A recent article in the Journal of the American Medical Association (McAlindon et al., 2000) reviewed all the clinical trials that looked at the effects of glucosamine and chondroitin supplementation on pain relief and functionality associated with OA. They analyzed 15 studies and found that these compounds demonstrate moderate to large effects on OA symptoms, but note concerns over the quality of study designs and have questions regarding bias in some of the publications. Nevertheless, they conclude that the effectiveness of this supplementation, although found to be varied and possibly exaggerated, appears to be positive.
Further research is definitely needed in this area, and there is currently large-scale research being conducted. Many of the problems associated with the design of previous studies are being corrected - namely large populations are being tested, a strict double-blinded, randomized, and placebo-controlled structure is being followed, and the funding for the studies is being provided by sources other than the manufacturers of the supplements. For example, the National Institutes of Health (NIH) recently allocated $6.6 million to fund the largest study ever on these compounds. This nine-center study will begin in the summer of 2000 and include over 1000 patients. Patients will either receive both glucosamine and chondroitin, one of the two and a placebo, or a placebo for both. The patients will receive monthly evaluations that will look at levels of pain and how well the patients are able to perform everyday activities.
Furthermore, they will also compare the radiographs of joints taken at the beginning and end of the study to look for anatomical differences over the four-month period.
Once studies like the one above are completed, more definitive scientific evidence will be available to the medical community and they may make responsible recommendations on the use of glucosamine and chondroitin in the treatment of OA. Until then, the benefits of these supplements remain questionable and backed by variable and questionable clinical studies.
McAlindon TE, LaValley MP, Gulin JP, Felson DT. Glucosamine and chondroitin for treatment of osteoarthritis: a systemic quality assessment and meta-analysis. JAMA. Mar 15, 2000; 283 (11): 1469-75.
Glucosamine and Chondroitin Sulfate for Hip and Knee Osteoarthritis
There are many treatments for osteoarthritis (OA) that are being aggressively marketed despite lacking clinical evidence supporting their effectiveness and safety. Recently, glucosamine and chondroitin sulfate have received a great amount of positive promotion in the popular press as a miracle panacea for maintenance and pain reduction in joints. However, the popularity of these treatments has become a source of controversy within the medical community because they are commonly being used without definitive evidence of their effectiveness. A small number of placebo-controlled, randomized clinical trials have been conducted and have shown favorable preliminary results, although there are concerns over their small population sizes and flawed study designs. Even though early research appears encouraging for supporting the use of glucosamine and chondroitin in the treatment of OA, additional well-designed clinical evidence is needed before they may be widely recommended.
The rationale for using glucosamine and chondroitin sulfate in the treatment of OA stems from their roles in the production of the spongy cartilage that cushions joints. The cells responsible for preserving the cartilage and its surrounding matrix need glucosamine and chondroitin to properly maintain an adequate level of protection. Glucosamine and chondroitin are key components of the building blocks of cartilage, called proteoglycans. The reasoning follows that if one adds these building blocks, then a higher level of joint protection may be achieved. OA is characterized by an imbalance in the constant cycle of cartilage synthesis and degradation, and some think that adding glucosamine and chondroitin may reset the balance. Both of these compounds are naturally occurring throughout the body, so they are believed to be relatively safe to take at the recommended dosage.