One in ten North Americans suffers from osteoarthritis or degenerative arthritis, a disease in which the currently-used medications, acetaminophen, aspirin and nonsteroidal antiinflammatory drugs, do not slow or reverse the progressive destruction of joints and no cause is known. Over the last two decades, reports have shown that pills containing chondroitin sulfate and glucosamine, two components of cartilage, may help alleviate the pain. Three major reviews in the scientific literature claim that the three studies showing that glucosamine relieves pain were poorly designed and therefore cannot be offered as proof of benefit. On the other hand, six studies from Europe and another from the United States show that chondroitin sulfate does help to slow joint destruction and pain caused by osteoarthritis.
Several studies show that glucosamine helps control pain, but it is very difficult to test the effect of any drug on pain because a very significant number of people will benefit just as much from placebos. The authors performed a double blind study over six months in which they gave either 1500 mg glucosamine or placebo pills daily to patients with arthritis. Neither the doctors nor the patients knew who received glucosamine. One out of three patients receiving glucosamine had excellent control of their pain. but one out of three people receiving placebos also had the same excellent response. One study in Rheumatology showed that glucosamine is not more effective than a placebo in controlling arthritic pain (8).
Another study in the British medical journal, Lancet, showed that glucosamine helps to retard the breakdown of cartilage. Up to then, studies showed only that glucosamine helps to relieve pain. People with arthritis received either 1500 mg of glucosamine or placebo. X rays of their knees showed that the placebo group lost more distance between the bones of their knees than the glucosamine group.
The ends of bones at the knee joint are covered with cartilage, so the greater the distance between the bones on X ray, the greater the amount of cartilage. There is a serious problem with the study. People with arthritis often cannot fully straighten their knees, so it is impossible to use distance between bones to determine how much cartilage is lost. For example, if a person bends his knees a little, he will have the bones closer together than when he holds his knees straight. That means that anything that blocks pain will allow person to straighten his knees and have a greater distance between the bones at the knee. You should get the same benefit from any pain medicine. Furthermore, the study was sponsored by Rotta Research Group, who could gain millions of dollars from sales promoted by this study.
An earlier editorial in Lancet raises questions about the safety of glucosamine (2). Most research shows that glucosamine can help to relieve some of the pain associated with arthritis (3), but does not help to prevent cartilaginous damage and has not been shown to heal broken cartilage. Therefore, it is no more effective in treating arthritis than aspirin, but costs more than aspirin, but less than most brand name arthritis pain drugs that your doctor prescribes.
Glucosamine helps form aggrecan, the part of cartilage that allows cartilage to swell and shrink, acting like a shock absorber to help protect your knees from the trauma of running and walking. Adding glucosamine to cartilaginous cells in a test tube causes them to increases production of aggrecan (4).
However, in light of this good news, you should know that glucosamine can block the effects of insulin, causing blood sugar levels to rise (5,6,7), increasing likelihood of suffering the side effects of diabetes in susceptible people.
