July 6, 2010 -- The popular supplement glucosamine doesn't help people who have low back pain, a clinical trial finds.
The study looked specifically at 250 people with evidence of osteoarthritis (OA) of the spine. All of the patients had at least some disability because of low back pain, but most were still able to work.
For six months, half the patients got 1,500-milligram daily doses of glucosamine sulfate and half got inactive placebo pills, notes study leader Philip Wilkens, MChiro, a research fellow at Norway's Oslo University.
"There was no benefit of glucosamine compared to placebo," Wilkens tells WebMD. "You would get the same result from taking sugar pills as taking the real deal."
On average, patients in both the glucosamine and placebo groups had less back pain and less disability after six months of treatment, and for six months after the end of the study.
Why did both groups improve? Part of the improvement is the placebo effect. That's the natural tendency of people to feel better when they believe they are being treated. But part of the reason is that patients come to treatment, and to clinical trials, when their condition is at its worst.
"People feel worse when they volunteer. That is a bad period, and it is usually followed by a good period. It's sort of a natural development of the condition of low back pain," Wilkens says.
In osteoarthritis, cartilage in the joints degenerates. Glucosamine is a building block for the molecules from which cartilage is made. The theory behind glucosamine supplements is that taking them will slow or reverse cartilage degeneration.
It's a popular theory. According to the supplement industry group Council for Responsible Nutrition (CRN), 7% of Americans take glucosamine and/or chondroitin, a component of cartilage usually derived from animal or fish cartilage.
And in an editorial accompanying the Wilkens study, Kaiser-Permanente researcher Andrew Avins, MD, MPH, notes that 25% of people with low back pain have tried glucosamine supplements.
Even so, glucosamine is usually taken for knee osteoarthritis, says Andrew Shao, PhD, CRN senior vice president for scientific and regulatory affairs. Shao notes that low back pain can be caused by a number of things besides osteoarthritis.
"I know the researchers had to include some patients who had some degenerative joint issues in the back, but low back pain is a very broad kind of term. There can be a lot of reasons people experience it," Shao tells WebMD. "It is a tall order for something to affect such a global condition."
Shao says it would be premature to conclude that glucosamine has no benefit for any patients with spinal osteoarthritis. But that's pretty much the take-home message from the study, Avins suggests.