Dissertationen zum Thema „Omega-3 fatty acids“
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1
Lalia, Antigoni. „Omega-3 fatty acids to combat sarcopenia“. Thesis, College of Medicine - Mayo Clinic, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10124986.
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Background: Age-related sarcopenia leads to frailty, physical disability and loss of independence. Although exercise is an effective strategy to counteract the prevailing loss of muscle mass, older adults exhibit blunted anabolic responses, and are often unable to adopt an active lifestyle due to comorbidities associated with aging. Long chain polyunsaturated fatty acids (n-3 PUFA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid, are non-pharmaceutical nutrients which have surfaced for their potential anabolic properties on skeletal muscle and may be particularly beneficial in the context of sarcopenia.
Objective: First, to determine if EPA and DHA increase muscle protein synthesis in older adults. Second, to determine if n-3 PUFA increase the anabolic response to an acute resistance exercise stimulus in older adults. Third, to assess if their effect is mediated through improved mitochondrial function, which is known to be impaired with aging.
Methods: Twelve old, sedentary, healthy women and men (65-85 years) were given 3.9 grams/day purified EPA/DHA for 4 months. 12 young adults (18-35 years) were included as a comparison group for baseline measurements. Muscle protein fractional synthesis rate (FSR) was measured before and after treatment for mixed muscle, and subcellular fractions of myofibrillar, mitochondrial and sarcoplasmic proteins. We infused a stable isotope tracer of [ring- 13C6] phenylalanine and monitored incorporation of the amino acid into muscle proteins, at the fasting, post absorptive state, and 16 hours following an acute bout of unaccustomed resistance exercise, using mass spectrometry. Muscle mitochondrial function was assessed ex vivo from skeletal muscle biopsies. Further mechanistic information was generated through large scale and individual mRNA gene expression, inflammatory markers, and protein phosphorylation signaling of the anabolic pathway.
Results: Protein synthesis was similar between age groups at baseline and post exercise, despite the robust decline in mRNA gene expression with aging. EPA/DHA supplementation increased total lean mass, and increased mitochondrial and sarcoplasmic FSR at baseline. Following acute exercise, mixed muscle and subcellular FSR did not change significantly, but participants were segregated into responders and non-responders. EPA/DHA further potentiated the anabolic response of mitochondrial FSR to levels greater than that in the young. There was no improvement in mitochondrial oxidative capacity and efficiency, but there was a significant decrease in ROS emissions.
Conclusion: In healthy older adults, EPA/DHA exhibited significant anabolic effect in baseline skeletal muscle mitochondrial and sarcoplasmic FSR, which was dissociated from mitochondrial oxidative capacity. The anabolic response to exercise was variable between responders and non-responders where some individuals presented with marked increase in mixed muscle and subcellular FSR. This observation sets the ground for identifying the phenotypic traits of the elderly who are likely to benefit from the therapeutic use of n-3 PUFA to combat sarcopenia of aging.
2
O'Shea, Karen Michelle. „Omega-3 Fatty Acids and Heart Failure“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1258128805.
3
Wang, Yanwen. „Omega-3 polyunsaturated fatty acids and chicken immunity“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60356.pdf.
4
McDaniel, Jodi C. „Omega-3 fatty acids effect on wound healing“. Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1186629013.
5
Purwaha, Preeti. „Effect of Dietary Omega-3 and Omega-6 Polyunsaturated Fatty Acids on Alcoholic Liver Disease“. Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26488.
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PUFAs have been shown to modulate ALD by several mechanisms, including free radical generation from hepatic lipid peroxidation. However, how they modulate lipid peroxidation and generation of bioactive metabolites in ALD is poorly understood and it is still not clear which PUFAs (?-3 or ?-6) are beneficial or detrimental in ALD. Thus, our objective was to study the effect of ?-3/?-6 PUFAs on lipid peroxidation and ethanol mediated steatosis and inflammation. Using standard liquid diet (LDC), LDC with fish oil (rich in ?-3) and safflower oil (rich in ?-6), we studied the generation of bioactive metabolites, such as eicosanoids and free radicals generated via lipid peroxidation. In addition, we determined the effect of PUFAs on several inflammatory and fibrotic factors, e.g. gene as well as protein expression, using western blot and RT-PCR, respectively. We also investigated the effect of PUFA diets on novel targets, such as hepatic membrane transporters with potential role in liver inflammation. Our results suggest that ?-3 diet prevented while ?-6 based diets promoted the development of fatty liver and inflammation. ?-3 PUFA reduced AA-peroxidation by lowering hepatic AA concentration and expression of peroxidation enzymes, COX-2 and 5-LOX, resulting in lower generation of pro-inflammatory AA-derived PGs (Series-2), HETEs and free radicals, along with increase in anti-inflammatory EPA and DHA-derived PGs (Series-3). ?-3 diet might also reduce liver inflammation by preventing activation of NF-?B and induction of TNF-?. Rats fed with ?-3 diet showed high protein expression of efflux transporters, MRP-2 and ABCA1, indicating elimination of peroxidation metabolites and triglycerides from the liver and decreased inflammation. In contrast, ?-6 diets led to increase in AA-peroxidation and generation of AA-derived pro-inflammatory metabolites. ?-6 based diets also promoted fatty liver and inflammation by activating NF-?B, inducing TNF-? and downregulation of efflux transporters, MRP-2 and ABCA1. This study not only provides new insights into the effects and possible mechanisms by which ?-3 and ?-6 PUFAs may alter hepatic steatosis and inflammation, but also put forward new targets of research, such as hepatic membrane transporters in relation to liver pathology in ALD.
6
Novak, Elizabeth Marie. „Dietary omega-3 and omega-6 fatty acids and neonatal liver metabolism“. Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/36743.
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It is well-known that the n-3 fatty acids are important regulators of fat and glucose metabolism in adult liver; however, to date most research on the importance of n-3 fatty acids in early development has focused on the brain, with little consideration of effects on other organs. This research addressed the importance of the essential n-3 and n-6 fatty acids for the liver during early development. A series of studies were conducted to address the impact of the amount, balance, and types of n-6 and n-3 fatty acids in the maternal diet and infant milk diet on lipids, protein abundance, gene expression, and relevant metabolites in the developing liver. Using milk-formula fed piglets, the first study demonstrated that the supply of n-6 and n-3 fatty acids impacts infant liver fatty acids, with high dietary n-6 fatty acids decreasing hepatic n-3 fatty acids in a pattern similar to n-3 fatty acid deficiency. Using the rat to address the impact of maternal fatty acid nutrition in gestation and lactation on the infant liver, the second study showed that adding n-3 fatty acids to the maternal diet lead to higher long chain n-3 fatty acids in neonatal liver, and this was associated with higher expression of enzymes of fatty acid oxidation and lower expression of enzymes of glycolysis and amino acid catabolism, with altered amino acid patterns when compared to n-3 fatty acid deficiency. In the third study, providing long chain n-3 fatty acids in the maternal diet led to marked increase in long chain n-3 fatty acids in milk and in the liver of the milk-fed rat pups, and this was associated with lower gene expression for enzymes of fatty acid synthesis and glycolysis and higher gene expression for an enzyme of ketogenesis in the neonatal liver. These studies provide new knowledge to show that the amount, types and balance of n-3 and n-6 fatty acids in the maternal and infant diet are relevant to hepatic metabolic regulation in the early postnatal period. Nutrition support of young infants should consider the needs and functions of n-3 fatty acids beyond the brain.
7
Metcalf, Robert Glenn. „Strategies for increasing consumption of N-3 polyunsaturated fatty acids and their effects on cardiac arrhythmias in humans“. Title page, table of contents and abstract only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phm5885.pdf.
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"October 2003" Bibliography: leaves 190-210. Ch. 1. Literature review -- Ch. 2. A practical approach to increasing intakes of n-3 polyunsaturated fatty acids: use of novel foods enriched with n-3 fats -- Ch. 3. Effects of fatty acids on the incidence of arrhythmias in patients with implanted cardioverter-defibrillators (ICDs) -- Ch. 4. A pilot study to investigate the effects of n-3 fatty acids on inducible, sustained ventricular tachycardia in patients undergoing electrophysiology testing -- Ch. 5. Conclusions and future directions.
8
Lewis, 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.
9
Scorletti, Eleonora. „Effect of omega-3 fatty acids in non-alcoholic fatty liver disease“. Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/422265/.
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The first chapter (Introduction) of the thesis summarises the pathogenesis of NAFLD and its associated risk factors such as type 2 diabetes and cardiovascular disease. Moreover, it describes: a) the potential beneficial effects of long chain omega-3 fatty acid treatment [docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA)] in NAFLD; b) the effect of genotypes patatin-like phospholipase domain-containing protein-3 (PNPLA3 I148M) and the transmembrane 6 superfamily member 2 protein (TM6SF2 E167K), on the level of DHA and EPA enrichment and end of study liver fat percentage after DHA+EPA treatment; and c) the effect of fatty acid desaturase (FADS) and Elongase (ELOVL) polymorphisms influencing omega-3 fatty acid metabolism. The second chapter describes the overall aim of this thesis. The aim of my research was to investigate in patients with NAFLD: a) the effect of long-chain omega-3 fatty acid treatment on liver fat percentage and liver fibrosis biomarkers; b) the effect of genotypes influencing NAFLD severity on treatment with DHA+EPA; and c) the effect of genotypes influencing omega-3 fatty acid metabolism in NAFLD. The third chapter describes in details the design and methods used in my research. Chapter four highlights my novel results from the WELCOME study. This chapter describes the baseline and end of study characteristics of the WELCOME study participants and shows the results of the DHA+EPA treatment on liver fat percentage and liver fibrosis biomarkers. This chapter also describes the association between DHA erythrocyte enrichment and decrease in liver fat percentage after DHA+EPA treatment. Chapter five illustrates the association between PNPLA3 I148M and DHA erythrocyte enrichment percentage and end of study liver fat percentage after DHA+EPA treatment. The chapter shows that PNPLA3 I148M was associated with higher end of study liver fat percentage and lower DHA tissue enrichment. Chapter six shows the negative association between FADS polymorphisms and omega-3 fatty acid metabolism in NAFLD. The chapter also shows that there was a gene-DHA+EPA interaction between the minor allele of the FADS1 rs174556 and Δ-5 desaturase activity after treatment with DHA+EPA. Finally, chapter seven, summarises my results in the context of current evidence and knowledge about the subject matter.
