The risk of children suffering from flu can be halved if they take vitamin D, doctors in Japan have found. The finding has implications for flu epidemics since vitamin D, which is naturally produced by the human body when exposed to direct sunlight, has no significant side effects, costs little and can be several times more effective than anti-viral drugs or vaccine. Only one in ten children, aged six to 15 years, taking the sunshine vitamin in a clinical trial came down with flu compared with one in five given a dummy tablet. Mitsuyoshi Urashima, the Japanese doctor who led the trial, told The Times that vitamin D was more effective than vaccines in preventing flu. Vitamin D was found to be even more effective when the comparison left out children who were already given extra vitamin D by their parents, outside the trial. Taking the sunshine vitamin was then shown to reduce the risk of flu to a third of what it would otherwise be. The trial, which was double blind, randomised, and fully controlled scientifically, was conducted by doctors and scientists from Jikei University School of Medicine in Tokyo, Japan.