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Title: The role of n-3 fatty acids in cardiometabolic risk
Author: Jones, Wendy Susan
ISNI:       0000 0004 5992 9527
Awarding Body: Liverpool John Moores University
Current Institution: Liverpool John Moores University
Date of Award: 2015
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The work described in this thesis addresses two questions relating to benefits of dietary omega-3 fatty acids (n-3 LCPUFA). Accretion of research knowledge indicates that adequate n-3 LCPUFA intakes may be instrumental in maintaining good health throughout life, including in the optimisation of cardiovascular health. Sources of n-3 LCPUFA traditionally include fish oils but concern regarding long-term sustainability of fish stocks has led to investigation of alternative sources. Krill oil, obtained from the crustacean Euphausia superba, contains n-3 fatty acids as phospholipids and triglycerides, astaxanthin and related carotenoid pigments, and has been proposed as a more effective alternative than triglyceride oils. Some foods rich in n-3-LCPUFA, including prawns, also contain cholesterol; concern regarding possible adverse health effects of such dietary cholesterol has led to public health advice to limit intake of these potentially beneficial foodstuffs. These questions are addressed in two food intake studies in male volunteers by monitoring markers of cardiovascular health, food intake and biochemical markers of compliance. Firstly, prawns and a white fish control were compared for effects on lipoprotein profiles and other markers. Dietary supplementation with 225 g prawns daily for 4 weeks was associated with a decrease in ApoB of 7.8mg/dL compared an increase (+2.4 mg/dL) for the white fish control. Participants with BMI > 25 kg/m2 also showed a reduction in plasma TAG (0.17 mmol/L) compared with baseline following prawn intake; those receiving the control showed an increase in plasma TAG (0.30 mmol/L), a decrease in HDL-C, and increases in VLDL-C and sdLDL-C. No overall adverse effect was found for prawns compared with processed white fish. Secondly, effects were compared of fish oil and krill oil on cardiometabolic profiles of a cohort of men with metabolic syndrome, using anthropometric measurements, biochemical markers of cardiovascular health and assessments of food intake. Krill oil and fish oil at the doses used showed no overall difference in effect on MetS markers after 6 weeks; correlations between magnitude of reduction and baseline measurement were observed in both groups for TAG, fasting glucose, NEFA and sdLDL after 3 weeks on both supplements, and for glucose and cholesterol after 6 weeks of fish oil. Comparison of analytical methods was also undertaken during both studies; use of a point-of-care system using capillary blood correlated well with plasma biochemistry using venous blood, while the Hirano method for sdLDL measurement correlated favourably with more labour-intensive centrifugation techniques. Limitations of the methods used are discussed, and proposals put forward for future work, including improving compliance through the use of newly emerging technologies such as metabolomics.
Supervisor: Davies, Ian ; Stevenson, Leo ; Abayomi, Julie Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TX341 Nutrition. Foods and food supply ; QP Physiology ; RA0421 Public health. Hygiene. Preventive Medicine