Osteoarthritis, or OA, is a common disorder of the joints and affects around 27 million people in the United States, according to the American Academy of Orthopedic Surgeons. If you are one of the millions with OA, you have probably looked into nonprescriptive therapies to ease your aching joints. Glucosamine, chondroitin and hyaluronic acid are three popular alternative therapies that have received the recent attention of researchers. These supplements are available over the counter and are touted by some researchers to actually rebuild worn cartilage.
Joints and Osteoarthritis
To understand how these supplements benefit OA, learn the basic structure of joints. A joint is the medical term for a point of contact between two or more bones. The ends of your bones are covered with a type of tough connective tissue known as cartilage, which allows the bones to glide smoothly over one another and protects the bones from damage. Certain joints, known as synovial joints, also contain a type of fluid known as synovial fluid that helps to lubricate and protect the joint. In osteoarthritis, the cartilage is gradually worn away. After time, the two bones may actually rub against one another, resulting in bone damage, swelling and pain. Thinning of the synovial fluid with age may also contribute to these symptoms.
Glucosamine and Chondroitin
Glucosamine and chondroitin are two of the principle constituents of cartilage. Glucosamine is a naturally occurring amino sugar. Chondroitin is a carbohydrate attached to proteins in cartilage. Glucosamine and chondroitin lubricate joints as well as ameliorate the degeneration of cartilage. Glucosamine may also aid in the regrowth of new cartilage, but this role not well documented.
Currently, several studies have examined the use of glucosamine or chondroitin for OA. The GAIT study, which stands for Glucosamine/Chondroitin Arthritis Intervention Trial, is the first large-scale study to investigate the effectiveness of glucosamine and chondroitin together on OA. The study, published in 2006 in the "New England Journal of Medicine," followed a total of 1,583 participants with mild to severe knee osteoarthritis over the course of 24 weeks. The glucosamine and chondroitin combination group reported a greater improvement in pain -- 22 percent higher than placebo. This effect was observed in patients with moderate to severe osteoarthritic pain only and not in those with mild to moderate pain. Reported pain in the glucosamine or chondroitin cohorts alone were slightly better than placebo and therefore was not statistically significant.
Hyaluronic Acid
Hyaluronic acid, or HA, is the primary component of synovial fluid. HA contributes to the viscoelastic properties of synovial fluid, thus defending joints against damage by lubrication. Studies on the effectiveness of HA for OA are mostly focused mostly on intraarticular injections, and little is currently known regarding the benefit of oral HA supplementation in humans. A 2008 study in "Nutrition Journal" may shed some light on this issue. The researchers found that oral supplementation of HA improved osteoarthritic joint pain by 75 percent, compared to 50 percent in those taking a placebo. Additionally, those taking placebo reported a higher usage of acetaminophen for pain relief.
Recommended Intake
The recommended intake for these supplements is currently based on studies, as no daily intake values have been established yet. The Arthritis Foundation recommends consuming 1,500 milligrams of glucosamine and 800 to 1,200 milligrams of chondroitin a day. To obtain the maximal benefit, these two supplements should be taken together. The recommended intake for HA is more of a gray area because studies on oral supplementation are limited. In the "Nutrition Journal" study, participants consumed 80 milligrams of HA a day.
Warnings
Glucosamine is made from the shells of some shellfish such as lobster, crab and shrimp. Do not take glucosamine if you have a shellfish allergy, due to the possibility of an allergic reaction. Other adverse effects include heartburn, constipation, diarrhea and nausea. Chondroitin should not be taken in conjunction with nonsteroidal antiinflammatories, warfarin or any other blood-thinner drug as it may increase bleeding. Use caution if you have a sulfonamide allergy. Other possible adverse effects include constipation, abdominal pain and diarrhea. No adverse effects were reported with the use of HA in the previously aforementioned "Nutrition Journal" study.
References
- American Academy of Orthopedic Surgeons; Glucosamine and Chondroitin Sulfate; September 2009
- "Arthritis Today": Supplement Guide: Glucosamine
- "Arthritis Today": Supplement Guide: Chondroitin Sulfate
- Wheeless' Textbook of Orthopedics; Dr. Clifford R. Wheeless; Proteoglycans in Cartilage; June 17, 2011
- "New England Journal of Medicine"; Glucosamine, Chondroitin Sulfate, and the Two in Combination for Painful Knee Osteoarthritis; Dr. Daniel O. Clegg, et al,; February 2006
- "Nutrition Journal"; Effect of Natural Extract of Chicken Combs With a High Content of Hyaluronic Acid (Hyal-Joint) on Pain Relief and Quality of Life in Subjects With Knee Osteoarthritis; Douglas S. Kalman, et al.; January 2008
