Does Vitamin C Really Help When You Are Sick?
Vitamin C has an almost legendary place among pharmaceutical supplements. Usually we take several pills when we are worried about an illness, or mix up a glass of Emergen-C at the first sign of a cold. It’s nice to think of it as a panacea, but reality doesn’t quite live up to our hopes.
Vitamin C probably wouldn’t be where it is today if Nobel laureate Linus Pauling wasn’t really excited about it . (Ironically, his enthusiasm was contagious.) But even today, the Linus Pauling Institute at Oregon State University writes: “The general public believes that vitamin C boosts immune function, but human studies published to date contradict each other.”
When Vitamin C Helps
As we noted in a previous post on immune boosting supplements, the proven benefits of vitamin C are small and probably not applicable to most of us. People under severe stress due to excessive physical exertion (such as marathon runners and soldiers training in subarctic conditions) may be less likely to catch a cold if they take vitamin C.
Several studies have shown that people who regularly take high amounts of vitamin C may suffer from shorter colds (recovering a day or half a day earlier), but the vitamin did not prevent them from getting sick in the first place. However, a 2013 Cochrane review concluded that the evidence is mixed and even shortened colds cannot be reliably detected in studies.
The National Institutes of Health summarizes the study as follows:
Overall, the evidence to date suggests that regular intake of at least 200 mg / day of vitamin C does not reduce the incidence of colds in the general population, but such intake may be beneficial for people exposed to extreme physical activity or cold environments and people with marginal vitamin C status, such as the elderly and chronic smokers.
When it isn’t
“There is no proven benefit to taking supplements after you have had cold symptoms,” says the Linus Pauling Institute. If you’ve already caught a cold, then the opportunity, perhaps, perhaps, to shorten the duration of the cold, has already passed.
The institute ‘s vitamin C information page contains information on research on other diseases, and I would recommend reading it if you want to know more. People who get enough vitamin C on a regular basis have a lower risk of certain diseases, including heart disease.
Fortunately, vitamin C is quite common in fruits and vegetables, and if you eat a healthy diet in general, you probably won’t have a problem meeting your needs. If you want to play it safe by taking pills or powder, there are not many drawbacks. High doses can sometimes cause diarrhea, but studies have not reliably shown any long-term or serious effects of a mega-dose of the vitamin. However, to be careful, a safe upper limit is considered to be a maximum of 2,000 mg per day.