Capsules filled with the powdered shells of crabs, lobsters and prawns: a miraculous aid for joints, and perhaps even an effective treatment for the painful symptoms of arthritis.
Relatively cheap, all natural, and with no side effects. Sounds too good to be true - and also rather improbable?
Not to the millions of Britons who bought glucosamine supplements last year. Worldwide we spent £2 billion in the hope that the fishy contents would protect our knees, hips, wrists and knuckles from deterioration. The £30 million we spend annually on Vitamin C pales by comparison.
Millions of Britons bought glucosamine supplements last year, spending £2 billion in the hope that the fishy contents would protect their knees, hips, wrists and knuckles from deterioration. Arthritis is an umbrella term for a group of diseases that affect the joints, all of which result in pain and disability.
Around 1.2million sufferers of osteoarthritis - characterised by loss of cartilage within the joints - visit their GP each year about the problem. And, according to Arthritis Research UK, as many as one in ten may suffer from joint degeneration.
There is no cure and few effective treatments besides painkillers and, eventually, surgery. So it's no surprise that sales of glucosamine have increased by more than 60 per cent since 2003.
While official medical guidance does not recognise it as an effective arthritis treatment, Arthritis Research UK does endorse it. So what is this super-supplement and does it deserve such acclaim?
WHAT IS GLUCOSAMINE?
Glucosamine is needed to produce a molecule called hyaluronic acid, which is found naturally in cartilage, tendons, ligaments, and synovial fluid around the joints and helps with elasticity. You cannot obtain glucosamine direct from your diet. Instead, our body produces it from the glucose and glutamine in all our foods.
Production of glucosamine slows with age, so some people decide to take it as a supplement. Glucosamine supplements are prepared using chitin, present in the shells of crabs, lobsters, prawns and shrimps. Vegetarian glucosamine is produced by a process of corn fermentation.
NOT ALL GLUCOSAMINES ARE ALIKE
There are numerous brands of glucosamine supplements. The most popular are branded as Glucosamine Sulphate and Glucosamine Hydrochloride.
Glucosamine Sulphate is the form most commonly used by the nutritional supplement industry. It contains sodium or potassium salts, so may not be suitable for people on a salt-restricted diet.
Glucosamine Hydrochloride is a purer form as it contains more glucosamine than glucosamine sulphate. However, it is likely that most forms of the supplement are converted to glucosamine hydrochloride as soon as they mix with the hydrochloric acid in the stomach.
SO DOES IT TREAT ARTHRITIS?
Arthritis is an umbrella term for a group of diseases that affect the joints, all of which result in pain and disability
At least 21 trials focusing mainly on glucosamine sulphate have taken place. Evidence is scarce about the effectiveness of glucosamine hydrochloride and vegetarian glucosamine.
The NHS has prescribed Alateris, a form of glucosamine, for mild osteoarthritis in the hips and knees, since late 2007.
But as of 2008, the National Institute for Health and Clinical Excellence, which provides guidelines for medics, does not recommend glucosamine on the NHS due to a lack of evidence that it works. Controversially, the NHS still spends £25.6 million on glucosamine prescriptions each year.
Arthritis Research UK suggests that those who want to try it should take glucosamine mixed with chondroitin (shark cartilage) supplements for three months and if the pain eases, carry on.
It's best to choose a product made by a well-established company. And anyone with an allergy to shellfish, should take the vegetarian alternative.
Glucosamine can sometimes increase the level of sugar in the blood so people with diabetes need to check their blood sugar.
Also, anyone taking Warfarin should be wary as this can affect blood-thinning control.
There are three brands of glucosamine - Alateris, Glusartel and Dolenio - licensed for prescriptiononly use in the UK for patients with osteoarthritis in their knees. All three have passed quality and safety tests. There is no evidence that rub-on glucosamine gels or creams work.
For those choosing an over-the-counter version try using the following information:
A glucosamine product should be manufactured by a facility that has Generally Recognised As Safe Status, a mark of approval from the U.S. Food and Drug Administration. This is internationally recognised and found on many British products.
It should be produced in a Hazard Analysis and Critical Control Point facility, and made according to Good Manufacturing Practices.
It should also be analysed and tested for the levels of glucosamine. Glucosamine hydrochloride is 83 per cent glucosamine while the sulphate version is only 59 per cent. Be wary of less specific descriptions of the glucosamine content on the label, such as blend.
Many supplements that contain glucosamine often include ingredients such as chondroitin sulphate but there is no proof that combining these adds any benefit.'