In the New York Times, Tara Parker-Pope looks at the (possible) false hope of vitamin supplements. Vitamins are essential—we’d quickly die without them. But it’s looking increasingly likely that vitamin supplements—vitamins in pill form—are significantly less effective than vitamins that occur naturally, in food. Vitamins may be what allow our bodies to avoid the sorts of diseases that occur in their absence (scurvy and rickets, for example), and are likely help for people who lack the ability to produce or process vitamins in food, due to age or ailment. But they’re apparently useless in preventing cancer, heart disease, etc. And they can even be harmful. A massive dose of vitamin C does nothing to prevent colds. High rates of beta carotene are correlated with lung cancer. People’s faith in vitamins exceeds the science.
The moral of the story? Get your nutrition from food. If you think you need vitamin C, have an orange. Need some beta carotene? Eat a carrot.