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Busting the vitamin C myth


3 Star

Busting the vitamin C myth

Our Review Summary

This report does a good job of using a recent, credible report to debunk the myth that taking vitamin C can prevent or treat colds. The segment uses its medium fairly well to deliver the key message.

The piece has two major weaknesses.

  • First, it fails to make clear the distinction between the benefits of vitamin C supplements and whole foods rich in the vitamin.
  • More important is the overstatement the physician-journalist made about the possiblilty the vitamin itself can help prevent cancer. This is a major error that can mislead viewers about a very serious condition. (This problem is compounded at the end of the piece when the host says, "I’m still taking vitamin C," without any challenge from the physician-journalist.)

At the end of the piece, the host tells viewers that more information is available from its online partner, WebMD. This is commendable, a best practice in broadcast medical news. The WebMD article does indeed provide additional details about the Cochrane report that can help viewers understand the topic better.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

Information about how much it would cost to take the vitamin prophylactically for a year would have made a useful point–taking vitamin C isn’t just ineffective, it’s costly. It would also have been good to report how much money Americans spend on vitamin C products to treat colds–not just the supplements but lozenges, often-expensive vitamin C products marketed for cold treatment, etc. 

Does the story adequately quantify the benefits of the treatment/test/product/procedure?


The physician-journalist accurately describes the findings in a way people can easily understand on television–essentially that there is no benefit of taking C in preventing colds, with the exception of one key subgoup of little relevance to most Americans. Given the nature of the findings, more precise quantification is not needed.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

The report fails to indicate that taking high levels of vitamin C, as some advocates suggest, can have serious health consequences, from dental erosion to kidney toxicity. It can also interact with aspirin and other drugs. 

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

The story looked at numerous trials that passed a high quality bar. It also identified the source of the information well. 

But the physician-reporter added a worrisome note that "it [vitamin C] may even help prevent cancer for sure." This is a broad, potentially misleading overstatement for which no evidence is given. In fact, the American Cancer Society makes clear that diets rich in fruits and vegetables, which are high in vitamin C and many other nutrients, are believed to reduce risk of cancer. The ACS makes clear that there is no evidence linking the vitamin itself to reduced cancer risk.

This problem is compounded at the end of the piece when the host says, "I’m still taking vitamin C," without any challenge from the physician-journalist.  

Does the story commit disease-mongering?


The report does not exaggerate the risks of the common cold.

Does the story use independent sources and identify conflicts of interest?


The segment accurately indicates the high crediblity of the Cochrane group, and there appear to be no underlying conflicts of interest that would call the conclusions into question.  

Does the story compare the new approach with existing alternatives?

Not Satisfactory

When the discussion shifts to the importance of adequate intake of vitamin C, the physician-journalist fails to make sufficiently clear that the known benefits of vitamin C are from eating whole foods high in the vitamin. Thus the viewer does not fully understand that eating these foods is a wise alternative to taking the supplements.  

The report ends nicely with the note that the only proven method of reducing colds risk is to wash hands.

Does the story establish the availability of the treatment/test/product/procedure?


Vitamin C supplements are widely available.

Does the story establish the true novelty of the approach?


The report accurately describes vitamin C as widely used.

Does the story appear to rely solely or largely on a news release?


Like most media reports of this study, this one drew heavily on the Cochrane abstract itself. It shares some language with other reports, but not in a way that demonstrates lack of rigor.

Total Score: 6 of 10 Satisfactory


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