rich in EPA; Schyzo group, rich in DHA. A behavioural Forced Swimming Test (FST) was performed to evaluate the active/passive state in rats. The animals were later euthanized, with their blood and organs removed for biochemical analysis. Fatty acid profile in faeces, erythrocytes and brain, as well as biochemical markers, serotonin and catecholamines levels were determined. Behavioural FST revealed benefit effects of the EPA+DHA intake, rather than individual fatty acid intake, since Fish Oil group presented a better overall performance. Both Milk Fat and Nanno groups presented the worse results in FST, with higher immobile levels, low latency times and higher frequencies. Schyzo group has more similar results to Fish Oil group than Nanno group, which might indicate a better role of individual DHA, contrarily to individual EPA, on promoting active behaviours. Plasma metabolites, as well as dopamine and epinephrine levels, also presented better results in Fish Oil group, with Nanno group having similar results as Fish Oil regarding plasma metabolites related with cardiovascular health. It can be concluded that an EPA+DHA diet is more adequate for the promotion of global health, as well as increasing active behaviours, which can be benefit for neurologic conditions.
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