For years, doctors, patients, and scientists have debated the benefit of two popular supplements—glucosamine and chondroitin sulfate—often used to manage pain and bone loss related to arthritis. While most research efforts have produced muddled results, a new 2-year study published in the Annals of Rheumatic Diseases reveals some significant reductions in cartilage loss among knee osteoarthritis (OA) patients who take the supplements. Researchers from the University of Montreal Hospital Research Center and the University of Maryland Medical Center followed 600 knee OA sufferers—roughly a third of whom took the two supplements—and conducted regular MRI measurements of cartilage loss. The results: Joint space width—a measure of the amount of cartilage left in the knee joint—was significantly more stable among the glucosamine and chondroitin sulfate takers. The supplements appeared to be the most beneficial in slowing cartilage loss among patients with early or moderate forms of OA.  But the supplements didn’t help everything: There were not significant reductions in pain scores among the supplement takers. The researchers also note that it was difficult for them to control the dosage and quality of the supplements taken, because glucosamine and chondroitin sulfate are considered “nutritional supplements” in the US—meaning they’re not regulated like medical drugs. (Patients reported their own supplement and drug use; the researchers did not dispense the medicines.)  So how do they work? The supplements appear to reduce the progression of OA by disrupting pathways leading to cartilage degradation and bone remodeling—though the exact mechanism at work isn’t clear, says study lead author Johanne Martel-Pelletier, PhD, of the University of Montreal.  Her advice? OA sufferers—especially those in the early stages of the disease—should consider taking glucosamine and chondroitin sulfate to slow cartilage loss. The recommended therapeutic daily dosage for glucosamine sulfate is 1500 mg, and 800-1200 mg for chondroitin sulfate, she says, and the two are nearly always sold in combination. Offerings from Simply Right ($20, amazon.com) and GNC ($20, amazon.com) were found to contain the proper amounts of both supplements without unhealthy contaminants, according to an analysis from ConsumerLab.com.
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