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NEW YORK (Reuters Health) - Two dietary supplements widely used by arthritis sufferers may indeed help slow the bone loss associated with the joint disease, a "basic science" study indicates.
In experiments with bone tissue samples from patients with knee arthritis, researchers found that the supplements -- chondroitin and glucosamine -- affected the activity of certain proteins involved in bone "remodeling."
Bone remodeling refers to the continuous process in which existing bone is broken down and replaced with new bone tissue. Osteoarthritis occurs when the cartilage cushioning the joints begins to break down; but there is also a breakdown in the bone underneath the cartilage.
Research suggests that this bone loss is related to an imbalance in the activity of the cells that break down bone (osteoclasts) and cells that build bone (osteoblasts).
The new findings, published in the journal Arthritis Research & Therapy, suggest that chondroitin and glucosamine may affect osteoblasts in a way that slows arthritis-related bone loss.
The results may help explain why the supplements have been shown to ease arthritis symptoms in some studies, according to the researchers, led by Dr. Steeve Kwan Tat of the University of Montreal Hospital Centre in Canada.
For the study, the researchers used osteoblast cells taken from patients undergoing knee-joint replacement for severe knee arthritis. They exposed some of the bone cells to chondroitin, glucosamine or a combination of the two, then analyzed the samples for changes in activity related to bone remodeling.
The researchers found that the supplements, particularly when used together, affected osteoblast activity in a way that may inhibit bone breakdown.
The results, they conclude, "provide interesting and insightful information about the mechanisms by which these drugs exert positive effects on the osteoarthritis disease process."
Whether arthritis sufferers actually benefit from the supplements is not completely clear. A recent large U.S. trial found that people with moderate-to-severe arthritis pain saw some relief, but those with milder symptoms did not.
In general, experts advise that arthritis patients talk with their doctors before trying chondroitin and glucosamine, and that they not abandon their current treatment.
SOURCE: Arthritis Research & Therapy, online November 9, 2007.
