As we head into cold and flu season, many people swear by megadoses of vitamins C and D to stave off sickness. However there's more and more evidence that they won't do much good.
According to a BBC News story, "Scientists say they can find no convincing evidence to show that taking vitamin D supplements will fend off a cold. A New Zealand team did the 'gold standard' of tests - a randomized placebo-controlled trial - to see what impact the supplements would have. The 161 people who took daily vitamin D for 18 months caught as many colds as the 161 who took fake pills."
The new study, "Effect of Vitamin D3 Supplementation on Upper Respiratory Tract Infections in Healthy Adults," was conducted at the University of Auckland, New Zealand, and concluded, "In this trial, monthly administration of 100,000 IU of vitamin D did not reduce the incidence or severity of URTIs (upper respiratory tract infections) in healthy adults."
The study was reported in the Journal of the American Medical Association.
It's not just vitamin D that's worthless in preventing colds, it's also the old standby vitamin C. The idea of vitamin C as a panacea got a huge boost in the 1970s from Nobel Prize winning chemist Linus Pauling, who took three grams of vitamin C daily to prevent colds, and later claimed that the vitamin could treat a variety of diseases including cancer.