The current obesity epidemic has intensified research on lifestyle interventions aimed at combating obesity and associated cardiovascular (CV) and metabolic risk. This clustering of risk factors with obesity is known as the “Metabolic Syndrome” (MS). There is now a large body of evidence detailing the ability of omega-3 fatty acids (n-3 FA) and regular moderate exercise to independently ameliorate several CV risk factors; however the combination of these interventions may be a more effective strategy in reducing CV risk than either treatment alone. This thesis describes the independent and combined effects of supplementation with docosahexaenoic acid (DHA) rich fish oil, and regular moderate exercise, on CV, metabolic and inflammatory biomarkers. Sedentary, overweight volunteers (BMI > 25kg/m2) with mild hypertension (140/90 – 160/100mmHg), elevated plasma triglycerides (TAG) (>1.6mmol/L) or elevated total cholesterol (TC) (>5.5mmol/L) were recruited in three cohorts for a 12-week intervention trial. Subjects were randomised to one of the following interventions: fish oil, fish oil and exercise, sunflower oil (placebo), sunflower oil and exercise. Subjects consumed 6 g/day of DHA-rich fish oil (26% DHA, 6% EPA; ~1.9g n-3 FA) or sunflower oil. The exercise groups walked 3 days/wk for 45 min, at 75% age-predicted maximal heart rate (HR). Outcome measures were assessed and compared across each intervention group at Weeks 0, 6 and 12, with the exception of body composition, heart rate variability (HRV) and immune functions, which were assessed at Weeks 0 and 12 only. Apart from the consumption of allocated capsules, all subjects were instructed to maintain their normal diet during the study. If not asked to exercise as part of the intervention subjects were also instructed to maintain their normal level of physical activity. Supplementation with DHA rich fish oil resulted in substantial increases in total long chain n-3 FA and DHA levels in erythrocyte membranes, accompanied by reduction of TAG, increase of high-density lipoprotein (HDL) cholesterol and reduction of superoxide production by stimulated neutrophils. Both the increase in HDL and the decrease in superoxide production were correlated with the change in erythrocyte DHA. Endothelium dependent arterial vasodilation (assessed by flow-mediated dilatation, FMD), HRV and HR response to exercise were also improved in subjects supplemented with the DHA-rich fish oil. Regular moderate intensity exercise, either alone or in addition to the DHA-rich fish oil supplementation, had no effect on these parameters, although it improved the compliance of small resistance arteries. Interestingly, however, both DHA-rich fish oil and regular exercise reduced body fat and these effects were additive when the interventions were combined. The change in fat mass was accompanied by an increase in fat oxidation during exercise, as measured by the respiratory exchange ratio. For the population as a whole, reductions in total and abdominal fat mass were associated with reductions in blood pressure. In summary, this study is the first to evaluate the metabolic and CV benefits that can be achieved by combining n-3 FA supplementation from fish oil and regular aerobic exercise in overweight/obese adults. While this combination did not produce any synergistic effects, several independent benefits were attained. The high compliance rate (>85%) within this study indicates that this intervention is well tolerated and may therefore be sustainable in the longer term. Future research should evaluate the mechanisms underlying the n-3 FA - mediated improvements in body composition. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1283720 / Thesis (PhD) -- School of Molecular and Biomedical Science, 2007

Thesis (MNutr (Interdisciplinary Health Sciences. Human Nutrition))--University of Stellenbosch, 2006. / Background At least 40 - 80% of all cancer patients develop some degree of clinical malnutrition and cachexia. The complex and multi-factorial nature of cancer cachexia and the inability of conventional nutrition intervention to reverse or attenuate the effects of this syndrome have driven investigators to consider new therapies and approaches to manage the syndrome of cancer cachexia including eicosapentaenoic acid (EPA), an n-3 fatty acid of fish oil origin. Objectives The aim of this study was to review Phase I, Phase II and Phase III (RCT) trials investigating the safety and efficacy of n-3 supplementation in the treatment of cancer cachexia in adult patients with unresectable solid tumours, with special reference to weight loss, body composition, appetite, dietary intake, energy expenditure, functional status, acute phase response and quality of life. Adverse effects associated with EPA supplementation were also reviewed. Methodology and data collection The major databases were systematically searched for studies that met the inclusion criteria using a structured keyword search strategy or various combinations of these keywords. Relevancy of studies was assessed by two independent reviewers according to pre-determined inclusion and exclusion criteria. Quality was assessed by two independent reviewers using the Jadad scale. Data extraction was performed by the principal reviewer and one of the independent reviewers, and investigators of the included studies were contacted where further information was required. Meta-analysis was not appropriate due to heterogeneity of the data. However, where possible, the paired t-test was used for analysis of the data. Descriptive or non-quantitative analysis of the tabulated data provided a summary of the characteristics of the included studies enabling comparisons to be made between interventions and outcomes within the specified population. Results The search resulted in a total of 1408 citations, of which only 16 studies met the inclusion and exclusion criteria. Of these, only 4 studies were of a good quality. Although the reported data was incomplete and variable, the combined analyses suggested that the effect of EPA supplementation on weight, fat mass, dietary intake, energy expenditure, and acute phase response was not significant. Interestingly there appeared to be a significant increase increased or decreased? in lean body mass (p<0.05). There was little or no data to draw any conclusions regarding the effect of supplementation on appetite and quality of life. Conclusion Despite several limitations in this review, the data collected and analysed are suggestive of the beneficial effects of EPA supplementation, but there remains a significant lack of substantial evidence and conclusive statistical analysis to confirm that EPA supplementation is a safe and effective method of intervention in the management of patients with cancer cachexia.

[Truncated abstract] The role of fish consumption and omega-3 polyunsaturated fatty acids (PUFAs) in the prevention of disease has been the subject of much investigation in recent years. A clue that these factors might be of importance was the observation that populations consuming high levels of marine omega-3 PUFAs had lower rates of morbidity and mortality from cardiovascular disease. From there, research in this area has expanded to include a range of chronic diseases and their prevention. An area of particular interest is the role of fish consumption in the prevention of various cancers. In Australia, one in three men and one in four women are expected to be diagnosed with cancer by the age of 75. Identifying preventive factors that can be translated into constructive health promotional messages is of great importance in addressing this group of diseases that has such a large impact on the health and wellbeing of the population. ... Results and conclusions Analysis of the data from the population-based case-control study suggests a protective effect of preserved fish consumption, possibly due to the high oil content of these fish. The developed questionnaire is a valid and reliable tool for measuring fish and seafood consumption as determined by regression analysis with an independent biomarker and reliability analysis using intra-class correlation. Importantly, reliability can be maintained despite asking a high level of detail from participants. For ranking according to overall fish consumption, detailed questioning is probably not necessary, however inclusion of variables representing multiple categories of fish and seafood consumption in a regression model enables us to better account for variation in blood omega-3 PUFA levels than a single variable representing overall consumption. For the purpose of questionnaire validation, plasma phospholipid and erythrocyte membrane levels of EPA and DHA are equivalent biomarkers of fish and seafood consumption. The choice between them by future investigators will be based on more practical aspects such as convenience and the fasting state of subjects. The tangible product of this thesis is additional evidence to support a protective association between fish consumption and prostate and breast cancers, and a valid and reliable questionnaire v for measuring habitual consumption of fish and seafood in a West Australian population, that could also be applied to other populations after minor adjustment for local fish and seafood consumption patterns.