Easing Arthritic Pain
How a supplement often used on animals is helping humans, too.
"While this study design won't answer how the supplements work," says Daniel O. Clegg, MD, professor of medicine at the University of Utah and the NIH study coordinator, "it will be able to say with some real authority whether or not they work." This kind of clarity is needed. A review in the March 15 Journal of the American Medical Association criticized many of the past studies for possible bias and exaggeration. Even so, author Timothy McAlindon, DM, concludes that the supplements appear helpful.
How might they work? Osteoarthritis results from a breakdown of cartilage, the protective coating around the bones at the joints, Clegg says. Without this smooth and springy substance, the bones scrape against each other, which can cause chronic pain and limit range of motion.
Both glucosamine and chondroitin are synthesized by the body and are naturally found in cartilage. Clegg and other researchers theorize that glucosamine somehow helps create new cartilage, while chondroitin may slow cartilage destruction. Taken together, some experts say, the combination offers a one-two punch against the wear-and-tear of osteoarthritis. NSAIDs, in contrast, primarily mask the symptoms.
Also unlike NSAIDs, glucosamine and chondroitin don't cause symptoms such as stomach upset, nor do they carry the risk of ulcer formation. Although some people have experienced mild gas, the side effects from the supplements are negligible, according to the Arthritis Foundation's position statement. If you're thinking about trying glucosamine and chondroitin, the Foundation advises a few precautions, however. Patients who are taking the blood-thinning medication heparin -- whose molecular structure is similar to chondroitin -- should have their blood clotting activity monitored if they add chondroitin. Taking both at the same time could increase the risk of bleeding. Diabetic patients wanting to try glucosamine (an amino sugar) should consider potential effects on their blood sugar control. If you're allergic to shellfish, avoid taking glucosamine, which is made from crab, lobster, or shrimp shells. (Chondroitin is manufactured from cow cartilage.) And before you rush out to buy either of them, make sure that osteoarthritis is the cause of your pain; glucosamine and chondroitin don't seem to help other forms of the disease, such as rheumatoid arthritis. Of course, it's always a good idea to talk to your doctor first.