StudyTaking a daily supplement of vitamin C will not protect most people from common colds, BBC News Online reports scientists as saying.
A review of 30 studies, involving 11,350 people, also found doses of at least 200 mg per day did little to reduce the length or severity of colds.
Researchers at the Australian National University and the University of Helsinki concluded that, for most people, the benefits of taking vitamin C every day were so slight that they were not worth the effort or expense.
The team found vitamin C could reduce the duration of colds by up to eight per cent in adults and 13.6 per cent in children, but as most people only have two or three colds every year, this benefit is small.
The study has been published in the Cochrane Library.