Laxatives cause cancer. Caffeine prevents pregnancy. Pizza prevents prostate cancer. Vitamins prevent cancer.
Vitamins cause cancer.
It seems like we've been bombarded by such claims recently. Despite their urgent tone, many of these claims actually mean little by themselves. And they usually mean even less to any specific individual. Any study gives only part of the rarely reported larger picture. A study may report that electric power lines, chlorinated tap water or some pesticide increases cancer risk.