At last, findings on arthritis supplements
A clinical trial of the popular dietary supplements glucosamine and chondroitin found no evidence that they’re better than placebos in easing arthritic knee pain, the study’s lead investigator has reported.
The good news: Like placebos, the supplements aren’t harmful either.
The government-sponsored trial involving 1,600 arthritis sufferers at 16 medical centers across the country was designed to see whether the supplements lived up to their billing as potent weapons against arthritis. Sales of the two supplements topped $700 million in 2004, according to the Nutrition Business Journal.
Dr. Daniel O. Clegg, speaking last week at a rheumatology convention in San Diego, said the supplements -- taken separately or in combination -- didn’t fare any better than placebos, pills with no active ingredients.
Remarkably, about 6 in 10 patients reported that their knees felt better after six months of therapy -- whether they took supplements or the dummy pills.
Psychology may have played an important role in the way participants felt. “Patients really believe in dietary supplements and I think patients wanted to do better,” Clegg said.
Patients taking the glucosamine-chondroitin combination fared slightly better than those on placebos, but not enough to qualify as statistically significant.
Meanwhile, patients taking the prescription drug Celebrex did better than those on placebos -- by a 70% to 60% margin.
“It’s a very confusing time right now,” said Clegg, noting that some previous studies showed the supplements worked better than placebos, while others did not.
The latest effort, funded by the National Institutes of Health, was the first that did not receive industry funding, he said.
An estimated 21 million people in the U.S. suffer from osteoarthritis, a condition caused by the breakdown of cartilage that cushions the ends of bones in joints throughout the body.
Glucosamine and chondroitin are natural substances found in cartilage. Scientists believe glucosamine reduces inflammation and spurs the growth of new cartilage, while chondroitin promotes strength and durability. It’s not understood what happens when the substances are taken as supplements.
Dr. Marc C. Hochberg, a rheumatologist with the University of Maryland Medical Center, said: “The reason for doing this study was to find out once and for all whether these nutritional supplements were effective for relieving the symptoms and signs of osteoarthritis of the knee. Unfortunately, there are still open questions.”
In the study, scientists randomly assigned patients to receive one or both supplements, the prescription drug Celebrex, or a placebo. Neither patients nor the scientists knew which participants were taking until the study’s completion.
