ABOUT THE GUIDE STUDY

The study was performed according to a multicentre, randomised, placebo- and reference-controlled, double-blind (double-dummy), parallel group, prospective design. This means the study was done at multiple hospitals, was randomized to prevent bias, tested against both placebo and real medications and the doctors did not know who was getting the placebo or the glucosamine.

Researchers followed 318 patients (88 per cent women) diagnosed with osteoarthritis of the knee. Based on randomised groupings, patients took either glucosamine sulphate (1500mg once a day), paracetamol (1000mg tablets three times a day) or a placebo over a six-month period. All patients were allowed to take ibuprofen as required.

Outcomes were assessed at clinic visits after 6 months. The primary measure was change in the Lequesne algo-functional index analysed by the General Linear Model (GLM) procedure for ANOVA, with Dunnet's pairwise comparisons versus placebo. Secondary measures included the changes in the WOMAC index and the calculation of the proportion of patients that can be defined responders to treatment according to the Osteoarthritis Research Society International (OARSI) criteria (2000). The use of the rescue medication was also assessed.

FINDINGS OF THE GUIDE STUDY

Results of the trial showed that both glucosamine and paracetamol were more effective than placebo in reducing pain. However, patients taking glucosamine seemed to experience more relief than those taking paracetamol.

The GUIDE study abstract, posted on the American College of Rheumatology website, concluded that “Glucosamine sulphate at the oral once-daily dose of 1500 mg might be the preferred symptomatic medication in knee OA.”

COMMENTS

“Based on these results, physicians who typically recommended paracetamol may well find their patients gain more comfort taking glucosamine sulphate.” GUIDE researcher, Gabriel Herrero-Beaumont, MD, Director of the Rheumatology Department, Jiménez Díaz Foundation - CAPIO, Madrid, Spain.

OSTEOARTHRITIS

Osteoarthritis is a disease that affects the joints. The surface of the joint is damaged and the surrounding bone grows thicker. When a joint develops osteoarthritis, the cartilage gradually roughens and becomes thin and the hone underneath thickens. The bone at the eds of the joint grows outwards, the synovium (a thin, layer of tissue which lines the joint space) swells slightly and may produce extra fluid. The joint capsule and ligaments slowly thicken and contract and muscles may weaken and become wasted.

In the past, OA was often referred to as 'wear and tear' arthritis and considered irreversible due to progressive wearing-out of the joint. New research challenges that thinking. It is now known that, at least in the early stages of OA, the cartilage cells in the joint are very active, with repair mechanisms operating against destructive breakdown. These repair mechanisms could account for reports of people in whom OA has halted or even reversed. However, if the repair cannot compensate for the damage, osteoarthritis may seriously affect the joint, making in painful, stiff and difficult to move.

CAUSES

Research funded by the Arthritis Research Campaign (www.arc.org.uk) has identified that multiple genes play a major part in the development of osteoarthritis of the knee in a study of 1,200 UK patients published in the February 2006 issue of Arthritis & Rheumatism. This research demonstrates that osteoarthritis has a genetic cause in addition to risk factors already known such as ageing, previous cartilage damage, overweight and under- or over-use.

GLUCOSAMINE SULPHATE

Glucosamine is a form of amino sugar found naturally in the body where it has a vital role in cartilage formation and repair.

Glucosamine is a major building block of proteoglycans and is needed to make glycosaminoglycans (GAGs) proteins that bind water in the cartilage matrix. Each person produces a certain amount of glucosamine but age affects the body's ability to produce enough. An insufficient supply of glucosamine restricts the efficiency of cartilage rebuilding and can delay repair of cartilage and other connective tissues. As well as proving its pain-relieving properties, the evidence supports the theory that glucosamine may have a role in correcting the cause of the osteoarthritis.

Glucosamine is found in only a small number of foods. Glucosamine supplements are derived from the shells of shellfish like crab, lobster or shrimp.

SUPPLEMENTARY SUPPLEMENTS

Two other supplements that nutritionists and rheumatologists agree can help ease arthritis pain and joint stiffness are chondroitin and cod liver oil.

Like glucosamine chondroitin is naturally present in cartilage and connective tissue and is involved in the attraction of fluid that lubricates the joints. It is also a building block of proteoglycans (one of the main structural components of cartilage). Oral administration of chondroitin also prompts a significant increase in hyaluronic acid, a major component of synovial fluid which is the lubricating fluid in joints. A natural amino sugar already present in the body, chondritin is not always available in sufficient quantity for joint health and repair.

Taken for many hundreds of years to relieve joint pain and stiffness, it was only with the discovery of the omega-3 essential fatty acids in the 1970s that scientists began to understand why cod liver oil was so effective. The vital omega-3 fats (EPA and DHA) found in cod liver oil have recognised anti-inflammatory properties (the word arthritis comes from the Greek arthro meaning 'joint' and itis meaning 'inflammation') and research from Cardiff University has shown that the omega-3s in fish and cod liver oils can halt, even reverse, cartilage degradation.

Each of the three supplements: glucosamine, chondroitin and cod liver oil; has a different mode of action on joint health and repair but together they have a synergy that suggests superior patient benefits from taking all three. There are no known adverse interactions.