They say that when you start to sniffle a bit, you must quickly fill yourself with fruit. Because a firm dose of vitamin C suppresses colds, or is at least good for your resistance.

But, is it true?

Vitamin C is necessary for a properly functioning immune system. We know from former sailors that a lack of vitamins creates scurvy and other health problems. But that does not prove that extra vitamin C helps if you are not having a shortage of vitamin C. In many western countries the people are already receiving almost twice the recommended amount of vitamin C, according to food consumption surveys.

Does it help to take even more vitamin C on top of that? Two umbrellas don’t help better against the rain, do they? Nevertheless, extra vitamin C keeps you protected a little bit more, was concluded in a study by the international research network Cochrane. The scientists looked at studies in which some subjects took vitamin C pills over a longer period of time, even when they were not sick. Others received a fake pill. All participants on both sides had a common cold just as often, but at the side of the fake supplement takers the cold lasted a little longer. According to the same study, taking vitamin C after a starting cold does not seem useful, although less research has been done. Subjects who only started taking extra vitamins at that time did not recover faster.

Swallowing extra vitamin C as soon a you feel a starting cold does not seem to work. But a regular dose of vitamin supplements shortens the disease duration. Not everyone needs the supplements, but some people who often have a cold could benefit from it.