WASHINGTON — Some of the botanical agents that are widely used among diabetic patients may have benefit—but more data are needed, Laura Shane-McWhorter, Pharm.D., said at the annual meeting of the American Association of Diabetes Educators.
Regardless of whether these unregulated products are beneficial, clinicians need to stay educated on the topic, since “this is something that all of us get asked about at one point or another,” said Dr. Shane-McWhorter, a certified diabetes educator and a professor at the University of Utah in Salt Lake City.
It's important to make sure patients aren't substituting complementary/alternative therapies for prescribed medications—cases of diabetic ketoacidosis have been reported among some who have, she said.
In addition, patients need to know that combining glucose-lowering botanicals with prescription diabetes medications may increase the risk of hypoglycemia.
The following are among the most popular of the more than 100 complementary/alternative therapies used to treat diabetes, Dr. Shane-McWhorter said.
Cinnamon
This everyday spice has received lots of attention lately. Its active ingredient, the polyphenolic polymer hydroxychalcone, is believed to enhance insulin action by increasing glucose uptake and glycogen synthesis. Side effects are limited mostly to the very rare topical allergic reaction.
But, like the others, it carries the theoretical potential for an additive hypoglycemic effect if combined with an insulin secretagogue.
In a randomized trial, 60 patients with type 2 diabetes were given 1, 3, or 6 grams of cinnamon four times daily or placebo. At 40 days, fasting blood glucose (FBG) had dropped from 209 to 157 mg/dL with 1 g cinnamon, from 205 to 169 mg/dL with 3 g, and from 234 to 166 mg/dL with 6 g. All changes were statistically significant compared with placebo, and the effect was still seen 20 days after cinnamon was stopped. Total cholesterol, triglycerides, and LDL cholesterol also dropped in the cinnamon groups (Diabetes Care 2003;26:3215–8).
The data are at least good enough to support a recommendation that patients use ½ to 1 teaspoon of ground cinnamon per day on cereal or other foods, she advised.
Gymnema sylvestre
From the Indian word “gurmar,” meaning “sugar-destroyer,” Gymnema sylvestre is thought to block both the craving for sweets and intestinal glucose absorption, increase cell permeability to insulin, and stimulate β-cell number and function.
Hypoglycemia has been reported with this agent when combined with insulin secretagogues.
In two small studies, 400 mg/day of Gymnema sylvestre leaves significantly reduced hemoglobin A1c values in both type 1 (from 12.8% to 8.2% at 26–30 months) and type 2 diabetic patients (from 11.9% to 8.5% at 20 months). The 27 type 1 patients were able to reduce their insulin doses by a mean of 15 units, while 5 of the 22 patients with type 2 diabetes were able to discontinue sulfonylureas (J. Ethnopharmacol. 1990;30:281–94).
However, these authors did not report randomization or blinding, and there was a high dropout rate among the type 1 patients. More human research using a standardized version of Gymnema sylvestre is now being conducted in the United States by the Omaha-based company Informulab Naturals (
Other diabetes medications may need to be adjusted for patients who choose to use Gymnema sylvestre, and it should not be used in patients already on combination therapy, Dr. Shane-McWhorter advised.
Fenugreek
Used for many years to promote lactation, fenugreek (Trigonella foenumgraecum) contains a variety of ingredients including saponins, alkaloids, coumarins, and glycosides. Its mechanism of action is thought to be related to its high fiber content. It delays gastric emptying and inhibits carbohydrate absorption, and may also stimulate insulin secretion. It has also been used to treat hyperlipidemia and constipation, in addition to diabetes.
Side effects include gastrointestinal hypersensitivity and topical allergies. It also may stimulate uterine contractions. Fenugreek should be used with care in peanut-allergic patients, since it belongs to the same plant family. Fenugreek may interact with other anticoagulants (including Ginkgo biloba and ginger), interfere with the effects of steroids and hormones, and/or potentiate the effects of monoamine oxide inhibitors, she said.
In a study of 25 patients newly diagnosed with type 2 diabetes, 12 received 1 g/day of hydroalcoholic extract of fenugreek seeds, while the other 13 received placebo. The differences in FBG and 2-hour postprandial glucose were not significant at 2 months. However, the area under the curve for both blood glucose and insulin levels were lower in the fenugreek patients, who also showed significant improvements in both serum triglycerides and HDL cholesterol compared with placebo (J. Assoc. Physicians India 2001;49:1057–61).