From the BBC
The University of Southern California found a lack of zinc, iron, vitamin B and protein in the first three years caused bad behaviour later on. At eight years old, children fed poorly were more likely to be irritable and pick fights than those fed healthily. Aged 11, they swore, cheated and got into fights, and at 17, they stole, bullied others and took drugs. The researchers analysed the development of more than 1,000 children on Mauritius, an island in the Indian Ocean off the coast of Africa, over 14 years. They found the more malnurished the children were, the greater the anti-social behaviour later on.