Omega‐3 Fatty Acids Modify Treatment Effect of High‐Dose B Vitamins in Cognitively Impaired Elderly

Abstract

ObjectiveTo investigate whether plasma omega‐3 fatty acid (FA) concentrations (eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA) modify the treatment effect of homocysteine‐lowering B vitamins on brain atrophy rates and cognitive decline in a placebo‐controlled trial.DesignThe effect of high‐dose B vitamins in the previously reported VITACOG trial [PLoS ONE 5(9) 2010: e12244] was analysed according to baseline omega‐3 FA concentrations. This study included 168 elderly (蠅70 y) with Mild Cognitive Impairment randomly assigned either to placebo, or to B vitamins.ResultsThere was a significant interaction (P = 0.024) between B vitamin treatment and plasma combined omega‐3 FA (EPA+DHA) on brain atrophy rates. In subjects with high baseline omega‐3 FA (˃590 μmol/L), B‐vitamin treatment slowed the mean atrophy rate by 40% compared with placebo (P = 0.023). B‐vitamin treatment had no significant effect on rate of atrophy among subjects with low baseline omega‐3 FA (<390 μmol/L). High baseline omega‐3 FA were associated with a slower rate of brain atrophy in the B‐vitamin group, but not in the placebo group. A similar interaction was found between omega‐3 FA and the beneficial cognitive effects of B vitamin treatment.ConclusionThe beneficial effect of B vitamin treatment on brain atrophy and cognitive decline was observed only in subjects with high plasma omega‐3 FA. It is also suggested that the beneficial effect of omega‐3 FA may be confined to subjects with good B vitamin status.