Researchers at St. Michael's Hospital and the University of Toronto have found that taking American ginseng before a meal reduces blood sugar in people both with and without diabetes. The study appears in the April 9 issue of the Archives of Internal Medicine, a publication of the Journal of the American Medical Association (JAMA).
Dr. Vladimir Vuksan, lead investigator for the study, says that these findings may have important implications for the treatment and prevention of diabetes, a disease affecting approximately eight per cent of North American adults and continually rising. "Although preliminary, these findings are encouraging and indicate that American ginseng's potential role in diabetes should be taken seriously and investigated further. Controlling after-meal blood sugar levels is recognized as a very important strategy in managing diabetes. It may also be important in the prevention of diabetes in those who have not yet developed the disease."
Study participants, both diabetic (Type 2) and non-diabetic, consumed capsules containing three grams of ground Ontario-grown American ginseng either 40 minutes before or during a glucose test meal. Among participants with Type 2 diabetes, those who took the ginseng capsules experienced a 20 per cent reduction in blood sugar levels compared to when they took placebo capsules. Among non-diabetic participants, similar reductions were only seen when the ginseng capsules were taken before, not together, with the test meal, suggesting that the timing of administration may be important. (The trial was an acute clinical study and did not compare the diabetic participants to the non-diabetic participants.)
Although the results are encouraging, Vuksan, who associate director of the Risk Factor Modification Centre at St. Michael's Hospital and assistant professor in the department of nutritional sciences at the University of Toronto, cautions that people should not use these findings as justification to start taking ginseng.
"This is an initial, short-term study that only indicates a need for more research. We don't know what the effects of long-term consumption of ginseng will be. Because of poor standardization in the herbal industry, we also don't know if these findings will hold true for all American ginseng products. Nor do we know whether taking different speciesof ginseng such as Chinese or Japanese will have the same outcome."
In addition to implications for diabetes management, this study has considerable significance for broader research on herbals as potential medical treatments, an area that has generated a great deal of public controversy in recent years. "This study represents an important step in the evaluation of herbals," says Vuksan. "A major criticism of the herbal field and past ginseng research has been the lack of scientific, placebo-controlled trials in humans. Our study applied traditional clinical trial standards to research on an alternative medical product."
The use of herbals in North America has increased dramatically over the last decade and ginseng is one of the most widely-used herbs worldwide. There are several types, including American, Chinese, Japanese and Siberian. For the last 2000 years of Chinese traditional medicine, ginseng has been used as a tonic with supposed curative, restorative and aphrodisiac properties. Most of these claims have been based on anecdotal and other non-scientific observations. It is only recently that tests of ginseng have begun in humans, using rigorous scientific techniques.
Chai-Na-Ta, Langlay B.C., the world's largest supplier of American ginseng, provided ginseng samples and, together with the Ontario Ministry of Agriculture, the funding for this study.
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St. Michael's Hospital