Since the book "The Arthritis Cure" was sold in bookstores across the country in 1997, physicians, pharmacists, and arthritis sufferers have frequently been asked their opinion of glucosamine as a treatment for arthritis. The word "cure" in the title of the book raised the hopes of many who suffer with the disease.
How Glucosamine Works
Glucosamine is found in high concentrations in the joints. It has been theorized that glucosamine stimulates the formation of cartilage that is essential for joint repair. In animal models, oral glucosamine sulfate has a beneficial effect on inflammation, mechanical arthritis, and immunological-reactive arthritis, though much less so than indomethacin and other such drugs.
Glucosamine is sometimes used in combination with chondroitin sulfate as a treatment for arthritis. Chondroitin sulfate is also found in cartilage. Chondroitin sulfate reportedly maintains the viscosity in joints, stimulates cartilage repair mechanisms, and inhibits enzymes that break down cartilage.
Glucosamine is sold in the United States as a dietary supplement. The Dietary Supplement Health and Education Act passed in 1994 by Congress allows the marketing of a product claimed to affect the structure or function of the body as a "dietary supplement" without the approval of any government agency. The labeling must include a disclaimer that the product has not been evaluated by the FDA and the product is not intended to diagnose, treat, or prevent any disease. Glucosamine is available in pharmacies and health food stores as the sulfate, hydrochloride, n-acetyl, or chlorhydrate salt.
Short term controlled studies have reported glucosamine as effective in relieving pain in patients with osteoarthritis and for increasing their range of motion. A four-week double-blind trial of 252 patients with osteoarthritis of the knee found oral glucosamine sulfate 500 mg. three times a day more effective than placebo in relieving symptoms.
Another four-week double-blind trial of 200 patients with osteoarthritis of the knee revealed 500 mg. of glucosamine sulfate as effective in relieving symptoms as ibuprofen 400 mg. three times a day, after the second week.
In a double-blind eight week study of 40 patients with osteoarthritis, glucosamine sulfate 500 mg. three times a day orally was as effective as ibuprofen 400 mg. three times a day in relieving pain after the first two weeks. In all reports glucosamine was generally well tolerated with the incidence of gastrointestinal upset no higher than placebo.
These studies, though yielding desirable results were not considered well-designed studies. Well-designed studies must be conducted using sufficient numbers of patients over sufficient periods of time, at least one year, by experienced investigators, using objective measures and statistical techniques that can determine if improvement is the direct result of the treatment. These studies met few of the criteria and were conducted on far too few patients.
According to a 2004 Canadian study, involving 137 patients, no significant difference was found between the percentage of participants who flared in a placebo group versus a glucosamine group.
At the ACR Annual Meeting 2005, results from two glucosamine trials were presented. GAIT (Glucosamine/Chondroitin Arthritis Intervention Trial) was funded by the NIH and designed to determine safety and efficacy with glucosamine, chondroitin, taken separately or together, and GUIDE (Glucosamine Unum In Die Efficacy) was a European clinical trial. GUIDE results showed glucosamine provided more relief than acetaminophen.
GAIT results showed the combination of glucosamine and chondroitin is better than placebo but the benefits seem to depend on severity of pain. In patients with mild knee osteoarthritis pain, the glucosamine chondroitin combination was not significantly more effective than placebo.
The consensus is that glucosamine and chondroitin supplements might lessen pain in some patients with osteoarthritis. Many doctors now believe it is worth trying these supplements for osteoarthritis. They appear to be safe, but doctors are warning patients that the quality and effectiveness of glucosamine and chondroitin varies because of the non-regulation. If you want to try them, buy high quality products from a reputable source.
Related Resources - Glucosamine
Related Resources - Osteoarthritis
Sources: The Book That Promises A Cure, Arthritis Today, May-June 1997; Try Glucosamine For OA, Arthritis Today, July-August 1998; Glucosamine For Arthritis, 1997 The Medical Letter, Quackwatch Home Page