Supplements taken for arthritis 'have no effect on pain'

Glucosamine and chondroitin are given out on NHS prescription or bought over the counter by patients to alleviate symptoms of osteoarthritis, which is is the most common type of arthritis in the UK.

Around 8.5 million Britons are thought to suffer from the condition, which causes damage to cartilage that is essential to allow joints to move easily and without friction. The condition can cause bony growths around the edge of the joints and inflammation of surrounding tissues.

Today, experts writing online in the British Medical Journal (BMJ) said their review of existing research concluded the supplements are not effective.

They examined 10 existing studies and found no evidence of improvement when supplements were taken alone or in combination.

More than 3,800 patients suffering from osteoarthritis in their hips, knees or both joints took part in the studies. Patients were typically aged 58 to 66 and had suffered symptoms for between six months and 10 years.

The results showed the supplements had no effect on joint pain or on the degree of narrowing between joints. Narrowing joint space indicates cartilage loss and worsening osteoarthritis.

But the authors, led by Professor Peter Juni at the University of Bern in Switzerland, said some patients did think the supplements were helping them and concluded this may be due to factors such as the natural course of arthritis, or patients simply believing they work.

"We are confident that neither of the preparations is dangerous," the authors said. "Therefore, we see no harm in having patients continue these preparations as long as they perceive a benefit and cover the costs of treatment themselves.

"Coverage of costs by health authorities or health insurers for these preparations and novel prescriptions to patients who have not received other treatments should be discouraged."

Both glucosamine and chondroitin are available on the NHS, with 907,400 prescriptions issued in England in 2009. Many more doses of the supplements are bought over the counter at chemists or health food stores.

This is despite guidance from the National Institute for Health and Clinical Excellence (Nice) saying neither is backed by clinical evidence.

Jo Cumming, helplines manager at Arthritis Care, said the charity would support more research in this area.