Dietary supplements are essentially unregulated. They can be marketed with little scientific research to back up their presumed safety and effectiveness.
Just since 2000, there have been 800 dietary supplement formulations geared toward relieving osteoarthritis introduced. While some of these are considered safe and effective, most do not come with that assurance. Let's look at the most popular dietary supplements being used for osteoarthritis.
Glucosamine is the dietary supplement most commonly used by osteoarthritis patients. The body produces glucosamine on its own, too, and its found in high concentrations in the joints. In theory, glucosamine stimulates the formation of cartilage that is essential for joint repair. Synthetic glucosamine, or that which is derived from shellfish exoskeletons, may have anti-inflammatory properties.
Glucosamine is available as glucosamine hydrochloride and glucosamine sulfate. It is sold in combination with other dietary supplements, too. It has been extensively studied for osteoarthritis (20 controlled studies and more than 2,500 study participants). Most of the research focused on glucosamine sulfate as a treatment for osteoarthritis of the knee and hip. Unfortunately, study results have been inconsistent.
In 2005, a review of glucosamine trials for osteoarthritis concluded that glucosamine significantly reduces osteoarthritis pain. The type of glucosamine used seemed to make a difference. Dona, a commercial glucosamine sulfate product, was found to significantly reduce osteoarthritis pain.
Another analysis, known as the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), used a glucosamine hydrochloride product. Glucosamine hydrochloride used alone or in combination with chondroitin did not reduce symptoms of knee osteoarthritis. It did, however, reduce pain in some patients with severe cases of the disease.
When compared to acetaminophen or NSAIDs, glucosamine sulfate was shown to be effective for reducing pain and improving joint function. Other studies have shown that glucosamine sulfate significantly reduces joint space narrowing in the knee following three years of treatment.
Glucosamine is considered safe to use. Side effects seen in studies were comparable to placebo and actually less than those seen with NSAID use.
Chondroitin is a glycosaminoglycan -- a building block for the joint structure. For marketing, it is usually combined with other supplements, but studies have focused on chondroitin alone.
There is less research on chondroitin than glucosamine sulfate. Study results have been inconsistent. Early trials (1980s to 2001) revealed some evidence that chondroitin reduced pain and slowed joint space narrowing. More recent studies, since 2005, have been less favorable, concluding that chondroitin is not beneficial for osteoarthritis.
Researchers concluded that chondroitin is not more effective than glucosamine sulfate. There is no evidence that suggests combining chondroitin and glucosamine sulfate offers anything better than glucosamine sulfate alone.
Studies on SAM-e for osteoarthritis have been consistent and positive. SAM-e was found to be more effective than placebo and comparable to NSAIDs for osteoarthritis pain relief. A more recent trial compared SAM-e to the drug Celebrex (celecoxib). During the first month, Celebrex was a more effective pain reliever than SAM-e, but there was no difference between SAM-e and Celebrex in terms of pain relief after two months of treatment. They were equally effective.
SAM-e is considered safe, but it can cause anxiety, headache, insomnia and nervousness in some patients. It can interact with certain other drugs, including Ultram (tramadol). You should discuss SAM-e with your doctor before taking it. Expense and product quality have been mentioned as negatives of SAM-e, too.
MSM (methylsulfonylmethane) is normally found in the human diet. It's found in plants, fruits, vegetables, meats, and dairy. MSM is also found in the human adrenal gland. MSM is thought to have anti-inflammatory properties. Results from two clinical studies of MSM revealed that MSM modestly reduced pain and swelling, but did not relieve joint stiffness.
MSM is considered safe and well-tolerated with side effects comparable to a placebo. Clinical trials have not been longterm, however, lasting just 12 weeks or less. Longterm safety studies are needed.
Devil's claw is derived from an African plant. The benefits of using Devil's claw are due to its anti-inflammatory effects; it inhibits COX and lipoxygenase, though it is said to inhibit COX-2 and not COX-1. A few clinical studies found that Devil's claw extracts, taken alone or with an NSAID, reduced osteoarthritis pain and were well-tolerated. More studies are needed to test its effectiveness and longterm safety before it can be recommended earnestly.
Turmeric is a spice used in curry powders. Curcumin, the pigment that gives yellow color to foods, is the active ingredient in turmeric. Curcumin has anti-inflammatory properties, as it inhibits COX-2, prostaglandin, and leukotrienes. But, no clinical trials have evaluated turmeric for osteoarthritis. Until more studies are done, turmeric is not recommended for osteoarthritis.
Ginger may have anti-inflammatory effects due to inhibition of COX and lipoxygenase. It may also affect tumor necrosis factor (a cytokine), as well as the synthesis of inflammatory prostaglandins. There is no evidence to support recommending ginger for osteoarthritis.
The Bottom Line
Discuss supplements with your doctor before spending money on them.
Dietary Supplements for Osteoarthritis. P. Gregory, M. Sperry, A. Wilson. American Family Physician. January 15, 2008.