Improving the vitamins, minerals and fatty acids in the diets of young offenders appeared to reduce their anti-social behaviour dramatically, according to a Home Office-backed study.
Yesterday it prompted calls for further research into the impact of nutrition on crime.
Results of trials in one maximum security institution for 18- to 21-year-old men suggested that inmates who took special supplements committed more than a quarter fewer disciplinary offences while serving their sentences than those who were unknowingly simply taking dummy pills.
Significant infringements of discipline, including violence, fell by 37%, according to authors of the study, which was organised with the help of the Home Office and prison service.
The results will be published soon in the British Journal of Psychiatry.
Hugh Montifiore, former bishop of Birmingham and chairman of Natural Justice, the charity behind the study at the young offenders' institution in Aylesbury, Buckinghamshire, suggested that there was a correlation, if not a direct connection, between the rises in fast food consumption and youth crime.
"More and more fast food is being consumed. More and more made-up dishes are sold in supermarkets. School meals are a matter of choice, the less nutritious they [pupils] like best, and there is less and less cooking with proper ingredients.
"None of us claims that lack of proper nutrition is the sole cause of anti-social behaviour. But the evidence does show that it is an hitherto unknown major contributor."
Bernard Gesch, who led the study while he was at Surrey University, Guildford, said: "The supplements just pro vided the vitamins, minerals and fatty acids found in a good diet which the inmates should be getting anyway. Yet the improvement in behaviour was huge."
It was not necessarily long-lasting, however. Shortly after the experiment ended staff reported that violence against them rose by 40%.
Mr Gesch is now a research scientist in physiology at Oxford University as well as director of Natural Justice, which investigates causes of criminal behaviour.
His team pointed out nutrients were crucial ingredients in the biochemical processes that produced brain transmitters like seratonin and dopamine, which affect mood.
Giving all prisoners an improved diet of micronutrients might cost about £3.5m a year, against an overall prison service budget of nearly £2bn.
Mr Gesch added: "This approach needs to be retested, but it looks to be cheap, highly effective and humane."
The results might be even better in adolescent children, he suggested.
Sir David Ramsbotham, former chief inspector of prisons, said the Home Office should carefully consider the implications of the study.
Alan Simpson, Labour MP for Nottingham South, called for other studies to be conducted in schools and hospitals.
He said: "We may be sitting on a timebomb which it is entirely within our ability to defuse. If we choose to feed up our kids rather than just bang them up, we may also discover we have found a better way of bringing them up."
The government is trying to find ways of changing people's eating behaviour without acting like a nanny state. Healthy eating messages appear to be quite well understood but are far from widely converted into action.
