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.
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.
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.
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.
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.
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.
The report does not exaggerate the risks of the common cold.
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.
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.
Vitamin C supplements are widely available.
The report accurately describes vitamin C as widely used.
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.