Can Vitamin C really prevent us from getting sick?

It’s that time of year again – cold season. You walk into class and can’t go a minute without hearing someone cough or sneeze, and being in close proximity with so many sick people and germs (especially in the dorms) makes it extremely hard not to be affected. Something that my roommate swears by, though, is Vitamin C. She told me that as soon as she feels the symptoms of a cold coming on, she takes Emergen-C, an immune system booster with 1,000 mg of Vitamin C in it. Can it be true that something as simple as Vitamin C can actually prevent a week and a half of coughs, sore throats, and fatigue? The null hypothesis would be that Vitamin C doesn’t have any real effect on sickness while the alternative would be that it prevents you from getting a cold! I researched the answer to this question, and it’s actually not so simple.



First Study

The most famous study done on this topic was the 2007 Cochrane review. The review examined placebo trials involving the consumption of at least 200mg/day of Vitamin C taken either continuously to prevent colds or after the onset of cold symptoms. The overall conclusion was that the continuous consumption of Vitamin C didn’t help prevent cold’s in the general population, but actually reduced the chance of people like athletes, runners, soldiers, and basically everyone exposed to extreme physical activity by 50%. It did show, though, that continuous consumption of Vitamin C can shorten a cold by a few days. Although the mechanism for these results is unknown, a possibility could be that the anti-histamine effect of high-dose Vitamin C. When we are exposed to histamines, they attach to the cells in our body and cause them to swell and leak fluid, also causing itching, sneezing, and watery eyes. By reducing these symptoms with Vitamin C, the cold could possibly last a shorter period of time.


Meta-Analysis Review

A meta-analysis review, published by Harri Hemila from the Department of Public Health at the University of Helsinki in Finland, talks about all the shortcomings of studies that claim that Vitamin C does in fact prevent colds. Hemila lays out all eight studies that have been done on the subject, as well as the results including Vitamin C’s effect on duration or severity on the cold. The results all had the same thing in common: the effect of Vitamin C was not great enough to claim that it effectively prevents colds or aids in getting rid of them.

Sadly, we have to reject the alternative hypothesis, but even though Vitamin C doesn’t necessarily prevent colds from happening, that doesn’t mean that it isn’t important. For example, we discussed in class how sailors would go on extremely long trips and would have their teeth fall out (scurvy). They figured out that sucking on lemons prevented this, even if they didn’t know the mechanism behind it. It was discovered that Vitamin C prevented scurvy, making it a necessary aspect of our diet. Vitamin C has many other uses other than cold prevention, let’s just hope that something that does prevent colds gets discovered soon. It would be incredibly useful, especially on college campuses.


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1 thought on “Can Vitamin C really prevent us from getting sick?

  1. dff5115

    This post was very well written and insightful. I am one of those people that as soon as i start to get sick i start to take vitamin C. I’ve known for a while that it does directly help shorten colds but i still do it anyway. I start to feel better after taking it but i believe this is do to a placebo effect. Just the fact that i think it will help me makes me start to feel better.

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