Chondroitin has simply no effect on arthritis, yet another study says. It neither prevents or reduces joint pain, researchers said after an analysis of 20 studies.
"We do not have evidence to suggest that chondroitin has a clinically relevant effect on patients' pain," says author Peter Jüni, head of clinical epidemiology and biostatistics at the University of Bern in Switzerland.
The paper comes a little more than a year after a major National Institutes of Health study found no clear proof that the popular supplement combo glucosamine and chondroitin reduces joint pain.
While glucosamine is believed to stimulate production of cartilage-building proteins, chondroitin may inhibit production of cartilage-destroying enzymes and fight inflammation too.
Cartilage is a smooth, connecting tissue that covers the ends of bones in a joint. It enables our joints to support the weight when bending, stretching, walking or running. It is the body's natural shock absorber.
Glucosamine supplements are derived from shellfish shells; chondroitin supplements are generally made from cow cartilage.
In recent years, glucosamine and chondroitin have been widely promoted as a treatment for osteoarthritis.
While arthritis means inflammation of the joints, and is the name given to a group of over 200 diseases, osteoarthritis (OA) is the most common type of arthritis. The most commonly affected joints are the knees, the hips, hands, feet, and spine.
The risk of developing the condition increases with age. It mainly affects people over the age of 40, and is most common among those over the age of 65. In fact, by the age of 65, around 50 per cent of people have OA in one or more of their joints, and around 10 per cent have some disability caused by it.
Glucosamine, an amino sugar, is thought to promote the formation and repair of cartilage. Chondroitin, a carbohydrate, is a cartilage component that is thought to promote water retention and elasticity and to inhibit the enzymes that break down cartilage. Both compounds are manufactured by the body.
In an analysis, Dr.Stephen Barret, running a non-profit organization, Quackwatch, observes,
"Human studies have shown that either one may relieve arthritis pain and stiffness with fewer side effects than conventional arthritis drugs. But two problems remain. First, there has not been enough high-quality or long-range research to determine whether their use is practical.
Second, because dietary supplement manufacture is not regulated, product quality (especially of chondroitin products) is not assured,".
The latest study is published in the Annals of Internal Medicine. The researchers analyzed chondroitin studies dating to 1970. The 20 clinical trials they studied included 3,846 patients. But early studies tended to involve small numbers of patients and were poorly designed, without proper documentation and analysis, Jüni says.
After examining those studies, the Swiss researchers concluded that there is no evidence that chondroitin is unsafe, but also none to suggest that it helps diminish joint pain.
As to why so many patients swear by chondroitin as a treatment, Dr.Peter Jüni suggests that osteoarthritis is a condition that does not progress invariably toward more severe symptoms.
"You tend to have severe symptoms, and then you get better again. And if you happen to start chondroitin at the moment of severe disease and then it gets better, you might be convinced that it's the drug, but it's actually the body (healing)," he says.
One thing the study did not rule out is the possibility that chondroitin may lessen pain in patients with less severe arthritis.
Whatever the case, skeptcism expressed repeatedly over the years does not seem to have diminished the enthusiasm of the US consumers for chondroitin and glucosamine.
The U.S. consumer market for glucosamine and chondroitin pills, almost always sold in combination, was 810 million dollars in 2005, notes Katja Rauhala, research manager with the Nutrition Business Journal.
Andrew Shao, vice president of scientific and regulatory affairs with the Council for Responsible Nutrition, a supplement industry group, says he doesn't think the analysis was fair in the criteria it used to exclude numerous studies that found chondroitin beneficial.
"Consumers speak with their wallets," Shao says. "This is not some kind of fad. Consumers are finding benefit from the drug."