Vitamin C, zinc and the common cold

When you start to get symptoms of a cold, do you rush to the store to stock up on vitamin C supplements and zinc lozenges? You might be better off saving your money. Here is a summary of the evidence:

Vitamin C:

Supplementing with high doses of vitamin C after the onset of cold symptoms showed no consistent effect on the duration or severity of the common cold.

However, taking vitamin C regularly as a preventative measure had no effect on the incidence of the common cold in the ordinary population, but  it had a small, but consistent effect in reducing the duration and severity of cold symptoms. Interestingly, regular vitamin C consumption reduced the risk of catching a cold in those exposed to short periods of extreme physical stress (such as marathon runners and skiers) by half.


Despite numerous clinical trials, there is no consistent evidence that zinc lozenges affect the duration or severity of the common cold.


Hemilä H, Chalker E, Douglas B. (2007). Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews, Issue 3. Art. No.: CD000980. DOI: 10.1002/14651858.CD000980.pub3.

Jackson, J.L, Lesho, E. & Peterson, C. (2000).  Zinc and the common cold: a meta-analysis revisited. Journal of Nutrition, 130(5): 1512S-1515S.

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About dinutrition

I hold a Master of Science degree in Human Nutrition. As you can imagine, food is a pretty big part of my life. However, I also enjoy painting, muay thai (yes I can throw a punch), yoga, writing, and am a certified personal trainer.

Posted on April 28, 2012, in Healthy eating, Nutrition and disease and tagged , , . Bookmark the permalink. 5 Comments.

  1. Fascinating. I thought that I’d read that zinc helped reduce the duration of a cold in half. I hadn’t read extensively on the subject, though.

    Also, I thought the Vitamin C thing was interesting when I learned about it in Nutrition class. It functions as an antihistamine, so it helps reduce the perceivable effects of the cold. However, it does nothing for the cold duration itself.

    Great post!

  2. You know–if you have enough zinc in your system– it will taste terrible to you! Otherwise, they are supposed to taste like nothing. I tested this with my accupunturist –we both had the same reaction and others didn’t. Your study could be a bit old (2000). There seems to be both pros and cons depending on where you look–seems to be a lot of controversy surrounding zinc.

    • Interesting, I didn’t know that! The study is a bit old, but the consensus is still the same. Some studies show a benefit, while others don’t. Zinc is necessary for the immune system, but there is no consistent evidence that taking zinc after you get sick will help. As with all nutrients, it is best to be consuming an adequate amount on a daily basis.

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