Osteoarthritis (OA) is the complete medical name for the condition generally referred to as “arthritis.” The most common joint disease in humans and all vertebrate animals, osteoarthritis is a universal affliction: virtually everyone who lives past age 75 has it to some degree. Nearly 50 percent of the population suffers from osteoarthritis by age 65. Osteoarthritis hits hard on the hardest working joints: the knees, the hips, the hands, and fingers. The weight-bearing joints and the spine are especially vulnerable. It is a fundamental fact of life that as we age, our joints lose their youthful flexibility and range of motion. Movement eventually becomes difficult and painful as we slowly, year by year, become less supple and stiffer. Osteoarthritis is characterized by progressive, degenerative changes in cartilage structure. The proteoglycans break down, losing their ability to form tight clusters. The water content of cartilage increases. Chondroitin sulfate shortens in length. Cartilage loses the ability to repair itself and develops clefts and crevices that eventually extend down to the underlying bone. The end result is weak, stiff, and deformed joints.
While it is present in the walls of blood vessels, chondroitin sulfate’s main role is in keeping cartilage fluid and elastic. It is found naturally in the body where it is one of the critical compounds that makes up connective tissue. Connective tissue is responsible for building and supporting cartilage found in the joints and elsewhere.
Glucosamine is an amino-sugar that is naturally produced in humans. It is the key building block in the synthesis of glycosaminoglycans, hyaluronic acid and proteoglycans. These substances are the foundation of many of the body’s tissues including tendons, ligaments, cartilage, collagen, basement membranes, mucous membranes of the digestive system, membranes in the respiratory tract, and synovial fluid in the joints.
The purpose of a recent study was to determine the effect of glucosamine and chondroitin on the progression of osteoarthritis of the knee. Researchers analyzed data from six randomized controlled studies, which included a total of 1,502 participants. Two of the studies used glucosamine sulfate and four of the studies used chondroitin sulfate. The results revealed that glucosamine sulfate did not show a significant effect of joint space narrowing over the first year of treatment. However, after three years a small to moderate protective effect was observed. Chondroitin sulfate revealed a small but significant effect on the progression of osteoarthritis after two years of supplementation. The results of this meta-analysis suggest that daily administration of glucosamine and chondroitin over two to three years may delay the progression of osteoarthritis of the knee.1
1 Lee YH, Woo JH, Choi SJ, et al. Effect of glucosamine or chondroitin sulfate on the osteoarthritis progression: a meta-analysis. Rheumatol Int. 2010;30(3):357-63.