A report in the July 28 New England Journal of Medicine (NEJM) provides no support for the efficacy of echinacea, one of the most popular herbal products, in preventing or alleviating the symptoms of the common cold. Millions of Americans use supplemental echinacea, which is made from any one of several species of the purple coneflower, for just those purposes. But should they rely on it?
In the study, supported by the federal National Center for Complementary and Alternative Medicine of the National Institutes of Health, researchers tested extracts of Echinacea angustifolia roots on 399 healthy young volunteers who agreed to be exposed to cold viruses. Some of the participants were given echinacea before being exposed to see if the supplement prevented illness, while others were given a placebo. After exposure, some continued to receive echinacea, while others got a placebo.
All the volunteers were secluded in hotel rooms for five days after exposure, while the researchers performed nasal washings (to look for virus particles and immune system response) and assessed the presence and severity of any cold symptoms.
The timing of the doses didn't make any difference. Echinacea neither prevented the onset of cold symptoms nor did lessened their severity in the cases of people who actually became ill.
The American Botanical Council, a non-profit organization based in Austin, TX, downplayed the significance of the study's results, suggesting that higher doses than those used in the study should be tested. The group also pointed out that the echinacea extracts tested were made in the researchers' lab and were not necessarily the same as the products consumers would buy in stores. They did admit, however, that the NEJM researchers were experienced in studying the herb and that the study was well designed and executed.
But Dr. Wallace Sampson, an ACSH scientific advisor, in a commentary in the NEJM, takes the opposite point of view. In his opinion, we have reached a point of marginal returns with respect to studying the effects of such remedies. Noting that the NIH has spent nearly $1.5 billion since 1999 supporting research into alternative medicine methods, with "no evidence of efficacy and little evidence of inefficacy," he states that NCCAM "must consider halting its search for active remedies through clinical trials of treatments of low plausibility."
Although the alternative medicine movement is alive and well in the United States, we must acknowledge that very few of the remedies in its domain have been shown to be efficacious by the standards of modern science. Some, as we have pointed out (see http://www.acsh.org/factsfears/newsID.389/news_detail.asp, http://www.acsh.org/factsfears/newsID.143/news_detail.asp, and http://www.acsh.org/publications/pubID.515/pub_detail.asp) can interfere with the action of prescription medications such as oral contraceptives and immunosuppressant drugs.
Perhaps, as Dr. Sampson has suggested, we might gain more by studying the "psychology of personal beliefs in irrational proposals [and] in the study of erroneous thinking" than by continued testing of products that seem to benefit their producers more than their consumers. Dr. Gilbert Ross, ACSH medical director adds, "There is no such thing as 'alternative' medicine. Medical science deals with effective and safe treatments, based on objective evidence. The 'alternative' is not medicine, but superstition or faith."
Ruth Kava, Ph.D., R.D., Director of Nutrition, American Council on Science and Health (ACSH.org, HealthFactsAndFears.com).
