Dietary supplements may slow bone loss

Two dietary supplements widely used by arthritis sufferers may help slow the bone loss associated with the joint disease.

In experiments with bone tissue samples from patients with knee arthritis, the supplements � chondroitin and glucosamine � affected the activity of certain proteins involved in bone "remodelling." Bone remodelling 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. 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).

Researchers from the University of Montreal Hospital Centre in Canada 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 analysed the samples for changes in activity related to bone remodeling. It was found that the supplements, particularly when used together, affected osteoblast activity in a way that may slow bone breakdown.

The results provide interesting information about and an insight into 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 US 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.