10
Wang, Lei. „MODULATION OF ENDOTHELIAL CELL ACTIVATION BY OMEGA-6 AND OMEGA-3 FATTY ACIDS“. UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/573.
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Endothelial activation is considered to be an early and critical event in the pathology of atherogenesis which can be modified by environmental factors such as diet, pollutants, and lifestyle habits. Dietary andamp;ugrave;-6 and andamp;ugrave;-3 fatty acids have been reported to either amplify or diminish inflammatory responses related to atherosclerosis development. However, the interactions of andamp;ugrave;-6 and andamp;ugrave;-3 fatty acids with inflammatory cytokines or organic pollutants on endothelial cell activation are not well understood. The studies presented in this dissertation tested the hypothesis that andamp;ugrave;-6 and andamp;ugrave;-3 fatty acids alone, or in varying ratios can differently modulate pro-atherogenic mediators and inflammatory responses that are initiated by tumor necrosis factor- andamp;aacute; (TNF-andamp;aacute;) or polychlorinated biphenyls (PCBs) in endothelial cells. Exposure to TNF-andamp;aacute; induced oxidative stress, p38 MAPK, NF-andamp;ecirc;B, COX-2 and PGE2, which was amplified by pre-enrichment with linoleic acid but blocked or reduced by andamp;aacute;-linolenic acid. Furthermore, TNF-andamp;aacute;-induced caveolin-1 up-regulation and the co-localization of TNF receptor-1 with caveolin-1 was markedly increased in the presence of linoleic acid and diminished by andamp;aacute;-linolenic acid. Silencing of the caveolin-1 gene completely blocked TNF-andamp;aacute;-induced production of COX-2 and PGE2 and significantly reduced the amplified response of linoleic acid plus TNF-andamp;aacute;. These data suggest that omega-6 and omega-3 fatty acids can differentially modulate TNF-andamp;aacute;-induced inflammatory stimuli and that caveolae and its fatty acid composition play a regulatory role in these observed metabolic events. Besides cytokines, lipophilic environmental contaminants such as PCBs can also trigger inflammatory events in endothelial cells. Our data suggest that increasing the relative amount of andamp;aacute;-linolenic acid to linoleic acid can markedly decrease oxidative stress and NF-andamp;ecirc;B-responsive genes. The inhibitor study revealed that the modulation effect of andamp;ugrave;-6 and andamp;ugrave;-3 fatty acids on PCB toxicity was mainly through the oxidative stress sensitive transcription factor, NF-andamp;ecirc;B. In conclusion, our studies demonstrate that different dietary fats can selectively modulate vascular cytotoxicity caused by TNF-andamp;aacute; as well as by persistent organic pollutants such as PCBs. We also demonstrated the important relevance of substituting dietary andamp;ugrave;-3 fatty acids such as andamp;aacute;-linolenic acid for andamp;ugrave;-6 fatty acid such as linoleic acid in reducing cardiovascular diseases.
11
Rees, Anne-Marie Psychiatry Faculty of Medicine UNSW. „Omega-3 fatty acids and depression in the perinatal period“. Publisher:University of New South Wales. Psychiatry, 2009. http://handle.unsw.edu.au/1959.4/43610.
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Omega-3 fatty acids are increasingly recognised as playing an important role in human brain development and mental health. The polyunsaturated fatty acids (PUFAs) include omega-3 and omega-6 fats which are essential fatty acids (EFAs), consumed via the diet. Omega-3 fatty acids are particularly abundant in fish oils. The omega-3 fatty acids are being focused on for their role in depression, the main types being docosahexaenoic acid (DHA), which is abundant in neural tissue, and also eicosapentaenoic acid (EPA) which is biologically very active. There is an emerging literature in relation to omega-3 fatty acid blood levels in depression and the effects of treatment with omega-3. Strong epidemiological evidence has also been published indicating an association between a population's fish intake and depression rates. A specific research focus on omega-3 as a treatment for depression in the perinatal period is also starting to emerge. The importance of this particular area is enhanced by the knowledge that omega-3 depletion occurs during the perinatal period due to fetal diversion for neurodevelopment. In view of the lay public promotion of omega-3 and its appeal to women as a 'natural therapy', there is a need to scientifically evaluate its effectiveness to treat depression in the perinatal period. It is also important to investigate omega-3 as an alternative to antidepressants given the ongoing uncertainties regarding their safety in pregnancy. In this thesis a literature review presents current research relating to this field. This is followed by a description of the methodology and results for the two trials conducted. The results of the double-blind randomised placebo controlled trial of omega-3 as a treatment for depression in the perinatal period were essentially negative. However this result is limited by the small sample size in the study and therefore it may be unwise to interpret the result as conclusive. The case-control study confirmed the hypothesis that omega-3 levels were more depleted in depressed women compared to non-depressed women. A discussion of the results and trial limitations then follows in the thesis. It is concluded that further larger studies are warranted in this area.
12
Ramakrishnan, Sarathiraja. „Encapsulation of omega-3 fatty acids by premix membrane emulsification“. Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/145770.
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In food and pharma industry, fish oils are highly demanded due to the many associated health benefits of omega-3 fatty acids. However, the delivery of fish oil through food is a major challenge as this oil is susceptible to oxidation and to produce off-flavors. To prevent these undesired effects, microencapsulation techniques are used. Typically oil encapsulation is carried out by two steps (i) emulsion preparation (ii) drying. The main objective is to study the effect of the emulsification method, emulsion formulation, membrane type and microcapsule formulation on relevant physic-chemical parameters of fish oil microcapsules.The approach of the project is to combine, for the first time, the advantages of using a low energy emulsification technique (membrane emulsification) and spray drying to obtain food-grade fish oil microcapsules. The results show a clear improvement in the oil encapsulation efficiency (OEE) when decreasing the droplet size of the emulsion and increasing the amount of wall material. The combination of a polysaccharide with a protein has been found to improve protection against oxidation during storage of the microcapsules, while the addition of denatured proteins as a part of the microcapsule wall material enhances OEE but does not improve the mechanical strength of the microcapsules.El aceite de pescado es altamente valorado en la industria alimentaria por su demostrada actividad en la prevención y tratamiento de numerosas patologías, asociada a su contenido en ácidos grasos omega-3. La incorporación de aceite de pescado en alimentos presenta algunas dificultades relacionadas con su rápida oxidación y su característico aroma y sabor. La encapsulación del aceite de pescado retrasa la oxidación y permite enmascarar sus propiedades sensoriales. Tradicionalmente, la encapsulación se lleva a cabo combinando una etapa de emulsificación seguida de secado por atomización. El objetivo principal del trabajo es estudiar el efecto del método de emulsificación y la formulación de la emulsión y las microcápsulas en los parámetros físico-químicos más relevantes de las microcápsulas. En este proyecto se combina por primera vez la emulsificación por membranas con el secado por atomización para obtener microcápsulas de aceite de pescado aplicables a la industria alimentaria. Los resultados muestran una clara mejora en la eficiencia de encapsulación del aceite cuando se reduce el tamaño de gota de la emulsión y se incrementa la cantidad de material de pared de las microcápsulas. La combinación de un polisacárido con una proteína para la formación de la pared mejora la estabilidad oxidativa de las microcápsulas durante el almacenamiento. Por otra parte la adición de proteínas desnaturalizadas para reforzar las paredes de las microcápsulas ha resultado en una mejora de la eficiencia de encapsulación de aceite pero no ha mejora su resistencia mecánica
13
Pickard, R. M. „The role of omega-3 fatty acids in sheep reproduction“. Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433539.
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Matsudaira, Toshiko. „Omega-3 PUFA fatty acids and attention-deficit/hyperactivity disorder“. Thesis, King's College London (University of London), 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.748628.
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Grosso, Giuseppe. „Omega-3 fatty acids and depression: epidemiological and experimental evidence“. Doctoral thesis, Università di Catania, 2015. http://hdl.handle.net/10761/3907.
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The changes of omega-6/omega-3 polyunsaturated fatty acids (PUFA) in the food supply of Western societies occurred over the last 150 years is thought to promote the pathogenesis of many inflammatory-related diseases, including depressive disorders. Among the biological properties of omega-3 PUFA, their anti-inflammatory effects and their role on the structural changing of the brain should be taken into account to better understand the possible pathway through which they can be effective both in preventing or treating the depressive status.
The use of omega-3 supplement in depressed patients reached notable improvements during last years. Meta-analysis of 11 and 8 trials conducted respectively on patients with a DSM-defined diagnosis of major depressive disorder and patients with depressive symptomatology but no diagnosis of major depressive disorder demonstrated significant clinical benefit of omega-3 PUFA treatment compared to placebo (standardized mean difference in clinical measure of depression severity was 0.56 [95% CI: 0.20, 0.92] and 0.22 [95% CI: 0.01, 0.43], respectively; pooled analysis resulted in 0.38 [95% CI: 0.18, 0.59] standardized mean difference). Use of mainly eicosapentaenoic acid (EPA) within the preparation, rather than docosahexaenoic acid (DHA), influenced final clinical efficacy. Significant clinical efficacy had the use of omega-3 PUFA as adjuvant rather than mono-therapy. No relation between efficacy and study size, baseline depression severity, trial duration, age of patients, and study quality was found. Omega-3 PUFA resulted effective in RCTs on patients with bipolar disorder, whereas no evidence was found for those exploring their efficacy on depressive symptoms in young populations, perinatal depression, primary disease other than depression (i.e., patients with schizophrenia, Alzheimer disease, cardiovascular disease) and healthy individuals.
