Herbal Products May Not Be What They Claim To Be   (November 10, 2013)

Diabetes, as well as many other medical conditions, has attracted charlatans who recommend various herbs, potions, and other alternative methods of treatment. Some of these products have been proven worthless (see the study mentioned below), and  none are recommended by diabetes authorities.

For example, the ADA’s Nutrition Therapy Recommendations for the Management of Adults With Diabetes  states that “There is no clear evidence of benefit from vitamin or mineral supplementation in people with diabetes who do not have underlying deficiencies. Routine supplementation with antioxidants, such as vitamins E and C and carotene, is not advised because of lack of evidence of efficacy and concern related to long-term safety. There is insufficient evidence to support the routine use of micronutrients such as chromium, magnesium, and vitamin D to improve glycemic control in people with diabetes. There is insufficient evidence to support the use of cinnamon or other herbs/supplements for the treatment of diabetes. It is recommended that individualized meal planning include optimization of food choices to meet recommended dietary allowance/dietary reference intake for all micronutrients.”

Finding reliable information about the benefits and safety of these products is difficult. In 2003, Diabetes Care published a Systematic Review of Herbs and Dietary Supplements for Glycemic Control in Diabetes; you can find an on-line tabulation of supplements that have studied in controlled clinical trials (many of which didn’t have any effect on glucose or other outcomes). The authors concluded “There is still insufficient evidence to draw definitive conclusions about the efficacy of individual herbs and supplements for diabetes.” I don’t think the situation has changed in the last decade.

In fact, it’s now worse. A recent study, DNA barcoding detects contamination and substitution in North American herbal products, looked at herbal products using a technique called DNA barcoding (whatever that might be!) and found that “Herbal products available to consumers in the marketplace may be contaminated or substituted with alternative plant species and fillers that are not listed on the labels.” In other words, what’s on the label ain’t necessarily in the bottle. The main herbal ingredient was substituted with some other product in 32% of the samples tested. Unlabeled fillers that were not listed on the label were identified, including rice, soybean and various grasses such as wheat. The authors pointed out that this could be a health concern for people allergic to these plants, as well as for people seeking gluten-free products.

This study was not aimed at diabetes herbal products per se, but instead the researchers used blind sampling, and  chose not to disclose any product names. So, unlike the products listed in the table mentioned above, we have no idea if the products found in this DNA barcoding study were, or were not, targeted at people with diabetes.

Two points are clear: If you buy a herbal supplement, what you think you may be buying isn’t necessarily what you’ll be getting. And there’s no place in the treatment of diabetes for herbal supplements (even if they were correctly identified on the label).