Getting the flu isn’t a pleasant experience for anyone, but when it strikes your child, it’s bad news all around. Fortunately, recent evidence suggests a vitamin D may help prevent the flu. According to the study, children who take vitamin D3 daily during the winter months can reduce their risk of getting the flu by almost half. The amount studied was 1,200 IU per day. Children in the study group who took their daily vitamin D3 were also much less likely to have asthma attacks.