The systematic review of epidemiological studies exploring the possible relation of fish or omega-3 PUFA consumption resulted in findings much harder to be interpreted. A total of 28 studies, including 251,464 individuals and over 20,000 cases of depression, were examined. Among the 18 studies exploring the possible association between fish consumption and depression, 5 out of 7 cross-sectional and 6 out of 11 prospective studies reported a significant relation. A protective effect of omega-3 PUFA intake on depression was reported in 7 out of 11 cross-sectional and 4 of 9 prospective studies. The high degree of heterogeneity did not allow to support or confute the hypothesis that dietary omega-3 PUFA decrease the risk to develop depression. Future researches should into account the methodological limitations retrieved, such as i) better assessment of depressive cases, ii) detailed consumption of all PUFA and their possible interactions, and iii) consider the possibility of a non-linear relationship between fish or omega-3 PUFA intake and the risk to develop depressive disorders. Whether future findings will confirm that omega-3 PUFA consumption would result effective in prevent depressive disorders, to correct the inadequate supply of omega-3 PUFA in Westernized countries diet is a priority in order to set food and health policies and dietary recommendations for individuals and population groups.
16
Jahangiri, Anisa. „n-3 PUFAs and reperfusion injury in isolated cardiomyocytes“. Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phj251.pdf.
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"September 2002" Bibliography: leaves 207-230. Ch. 1. Literature review -- Ch. 2. General methods -- Ch. 3. Dietary n-3 PUFAs and reperfusion injury in isolated cardiomyocytes -- Ch. 4. The effect of dietary n-3 PUFAs on cardiomyocyte membrane fluidity, intracellular ROS and Ca 2+ levels during oxidative stress -- Ch. 5. The effect of dietary fish oil supplementation on antioxidant enzyme gene expression in rat myocardium -- Ch. 6. The effect of dietary lipids on ischaemia-reperfusion injury in rat myocardium -- Ch. 7. General discussion -- Ch. 8. Appendices. The broad aims of this thesis were to develop a cellular model for studying reperfusion injury, in order to investigate the reported protective effects of n-3 PUFAs, and to examine the underlying mechanisms associated with such protection.
17
Alghamdi, Fatmah. „ANALYSIS OF THE OMEGA-3 FATTY ACIDS CONTENT IN COMMERCIAL OMEGA-3 SUPPLEMENTS IN ARAB GULF COUNTRIES“. OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2571.
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The consumption of omega-3 fatty acids has increased over the past years for multiple reported health benefits. The omega-3 fatty acids of particular interest are eicosatetraenoic acid (C20:5n3; EPA) and docosahexaenoic acid (C22:6n3; DHA). High quality supplements are essential for safe intake. Studies from different countries including the United States and South Africa showed discrepancies between measured versus the claimed content of EPA and/or DHA in omega-3 supplements sold in Arab Gulf Countries. Therefore, the objective of this study was to analyze and compare the EPA and DHA content of omega-3 supplements with the contents claimed on the product label. Thirty-one commercial supplements purchased from stores in 3 different countries (Saudi Arabia, Kuwait, and Bahrain) had their fatty acid composition and content were analyzed using Gas- Chromatograph with a 100-m SP-2560 fused silica capillary column. The range of measured EPA was 5.09 mg to 469.63 mg per capsule and for DHA was 10.47 to 357.26 mg per capsule. The percentage of the stated label amount for EPA and DHA ranged from 6.5 to 138.6% and 10.9 to 126.3%, respectively. Using the U.S. Food and Drug Administration (FDA) labeling requirements where a supplement must contain at least 80% of the stated label amount of each component listed, only 43.8% of the supplements were compliant for EPA and 40.6% were compliant for DHA. Additionally, only 21.9% of the measured EPA and DHA fall within the 10% of the stated label amount. These results demonstrate the wide variability between the stated label amounts of EPA and DHA in omega-3 supplements sold in Arab Gulf Countries and the need for governmental agencies to perform testing to ensure compliance.
18
Qadir, Abdul. „The effects of endotoxaemia and omega-3 fatty acids on membrane fatty acids and cardiac G-proteins“. Thesis, University of Aberdeen, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300911.
Annotation:
Dietary manipulation was undertaken with the aim of influencing membrane composition and improving adrenergic dysfunction. The objective was to explore the effects of 5 days of continuous intra-duodenal feeding of diets containing n-3 PUFA on myocyte membrane phospholipids, contractility and G-protein. The control diet was omega-6 (n-6) PUFA from safflower oil. The animals were infused with either saline or endotoxin (1 mg/kg) in the last 24 hours. The diets resulted in incorporation of lipids with alteration in myocyte membrane lipid composition. The relative percentage of n-3 PUFA was increased in the fish oil group (22.61± 1.30, 20.46±1.35 for control and endotoxin) compared to safflower oil group (15.21±1.77, 14.16±0.56 for control and endotoxin). The mean inotropic response to isoprenaline was improved by feeding of n-3 PUFA enriched diets (0.175±0.027 for safflower oil endotoxin group vs 0.264±0.03 for safflower oil control, 0.261±0.064 for fish oil control and 0.275±0.073 for fish oil endotoxin group). The adenylyl cyclase activity on forskolin stimulation was not affected by diet or endotoxin (0.165±0.036, 0.176±0.058 for safflower control and endotoxin, and 0.163±0.036, 0.173±0.017 for fish oil control and endotoxin). The data on forskolin stimulation suggested distal contractile mechanisms were intact and that the defect in βAR signal was occurring at a site proximal to adenylyl cyclase. Sodium fluoride, a direct activator of G-proteins revealed a much greater degree of stimulation in the fish oil endotoxin group compared to the safflower oil endotoxin group (0.013±0.030 for safflower oil endotoxin, 0.053±0.015 for fish oil endotoxin and 0.055±0.022 for safflower oil control, 0.088±0.26 for fish oil control). The mean relative percentage of Gαo subunits was reduced in fish oil endotoxin group compared to safflower oil endotoxin group (16.65±3.01 for fish oil endotoxin, 25.37±1.29 for safflower oil endotoxin and 15.63±0.91 for safflower oil control, 13.06±2.70 for fish oil control). In summary, n-3 PUFA improve βAR transmembrane signal in endotoxaemia by favourably altering G-regulatory proteins possibly through membrane displacement of n-6 fatty acids.
19
Rodrigues, Ana Sofia de Figueiredo. „Industrial production of omega-3 polyunsaturated fatty acids from fish oil and microalgae“. Master's thesis, ISA/UTL, 2012. http://hdl.handle.net/10400.5/5257.
Annotation:
Mestrado em Engenharia Alimentar - Instituto Superior de Agronomiaω-3 polyunsaturated fatty acids (PUFAs) ingredients, especially eicosapentaenoic acid (EPA, 20:5ω3) and docosahexaenoic acid (DHA, 22:6ω3) are known for its vital and unique role in human health and well-being by an extensive scientific research. These facts are widely spread by media. At present, the major source of ω-3 PUFAs is fish oil from oily fish like sardine (Sardina pilchardus). This work proposes the use of heterotrophic microalgae such as Crypthecodinium cohnii as an alternative source of interest for the commercial production of ω-3 EPA and DHA. It is also suggested the use of a common process suitable for both feedstock. EPA and/or DHA production are accomplished through oil saponification and PUFAs concentration winterization and urea concentration. PUFAs purification by chromatography is only necessary when oil is extracted from fish since fractions obtained from C. cohnii have high proportions in DHA and they do not require further purification steps for food applications. The combination of traditional (seasonal) and alternative sources (year-round) using a common production process shows an economic advange with increasing earnings for market development.
20
Asch, Ruth H. „Neurodevelopmental Consequences of Maternal Omega-3 Fatty Acid Deficiency“. University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1583154907162725.
21
Abad, Sánchez Sergi. „Biotechnological production of polyunsaturated fatty acids omega-3 by heterotrophic microalgae“. Doctoral thesis, Universitat Ramon Llull, 2017. http://hdl.handle.net/10803/400556.
Annotation:
La tesi descriu el desenvolupament d’un procés biotecnològic per a l’obtenció d’àcids grassos poliinsaturats (PUFA) omega-3 mitjançant microalgues heterotròfiques. El microorganisme seleccionat és l’Aurantiochytrium limacinum SR21 degut a la seva capacitat per produir PUFA, créixer utilitzant fonts de carboni de rebuig i tolerar medis amb elevades salinitats. Durant la investigació descrita en aquesta tesi, diversos mètodes analítics han estat desenvolupats per tal de monitoritzar el creixement d’ A. limacinum. Diferents eines de disseny d’experiències i modelatge com les matrius ortogonals de Taguchi, les Xarxes neuronals artificials i les superfícies de resposta, han estat utilitzades per desenvolupar el medi de cultiu específicament per A. limacinum. En lloc d’utilitzar les fonts de carboni tradicionals, el procés biotecnològic ha estat desenvolupat utilitzant un subproducte industrial com és el glicerol cru.
Les mateixes eines de disseny i modelització han estat utilitzades per determinar les millors condicions d’aeració i agitació per a estimular la producció d’àcid Docosahexaenoic (DHA). S’han estudiat diferents estratègies de cultiu com el batch, fed-batch, continuous and “multi-stage” continuous reactor per determinar quina ofereix una millor productivitat de DHA. Els cultius operats en batch i fed-batch han generat el major rendiment de DHA (g DHA/ g biomassa). Contràriament, els reactors continus han ofert majors productivitats de DHA DHA (g DHA/l·h), especialment els “multi-stage”. Utilitzant l’estratègia “multi-stage”, el primer bioreactor es programa per estimular la producció de biomassa mentre que els següents bioreactors s’orienten a la producció de DHA.
