Glucosamine and chondroitin sulphate are widely taken, alone or in combination, for knee pain attributed to osteoarthritis.
They are expensive and joint health is MEGA business. So how can 'joebloggs' decide whether the expense is worth it?
Why should taking glucosamine and chondroitin sulphate help with pain from osteoarthritis?
Well, glucosamine and chondroitin sulphate are both substances found naturally in cartilage in the body -
- Glucosamine is an amino sugar that is found in the 'extra cellular matrix'(background material) of cartilage and is thought to promote its formation and repair.
- Chondroitin sulphate is a complex carbohydrate that helps cartilage to retain water and is believed to inhibit enzymes that break down cartilage.
The general belief is that osteoarthritis is connected with a local deficiency in some key natural substances and that by increasing the body's supply of these substances via supplementation it is possible to have an effect on symptoms as well as the progression of the disease. It is thought that glucosamine and chondroitin sulphate may have both symptom-modifying (i.e. be able to alter pain, stiffness and function) and disease-modifying properties (i.e. be able to slow down the progression of osteoarthritis) but these claims haven't been thoroughly evaluated and the exact mechanism of these actions are largely unknown.
Since 2000 forty-eight percent of new joint health supplements in the US contained glucosamine and twenty-four percent chondroitin (Mintel Global New Products Database). This makes glucosamine the biggest selling US dietary supplement.
Plus demand is on the increase. Since the prescription drug Vioxx was taken off the shelves more people have been turning to 'natural' dietary supplements - such as glucosamine - for their arthritis relief. Prices have also rocketed in recent years, in part due to the Asian tsunami interrupting supplies of shrimp and crab shells, the main raw material in the production of glucosamine. No one can question that glucosamine and chondroitin sulphate supplements are big business - but do they work?
To try to answer this question $12.5 million of US tax payers money was invested by the National Institutes of Health (NIH) into a study to look at whether glucosamine and chondroitin sulphate are effective in providing relief in the management of knee pain from osteoarthritis. The study was named 'The Glucosamine/Chondroitin Arthritis Intervention Trial' - or 'GAIT'.
Recruitment for the study began in May 2002. On November 14, 2005, at the Annual Meeting of the American College of Rheumatology in San Diego, California, Dr Daniel O Clegg, Professor of Medicine and Chief of Rheumatology, Division of Rheumatology, University of Utah School of Medicine, presented the long awaited findings of this multicentric trial in which 1,583 people participated. The results of the study were eagerly anticipated - but at the end of the day they were shrouded in controversy and left medical practitioners hard-pressed to decide whether or not to continue recommending or prescribing these substances for their patients.