Osteoarthritis imageOsteoarthritis (OA) is by far the most common form of arthritis. You may already show signs, though you probably don't know it. It's not until later in life that OA becomes one of the leading causes of chronic pain and disability.

Joint Wear and Tear

Degenerative joint disease, another term for OA, is a better description of the process of wear and tear that gradually softens and breaks down the joint cartilage that normally prevents bones from rubbing together. X-rays of osteoarthritic joints often show narrowing of the joint space and destructive changes in the adjacent bone.

Patients with OA generally complain of joint pain and stiffness, particularly after physical activity. The hips, knees, ankles, and spine are most susceptible to OA, since they absorb the brunt of gravitational forces.

Cartilage Health

Joint cartilage is made up of cells, called chondrocytes, embedded in a substance called the extracellular matrix. One of the primary components of this matrix is a material called proteoglycan. This material helps cartilage absorb the forces of friction.

With normal aging, the proteoglycan content of the matrix decreases. This decrease can be accelerated by injury, excessive mechanical force, or joint deformity. This explains why certain occupations, like dockworkers and professional football players, become disabled from OA sooner than the rest of us. It also explains why obesity, which adds considerable stress to joints of the lower extremities, greatly increases the risk of OA, particularly in the knees.

Even after OA begins to set in, there is evidence that regular exercise can delay or prevent the onset of pain and disability. Aerobic activity protects against obesity, while weight training enhances the strength and flexibility of the muscles, tendons, and ligaments around the joints, which improves joint stability and resilience. Keep in mind that acute injuries and repetitive strain increase the risk of OA. Therefore, exercise is only beneficial to joint health if it is done gradually, and with proper preparation (stretching) and equipment (quality footwear).

Treating Osteoarthritis

Standard treatments for symptomatic OA include:

  • Physical therapy to increase the strength and flexibility of affected joints
  • Prescription or nonprescription pain medication, most commonly nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Injections of more powerful anti-inflammatory steroid medication into the joint
  • Joint replacement surgery

Although often effective at relieving pain, these interventions do nothing to slow or reverse the deterioration of cartilage. Therefore, researches have turned their attention to two natural constituents of human cartilage thought to preserve, or even enhance, cartilage integrity— glucosamine and chondroitin.

Glucosamine and Chondroitin

Glucosamine and chondroitin are thought to stimulate the production of proteoglycan and stop its breakdown. Glucosamine is derived from the exoskeletons of shrimp, lobster, and crabs. Chondroitin is manufactured from natural sources, such as shark and bovine cartilage.

Numerous clinical studies have evaluated the effectiveness of these supplements in treating OA of the knee and hip. Some studies have shown glucosamine and/or chondroitin to be moderately more effective than a placebo, with no significant side effects. However, more recent studies have not shown glucosamine to be effective. In fact, many of the studies that had positive results were funded by manufacturers of these products. Studies done by neutral researchers failed to find benefits. Talk to your doctor about the potential risks and benefits for you.

Buyer Beware

Since there is little government regulation of dietary supplements, the products you buy over-the-counter may not contain exactly what the label indicates. You may need to do a little homework to find out about the dose and purity of the supplement you plan to buy. A good place to start is http://www.consumerlab.com, an online service that conducts independent tests on a variety of products, including glucosamine and chondroitin. You can also learn more about glucosamine and chondroitin from other online drug databases and books. Also look for products that bear USP (United States Pharmacopeia) notation.

Other Supplements for OA

Many other dietary supplements are purported to benefit OA patients. While most appear to be safe, and some may be effective, there is not enough evidence to recommend them. These supplements include:

  • S-adenosylmethionine (SAMe)–an analgesic/anti-inflammatory
  • Vitamins C and E, and beta-carotene–antioxidants
  • Vitamin D–essential to normal bone and cartilage metabolism
  • Avocado/soybean oil extracts–may stimulate chondrocyte activity