El productes de DHA que es comercialitzen actualment, estan formulats com a esters metílics o triglicèrids re-esterificats, però en cap cas com a triglicèrids naturals extrets sense modificar. En aquesta tesis es presenta una proposta de purificació per cromatografia (a escala industrial i de laboratori) per tal d’obtenir triglicèrids naturals amb cadenes de DHA.La tesis describe el desarrollo de un proceso biotecnológico para la obtención de ácidos grasos poliinsaturados (PUFA) omega-3 mediante microalgas heterotróficas. El microorganismo seleccionado es Aurantiochytrium limacinum SR21 debido a su capacidad para producir diferentes PUFA, crecer utilizando subproductos Industriales y su tolerancia a elevadas salinidades. Durante la investigación descrita en esta tesis, diferentes métodos analíticos fueron desarrollados para monitorizar el crecimiento de A. limacinum. Diferentes herramientas de diseño de experiencias y modelización tales como, matrices ortogonales de Taguchi, redes neuronales artificiales o superficies de respuesta, han sido utilizadas para desarrollar el medio de cultivo específico para A. limacinum. En lugar de utilizar fuentes de carbono tradicionales, el proceso biotecnológico se ha desarrollado utilizando un subproducto industrial como el glicerol crudo. Las mismas herramientas de diseño y modelización han sido utilizadas para determinar las mejores condiciones de aireación y agitación para estimular la producción de ácido docosahexaenoico (DHA). Se han estudiado diferentes estrategias de cultivo como el batch, fed-batch, continuo y “multi-stage” continuo para determinar cual ofrece mayores productividades de DHA. Los cultivos operados en batch y fed-batch han ofrecido mejores rendimientos de DHA (g DHA/ g biomasa). Sin embargo, los cultivos operados en continuo han ofrecido una mayor productividad de DHA (g DHA/l·h). Utilizando la estrategia de cultivo continuo “multi-stage”, el primer biorreactor se orienta a la producción de biomasa y los siguientes biorreactores se programan para la estimulación de producción de DHA. Los productos de DHA que se comercializan actualmente, se formulan como esteres metílicos o triglicéridos re-esterificados, pero en ningún caso como triglicéridos naturales sin modificar. En esta tesis se presenta una propuesta de purificación por cromatografía (a escala industrial i de laboratorio) para obtener triglicéridos naturales con cadenas de DHA.
This dissertation describes the development of a biotechnological process to obtain polyunsaturated fatty acids (PUFA) omega-3 by heterotrophic microalgae. The selected heterotrophic microorganism was Aurantiochytrium limacinum SR21 due to its capacity to produce PUFA, grow with different carbon sources and tolerate high salinity. During the thesis investigation, diverse analytical methods have been developed in order to monitor A. limacinum growth. Moreover, different experimental design strategies/tools, such us Taguchi orthogonal matrices, Artificial neural network, Response surface methodology, etc. have been used to develop a growth medium specifically optimized for A. limacinum. Instead of using traditional carbon sources, the process has been developed to grow A. limacinum with crude glycerol, an industrial by‐product. The same experimental design tools served to find the best oxygen supply conditions to stimulate either biomass or DHA production. Batch, fed‐batch, continuous and multi‐stage continuous bioreactors have been studied to find the most prolific strategy. Batch and fed‐batch reactor generated the highest DHA yields (g DHA /g biomass). However, continuous cultivations produced higher DHA productivity values DHA (g DHA/l·h), especially the multi‐stage strategy. In a multi‐stage, continuous bioreactor, the first tank/s were dedicated to biomass production whereas the following tanks were set to stimulate DHA production. DHA products currently in market are formulated as DHA methyl esters or re‐esterified triglycerides, but not as unmodified triglycerides. In this thesis, an approach for preparative and process scale chromatography purification of unmodified triglycerides containing DHA has been developed.
22
Mulder, Kelly Ann. „The complex relationship between omega-3 fatty acids and early neurodevelopment“. Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54842.
Annotation:
Docosahexaenoic acid (DHA, 22:6ω-3) is an omega-3 fatty acid that is an important component of neural lipids accumulating in neural tissue during development. Decreased brain DHA is accompanied by increased 22:4ω-6 and 22:5ω-6, which has been shown to lead to deficits in neural function. However, dietary and other variables may impact DHA status and the potential for early deficiency to have lasting adverse effects on neurodevelopment remains unclear. Therefore, the effect of prenatal DHA and children’s DHA intake and status on neurodevelopment was examined.
Pregnant women, n=271, were enrolled at 16 wk gestation and randomized to 400 mg/day DHA or placebo until delivery. Infant neurodevelopment was assessed at multiple time-points until 18 mo. Children returned for follow-up between 5-6 y (n=98). An additional group of 187 children (5-6 y) was enrolled at the same time to increase the sample size. Venous blood was collected, diet was assessed by food frequency questionnaire, and neurodevelopment was assessed.
Infants from the placebo group were less likely to achieve high neurodevelopmental test scores up to 18 mo than infants from the DHA group (OR=2.23-3.22, P<0.05), suggesting that fetal DHA inadequacy occurred in our population. No differences were detected in children (5-6 y, n=98) from the placebo and DHA groups achieving a high neurodevelopment test score (P>0.05). However, child DHA intake and status (n=98) were related to the mother’s intake and status during pregnancy. For all children (n=285), DHA intake was positively associated with erythrocyte DHA. Child DHA status was associated with neurodevelopment test scores, but only short-term memory was associated with dietary DHA. These results suggest that DHA low enough to constrain infant neurodevelopment to 18 mo does occur among pregnant women in Vancouver, but the long-term effects remain unclear. We also provide evidence that DHA status is related to cognitive performance in young children. However, the association of maternal and child DHA intake and status limits the interpretation of whether DHA before or after birth is important. Finally, the variability in erythrocyte DHA was high, raising questions about the relationship between DHA intake and other fatty acids, DHA status, and neural function.Land and Food Systems, Faculty of
Graduate
23
Broughton, Richard. „Omega 3 fatty acids : identification of novel fungal and chromistal sources“. Thesis, Royal Holloway, University of London, 2012. http://repository.royalholloway.ac.uk/items/38797691-c5ac-ef52-3a6c-12c3097e2765/6/.
Annotation:
There is a wealth of scientific evidence associating the dietary intake of omega 3 long-chain polyunsaturated fatty acids with beneficial health properties. In this study, alternative natural sources of these polyunsaturated fatty acids are sought from novel low temperature isolated fungi. Over 100 low temperature isolated fungi were screened for very long chain polyunsaturated fatty acids (VLCPUF As), such as C20:5 n3 and C22:6 n3. Of those screened, only ten fungi were capable of VLCPUFA production, with Mortierella the predominant VLCPUF A producing species. Four Oomycete species were also capable of VLCPUF A production. It is thought that only basal fungal lineages, such as species from the Chytridiomycota and Zygomycota, are capable of VLCPUF A production. It was also found that VLCPUF As are not essential for growth at low temperatures, as Penicillium rugulosum, capable of producing 'fatty acids no longer or more unsaturated than C18:3 n3, demonstrated over 2 g of biomass per 100 ml of broth when grown at 5°C. This indicates that trienoic fatty acids are sufficient for maintaining membrane fluidity, although other factors may play a role in P. rugulosum's low temperature growth. Comparatively, VLCPUFA producing Mortierella species produced 200-250 mg of biomass, whereas the majority of non- VLCPUF A producing isolates produced 106-115 mg of biomass per 100 ml of broth. The total lipid unsaturation indices of nine isolates grown under three temperature regimes showed that the lowest growth temperature, 5°C, produced the highest un saturation index value III SIX of the organisms. 15°C produced the highest unsaturation index value in two of the isolates. This suggests that temperature has an effect on fungal lipid composition, and that lower temperatures may increase lipid unsaturation levels. It was also found that the ~6 elongase, initially identified from Mortierella alpina, is indicative for VLCPUF A producing fungi. The genomic conserved sequence found within ~6 elongases was used to develop primer sets that could be used with a PCR based methodology to screen fungal isolates for VLCPUF A production. The method successfully identified VLCPUF A producing Mortierella and Allomyces species, and was not found to amplify non-Ad elongases. Finally, recombinantPhaffia rhodozyma strains were developed using the ~5 desaturase and ~6 elongase from Mortierella alpina. The fatty acid profiles of the recombinant strains displayed novel fatty acids such as C20:2 n6 and C20:3 n3, and putatively, C18:2 ~5, 9 and C18:3 ~5, 9, 12 which correlated with the inserted genes.
24
Din, Jehangir Nasim. „Vascular and antithrombitic effects of omega-3 fatty acids in man“. Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/24525.
