Dietary fish intake and plasma phospholipid n\u963 polyunsaturated fatty acid concentrations in men and women in the European Prospective Investigation into Cancer\u96Norfolk United Kingdom cohort

Dietary fish intake and plasma phospholipid n\u963 polyunsaturated fatty acid concentrations in men and women in the European Prospective Investigation into Cancer\u96Norfolk United Kingdom cohort1,2,3 Ailsa A Welch, Sheila A Bingham, Jessica Ive, Marlin D Friesen, Nick J Wareham, Elio Riboli and KT Khaw 1 From the Department of Public Health and Primary Care and the Clinical Gerontology Unit (KTK), University of Cambridge, Cambridge, United Kingdom (AAW and JI); the Medical Research Council Dunn Human Nutrition Unit, Cambridge, United Kingdom (SAB); the Johns Hopkins Bloomberg School of Public Health, Deptartment of Environmental Health Sciences, Baltimore, MD (MDF); the MRC Epidemiology Unit, Elsie Widdowson Laboratory, Cambridge, United Kingdom (NJW); and the IARC, Lyon, France (ER) Background: The n\u963 polyunsaturated fatty acids (n\u963 PUFAs) docosahexaenoic acid and eicosapentaenoic acid, found in fish and fish-oil supplements and also formed by conversion of -linolenic acid in soy and rapeseed (canola) oils, are thought to have cardioprotective effects. Objective: Because the relative feasibility and measurement error of dietary methods varies, this study compared fish and fish-oil intakes obtained from 4 dietary methods with plasma n\u963 PUFAs in men and women in a general population. Design: The study participants were 4949 men and women aged 40\u9679 y from the European Prospective Investigation into Cancer\u96Norfolk United Kingdom cohort. Measurements of plasma phospholipid n\u963 PUFA concentrations and fish intakes were made with the use of 4 dietary methods (food-frequency questionnaire, health and lifestyle questionnaire, 7-d diary, and first-day recall from the 7-d diary). Results: Amounts of fish consumed and relations with plasma phospholipid n\u963 PUFAs were not substantially different between the 4 dietary methods. Plasma n\u963 PUFA concentrations were significantly higher in women than in men, were 20% higher in fish-oil consumers than in non-fish-oil consumers, and were twice as high in fatty fish consumers as in total fish consumers. Only 25% of the variation in plasma n\u963 PUFA was explained by fish and fish-oil consumption. Conclusions: This large study found no substantial differences between dietary methods and observed clear sex differences in plasma n\u963 PUFAs. Because variation in n\u963 PUFA was only partially determined by fish and fish-oil consumption, this could explain the inconsistent results of observational and intervention studies on coronary artery disease protection