WebMD Health News, along with many other news outlets, are reporting that the results from a national study which examined whether two popular supplements (glucosamine and chondroitin) slow the progression of knee arthritis. The news stories tell you the study shows that the supplements are NOT effective. But, is that true?
Actually, these results are far from conclusive.
The headlines you are reading are accurate when they say, the “supplements glucosamine and chondroitin sulfate, taken together or alone, failed to show a clear advantage over placebo as a treatment to slow the progression of osteoarthritis of the knee.”
However, what the news stories are NOT telling you is that the form of glucosamine that was tested was glucosamine hydrochloride (or glucosamine HCL).
First, let me tell you about this new study. Then, I’ll tell you about the encouraging studies for the effective form of glucosamine – which is glucosamine sulfate.
The latest findings are an extension of the National Institutes of Health-funded Glucosamine/chondroitin Arthritis Intervention Trial (GAIT).
In 2006, GAIT researchers reported that the supplements (glucosamine HCL and chondroitin) were not much better than placebo for reducing knee pain associated with osteoarthritis.
Researchers followed close to 1,600 patients who took one or both of the supplements, the painkiller Celebrex, or placebo for six months.
Some benefit was seen in patients with moderate to severe pain who took both glucosamine HCL and chondroitin, but the finding was not conclusive because only a small number of patients in the study had pain that was considered moderate to severe.
This new study was an effort to determine if the supplements help slow the destruction of knee cartilage. In it, 572 of the original GAIT participants continued to take their original study treatment for an additional 18 months. All these patients had moderate to severe osteoarthritis.
The researchers used a specific X-ray protocol to determine the rate of osteoarthritis progression over time.
After two years, there was no significant difference between treatment and placebo groups.
“While we found a trend toward improvement among those with milder osteoarthritis of the knee in those taking glucosamine (hydrochloride) alone, we were not able to draw any definite conclusions,” Sawitzke says.
Interpretation of the results was also complicated by the fact that the placebo group had less arthritis progression during the two-year study than the researchers had predicted.
The X-ray protocol used to measure osteoarthritis progression also proved to be less than optimal, says Josephine Briggs, MD, who directs the NIH’s National Center for Complementary and Alternative Medicine, which co-sponsored the study.
Briggs told WebMD that better ways of measuring osteoarthritis progression may be on the horizon, including the use of MRI.
“To really understand the promise of these interventions our measures must be maximally sensitive,” she says.
The latest GAIT findings appear in the October issue of the journal Arthritis & Rheumatism.
Why might glucosamine sulfate be a better choice?
In my book, Alternative Medicine: The Christian Handbook, my co-author and I evaluated the evidence on both forms of glucosamine and on chondroitin.
Here’s part of what we wrote about glucosamine:
Overall, there is some evidence to suggest that glucosamine sulfate may provide relief from the symptoms of osteoarthritis.
McAlindon’s 2000 review concluded that although the positive effects of glucosamine are “exaggerated,” “some degree of efficacy appears possible.” There is no evidence to suggest that it cures arthritis, as has been suggested in popular literature.
Many recommend using glucosamine in combination with chondroitin sulfate, but this has not been studied well to date.
Glucosamine alone appears to produce a smaller benefit than chondroitin alone.
However, chondroitin products in the United States are often substandard. Only reputable brands, certified by independent labs, should be used (you can find a list of approved products at www.ConsumerLab.com). There is no information on the safety or effectiveness of taking glucosamine for longer than three years.
The most frequently recommended dosage of glucosamine alone is 500 mg three times daily. The dose depends on the person’s weight, and is often in combination with chondroitin.
An average daily dose would be 1200 mg chondroitin and 1500 mg glucosamine. This is usually divided into two to four doses, taken with food.
Remember that it can take up to 12 weeks for glucosamine sulfate to begin to work.
Also, here’s our conclusion about chondroitin:
Research with chondroitin sulfate has produced promising results. Arthritis is a common and painful condition affecting millions of people around the world. The most common treatments for osteoarthritis usually involve pain relievers that are prone to serious adverse effects. A safe and effective remedy directed at the underlying cause of the disease would be a welcome addition.
Long-term studies are needed to ensure that the chondroitin sulfate benefits seen over a few months will last into years. This research also would help to determine whether there are any harmful effects from taking chondroitin for prolonged periods of time.
Glucosamine, along with chondroitin sulfate, is widely recommended, but the combination has not been as well studied in clinical trials. Since chondroitin sulfate is sold as a dietary supplement, products of different quality will remain available. Choose only reputable brands.
As WebMD points out, roughly 21 million American have osteoarthritis. And, the GAIT study and others suggest that glucosamine and chondroitin are safe supplements, but Briggs says patients who take them or any supplement should always discuss it with their doctor.
She says more than two out of three adults in the U.S. use some type of complementary or alternative medicine, but only about one in three tell their physicians about it.
“It is important to discuss any medication you take with your doctor, including complementary and alternative medicines,” she says.
Sawitzke, A.D., Arthritis & Rheumatism, October 2008; vol 58: pp 3183-3191.
Allen D. Sawitzke, MD, University of Utah School of Medicine, Salt Lake City.
Josephine P. Briggs, MD, director, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, Md.