Annotation:
Background: Dietary intake of omega-3 fatty acids is associated with a reduction in cardiovascular events. The mechanisms for this are uncertain and previous studies investigating effects on vascular function and thrombosis have produced inconsistent results. We aimed to study the effect of omega-3 fatty acids on endothelial vasomotor function, endogenous fibrinolysis and platelet activation in man. Methods: Firstly, we assessed the effect of dietary intervention with fish rich in marine-derived omega-3 fatty acids on platelet activation in 14 healthy volunteers, using flow cytometric analysis of platelet-monocyte aggregates. Secondly, we investigated the effect of dietary intervention on both platelet-monocyte aggregates and arterial stiffness in a single-blind randomised crossover trial with 30 healthy volunteers. Thirdly, we performed double-blind randomised controlled trials to assess the effect of dietary supplementation with omega-3 fatty acid capsules on endothelial function, endogenous fibrinolysis and platelet-monocyte aggregates in 20 healthy smokers and 20 patients with stable ischaemic heart disease. Endothelial function was assessed using venous occlusion plethysmography during intra-arterial infusions of Substance P, acetylcholine and sodium nitroprusside. Endogenous fibrinolysis was assessed by measuring stimulated release of tissue plasminogen activator (t-PA) from the forearm vasculature during substance P infusion. Results: Dietary intervention with fish rich in marine-derived omega-3 fatty acids reduced platelet-monocyte aggregates in healthy volunteers (16.0±9.0% versus 24.8±10.9%, P < 0.01). Dietary intervention with walnuts rich in plant-derived omega-3 fatty acids did not affect platelet-monocyte aggregates or arterial stiffness in healthy volunteers. Supplementation with omega-3 fatty acid capsules increased endothelium-dependent vasodilatation (P=0.032) and stimulated t-PA release (P < 0.01) in healthy smokers. There was no effect on platelet-monocyte aggregates. Supplementation with omega-3 fatty acids did not affect endothelium-dependent vasodilatation, t-PA release or platelet-monocyte aggregates in patients with stable ischaemic heart disease. There was a marked increase in plasma concentrations of marine-derived omega-3 fatty acids during dietary intervention with oil-rich fish and supplementation with omega-3 fatty acid capsules (P < 0.0001). Discussion: We have demonstrated that dietary intervention with oil-rich fish reduces platelet-monocyte aggregates in healthy volunteers. Dietary intervention with walnuts did not have any effect on platelet-monocyte aggregates or arterial stiffness. Supplementation with omega-3 fatty acids improved endothelial function and endogenous fibrinolysis in healthy smokers, but had no effect on platelet-monocyte aggregates. Omega-3 fatty acids did not affect endothelial function, endogenous fibrinolysis or platelet-monocyte aggregation in patients with ischaemic heart disease.
25
Orders, Margaret. „Fate of Omega-3 Fatty Acids from Algae in Mozzarella Cheese“. Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/34829.
Annotation:
Increased consumer interest in omega-3 fatty acids (FA) has led to novel foods with added omega-3 FA. Additional information regarding omega-3 FA fate within foods is needed for improving quality and stability. This research modeled DHA, an omega-3 FA, fate and explored means of preventing degradation and oxidation of FA in algal oil and mozzarella cheese.
In algal oil, TBHQ (synthetic antioxidant) at 0.0175g/g algal oil prevented DHA degradation for at least 6 weeks, and mixed tocopherols (natural antioxidant) at 400ppm prevented DHA degradation and oxidation for about 4 weeks. DHA degradation in algal oil was modeled by an autocatalytic equation.
The fate of DHA from algal oil in mozzarella cheese was also modeled by an autocatalytic equation. In an effort to prevent DHA degradation and oxidation, mixed tocopherols were added. The optimum combination of those tested was found, using a response surface design, to be 3% algal oil with 110ppm mixed tocopherols for maximum DHA and minimum oxidation over 2 weeks. This algal oil/antioxidant combination in mozzarella cheese successfully prevented oxidation and DHA degradation over 3 weeks of storage. Approximately 0.1g DHA may be consumed from a 28g serving of this cheese. Approximately 0.5-18 servings of this cheese are equivalent to DHA consumed from a 3oz serving of fish, depending on fish type. Sensory evaluation tests found consumers could distinguish between mozzarella cheese with/without algal oil. Results from this study improve understanding of omega-3 FA behavior in mozzarella cheese and provide a means for preserving quality and nutrition.
Master of Science
26
Ren, Hui Xia. „Neuroprotection of ω-3 polyunsaturated fatty acids in brain disorders“. Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3953276.
27
Hanson, Jennifer Ann. „Omega-3 fatty acids and cognitive outcomes in soldiers deployed to combat areas“. Diss., Kansas State University, 2011. http://hdl.handle.net/2097/12016.
Annotation:
Doctor of PhilosophyDepartment of Human Nutrition
Mark D. Haub
Mark D. Haub
Psychological problems and human error are leading causes of death and disability among military service members. Strategies to improve the psychological health and cognitive performance of those in the military are much needed. Recent advances in neuroscience suggest that omega-3 fatty acids may play an important role in the psychological well-being of those in the military. The purpose of this research was to explore the relationship between omega-3 status and psychological outcome variables among soldiers deploying to combat. Data collection was preceded by the development and reliability testing of a novel food frequency questionnaire (FFQ) designed to capture intake from contemporary sources of omega-3 fatty acids including functional foods and supplements. Based on the instrument assessment study (Chapter 2) conducted among university students (n = 165), this FFQ appears to be a comprehensive and reliable (n = 54, ρ = 0.86, p < 0.001) instrument for measuring docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) intakes in young adults. As described in Chapter 3, intake of EPA + DHA as estimated by the FFQ was positively correlated (r = 0.39, p < 0.001) with biomarker measurements of omega-3 status. Primary data were obtained from a volunteer sample of soldiers (n = 272) scheduled for deployment to Iraq. Preliminarily analyses revealed relationships between attention deficit hyperactivity disorder (ADHD) screening scores and psychological outcome variables (Chapter 4). Primary analyses (Chapter 5) indicated intake of EPA + DHA was not significantly correlated with mood, nor were omega-3 exposure variables correlated with cognitive performance based on the required p value (< 0.001) calculated using the Bonferroni correction for multiple tests. Among participants with EPA + DHA intakes at or below the median, omega-3 HUFA was related (p < 0.002) to happiness (β = -0.46), depression (β = 0.44), and fatigue (β = 0.43). Although exploratory in nature, the results of this study suggest a relationship between omega-3 fatty acids and mood. Given the current concerns regarding the psychological health of those in the military, additional research is warranted.
28
Hawkes, Joanna Susan. „N-3 fatty acids, eicosanoids and control of inflammation /“. Title page, contents and summary only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phh392.pdf.
Annotation:
Thesis (Ph. D.)--University of Adelaide, Dept. of Clinical and Experimental Pharmacology, and Rheumatology Unit, Royal Adelaide Hospital, 1994.Errata slip inserted. Includes bibliographical references (leaves 178-199).
29
Moore, Robert Lee. „Antioxidant Protection of an Omega-3 Fatty Acid Fortified Dairy-Based Beverage“. Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/36376.
Annotation:
Skim, butter-derived aqueous phase, anhydrous milk fat, and fish oil were used to
formulate ultra high temperature (UHT) processed extended shelf-life omega-3 fatty acid
fortified dairy-based beverages with fat contents mimicking whole milk (3.25%).
Oxidation of the lipids in the formulated beverages was investigated during storage for 35
days at 4 °C using GC/MS analysis, conjugated diene analysis, and headspace solid phase
micro-extraction GC/MS (SPME-GC/MS) analysis of headspace. Omega-3 fatty acid
fortified dairy-based beverages were produced that mimicked the physical properties of
3.25% fat whole milk. Oxidation resulted in only small changes in omega-3 lipid content
and sensory analysis by an untrained panel indicated that the overall aroma was no
different than that of commercially available UHT processed milk. An omega-3 fatty acid
fortified dairy-based beverage was produced that delivered 440mg of omega-3 fatty acid
per 8oz serving. When consumed daily, the beverage could provide the equivalent
amount of omega-3 fatty acids recommended by the American Heart Association, and the
equivalent amount of omega-3 fatty acids found in two fatty fish meals over the period of
one week.
Antioxidants were added to the lipid phase, immediately prior to processing, of
additionally produced formulations to determine if a reduction in omega-3 lipid oxidation
was observed. No overall reduction in oxidation was observed, as indicated by GC/MS
and SPME-GC/MS analysis. Sensory analysis indicated that oxidative aromas increased
during storage for the antioxidant and omega-3 fatty acid fortified dairy-based beverage.
Ascorbyl palmitate was determined to have a pro-oxidative effect on the formulated
omega-3 fortified dairy-based beverages. Antioxidants present in the commercial grade
fish oil used for fortification were effective in controlling oxidation in the formulated
omega-3 fatty acid fortified dairy-based beverages.
Master of Science
30
Wanasundara, Udaya Nayanakantha. „Marine oils : stabilization, structural characterization and omega-3 fatty acid concentration /“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ54853.pdf.
31
Kimono, Diana Agnes. „The production of Omega 3 fatty acids by a mixed microalgae culture“. Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/6498.
Annotation:
Background and Aim: Microalgae are a potential economical source of omega-3 fatty acids, which are known for their health benefits. Omega-3 fatty acids derived from microalgae are however still expensive due to high costs involved in production. These costs can partly be attributed to cultivation of microalgae in unialgal cultures, which are prone to contamination, difficult to scale up and require stringent control of growth conditions. This study therefore is aimed to investigate the feasibility of using a mixed microalgae culture for the production of omega-3 fatty acids. Methods and materials: The microalgae were grown under uncontrolled conditions in a hanging-bag photo-bioreactor, with only the phosphorus-nitrogen ratio (P:N-ratio) varied. Variations in the different population proportions in the culture were studied and related to the biomass, total fatty acid and omega-3 fatty acid productivity of the culture. Finally, a comparison was made between the results obtained in this study and similar studies found in literature. Results and discussion: The mixed culture used was composed of several green microalgae, whose proportions varied with P:N-ratio, season, and age of the culture. Different interactions between the populations were observable, and these were thought to influence the culture’s biomass, total fatty acids (TFAs) and omega-3 fatty acid productivity. The TFA content of the culture was ~10-20% by the end of the exponential phase, depending on the nutrients supplied. The fatty acids were composed of mostly unsaturated fatty acids, the majority of which were omega-3 fatty acids; C18:3ω3 (up to 50% of TFA), C16:4ω3 (up to 15%) and C18:4ω3 (up to 5%). Other fatty acids observed included C16:0 (up to 25%), C18:1ω9/C18:1ω8 (up to 20%), C18:2ω6 (up to 5%), traces of C18:0, C18:3ω6, C17:0, C16:3ω3 and C16:1ω7 were also detected. The presence of these fatty acids was found to vary depending on season, P:N-ratio, and age of the culture. When compared to studies in the literature, the mixed culture was found to perform better than, or as well as reported studies, where unialgal cultures were cultivated under controlled laboratory conditions. Conclusion: In view of the reported advantages of cultivating mixed cultures, the production of omega-3 fatty acids via such cultures appears attractive. More research however is needed to optimise the culture; study interactions between the organisms and their effect on biomass, total fatty acid and omega-3 fatty acid productivity. Finally, the economic implications of using mixed cultures need to be evaluated as well.
