File this under “if a little bit is good, a lot isn’t necessarily better:” taking high-dose vitamin C appears to double a man’s risk of developing painful kidney stones. In an article published yesterday in JAMA Internal Medicine, Swedish researchers detail a connection between kidney stone formation and vitamin C supplements among more than 23,000 Swedish men. Over an 11-year period, about 2% of the men developed kidney stones. Men who reported taking vitamin C supplements were twice as likely to have experienced the misery of kidney stones. Use of a standard multivitamin didn’t seem to up the risk. Many people believe that extra vitamin C can prevent colds, supercharge the immune system, detoxify the body, protect the heart, fight cancer, and more. To date, though, the evidence doesn’t support claims that extra vitamin C is helpful. If high-dose vitamin C doesn’t improve health, then any hazard from it, even a small one, is too much.