Cognitive function after supplementation with B vitamins and long-chain omega-3 fatty acids: ancillary findings from the SU.FOL.OM3 randomized trial

BACKGROUND: Rapid aging of the population worldwide necessitates a heightened concern about preventing cognitive decline. OBJECTIVE: We investigated the effects of B vitamins and omega-3 (n-3) fatty acid supplementation on cognition in a high-risk population. DESIGN: This was an ancillary study of the SU.FOL.OM3 (SUpplementation with FOLate, vitamins B-6 and B-12 and/or OMega-3 fatty acids) secondary prevention trial conducted in France between 2003 and 2009. The present sample included 1748 men and women aged 45-80 y with a history of myocardial infarction, unstable angina, or ischemic stroke and who were recruited via a network of 417 physicians. With the use of block randomization with stratification by sex, age, prior cardiovascular disease, and city of residence, participants were assigned in a 2 x 2 factorial design to 1 of 4 groups: 1) 5-methyltetrahydrofolate (folate, 0.56 mg) and vitamins B-6 (3 mg) and B-12 (0.02 mg), 2) eicosapentaenoic and docosahexaenoic acids (600 mg) in a 2:1 ratio, 3) B vitamins and omega-3 fatty acids, or 4) placebo. Cognitive function after 4 y of supplementation was assessed with the French version of the modified Telephone Interview for Cognitive Status. RESULTS: No significant main effects of group assignment on cognitive function were found; however, we found some evidence of disease history- and age-specific effects. In the subgroup with prior stroke, for example, participants assigned to receive B vitamins plus omega-3 fatty acids were significantly less likely to have a decreased score on the temporal orientation task than were those assigned to receive placebo (odds ratio: 0.43; 95% CI: 0.21, 0.86). CONCLUSIONS: If present, dietary effects on cognition are likely group-specific. These results could be useful in interventions aimed at preventing cognitive decline in high-risk individuals. This trial is registered at controlled-trials.com as ISRCTN41926726.