32
Peoples, Gregory Edward. „Skeletal muscle fatigue can omega-3 fatty acids optimise skeletal muscle function? /“. Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20041217.123607.
Annotation:
Thesis (Ph.D.)--University of Wollongong, 2004.Typescript. This thesis is subject to a 12 month embargo (06/09/05 - 14/09/05) and may only be viewed and copied with the permission of the author. For further information please contact the Archivist. Includes bibliographical references: leaf 195-216.
33
Hartweg, Janine. „Omega-3 polyunsaturated fatty acids on cardiovascular disease in type 2 diabetes“. Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504428.
34
Vaezi, Royah. „Enhancing the production of omega-3 polyunsaturated fatty acids in marine diatoms“. Thesis, University of East Anglia, 2015. https://ueaeprints.uea.ac.uk/53379/.
Annotation:
The primary producers of essential omega-3 polyunsaturated fatty acids are marine microalgae, which form the base of the aquatic food web. One alternative source of our ever diminishing stocks of fish and fish oil is via the cultivation of these microorganisms. Unfortunately, these microalgae, of which diatoms are the dominant class, only accumulate oil during specific stages of their life-cycle and/or under nutritional states which are incompatible with the required high density of growth and target fatty acid profile. Additionally, the endogenous levels of desirable fatty acids such as eicospantaenoic acid (EPA; 20:5, n-3) and docosahexaenoic acid (DHA; 22:6, n-3) are usually relatively modest (in the range of 10-35% of total fatty acids) and therefore present an opportunity for enhancement. A database search carried out on the genomes of omega-3-producing unicellular photoautotrophic green alga Ostreococcus sp. RCC809 and cold-water diatom Fragilariopsis cylindrus led to the identification of four novel genes involved in omega-3 biosynthesis. These genes encoded an omega-3-specific Δ6-desaturase, a Δ4-desaturase, a Δ6-elongase and a Δ5- elongase. Overexpression of genes encoding Δ6-desaturase and Δ6-elongase activities in Thalassiosira pseudonana impacted the fatty acid and acyl-CoA profiles of this model centric diatom. Changes to chloroplast and lipid droplet phenotype were also observed. Targeted knock-down of native genes involved in the omega-3 biosynthetic pathway was carried out in T. pseudonana to further understand endogenous omega-3 fatty acid production. Cells targeted for the knock-down of Δ9-desaturase exhibited a drastically altered growth phenotype, but maintained a wild type-like fatty acid profile. This phenotype was attributed to the possibility of another, functionally redundant, protein that escaped sequence-based silencing, masking the knock-down of Δ9-desaturase. The results and observations provided in this thesis contribute new valuable information to the field of lipidomic research in microalgae, breaking new ground in metabolic engineering of lipid metabolism in diatoms.
35
Tachtsis, Bill. „Protective effects of omega-3 fatty acids against skeletal muscle cell lipotoxicity“. Master's thesis, Australian Catholic University, 2020. https://acuresearchbank.acu.edu.au/download/13b52b5e5ba427fd260a4ecb3eebffc1933ecec189f6919b225d92214d93a8bb/2055279/Tachtsis_2020_Protective_effects_of_omega-3_fatty_acids.pdf.
Annotation:
Skeletal muscle is a highly malleable tissue with the capacity to alter its phenotype in response to exercise and nutrient availability. Adult skeletal muscle is primarily composed of terminally differentiated post-mitotic cells and relies on specialised muscle stem cells (satellite cells) to facilitate repair and regeneration. Satellite cell regenerative capacity is impaired by diets enriched with high concentrations of saturated fat as well as other environmental lifestyle factors such as obesity and physical inactivity. Omega-3 polyunsaturated fatty acids (n-3 PUFAs), commonly found in fish oil supplements, possess anti-inflammatory properties and have been shown to improve aspects of skeletal muscle function and metabolism. These protective properties have established n-3 PUFAs as a potential dietary supplement strategy to help combat muscle wasting and promote muscle growth and repair. However, the cell signalling pathways underlying their efficacy in skeletal muscle cells are not completely understood.
This Master’s thesis comprises a published review of the literature pertaining to the potential roles of n-3 PUFAs during muscle growth and regeneration, and an original research study investigating and comparing the purported beneficial protective effects of n-3 PUFAs in skeletal muscle cells against lipotoxicity induced by the saturated fatty acid palmitate (PAL). The experimental data collected for this thesis demonstrate that the n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), commonly found in fish oil supplements, protect skeletal muscle cells against the deleterious effects of PAL. Furthermore, the work in this thesis provide novel data regarding the beneficial effects and potential mechanisms of Docosapentaenoic acid (DPA), a lesser studied intermediary n-3 PUFA, on maintaining skeletal muscle cell viability in an environment of high fat availability.
The results obtained demonstrate that all n-3 PUFAs induce protective effects against the deleterious effects of PAL on skeletal muscle cell viability and subsequent differentiation capacity. However, DPA confers the greatest protection against the induction of PAL-induced ER stress. Mechanistically, DPA protects against PAL-induced cytotoxicity via maintaining muscle cell mitochondrial membrane integrity.
In the context of the previous literature overviewed in the published review article, these data contribute important novel findings demonstrating that all n-3 PUFAs including DPA protect skeletal muscle cells in vitro against stimuli known to be deleterious to skeletal muscle growth and repair in vivo. These data also reveal that DPA has the potential to elicit superior protective effects against lipotoxicity compared to EPA and DHA, setting the stage for further research into the mechanisms underlying DPA’s beneficial effects and potential future therapeutic applications in fish oil supplements to help promote muscle growth, maintenance and repair.
36
Radhakrishnan, Ganesh Kumar. „Produktion av fettsyror i mikrobiella system“. Thesis, KTH, Skolan för bioteknologi (BIO), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-163698.
37
Orchard, Tonya Sue. „Fatty Acids and Risk of Fracture in Postmenopausal Women“. The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306513275.
38
Jor, Wing-yan Irene. „Proteomic analysis of the effects of omega-3 fatty acids on human hepatocarcinoma“. Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/b40204042.
39
Jor, Wing-yan Irene, und 左穎欣. „Proteomic analysis of the effects of omega-3 fatty acids on human hepatocarcinoma“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40204042.
40
Zhang, Jinwei. „The diversity and biotechnological application of marine microbes producing omega-3 fatty acids“. Thesis, University of Newcastle upon Tyne, 2011. http://hdl.handle.net/10443/2394.
Annotation:
Omega-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA, 20:5ω3) and docosahexaenoic acid (DHA, 22:6ω3) play a role in the modulation and prevention of human diseases, in particular cardiovascular diseases. The omega-3 family is found mainly in fish, of which wild stocks are becoming limited. Therefore production of omega-3 PUFAs by marine microbes may provide an alternative source of such componds. The diversity of marine microbes was studied using 16S/18S rRNA gene sequencing of different marine biota with 1500 bacterial strains and 50 microalgae were isolated. The diversity of culturalbe microorganisms inhabiting Mid-Atlantic Ridge (MAR) non-vent sediments was examined for the first time in this area with findings of high diversily of Gram-positive strains, good production of squalene by an unusual strain Bacillus sp. MAR089 and the highest yield of EPA ever recovered from strain Shewanella sp. MAR441. North Sea sponge associated Vibrio sp. strain NSP560 produced considerable levels of EPA, whereas no PUFAs producers were found from tropic Caribbean marine sponge associated bacteria. Photobacterium sp. strain MA665, isolated from the coast of North Sea, was described for the first time of this genus and could be cultured easily under atmospheric conditions with appreciable levels of EPA -1 with up to 25 % of total fatty acids (TFA) (or 10.6 mg g in dried cell). Strain MAR441 was identified as a new species, designated as Shewanella dovemarina sp. T nov. (Type strain MAR441 ). The level of EPA production of strain MAR441 has been optimized by varying fermentation conditions, and 15-25 % EPA of TFA (or 17-30 mg -1 g in dried cell) could be achieved with 40 % improvement. In order to understand the PUFAs biosynthesis pathways and better predict the maximum EPA production, EPA gene clusters (pfaA, pfaB, pfaC, pfaD and pfaE) were cloned and sequenced from the following three species Shewanella, Vibrio and Photobacterium. Great potential was found in marine algae Phaeodactylum tricornutum strain M7 with lipid content of 10 % in dry wt biomass and 22-30 % EPA of TFA when it was cultured outdoors under local weather conditions in UK. Under anaerobic conditions, strain MAR441 contained less -2 amount of EPA and produced electricity of ~100 mW m . Enhanced electricity production using artificial consortia of estuarine bacteria grown as biofilms was -2 observed with power generation of ~200 mW m . In conclusion, bacteria taxonomic resolution based on complete cell fatty acid composition is possible and marine microbes with considerable production of EPA could be potential candidates for industrial production of PUFAs.
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Ethier, Shannon Elizabeth. „Producing Omega-3 Polyunsaturated Fatty Acids from Biodiesel Waste Glycerol by Microalgae Fermentation“. Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/32716.
Annotation:
Crude glycerol is a major byproduct if the biodiesel industry. Biodiesel manufacturers are currently facing the challenges of appropriate disposal of this waste material. Crude glycerol is expensive to purify for use in food, cosmetic, and pharmaceutical industries and therefore, alternative methods for use of this crude glycerol are needed. A promising alternative is to use this crude glycerol as a carbon source for microalgae fermentation.
