‘Vitamin C is important for your health in lots of ways,” says Daniel M Davis, the head of life sciences at Imperial College London. It is a strong antioxidant, helping protect cells from harmful unstable compounds that arise from toxins and pollution. It helps the body absorb iron, and is also used in the production of collagen. “But the idea that taking high doses of vitamin C – or drinking lots of orange juice – will stop you catching a cold, or help you recover faster, is a myth.”

Davis, the author of Self Defence: A Myth-Busting Guide to Immune Health, explains that the popular belief in vitamin C’s cold-fighting powers has persisted for more than 50 years, “pretty much solely because of the evangelical view of one man: Linus Pauling”.

A double Nobel prize winner and one of the most influential chemists of the 20th century, Pauling made a major contribution to our understanding of vitamins. However, he exaggerated vitamin C’s benefits. Pauling’s 1970 book Vitamin C and the Common Cold became a bestseller, explains Davis, sparking such high demand that factories were built to keep up with supplement production.

In truth, research shows that people who take vitamin C supplements are just as likely to catch a cold as those who don’t. And while supplementation may slightly reduce symptom duration (by about 8% in adults) the effect is modest.

“It’s also difficult to interpret that data,” says Davis, “because people who regularly take high doses of vitamin C are often more health-conscious in general.”

Instead, he recommends focusing on vitamin D if you want to fight off sickness. “It is much more clearly established as important for immune health,” he says. Vitamin D is available from exposure to sunlight between March and October, but the NHS suggests that during winter people may want to take it as a supplement.