Every year we spend £300 million on vitamin supplements, but do they actually do us any good? Some believe they offer the promise of preventing or even curing some of the world's biggest killers, such as heart disease and cancer. Others claim that taking large doses of some vitamins may in certain cases be harmful. So what are the facts? Nearly 40 years ago, one of the greatest scientists of the 20th century and double Nobel Prize winner, Linus Pauling, revolutionised the way people thought about vitamins. He claimed that by taking huge doses of vitamin C you could prevent or even cure the common cold. He predicted that if everybody followed his advice, the common cold could even be eradicated. Many scientists dismissed his theory as quackery, but the public loved it and it helped launch a huge industry. But the latest evidence shows the great man was mistaken. Vitamin C can help you once have got a cold, but for most people it does nothing to prevent you from catching one in the