In this project, we investigated the use of crude glycerol as a less expensive substrate for the fermentation of the microalgae Schizochytrium limacinum and Pythium irregulare which are prolific producers of omega-3 polyunsaturated fatty acids. Omega-3 fatty acids have many beneficially effects on treating human diseases such as cardiovascular diseases, cancers, and neurological disorders. In addition, the omega-3 fatty acids docosahexaenoic acid (DHA) has been shown to be an important factor in infant brain and eye development.
The first part of this study focused on the continuous fermentation of S. limacinum, a prolific producer of DHA. The objective of this study was to examine the algal cellular physiology and maximize its DHA productivity. Two important parameters used in continuous fermentation were studied: dilution rate (D) and feed glycerol concentration (S0). The highest biomass productivity of 3.88 g/L-day was obtained at D = 0.3 day-1 and S0 = 60 g/L, while the highest DHA productivity (0.52 g/L-day) was obtained at D = 0.3 day-1 and S0 = 90 g/L. The cells had a true growth yield of 0.283 g/g, a maximum specific growth rate of 0.692 day-1, and a maintenance coefficient of 0.2216 day-1.
The second part of this study focused on morphology issues with P. irregulare, a prolific producer of eicosapentaenoic acid (EPA). P. irregulare has a filamentous morphology, which can make fermentation difficult. The mycelium can stick to the agitation blades resulting in mechanical problems. In addition, this filamentous morphology prevents adequate amounts of oxygen from reaching some cells resulting in decreased productivities. The focus of this research was to control the fermentation conditions to make the algae grow in small pellets, a morphology more suitable for fermentation. In flask culture studies, pellets were formed at an agitation speed of 110 rpm in both regular and baffled flasks. Baffled flasks resulted in pellet formation at 90 and 130 rpm as well. Fermentation studies resulted in pellet formation at agitation speeds of 150 and 300 rpm. Pellets were better able to form when a baffle was not in place. In addition, agitation speed influenced pellet size, with smaller pellets forming at the higher agitation speed.
Overall, this study showed that crude glycerol can be used as a carbon source for the continuous fermentation of S. limacinum with high DHA productivity and the morphology of P. irregulare could be controlled by manipulating culture conditions, mainly agitation speed. These results show the potential for scale-up studies for both algal species.Master of Science
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Eratte, Divya. „Co-encapsulation of Omega-3 fatty acids and probiotic bacteria through complex coacervation“. Thesis, Federation University Australia, 2016. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/156001.
Annotation:
The research described in this thesis investigated the microencapsulation of omega-3 oil and probiotic bacteria together in a protein-polysaccharide complex coacervate matrix. The synergistic or competitive interactions between the probiotic bacteria and omega-3 fatty acids when packaged in a single microcapsule was determined including how best to utilise such interaction to achieve improved oxidative stability of omega-3 fatty acid and better survival of the probiotic bacteria. Encapsulation and co-encapsulation of tuna oil (O) and Lactobacillus casei 431 (P) as models of omega-3 and probiotic bacteria, respectively, were carried out and the works is described in this thesis in five distinct sections. (1) The optimisation of the complex coacervation process between whey protein isolate (WPI) and gum Arabic (GA). (2) Microencapsulation of tuna oil (O) in WPI-GA complex coacervates followed by spray and freeze drying to produce microcapsules (WPI-O-GA). (3) Microencapsulation of probiotic bacteria L. casei 431 (P) in WPI-GA complex coacervates followed by spray and freeze drying to produce microcapsules (WPI-P-GA). (4) Co-encapsulation of omega-3 oil and L. casei 431 together in WPI-GA coacervate matrix followed by spray and freeze drying to produce co-microcapsules (WPI-P-O-GA). (5) In-vitro digestion evaluation of co-microcapsules and microcapsules to indicate bioavailability. The viability of L. casei was significantly higher in WPI-P-O-GA co-microcapsules than in WPI-P-GA microcapsules in both spray and freeze dried microcapsules. The oxidative stability of tuna oil was significantly higher in spray dried co-capsules. Also, co-microencapsulation increased the survivability of L. casei during simulated digestion. There was no significant influence observed on the release properties of omega-3 oil due to co-microencapsulation. However, the total omega-3 fatty acids in the released oil during in-vitro digestion were found to be higher, when co-microencapsulated. Hence, co-microencapsulation was shown to protect the L. casei and deliver both viable cells and omega-3 oil to human intestine without any significant adverse effect on their functionality and properties.Doctor of Philosophy
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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.
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Aung, Theingi. „The role of omega-3 fatty acids and aspirin in the prevention of cardiovascular disease in diabetes and biochemical effectiveness of omega-3 fatty acids and aspirin in the ASCEND trial“. Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/36213.
Annotation:
Background: The role of aspirin (100 mg daily) and omega-3 fatty acids (FA) (1 g daily) for primary prevention of cardiovascular disease in diabetes is being investigated in the 2x2 factorial design ASCEND trial. To support the interpretation of the trial's efficacy findings, it is important to compare self-reported compliance by participants with measures of the biochemical effects of each intervention. The previous data on the effect of supplementation with omega-3 FA on coronary heart disease is uncertain. Methods: The ASCEND trial randomly allocated 15480 people with diabetes (94% type 2 DM) who do not already have diagnosed occlusive arterial disease to receive aspirin or placebo and to omega-3 FA or placebo. Blood and urine samples were collected by mail at baseline and after 3 years follow-up. The effectiveness of aspirin to suppress urinary thromboxane B2 (UTxB2), a marker of platelet activity, and, of omega-3 FA supplements to increase red cell membrane omega-3 index were assessed. A systematic review of previous trials of omega-3 FA was conducted to summarize the prior evidence for the effects of omega-3 FA supplements on major vascular events (MVEs). Results: Aspirin reduced UTxB2 levels by 67% (63-70%) (p < 0.0001) compared with placebo, from 3453 pg/mg (95% CI 3061-3895) at baseline to 1190 pg/mg (1100-1287) on those allocated to aspirin during the trial. During follow-up, the omega-3 index increased by 33% (95% CI 26%-39%) in those allocated omega-3 FA compared to placebo (p < 0.0001). The meta-analysis of previous studies of omega-3 FA showed no effect on MVEs (HR 0.97; [0.93-1.01]) overall or in any pre-specified sub-groups. Conclusions: Low dose aspirin and omega-3 FA are biochemically effective at reducing UTxB2 and increasing the omega-3 index, respectively. Previous trials show that supplementation with omega-3 FA had no significant effect on MVEs. The results of the ASCEND trial, assessing the effects of both aspirin and omega-3 FA on MVEs, will be available in 2018.
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Kaushik, Pratibha. „Microencapsulation of omega-3 fatty acids from flaxseed oil in flaxseed protein and flaxseed gum based matrix“. Thesis, Federation University Australia, 2016. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/154235.
Annotation:
The overarching goal of this research was to develop microencapsulated flaxseed oil as a plant based source of omega-3 fatty acids. To accomplish this, flaxseed oil was microencapsulated in a novel matrix composed of flaxseed protein isolate (FPI) and flaxseed gum (FG) and converted into a powder by freeze drying and spray drying. The primary objectives were: a) To evaluate the physicochemical and functional properties of FPI and FG; b) to optimise the process of complex coacervation between FPI and FG to maximise the yield of complex coacervates; c) to characterise the flaxseed oil microcapsules obtained through complex coacervation followed by freeze drying or spray drying. FPI and FG were extracted from whole flaxseeds at optimised temperatures to obtain 90% purity. The physicochemical and functional properties of FPI were found superior to most of the commonly used proteins. Lower extraction temperatures (30, 50 °C) of FG yielded higher levels of neutral monosaccharides and lower levels of acidic monosaccharides. The functional properties of FG, such as EAI and WAC, were negatively affected by the rise in extraction temperature. Electrostatic complexation studies between these two biopolymers showed that the optimum FPI-to-FG ratio is 3:1 and the optimum pH is 3.1. The complex coacervates of FPI-FG were used to microencapsulate flaxseed oil at different core to wall ratios (1:2, 1:3 and 1:4), and converted to powder through spray drying and freeze drying. The spray dried solid microcapsules had higher oil microencapsulation efficiency, lower surface oil content and higher oxidation stability compared to the freeze dried microcapsules. The oxidation stability obtained from spray dried microcapsules at core-to-wall ratio of 1:4 was nearly double to that of the unencapsulated flaxseed oil. This study affirms the potential of a solely plant based encapsulating matrix that returns superior nutritional outcomes to other commonly used wall materials.Doctor of Philosophy
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Mooney, Alaina. „Stability of essential nutrients in pet food manufacturing and storage“. Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32683.
