Eat it up and be a good boy

SUPPLEMENTS are all the rage: evening primrose oil; St John's wort; fish oils; glucosamine; selenium; zinc; iron; molybdenum; probiotics. And don't forget those old standbys, multivitamin tablets. It is hard to walk through a pharmacy without seeing a promise of clearer skin, a stronger immune system or less squeaky joints. But what about a pill or potion to make you better behaved?

That is exactly the intention of a study led by John Stein, a professor of neuroscience at Oxford University, that is about to start in three British prisons. Not only is there a growing body of evidence that good nutrition can improve behaviour, there is also a theoretical basis for supposing that a lack of essential nutrients has an impact on the way the brain works.