Vitamin C only prevents colds in outdoors types

Taking extra vitamin C does little to stop most people from catching a cold, according to a new survey, but it helps stop those exposed to extreme physical conditions from coming down with the sniffles. Soldiers and skiers are among those most likely to benefit from taking extra doses of the vitamin and marathon runners are clear winners, said Professor Bob Douglas of the Australian National University.
"The marathon runners are the most impressive and I don't think we can assume it necessarily protects to the same extent people who are engaged in moderate physical activity and cold stress," he told AFP.
"But we can be quite confident that for ordinary people it doesn't make much difference.
"It doesn't lessen their risk; they might have a very slight reduction in the length of their cold - about half a day or a day."
The study into the impact of vitamin C in preventing colds and flu, conducted in collaboration with associate professor Harri Hemila of Finland's University of Helsinki, surveyed 55 other studies carried out over the past 65 years and is the most extensive of its kind.