Fish oil may curb depression among teen boys

NEW YORK (Reuters Health) - Eating more oily fish like sardines, salmon and yellowtail could help teenage boys feel less blue, suggests a new Japanese study.

A worker arranges Sardine fishes at a fishing harbour in the southern Indian city of Kochi July 5, 2008. REUTERS/Sivaram V

The same does not appear to hold for teen girls, however.

Omega-3 fatty acids, including EPA and DHA, are found predominantly in oily fish. Because these nutrients are thought to play a role in brain function, many researchers have wondered whether increased consumption could lower the risk of depression. But studies of such an association among adults have yielded inconclusive results.

Until now, investigators had yet to look for the potential link in youth, a population also prone to the debilitating problem. So Kentaro Murakami of the University of Tokyo and colleagues analyzed the diets and rates of depression in more than 6,500 Japanese junior high school students between the ages of 12 and 15.

Overall, 23 percent of the boys and 31 percent of the girls suffered from symptoms of depression, including feelings of worthlessness, hopelessness and sleep disturbances, they report in the journal Pediatrics.

Based on questionnaires of food intake, and adjusting for factors including age and parents’ education level, the investigators found that boys who ate the most fish -- the top fifth based on total consumption -- had a 27 percent lower odds of being depressed compared to those ranked in the bottom fifth.

Similar differences were seen when looking specifically at the EPA and DHA content of the fish consumed.

Meanwhile, no effect of fish oil on depression was seen among the girls.

The investigators admit that the differing effect of fish oil between boys and girls is difficult to explain, although they point to a few possibilities such as a stronger genetic role for depression in women compared to men.

They also caution that their findings do not provide enough evidence to determine if fish oil actually lowers the risk of depression. It might be, for example, that those who are depressed eat less fish.

Although more research is needed to confirm a cause-and-effect link, the researchers conclude that boosting the intake of fish, EPA and DHA “may be an important strategy for the prevention of depression.”

SOURCE: Pediatrics, September 2010.