Adding DHA to kids’ diets may increase cortical activation

Supplementing children’s diets with docosahexaenoic acid (DHA) increases activation of the prefrontal cortex during tasks that demand sustained attention, according to a new study.

Robert McNamara and colleagues evaluated 33 healthy boys between 8 and 10 years of age. The researchers randomly assigned the boys to receive high-dose DHA (1200 mg per day), low-dose DHA (400 mg per day), or a placebo for eight weeks.

At the end of the period, the boys receiving DHA had significantly higher levels of DHA in their red blood cell membranes than children taking the placebo. Tests showed a two-fold increase in erythrocyte DHA composition in the low-dose group and a three-fold increase in the high-dose group.

During a test measuring sustained attention, both the high-dose and low-dose groups showed greater increases in activation of the dorsolateral prefrontal cortex than the placebo group did. They also showed decreased activity in the occipital cortex (low-dose group) and the cerebellar cortex (high-dose group). In addition, higher DHA composition in red blood cells correlated with faster reaction times on the attention task.

The researchers conclude, “The present findings add to an emerging body of evidence from preclinical and clinical imaging studies that suggest that dietary DHA intake is a robust modulator of functional cortical activity.” They note that deficits in erythrocyte and plasma DHA and reductions in prefrontal cortical blood flow have been reported in attention deficit hyperactivity disorder (ADHD), and that patients with major depression exhibit both red blood cell DHA deficits and cortical pathology.