Omega-3 fatty acids (especially the type known as DHA) are essential for brain development and functioning, but most people eating a modern western diet consume low amounts of these compared to omega-6 fatty acids. Omega-3s are anti-inflammatory while omega-6s are pro-inflammatory. A large UK study published in the journal PLOS One in 2013 reported that healthy 7- to 9-year-olds with lower levels of omega-3 long-chain polyunsaturated fatty acids in their blood (including DHA, DPA, and EPA) had lower reading ability and working memory, and also had more behavior problems.
The oils in fish are the best source of omega-3 fatty acids, and most of the children with poor reading ability in the study fell short of the UK nutritional guideline that recommends eating two portions of fish per week.
Girls in the study had more dramatic deficits in omega-3 levels than boys. In adults, women tend to metabolize long chain polyunsaturated fatty acids more easily than men, but this difference is driven by hormones, and because the girls in the study had not yet reached child-bearing age, they did not reflect this benefit.
Omega-3 deficits in children have been connected with attention deficit hyperactivity disorder (ADHD), and supplementation with extra omega-3 fatty acids in the diet has led to improvements in ADHD.
Several studies in adults and children suggest that omega-3 fatty acid supplementation may have antidepressant effects. At the 2013 meeting of the American Academy of Child and Adolescent Psychiatry in October, Melissa DelBello, a professor at the University of Cincinnati, reported on a new study of omega-3 fatty acids in depressed children who had a parent with bipolar disorder. The children taking omega-3 fatty acids were more likely to improve than those taking a placebo, but the findings were only of marginal significance.
Cold-water fish are a good source of omega-3 fatty acids, and DelBello said salmon is by far the best in this regard. People who live in countries where fish is consumed in greater quantities are less likely to suffer from depression. Other sources of omega-3 fatty acids include shellfish, plant and nut oils, English walnuts, flaxseed, algae oils, and fortified foods.
The omega-3 fatty acids from fish are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), while the omega-3 fatty acids from plants are alpha-linolenic acid (ALA), which breaks down into EPA and DHA. All of these are anti-inflammatory, though one must consume much greater quantities of ALA to match the benefits of EPA and DHA. In contrast, omega-6 fatty acids, which are much more common in the typical American diet, are pro-inflammatory.
In DelBello’s study of 56 depressed children of a parent with bipolar disorder, the participants were randomized to either 1.8 g of omega-3 fatty acids (1.2 g of EPA and 0.6 g of DHA) or placebo (olive oil). Those who received the omega-3 fatty acids had a 55.6% rate of remission versus 34.5% for those who received placebo, but while the odds ratio of 2.4 favored the omega-3 fatty acids, the difference in remission rates was not statistically significant, likely because of the small size of the study. However, improvement on the Children’s Depression Rating Scale was significantly different across the two groups, with children taking omega-3s improving more. Omega-3 fatty acids are known to have an anticoagulant effect (preventing the clotting of blood), and four children in the study did have prolonged clotting times (but no clinical problems with bleeding).
Editor’s Note: Given the existing literature on omega-3 fatty acids and the trend in this study, omega-3s are worthy of consideration for the treatment and potentially for the prevention of depression in children. This later possibility is further suggested by findings from Australia that, when compared to placebo, omega-3 fatty acids significantly reduced the rate of conversion from prodromal (preliminary) psychotic symptoms to a full-blown diagnosis of schizophrenia.