Friday, September 4, 2009
Osteoarthritis, or degenerative joint disease, is the most common form of arthritis, most often affecting middle-aged and older people.
The disease, which can cause severe disability and pain, tends to develop in the joints of the neck, lower back, knees, hips and fingers.
However, it may also occur in joints that have been previously injured, or subjected to prolonged heavy use.
Experts estimate that 60% of those aged 65 have moderate to severe osteoarthritis in at least one joint.
It is caused by the degeneration of the cartilage, the protective material that stops bones rubbing together in the joints.
The dietary supplement glucosamine sulphate has been shown to reduce the severity of symptoms in the short term.
But now researchers have achieved the same effect in the longer term.
The work was carried out by Professor Jean Reginster and colleagues from CHU Centre Ville, Liege, Belgium.
Patients with the disease either received a daily 1,500 mg dose of a form of the compound, or a placebo over a period of three years.
The researchers took radiograph images of the patients' knees while lifting a weight after one and three years.
They found that the space between the joints of the knee narrowed significantly over time in the 106 patients who received the placebo. After three years the average loss was 0.31mm.
However, there was no such narrowing among patients on glucosamine sulphate.
Those patients who completed the full course of treatment showed a 20-25% improvement in their symptoms, compared with slight worsening of symptoms in the placebo group.
Dr Madeleine Devey, scientific secretary of the Arthritis Research Campaign, said many people with osteoarthritis had been taking glucosamine sulphate for many years.
She said a small scale trial of the supplement in the UK found that it had a small beneficial impact on patients who were in mild pain - but not those in severe pain.
A larger scale study is currently being undertaken in the US.
Dr Devey told BBC News Online: "Many people with osteoarthritis take glucosamine sulphate, but until now the evidence that it does any good is very inconclusive.
"These results are encouraging, but we would welcome properly conducted clinical trials to answer the question one way or another.
"Osteoarthritis causes a great deal of social exclusion for elderly people who cannot get out."
Dr Tim McAlindon from Boston University Medical School, USA, said the study was a landmark piece of research.
He said: "It is time for the [medical] profession to accommodate the possibility that many nutritional products may have valuable therapeutic effects and to regain the credibility of the public at large".
The only current treatments for osteoarthritis are painkillers and non-steroidal anti-inflammatories, which are also given to dull pain. Some patients undergo joint replacement surgery.
The best way to minimise risk is to take regular exercise and to lose excess weight. It is also a good idea to wear proper trainers when taking exercise to protect the ankle and knee joints.
The research is published in The Lancet medical journal.
Taking glucosamine does not adversely affect blood sugar control in diabetics, according to a report in Archives of Internal Medicine (2003;163:1587?90). This study confirms the results of a previous report and should allay the concern voiced by some scientists that glucosamine has the potential to increase blood sugar levels.
Glucosamine, a compound that occurs naturally in the body, is available as a nutritional supplement and usually taken in the form of glucosamine sulfate. Glucosamine serves as a building block in the production of a type of cartilage present in joints. Studies have shown that glucosamine can promote the repair of damaged or degenerating joint cartilage. Numerous double-blind studies of people with osteoarthritis have demonstrated that glucosamine is significantly more effective than a placebo and at least as effective as commonly used anti-inflammatory medicines at relieving pain and improving joint function. Moreover, glucosamine is one of only a few substances that have been shown to slow the progression of osteoarthritis. In contrast, anti-inflammatory drugs may actually accelerate the disease process, even though they may temporarily improve symptoms.
While glucosamine is generally considered to be safe and has not been associated with any serious side effects, preliminary studies in animals suggest that it could cause insulin resistance and other abnormalities of blood sugar metabolism. The relevance of these studies to humans has been questioned, however, since glucosamine was administered in the animal studies in relatively large amounts by continuous intravenous infusion.
In the new study, a group of elderly people with type 2 (adult onset) diabetes were randomly assigned to receive either a placebo or the combination of glucosamine hydrochloride (1,500 mg per day) and chondroitin sulfate (1,200 mg per day) for 90 days. Chondroitin sulfate is another natural substance that is sometimes used in combination with glucosamine to treat osteoarthritis. Chondroitin sulfate has not been found to affect blood sugar levels. A laboratory test that assesses long-term blood-glucose control (hemoglobin A1c) was performed at the beginning and the end of the study. Compared with the placebo, glucosamine-chondroitin treatment had no significant effect on hemoglobin A1c levels. None of the participants required a change in their diabetes medication during the study.
The absence of any effect on blood sugar control is consistent with the results of a previous study of nondiabetics. In that study, supplementing with 1,500 mg of glucosamine sulfate per day for three years was associated with a slight decrease in blood sugar levels. Taken together, these studies strongly suggest that people with diabetes can safely take glucosamine, and that supplementing with this natural osteoarthritis remedy does not increase the risk of developing diabetes.
Alan R. Gaby, MD, an expert in nutritional therapies, testified to the White House Commission on CAM upon request in December 2001. Dr. Gaby served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A?Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient?s Book of Natural Healing (Prima, 1999). A former professor at Bastyr University of Natural Health Sciences, in Kenmore, WA, where he served as the Endowed Professor of Nutrition, Dr. Gaby is the Chief Medical Editor for Healthnotes, Inc.
Two hundred and twelve patients with osteoarthritis of the knee were randomly assigned to receive either a placebo or 1,500 mg of glucosamine once per day for three years. At the end of the trial, for those who were followed throughout the trial, symptom scores increased by 10% in the placebo group but decreased 24% in those given glucosamine. X-rays of the knees of patients assigned to take placebo continued to show a significant increase in abnormalities, while no deterioration appeared in the average X-ray of the knees of people given glucosamine. All differences in outcome between people given glucosamine and people given a placebo were statistically significant.
For conventional medicine, previous skepticism may now be replaced by a new attitude regarding not only glucosamine but also other dietary supplements as well. A landmark editorial accompanying the new report concludes that it is time for medical doctors to accommodate the possibility that many nutritional products may have valuable therapeutic effects.
The Take-Home Message
For arthritis sufferers, there are several take-home messages to be found in the new report. First, glucosamine is safe. Since glucosamine does not cure people with osteoarthritis and they may need to take the supplement for the rest of their lives, the issue of long-term safety is important. The Lancet report is the first to show that glucosamine has essentially no side effects, even after three years of supplementation. Overall, problems were no more common in people given GLUCOSAMINE than in those given a placebo.
The fact that X-rays continued to show deterioration with placebo but not with glucosamine suggests that glucosamine directly affects the structure of joints. The difference in X-ray finding between the glucosamine group and the placebo group strongly suggests that glucosamine is not simply reducing pain, but is somehow preventing further damage.
Glucosamine May be Your Stomach´s Best Friend
Conventional medicine has no osteoarthritis therapy that maintains joint structure. In fact, the most common treatment - aspirin and related drugs - used to reduce pain, have been reported to increase the rate of joint deterioration in arthritis suffers. But the most common serious side effect from chronic aspirin use is irritation to the stomach, which often turns into gastritis or even ulcers. By significantly reducing pain levels, long-term use of glucosamine is likely to translate into less aspirin use, and with that, less gastritis and fewer ulcers.
Steve Austin, ND, is the Chief Science Officer for Healthnotes, Inc. He is a former Professor of Nutrition at the National College of Naturopathic Medicine in Portland, Oregon. Dr. Austin has also headed the nutrition department at Bastyr University.