Josephine P. Briggs, M.D.
During the peak of cold and flu season, it's hard not to notice the cascade of claims about products that “boost immune health” and prevent and treat the viruses that cause the flu and the common cold. Many of these products are sold as dietary supplements and marketed as “natural” remedies. Dietary supplements for colds and flu is a big business, generating about $2 billion in sales in 2010, according to the Nutrition Business Journal. But behind these claims, what does the science say about these products?
The flu can cause serious complications, especially in very young children, older adults, pregnant women, and people with underlying medical problems, which is why vaccination is the best protection against contracting the flu. Starting in 2010, the Centers for Disease Control and Prevention has recommended annual flu vaccination for all people aged 6 months and older. There currently is no strong scientific evidence that any natural product is useful against the flu.
Colds are generally less severe than the flu and in most cases don't cause serious complications. Unlike the flu, there is scientific evidence about several natural products for colds, such as zinc, vitamin C, echinacea, and probiotics. For information on what the science says about these natural products, take a look at our updated fact sheet, The Flu, the Common Cold, and Complementary Health Practices.
In previous Director's Messages, I've talked about excessive product claims and emphasized the importance of consumers to educate themselves and be wary of unsupported health claims. I cannot overstate this point—consumers should think critically about what they read in advertisements or on product labels. Does a claim sound too good to be true? Is it supported by rigorous scientific research?
If you are thinking about using a natural product to prevent or treat the flu or colds, first get information on the product from reliable sources. The NCCAM Web site offers information about complementary health practices, including natural products, for the flu and colds. The NIH Office of Dietary Supplements and MedlinePlus also provide reliable information. You should keep in mind that although many dietary supplements (and some prescription drugs) come from natural sources, “natural” does not always mean “safe.” Talk to your health care provider about your use of dietary supplements or other forms of complementary health practices to help ensure safe and coordinated care during this cold and flu season. Take care and be well!