Since the FDA (Food and Drug Administration) does not regulate dietary supplements as stringently as pharmaceutical drugs, manufacturers of the former can market their products with untested and unsupported claims. While some claims border on fantasy and may breach ethical standards (”pill that cures all cancers”), most claims are plausible. Calcium and vitamin D supplements may build bones. Iron sulfate may help with some forms of anemia. But, do we know whether the supplements truly provide their advertised effect?
Chondroitin sulfate and glucosamine have long been marketed as substances to alleviate the arthritides. This is a reasonable conjecture, given that chondroitin sulfate is a polysaccharide found in joint cartilage. One would logically assume that oral supplementation of this substance would help replenish eroded joints. Even the Mayo Clinic states that “consensus of expert and industry opinions support the use of chondroitin and its common partner agent, glucosamine, for improving symptoms and arresting (or possibly reversing) the degenerative process of osteoarthritis.” The Mayo Clinic, however, does not go so far as to fully endorse chondroitin use. It admits that “(s)afety and effectiveness have not always been proven”.
So, does it work? A meta-analysis published this week in the Annals of Internal Medicine hopes to address the question and controversy. The study included 22 independent research trials examining the efficacy of chondroitin use with osteoarthritis of the knee or hip. Twenty trials (3846 patients) had sufficient data to calculate effect of chondroitin use on joint pain. Twelve trials were used to assess adverse events, and 5 trials reported radiologic measurements of joint space width.
The authors understand the limitations of their study and concede to the variable experimental and reporting methodologies among the trials. They nevertheless assert that the “large-scale, methodologically sound trials indicate that the symptomatic benefit of chondroitin sulfate is minimal or nonexistant. Use of chondroitin in routine clinical practice should therefore be discouraged.” On the flip side, they did not identify any significant adverse effect. I suppose one downside of continued use would be wasted money.
In our subjective world, evidence-based medicine does not always determine our health choices. As long as there are proponents of chondroitin use, and deep pockets to keep the marketing campaigns moving, the sale of chondroitin and similarly questionable supplements will retain their presence on store shelves. At least we have the freedom of choice.
- Source
- Reichenbach S, Sterchi R, Scherer M, Trelle S, Burgi E, Burgi U, Dieppe PA, Juni P. Meta-analysis: chondroitin for osteoarthritis of the knee or hip. Ann Intern Med 2007;146:580-90.