Annotation:
Master of ScienceGrain Science and Industry
Greg Aldrich
Processing pet food can be beneficial, but can also have adverse effects on shelf-life and nutrient survival. Most affected are supplemental vitamins and essential fatty acids (EFA). Pet food complicates this relative to human foods by combining all elements into the product before processing and requiring an extensive shelf-life (up to 2 years). The objective of this research was to determine the effects of processing, diet, and storage conditions on vitamin (vitamin A, vitamin D₃, vitamin E, folic acid and thiamine) and omega-3 fatty acid (with an emphasis on eicosapentaenoic acid; EPA 20:5n3, and docosahexaenoic acid; DHA; 22:6n3) retention. The research was conducted in two separate experiments. Each experimental diet was produced on a single-screw extruder and triple-pass dryer. Target nutrients were evaluated in premixes in tandem to extruded diets. The vitamin study was conducted as a 3 X 2 X 2 factorial arrangement of treatments with 3 levels of dietary crude protein (CP), 2 screw speeds in the extruder, and 2 levels of time X temperature combinations in the dryer. Vitamins were added at 10 times normal levels to aid in analysis. The EFA study was conducted as a 3 X 3 factorial arrangement of treatments with 3 levels of dietary protein and 3 different omega-3 sources: fish oil, fish meal, or purpose-grown algae rich in DHA. In the vitamin premix study, the quantity of vitamins declined by approximately 50% over 6 months storage in ambient conditions (AMB; 20C, 50%RH), and all except folic acid were lost to some degree in stressed shelf life testing (SSLT; 50C, 70% RH) over 6 weeks. In all cases, the concentration of vitamins in food exiting the extruder and dryer were lower than target levels. As CP increased, the retention was higher (P ≤ 0.05) for vitamins A, E, and folic acid off the extruder (e.g. 225,352 vs. 219,184 and 206,249 IU/kg of vitamin A for high vs. medium and low CP, respectively), and vitamin D₃, E, and folic acid off the dryer (e.g. 9,047 vs. 7,473 and 6,945 IU/kg of vitamin D₃ for high vs. medium and low CP, respectively). During storage of finished pet food in AMB, vitamins A and D₃ were lost (P < 0.05) to the greatest degree (49 and 22%, respectively). The total retention following both processing and AMB storage was 27, 68, 78% for vitamins A, D₃, and E, respectively, while folic acid and thiamine were relatively stable. In SSLT storage, all vitamins except vitamin E were depleted more than 60% (P < 0.05) by 24 weeks, whereas total retention following both processing and SSLT storage was 3, 59, 43, 33, and 7% for vitamins A, D₃, and E, folic acid, and thiamine, respectively. This would suggest that beyond processing losses, the vitamins are relatively stable in premixes and foods if stored in AMB conditions. In the study to evaluate fatty acid stability within a vitamin premix, EPA, DHA, and total omega-3 fatty acids were relatively stable during storage over 6 weeks with losses no greater than 12% in stressed shelf life testing (SSLT; 40C, 70% RH). While in ambient conditions (23C, 50% RH) over 3 months, there was a total loss of EPA, DHA and total fatty acids by 17, 9, and 11%, respectively. Exiting the extruder and dryer, EPA and DHA were not affected by CP level or Omega-3 source. As SSLT storage of finished pet food increased through 24 weeks, EPA, DHA, and total fatty acids declined slightly (P < 0.05; 125, 82 mg/kg for EPA and 77, 60 mg/kg for DHA, and 418, 476 mg/kg for total fatty acids at 0 vs. 24 wk. As time in ambient storage reached 24 months, EPA, DHA, and total fatty acids declined slightly (P < 0.05; 125 vs. 78 mg/kg for EPA and 77 vs. 50 mg/kg for DHA, and 387 vs. 373 for total fatty acids at 0 vs. 24 mo.) Algal-DHA appears to be a stable source of DHA when compared to fish oil and fishmeal. During processing retention of fat soluble vitamins was less than water soluble vitamins, and the omega-3 fatty acids were relatively unaffected. Whereas, vitamins appeared to be more sensitive to temperature during storage and the omega 3 fatty acids more affected by time.
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Nikravan, Ramin. „Antioxidant and omega-3 fatty acid intake in the modulation of respiratory illness & asthma in children“. Thesis, Curtin University, 2011. http://hdl.handle.net/20.500.11937/689.
Annotation:
Background and aim: Asthma is one of the major public health problems in Australia with prevalence in West Australian children reported up to 31%. The rise in asthma prevalence in Western societies may be related to changes in dietary habits, as diets are often low in antioxidant nutrients and omega-3 fatty acids (n-3) and high in omega-6 fatty acids (n-6).The association between antioxidants, fatty acids and asthma is however controversial and there is a need for further investigation to clarify the role of these nutrients on asthma.The aim of this study was to investigate the dietary exposures of n-3, n-6 and antioxidant nutrients proposed to have protective effects against asthma symptoms. Data gathered over fourteen years in a prospective pregnancy cohort study were analysed. We hypothesised that n-3 fatty acids and antioxidant nutrients (vitamins A, C, E, β-carotene antioxidants manganese and zinc) would be protective against asthma symptoms.Methods: The Western Australian Pregnancy Cohort (Raine) study is a longitudinal study following 2868 children from birth to 14 years of age. This project consisted of two analyses as part of the overall study. Study One was a cross-sectional analysis of 1531 children at age 14 identified as having current asthma (n=167) or no asthma (n=1364). Study Two was a longitudinal analysis from a subset of the overall study whereby children were identified as having current asthma or no asthma at eight (n=335) and 14 (n=242) years of age. Dietary information was collected from food frequency questionnaires (FFQ) in both studies and red blood cell fatty acid content was measured in children for Study One. Student’s t-tests and ANOVA allowed comparisons of food and nutrient intakes between children with asthma or no asthma for both studies. In Study One depending on the outcome of interest, multinominal or binary logistic regression was performed. In Study Two, food and nutrients that showed a significant difference between asthma groups in ANOVA analyses (p<0.05) were included in analysis of covariance (ANCOVA) to determine whether they made an independent contribution after adjustment for age, sex, BMI and total energy intake. The Bonferroni post hoc test was applied to control for false positive results.Results of Study One: The participants were 50.8% male (n=778) and 49.2% female (n=753). One hundred and sixty seven adolescents (10.9%) had asthma categorised as mild (4.0%), moderate (4.4%) or severe (2.5%). Two hundred and eighteen adolescents (14.2%) had current wheeze. The most common allergy outcome was atopy (44.5%) n= 682. The least common allergy outcome was eczema (10.7%).The large majority of dietary antioxidants and fatty acids tested were unrelated to asthma and asthmatic symptoms. However, after performing regression analysis and adjusting for potential confounders (BMI, age, gender and total daily energy intake) increased intake of vitamin C showed protective association with asthma (adjusted OR= 0.997, 95% CI= 0.994–0.999) and increased consumption of berry fruits showed protective effects on atopy (adjusted OR= 0.988, 95% CI= 0.976–0.999).Increased level of docosahexaenoic acid (22:6n3) in RBC membrane showed protective effects on BHR (adjusted OR= 0.814, 95% CI= 0.669–0.989). The adjusted ratio of n6:n3 showed detrimental association with asthma (OR= 1.072, 95% CI= 1.009–1.139) and wheezing episodes (OR= 1.064, 95% CI= 1.007–1.124).Results of Study Two: None of the antioxidant nutrients were shown to be associated with asthma. Unadjusted ANOVA analysis demonstrated a significant association between asthma diagnosis and arachidonic acid (20:4n6) (p=0.039). However, after performing ANCOVA and controlling for the confounders (age, sex, BMI and total energy) the association became non-significant (p=0.330). In crude analyses the n6:n3 ratio was higher for asthmatic adolescents at eight and 14 years (3.38) compared to those with no asthma (2.78) (p=0.013). This ratio remained significant after adjusting for the confounders (p=0.030)Conclusions: Study One and Two provide some evidence on protective effects of antioxidants and fruits on asthmatic symptoms in adolescents. We found that while controlling for potential confounders, increasing intake of vitamin C by 1 mg/day results in a 0.3% reduction in the risk of developing asthma. We demonstrated that for every 1 g/day increased intake of berry fruits there was 1.2% reduction in the risk of having atopy. We showed that by increasing 1 mmol/L in the level of docosahexaenoic acid in RBC membrane there was 18.6% reduction in the risk of having BHR. We also demonstrated that for every 1 unit increase in n6:n3 ratio, there was 6.4% increase in the risk of developing wheezing episodes and 7.2% increase in the risk of having asthma. Therefore, Our study suggests that the ratio of n6:n3 in diet may play a modulatory role in the expression of asthma, suggesting that promotion of increased total n-3 and reduced n-6 may protect against asthmatic traits in childhood and early adolescence.
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Jackson, Philippa. „Biobehavioural and cerebral hemodynamic effects of omega-3 polyunsaturated fatty acids in healthy individuals“. Thesis, Northumbria University, 2010. http://nrl.northumbria.ac.uk/2386/.
Annotation:
The omega-3 polyunsaturated fatty acids (n-3 PUFAs) are a unique class of fatty acids that cannot be manufactured by the body, and must be acquired via dietary sources. In the UK, as well as in other Western nations, these ‘essential’ fatty acids are consumed in quantities that fall below government guidelines. This thesis examined the relationship between n-3 PUFAs and cognitive function and mood in healthy children (8-10 years) and adults (18-35 years), with a view to evaluate their efficacy for cognitive and mood enhancement in these populations. A second aim was to evaluate the effects of n-3 PUFAs on cerebral hemodynamics, a novel line of enquiry. Chapters 2 and 4 describe novel intervention studies that assessed the effects of n- 3 PUFA supplements on cognitive function and mood in healthy children and adults, respectively. In Chapter 3, the relationship between peripheral PUFA concentrations, a correlate of dietary PUFA intake, and cognitive and function and mood was examined for the first time in healthy adults. Chapter 5 describes a pilot trial in which Near Infrared Spectroscopy (NIRS) imaging technique was applied to investigate the cerebral hemodynamic effects of n-3 PUFA supplements. The results of this study were explored in more detail in Chapter 6, with the additional inclusion of parallel cognitive measures. Most notably, the behavioural data from the intervention studies described herein do not support the use of n-3 PUFA supplements for cognitive and mood enhancement in healthy children and adults not consuming appreciable amounts of oily fish. However, the results do suggest that supplementation with dietary n-3 PUFAs has an impact on peripheral fatty acid status and cerebral hemodynamics in healthy adults. Taken together, these findings suggest that, in healthy, cognitively intact individuals, short-term use of n-3 PUFA supplements has a minimal effect on behaviour; the impact of long-term n-3 PUFA dietary intake or supplement use over the course of the entire lifespan on behaviour should be addressed further.
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Hawthorne, Antony Barnabas. „Omega - 3 fatty acids and lipoxygenase inhibitors in the the treatment of ulcerative colitis“. Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317408.
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Clarke, Paul Noel. „An Investigation into the mechanisms whereby omega-3 polyunsaturated fatty acids affect plasma lipids“. Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269713.