Herbs for Diabetes
Are supplements safe?
July 31, 2000 -- When 40-something Jeff Cottingham was diagnosed with type 2 diabetes, his doctor immediately started him on drugs to control his blood sugar. But Cottingham worried.
Some drugs for diabetes can have dangerous side effects. In a striking example, on March 21, 2000, the U.S. Food and Drug Administration (FDA) removed one of the most widely prescribed diabetes drugs, Rezulin (troglitazone), from the market after it was linked to 90 cases of liver failure and 63 deaths.
Already concerned about such problems two years ago, the Aptos, Calif., resident began taking Sweet Eze, a mixture of herbs and minerals sold for diabetes. The supplement seemed to work wonders for the self-described "old hippie."
His level of glycosylated hemoglobin (HbA1c) -- a protein that reflects blood glucose levels over the past two to three months -- plummeted from 11 to well below the danger threshold of 6. "I feel great," says Cottingham, who has experienced no side effects from the supplement. "I'm completely off diabetes medications now."
A success story? Perhaps. But experts advise caution. For one thing, because Sweet Eze contains six different ingredients -- and because the severity of diabetes symptoms can fluctuate on their own -- it's hard to say what exactly is responsible for Cottingham's improvement. For another, supplements carry their own risks. Some products don't contain the ingredients listed on their labels. Others come mixed with dangerous -- and unlisted -- ingredients. And scientists are just beginning to verify which ones actually work.
Doing Ginseng Justice
One herb touted for diabetes got a boost recently from a Canadian clinical trial. University of Toronto researcher Vladamir Vulksan, PhD, announced at the American Diabetes Association (ADA) annual meeting in June 2000 that he'd gotten some positive results using ginseng.
In addition to their usual diabetes regimen -- a careful diet, regular exercise, and in some cases, medication -- 23 type 2 diabetic patients took either 3 grams of American ginseng or a placebo each day for eight weeks, at which point they switched treatments. The diabetic patients' fasting blood sugar levels dropped about 9% more when they took ginseng compared with when they took the placebo; glycosylated hemoglobin levels between the two groups differed by 4%, with the ginseng group being lower.
Despite these encouraging results, Vulksan cautions that it's too early for diabetic patients to rely on ginseng. Herbs sold in this country are not standardized, he says, so it's difficult to know for certain what you're buying and impossible to ensure consistent dosages. Besides, his study looked only at American ginseng, and he's not certain the results would hold true for the seven other varieties. What's more, researchers haven't conclusively identified ginseng's active ingredients.
Meanwhile, other scientists are studying fenugreek seeds, a folk remedy for diabetes. Several studies, including one published in 1990 in the European Journal of Clinical Nutrition suggest that this herb can lower blood sugar. Researchers found that type 1 diabetics who took 50 grams of fenugreek seed powder twice daily had significantly lower blood sugar levels than those who took a placebo.
Little is known about how other herbs might help control diabetes. Stevia and bilberry have been studied in animal experiments, but have yet to undergo large, controlled human studies. The reputation of two other herbs, gymnome and jambul, rests on anecdotal evidence alone.
The ADA steers people away from herbal remedies altogether. "The regulation of herbs isn't very good," says Anne Daly, MS, RD, a diabetes educator with the organization. "And we can't be sure that all supplements are equivalent."
Some herbal diabetes products have turned out to be downright dangerous. In February 2000, the FDA recalled five Chinese herbal products after discovering that they contained various amounts of two prescription diabetes drugs, phenformin and glyburide. (The products are listed at www.fda.gov/oc/po/firmrecalls/Herbal.html.) Phenformin was withdrawn from the U.S. market 20 years ago after it caused serious side effects, including several deaths.
Given these uncertainties, some people are turning to mineral supplements instead of herbs. One that shows great promise, chromium, is a trace element that seems to help insulin work properly.