Taking glucosamine does not adversely affect blood sugar control in diabetics, according to a report in Archives of Internal Medicine (2003;163:1587?90). This study confirms the results of a previous report and should allay the concern voiced by some scientists that glucosamine has the potential to increase blood sugar levels.
Glucosamine, a compound that occurs naturally in the body, is available as a nutritional supplement and usually taken in the form of glucosamine sulfate. Glucosamine serves as a building block in the production of a type of cartilage present in joints. Studies have shown that glucosamine can promote the repair of damaged or degenerating joint cartilage. Numerous double-blind studies of people with osteoarthritis have demonstrated that glucosamine is significantly more effective than a placebo and at least as effective as commonly used anti-inflammatory medicines at relieving pain and improving joint function. Moreover, glucosamine is one of only a few substances that have been shown to slow the progression of osteoarthritis. In contrast, anti-inflammatory drugs may actually accelerate the disease process, even though they may temporarily improve symptoms.
While glucosamine is generally considered to be safe and has not been associated with any serious side effects, preliminary studies in animals suggest that it could cause insulin resistance and other abnormalities of blood sugar metabolism. The relevance of these studies to humans has been questioned, however, since glucosamine was administered in the animal studies in relatively large amounts by continuous intravenous infusion.
In the new study, a group of elderly people with type 2 (adult onset) diabetes were randomly assigned to receive either a placebo or the combination of glucosamine hydrochloride (1,500 mg per day) and chondroitin sulfate (1,200 mg per day) for 90 days. Chondroitin sulfate is another natural substance that is sometimes used in combination with glucosamine to treat osteoarthritis. Chondroitin sulfate has not been found to affect blood sugar levels. A laboratory test that assesses long-term blood-glucose control (hemoglobin A1c) was performed at the beginning and the end of the study. Compared with the placebo, glucosamine-chondroitin treatment had no significant effect on hemoglobin A1c levels. None of the participants required a change in their diabetes medication during the study.
The absence of any effect on blood sugar control is consistent with the results of a previous study of nondiabetics. In that study, supplementing with 1,500 mg of glucosamine sulfate per day for three years was associated with a slight decrease in blood sugar levels. Taken together, these studies strongly suggest that people with diabetes can safely take glucosamine, and that supplementing with this natural osteoarthritis remedy does not increase the risk of developing diabetes.
Alan R. Gaby, MD, an expert in nutritional therapies, testified to the White House Commission on CAM upon request in December 2001. Dr. Gaby served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A?Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient?s Book of Natural Healing (Prima, 1999). A former professor at Bastyr University of Natural Health Sciences, in Kenmore, WA, where he served as the Endowed Professor of Nutrition, Dr. Gaby is the Chief Medical Editor for Healthnotes, Inc.