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Glucosamine: a supplement which may ease arthritis

Chris Turner
DC CCSP
DipSportsMed
Principal
Maidenhead Chiropractice
Maidenhead

One much hyped supplement is glucosamine sulphate, available in various forms from chemists and healthfood shops. So can the claims made for glucosamine as a protector of joints and an analgesic be substantiated?

Glucosamine is a naturally occurring aminomonosaccharide found in almost all tissues in the body, and in especially high concentration in cartilage, tendon and ligamentous tissues. It is formed in the body from glucose and glutamic acid and is a precursor for the biosynthesis of N-acetylglucosamine, which in turn is one of the precursors for the biosynthesis of various kinds of glycoaminoglycans (GAGs) that are important constituents of articular cartilage.

Glucosamine is commercially available as glucosamine sulphate. It is manufactured by synthesis and is most commonly available in tablet form. A topically applied gel is also obtainable.

The role of glucosamine
Glucosamine is an essential substrate of the GAG matrix that forms the bulk of cartilaginous tissue. Studies in vitro demonstrate that glucosamine can increase the rate of GAG growth in cartilage tissue cultures.(1) It therefore has an important role in the repair and replacement of the "glue" that holds cartilaginous tissue together. Deficiency can lead to an impaired ability of cartilage to regenerate and could lead to increased levels of joint ­degeneration.

Glucosamine is not found in appreciable quantities in the diet and is synthesised in the body. The ability to synthesise glucosamine decreases with age.

The synthesis of GAG in the body has an important role in chondroprotection, which is based on the exogenous introduction of GAG used by chondrocytes for the synthesis of proteoglycans. Although this is thought to help the physiological processes of a joint, GAG also has an antireactive effect.

Trials comparing the use of glucosamine sulphate and aspirin in models of inflammatory reactions have shown that glucosamine has a similar, if reduced, antireactive effect to aspirin. However, glucosamine is practically devoid of toxicity and can be taken in larger quantities with no side-effects.

A recent randomised, double-blind trial of glucosamine 1,500mg as an analgesic in symptomatic osteoarthritic knees demonstrated that glucosamine seemed to benefit those patients with mild to moderate pain whilst having little discernible effect on patients with severe pain. This finding leads to the suggestion that future trials involve the stratification of patients for the severity of pain at the start of the trial.(2)

Clinical studies have demonstrated efficacy comparable to that of commonly prescribed nonsteroidal anti-inflammatory drugs. A randomised double-blind parallel group study compared the efficacy of glucosamine (1,200mg/day) with that of ibuprofen (1,200mg/day) in 200 hospitalised patients with active osteoarthritis of the knee for at least the preceding three months and a Lequesne's index of at least  seven points. Response was defined as a reduction in the Lequesne's index of at least two points if the enrolment value was higher than 12 points, or by at least one point if the enrolment value was 12 or less. The success rate for glucosamine (48%) was similar to that of ibuprofen (52%), with the average value of the Lequesne's index decreasing from around 16 points to around 12 points in both groups. However, while 35% of patients taking ibuprofen reported adverse effect, mainly of gastrointestinal origin, only 6% of patients taking glucosamine reported adverse effects.

Glucosamine may well have other uses, such as in the treatment of back pain. McCarthy has recently published a paper describing a pilot study investigating the effects of glucosamine sulphate and a placebo on the overall spinal height measured over a day.(3)
 
This was an eight-week study investigating the loss of height each day due to the compression of the intervertebral discs and to see whether glucosamine has an effect in maintaining spinal height.

The conclusion was that taking glucosamine sulphate (1,500mg) had an effect on the reduction in the daily rate of spinal shrinkage. It is surmised that by taking glucosamine it may be possible to prevent increased pressure on the facet joints in the spine and thus prevent the pain felt at the end of each day by those suffering from discal degeneration.

Safety and toxicity
Glucosamine has no known side-effects. Any adverse reactions are due to substrates present in the tablets.

Conclusion
Glucosamine sulphate is a widely available dietary supplement. There is much anecdotal evidence for its use as an antiarthritic agent. A careful examination of the literature shows that there is much substantiated research into the use of glucosamine sulphate as a chondrometabolic, antireactive and antiarthritic agent. An important feature is that there are few contraindications to its use as it has little or no adverse reactions in the body.

References

  1. Basleer C, Henrotin V, Franchimont P. In-vitro evaluation of drugs proposed as chondroprotective agents.Int J Tissue React 1992;14:231-41.
  2. Hughes RA, Carr AJ. A randomised, double blind, placebo controlled trial of glucosamine to control pain in osteoarthritis of the knee. Arthritis Rheum 2000;43:S1903.
  3. Swindells R, McCarthy PW. The effects of glucosamine sulphate on spinal height. A randomised, double blinded, placebo controlled pilot study. Eur J Chiropractic 2002; (in press).