Does Vitamin C Help Against Colds?

It’s an article of faith for many of us: popping a vitamin C supplement to protect ourselves from a cold or hoping the one we got will be shorter. Does it really work?

Linus Who?

The whole craze about vitamin C and colds started with chemist Linus Pauling and his book Vitamin C and the Common Cold. In it he claimed that high dosages of vitamin C prevent colds and make their durations shorter.

Since then it turned into common wisdom that vitamin C is the go-to vitamin once days get shorter and noses runnier. It probably didn’t hurt that Pauling had two Nobel prizes to his name.

The Science

Well, Nobel prizes don’t guarantee that you are right about everything. Since the 1970s, dozens of studies examined vitamin C and colds and most come to results like these three:

• In 1979, scientists conducted an experiment featuring 764 Marine recruits. Half of them received two grams of vitamin C per day, the other half got a placebo. Regardless of group, almost all participants got colds, with no difference in severity or length (PDF).
• A 1984 study put half of 528 volunteers into a placebo group and gave the other half 1 g vitamin C per day. In the vitamin C group 47% got colds, while it was 46% in the placebo group.
• In 2001, Australian researchers asked 149 volunteers to use vitamin C at daily doses of either 0.03 g (placebo), 1 g, or 3 g at the beginning of a cold and for the following two days. After monitoring these people and their colds for 1 1/2 years, no group had different experiences than any of the others.

Why I did say the most? Because a 2007 meta-analysis of available research came to similar conclusions as the above papers, with one important difference: for people who are under severe physical strain there can be an effect.

The Australians who did the review found six studies where vitamin C or a placebo were given to marathon runners, soldiers or skiers, all of whom experienced severe cold and high amounts of physical stress. Those taking vitamin C reduced their chance of getting a cold by about 50%.

Your Best Bet To Prevent Colds

So if you are very physically active, there’s a slight chance vitamin C can help you. Just don’t overdo it, because too much can lead to kidney stones. You are also well-advised to use two simple cold prevention methods that work for anyone: frequently wash your hands and get enough sleep.

People less often catch a cold by inhaling someone’s violent exhale (aka. sneeze), but by touching infected surfaces. Someone has a cold, sneezes, wipes his nose and then opens a door. You are next to push the handle, transfer the virus to your hands and then all it takes is you touching your nose or eyes and pretty soon …achoo!

Sleep is important because your immune system works best when you get enough rest. Carnegie Mellon researchers found that if you get less than seven hours per night, you are three times more likely to catch a cold.

Picture courtesy of William Brawley.