Glucosamine & Chondroitin: Joint Relief?

A ching knees. Tender knuckles. Stiff joints.

Twenty-one million Americans suffer from osteoarthritis. Painkillers like aspirin, ibuprofen, and indomethacin can help, but the gastrointestinal distress and other side effects bother many people.

When we last looked at dietary supplements for arthritis, we found that two--glucosamine and chondroitin--seemed to ease the symptoms for many people (see "Relieving Arthritis Pain," Jan./Feb. 1998). That's still true.

We also found that many chondroitin pills contained far less chondroitin than their labels said. Unfortunately, that's also still true.

Two to Tango

When the cartilage that cushions the joints in your hands, hips, knees, or back breaks down faster than your body can replace it, you've got osteoarthritis. Without this protective tissue, bone rubs painfully against bone, causing tenderness, swelling, and stiffness.

Glucosamine and chondroitin, two of the many components of cartilage, are found in some foods and can also be made in our bodies. Both are now widely marketed, alone or in combination, to arthritis sufferers for relief of their pain. And there's solid research to back them up.

Timothy McAlindon and his colleagues at the Arthritis Center of the Boston University School of Medicine recently pooled the results of the six best studies on glucosamine and the nine best studies on chondroitin into two large studies, called meta-analyses.(1)

"We found that glucosamine given alone had a moderate effect on symptoms. It seemed to help at least half of those who took it," says McAlindon. "Chondroitin alone had an even greater effect on pain relief."

While it usually takes a month or two before symptoms improve, says McAlindon, "both compounds caused substantially fewer side effects than the anti-inflammatory drugs that people usually take for osteoarthritis."

McAlindon's conclusion: "It seems probable that these compounds do have some efficacy in treating osteoarthritis symptoms."

Researchers still aren't sure how glucosamine and chondroitin work. Do they supply the raw materials to make new cartilage? Or do they ease inflammation, like aspirin and most other arthritis drugs?

And is a combination of glucosamine and chondroitin more effective than either one by itself?

The National Institutes of Health (NIH) is launching a four-year, $6.6 million study to find out. At nine medical centers across the country, researchers will test glucosamine and chondroitin, alone and in combination, on more than 1,000 people with osteoarthritis of the knee. Results aren't expected until 2003.

Poor Quality Chondroitin

Glucosamine is a simple compound and is easy to manufacture. It's extracted from the shells of crabs and other crustaceans. Chondroitin, which is prepared from cow tracheae (wind pipes) or shark cartilage, is more difficult to make.

Consumerlab.com, a Web site that independently tests dietary supplements, recently analyzed 25 brands of glucosamine, chondroitin, and combinations of the two.

"All ten glucosamine samples contained what their labels indicated," says Consumerlab.com president Tod Cooperman. "However, both of the chondroitin-only samples flunked, and six of the 13 combination samples failed because they contained low levels of chondroitin."

Natalie Eddington of the University of Maryland School of Pharmacy found similar problems.(2) Twelve of the 14 glucosamine samples she tested since 1996 had at least 90 percent of the glucosamine listed on the label. But only five of the 32 chondroitin samples contained at least 90 percent of the amount listed. More than half had less than 40 percent.

(See www.consumerlab.com for the brands that passed its analysis. Bear in mind that the results are based on testing only one sample of each brand and that they don't list brands that failed. Eddington and the University of Maryland declined to release brand names.)

THE BOTTOM LINE

* Glucosamine and chondroitin relieve symptoms in at least half of the arthritis sufferers who take either one for at least a month. Researchers don't know whether taking both together is better than taking either one separately.

* I Most of the successful studies used 1,500 milligrams a day of glucosamine and/or 1,200 milligrams a day of chondroitin.

* Many chondroitin supplements don't deliver the amount listed on the label.

(1.) Amer. Med. Assoc. 283: 1469. 2000.

(2.) Amer. Nutraceut. Assoc. 3: 37, 2000.

For more information, see www.cspinet.org/nah/arthritis.html.