SCIENCE is a strange fish. What is believed to be the world's first study into the scientific causes of criminal behaviour and lower educational achievement has come to a conclusion that is as old as the hills.

Our parents, like their parents before them, drummed into us that we had to "eat our greens" and that fish was "brainfood". They usually finished their exhortations with the old adage: "After all, you are what you eat."

More than £100,000 later, North-East scientists have concluded much the same. Offenders given nutritional supplements went on to commit 40 per cent fewer offences than those who were not; schoolchildren in County Durham given nutritional supplements have seen their reading ages improve dramatically. Now, students at Durham University who have learning difficulties like dyslexia - which means they have done extremely well just to make it to university - are to be given the supplements to see how they fare.

The supplements include fish oils - "it's brainfood, y'know" as our parents said - and vitamins and nutrients found in cabbages, carrots and other fresh vegetables - "you're not leaving the table until you've eaten your greens".

The study also found that although jails did offer reasonable diets, most inmates opted for the least healthy options - "you are what you eat".

And, of course it makes sense. Everyone knows that poor diet and vitamin deficiencies can cause physical problems like rickets, so it seems likely to the layman that such deficiencies can hinder mental development.

Anything that can reduce crime and improve educational achievement is welcome, and it is positive that Durham University and Durham schools have so embraced the study.

Science, though, can veer from the totally comprehensible to the frankly incredible. As part of the study, a breath test has been invented whereby a sample of air exhaled by a two-year-old child can show which nutritional elements they are lacking.

This gives rise to the extraordinary futuristic vision in which a driver is breathalysed to see how much alcohol is in their system, and whether they've eaten enough greens and fish to be in a fit mental state to be in control of a car.

Could it be that a lack of nutrition is the cause of the rank stupidity that is seen on our roads everyday?