Can Diet Help Stop Depression and Violence?

The best way to curb aggression in prisons? Longer jail terms, maybe, or stricter security measures? How about more sports and exercise? Try fish oil. How can children enhance their learning abilities at school? A well-balanced diet and safe, stimulating classrooms are essential, but fish oil can provide an important extra boost. Is there a simple, natural way to improve mood and ward off depression? Yoga and meditation are great, but -- you guessed it -- fish oil can also help do the trick.

A diet rich in vitamins, minerals and fatty acids like omega-3 is the basis for physical well-being. Everybody knows that. But research increasingly suggests that these same ingredients are crucial to psychological health too. And that's a fact a lot of people seem to find hard to swallow.

The relationship between nutrition and aggression is a case in point. In 2002, Bernard Gesch, a physiologist at Oxford University, investigated the effects of nutritional supplements on inmates in British prisons. Working with 231 detainees for four months, Gesch gave half the group of men, ages 18 to 21, multivitamin, mineral and fatty-acid supplements with meals. The other half received placebos.

During the study, Gesch observed that minor infractions of prison rules fell by 26 percent among men given the supplements, while rule-breaking behaviour in the placebo group barely budged. The research showed more dramatic results for aggressive behaviour. Incidents of violence among the group taking supplements dropped 37 percent, while the behaviour of the other prisoners did not change.

Gesch's findings were recently replicated in the Netherlands, where researchers at Radboud University in Nijmegen conducted a similar study for the Dutch National Agency of Correctional Institutions. Of the 221 inmates, ages 18 to 25, who participated in the Dutch study, 116 were given daily supplements containing vitamins, minerals and omega-3 for one to three months. The other 105 received placebos. Reports of violence and aggression declined by 34 percent among the group given supplements; at the s;ame time, such reports among the placebo group rose 13 percent.

Gesch is quick to emphasize that nutritional supplements are not magic bullets against aggression, and that these studies are just "promising evidence" of the link between nutrition and behaviour. "It is not suggested that nutrition is the only explanation of antisocial behaviour," he says, "only that it might form a significant part."

But Gesch is just as quick to emphasize that there is no down side to better nutrition, and in prisons in particular, the cost of an improved diet would be a fraction of the cost of other ways of addressing the problem of violence among inmates.

Still, the menu in British prisons hasn't changed in the five years since Gesch published his results, even though the former chief inspector of prisons in the UK, Lord Ramsbotham, told the British newspaper The Guardian last year that he is now "absolutely convinced that there is a direct link between diet and antisocial behaviour, both that bad diet causes bad behaviour and that good diet prevents it."

Yet the effect of nutrition on psychological health and behaviour is still controversial, at least in part because it is so hard to study. Our moods, emotions and actions are influenced by so many factors: everything from our genes to our communities to our personal relationships. How can the role of diet be isolated among all these competing influences? That's exactly why Gesch conducted his study in prisons. In a prison, there are far fewer variables, since all detainees have the same routine. Do the results of the inmate trials reach beyond the prison walls? Gesch thinks so: "If it works in prisons, it should work in the community and the society at large. If it works in the UK and in the Netherlands, it should work in the rest of the world."