Increased selenium intake in elderly high fish consumers may account for health benefits previously ascribed to omega-3 fatty acids

Objective To examine relationships between fish consumption and plasma selenium (Se) and red blood-cell fatty acid (RBC FA) profile in aged subjects. We hypothesised that the importance of Se has been underestimated when interpreting the beneficial effect of fish consumption on health. Design Cross-sectional analysis of data from a prospective cohort study. Setting The EVA study in Nantes, France (1991–2002). Subjects 200 subjects aged 69 y with information on RBC FAs, plasma Se and completed food frequency questionnaires. Methods We examined correlations between the most abundant FAs, Se and number of fish meals per week. Linear regression models were used. Results Plasma Se was negatively correlated with RBC 6 poly-unsaturated FA (PUFAs) and positively with 3 PUFAs. Plasma Se, RBC 3 PUFAs, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) increased with fish consumption. Conversely, levels of 6 PUFAs were lower in the highest fish consumption group. All associations between plasma Se and fish consumption remained significant when adjusting for 6 PUFAs alone or additionally for age, sex, education, diabetes, hypertension, dyslipidemia, cardiovascular diseases, and broad food categories (meat, eggs, dairy products, cereals, fruit and vegetable). Associations between 3 PUFAs and fish also remained significant in the same model independently of Se. In linear regression models adjusted for demographic indicators, fish consumption explained only 2.6% of the variance in RBC 3 FAs (6.2% for 6) but as much as 15% of the variance in plasma selenium. Conclusions The observed health benefits of fish consumption in the elderly could be related not only to the increase in 3 FA intake but also to other nutrients such as selenium. It is important to consider this observation when interpreting associations between fish consumption and health status in the elderly, particularly with regard to brain function.