American Ginseng Helps the Common Cold
February 16, 2006—A proprietary extract of American ginseng has been shown to reduce the number of colds suffered during the months of November through February, according to the Canadian Medical Association Journal (2005;173:1043–8). The study also found that the length of each illness, as well as the severity of symptoms, was reduced in the American ginseng group when compared to those taking placebo.
The study included 323 healthy people who took either American ginseng (Panax quinquefolium) extract, 200 mg twice a day, or a matching placebo, for four months. They kept a daily log to document the severity of cold symptoms, such as runny nose, sore throat, sneezing, nasal congestion, and headache. People taking the American ginseng extract had fewer colds throughout the study period than did those taking placebo. The proportion of people who had two or more verified colds during the study period was significantly lower in the American ginseng group. The severity of symptoms for each cold and the total number of days spent ill were also significantly lower in those taking the American ginseng.
American ginseng is different in its composition and effects than either Asian ginseng (Panax ginseng) or Siberian ginseng (Eleutherococcus senticosus), which have been studied extensively and have shown well-documented effects on energy levels and stamina. They are considered “adaptogens,” meaning they protect against the adverse effects of stress. American ginseng is not an adaptogen per se but is instead known for its immune-modulating effects, with particular potential as an antiviral agent. The immune-enhancing properties of American ginseng are mostly due to its polysaccharide content. It is not known how the proprietary extract used in the present study, which comprises 80% polysaccharides, compares in its composition or efficacy to other American ginseng extracts.
The study has its limitations. First, the researchers studied only healthy adults, so the effects on healthy children and on adults with chronic diseases or immune deficiency are not known. Second, the mechanism of action of the patented extract, as well as its comparative efficacy relative to other American ginseng extracts, is unknown. Lastly, there are potential conflicts of interest, as two of the authors were also employees of the sponsor, the same company that manufactures the patented product used in the study.
Nevertheless, this randomized, double-blind trial appears to have been otherwise well-designed and well-conducted. Further clinical trials of American ginseng for the common cold, and for influenza, are warranted by these encouraging results.
Jeremy Appleton, ND, CNS, is a licensed naturopathic physician, certified nutrition specialist, and published author. Dr. Appleton was the Nutrition Department Chair at the National College of Naturopathic Medicine, has served on the faculty at Bastyr University of Natural Health Sciences, and is a former Healthnotes Senior Science Editor and a founding contributor to Healthnotes Newswire. He has worked extensively in scientific and regulatory affairs in the supplement industry and is now a consultant through his company Praxis Natural Products Consulting and Wellness Services.
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