Earlier we discussed the link between environmental lead concentration and criminal behaviour. New research lead by Jill Portnoy has indicated that another substance might have significant effect on criminal behaviour: omega 3.
According to this study giving a supplement of omega-3 fatty acids will improve the development of children and this will reduce disruptive and abusive behaviour. As this kinds of behaviour are related to (juvenile) crime, this reduction will also result in less crime.
Though not mentioned in the linked article an omega-3 supplement might also improve overall performance at school as a result of better brain development.