CINCINNATI—Supplementation with docosahexaenoic acid (DHA) positively impacts functional cortical activity in humans, according to a new study in the American Journal of Clinical Nutrition (April 2010; 91(4):1060-67; DOI:10.3945/ajcn.2009.28549). Researchers from the University of Cincinnati conducted the placebo-controlled, dose-ranging study, supported with a grant from the National Institutes of Health and Martek Biosciences. The research team randomized healthy boys ages 8 to 10 years (n=33) to receive placebo or one of two doses of DHA (400 mg/d or 1,200 mg/d) for eight weeks. Relative changes in cortical activation patterns during sustained attention were determined by functional magnetic resonance imaging.
After eight weeks, erythrocyte membrane DHA composition increased significantly from baseline in both the low-dose (up 47 percent) and high-dose (70 percent increase) DHA groups, and dropped by 11 percent in the placebo group. During sustained attention, the subjects in both DHA groups had significantly greater changes in activation of the dorsolateral prefrontal cortex compared to the placebo group; the low-dose DHA group had greater decreases in the occipital cortex, while high-dose intervention decreased activation in the cerebellar cortex. High-dose DHA supplementation had a greater decrease in activation of bilateral cerebellum compared to the low-dose group. Erythrocyte DHA composition was positively correlated with dorsolateral prefrontal cortex activation and inversely related with reaction time.
