Omega-3 fatty acids may benefit mental performance

Increased intakes of docosahexaenoic acid may improve memory and reaction times among young adults, says a new study from New Zealand.

The randomized controlled trial measured the cognitive performance of 176 healthy adults (mean age = 33.4 years) who received 1.16 g docosahexaenoic acid (DHA in fish oil) per day or a placebo for 6 months (1). The study results showed that participants who supplemented with DHA—particularly those whose habitual diets were low in the omega-3 fatty acid—showed significantly improved reaction times (how fast you think) for working memory (e.g., “Where did I just put my keys?”) and episodic memory (e.g., “Where was I yesterday?”) compared to the placebo group. The effect of DHA on cognitive function was sex-dependent: For example, male participants showed a positive effect of DHA on working memory reaction time (i.e., no effect in women), whereas in female participants, DHA affected episodic memory accuracy (not just reaction time), which was not the case for men. No effect of DHA supplementation was detected on measures of attention or processing speed.

The researchers commented that this would be the first study to show that DHA supplementation improves memory and reaction times for memory among healthy young adults, as most studies examining the effect of DHA on cognitive performance focused on preventing cognitive decline in ageing. DHA is the dominant long-chain omega-3 fatty acid in the brain, where it performs structural functions and influences numerous neuronal and glial cell processes (2). DHA has been shown to accumulate in areas of the brain involved in memory and attention.

1. Stonehouse W. et al. DHA supplementation improved both memory and reaction time in healthy young adults: a randomized controlled trial. American Journal of Clinical Nutrition. Published online April 2013.
2. Innis S. M. Dietary (n-3) fatty acids and brain development. J Nutr. 2007; 137:855–859.