Can chondroitin relieve pain of osteoarthritis?
BACKGROUND
Osteoarthritis is the most common form of arthritis and a very common cause of muscle and joint pain. It is especially prevalent among the elderly, and can severely limit daily activities.
Although exercise, weight loss and physiotherapy can help, treatment is limited to pain-relievers and anti-inflammatory drugs. These medications can have adverse effects and do not address the underlying cause of the symptoms.
Osteoarthritis involves the breakdown of cartilage within joints. Ways to prevent this breakdown are being sought. Much attention has been given to supplementation with glucosamine and chondroitin as these are natural components of cartilage. These have become some of the most popular food supplements, with global sales approaching €1 billion annually.
While glucosamine sulphate has some evidence to support its effectiveness, chondroitin has been more controversial. Very few studies have examined chondroitin, but in the past couple of years some important new research findings have been published.
EVIDENCE FROM STUDIES
Part of the challenge in evaluating the effectiveness of chondroitin is that earlier studies used small numbers of patients and had problems in their design, but tended to find positive results. More recent, larger studies tend to find few benefits.
However, a study published this summer shed some important light on how chondroitin might be helpful. This study used MRI measurements to monitor the volume of cartilage in osteoarthritis patients. Patients were randomly assigned to take 800mg chondroitin sulphate daily. After six months, the MRIs showed that patients taking chondroitin had significantly less loss of cartilage than those taking placebo.
This study adds further evidence to the results of a systematic review published in 2010. This review looked at studies measuring cartilage loss using X-rays. Such changes take longer to appear, so the review examined studies lasting at least two years.
Taking into account the results of new studies, this review found evidence that loss of cartilage was significantly slower in people taking chondroitin compared with placebo.
A second systematic review published in 2010 also examined the impact of chondroitin on osteoarthritis pain. In this, those taking chondroitin did not have greater pain relief than those taking placebo. This review also examined the X-ray studies and failed to find evidence of a benefit.
This different conclusion arose because the two reviews used different statistical methods to examine the data. Such inconsistencies point to the fact that the changes found in individual studies are small.
PROBLEMATIC ASPECTS
The controlled studies using chondroitin have found few adverse effects. Some people experience gastrointestinal problems such as heartburn and nausea.
The main problem with chondroitin is related to product quality. Hundreds of chondroitin products are on the market, many in combination with glucosamine and other supplements. Independent analyses have found much variability in their quality. For this reason, using products made by reputable manufacturers is important.
RECOMMENDATIONS
The Osteoarthritis Research Society International recommends a combination of medications and non-pharmacological approaches to treating osteoarthritis.
While acknowledging that little evidence is available to support chondroitin, their guidelines suggest that it may be effective in preventing the loss of cartilage in joints.
A small number of studies continue to provide evidence suggesting that at least some osteoarthritis patients benefit from chondroitin. However, the changes are not dramatic and can take months to appear.
Some people may want to try chondroitin for a set period and monitor their symptoms to see if they improve. In contrast, taking chondroitin for the immediate relief of pain or inflammation does not appear warranted.
If you would like to see a particular herbal remedy or food supplement discussed here, e-mail your request to healthsupplement@irishtimes.com.
Dónal OMathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing, Dublin City University.
