An Australian randomised controlled trial of vitamin D supplements, led by QIMR Berghofer Medical Research Institute has found they do not protect most people from developing colds, flu and other acute respiratory infections. The trial, which is the largest of its kind to study the relationship between vitamin D and respiratory infection to date did show, however, that the supplements may shorten the length of infection slightly and help ease the severity of those illnesses. The study results have been published this week in the scientific journal The Lancet Diabetes and Endocrinology. The researchers analysed self-reported health data from 16,000 Australians aged between 60 and 84, who participated in the QIMR Berghofer Medical Research Institute-led D-Health Trial.