Fish may reduce criminal aggressiveness

When they're released from prison, inmates might want to increase their intake of fish or take omega-3 supplements to curb aggressive behaviors and reduce the risk of relapse, a leading psychologist suggested here last week.

"Why not try it? What would be the harm?" said Dr. Adrian Raine, professor of Criminology, Psychiatry and Psychology at the University of Pennsylvania, speaking at the IV Brazilian Congress of Brain, Behavior and Emotions.

"Omega-3 fatty acids...have been shown to improve the functioning of brains and reduce violent behaviors," he told Reuters Health. "And actually, American prisoners eat very little fish."

The proposal is based on a growing but controversial body of evidence that attributes criminality to biological factors, such as a genetically driven dysfunction in the prefrontal cortex. Biological predisposition might explain at least 50 percent of criminal behavior, Raine estimates.

In this context, nutritional intervention in prisoners might become a "naturalistic" way of helping change brains at risk. "It might not only reduce (further) serious offending, but could also make prisoners more amenable to other treatments, such as cognitive behavior therapy," he said.

Raine based his hypothesis upon the results of some "compelling" trials in children and adults, he said. A 2002 study conducted with 231 young English prisoners showed that taking nutritional supplements containing omega-3 fatty acids, for at least 2 weeks, was associated with a 35 percent reduction in offenses after 5 months.

In another study, conducted by Raine and published in the American Journal of Psychiatry in 2003, children aged 3 to 5 participated in an "environmental enrichment" program, including a fish-enriched diet, physical activity and cognitive stimulation. Twenty years later, it was found that the crime rate in the intervention group had been lowered by 35 percent.

A third trial, published in 2005, showed that normal 8-to-11 year-old children reduced their aggressive behavior by taking omega-3 fatty acids supplements for only 4 months.

In addition, a 2001 cross-national ecological analysis found a direct link between seafood intake and lower murder rates.

A nutritional intervention, perhaps combined with some cognitive behavior therapy, might work not only in prisoners but also in aggressive children and others at risk for antisocial behaviors.

"Fish oil and omega-3 fatty acids improve brain structures and attention abilities. And maybe (violent people) need better brains to learn instructions to regulate their emotions," Raine said.

Effective dosages of omega-3 or fish intake to prevent antisocial conduct or criminal relapses are unknown, but about 1 g/d of omega-3 or two to three meals of fish a week might be needed, the investigator added.