Vitamins and antioxidant supplements are useless at preventing prostate cancer, according to two huge clinical trials published in the US on Tuesday. The Journal of the American Medical Association said it was releasing the results early in its online edition “because of public health implications”.

The first study, one of the largest controlled trials of cancer prevention yet conducted, involved 35,500 middle-aged men who took vitamin E, selenium or placebo pills for more than five years. The second trial looked at the effect of vitamins C and E on almost 15,000 male doctors over eight years.