There can be very few people who haven’t heard the
words glucosamine and chondroitin in relation to joint health, but
what exactly are they and how do they work?
These products are some of the most popular nutritional
supplements in the UK. Numerous research studies testify to their
popularity and effectiveness. Most indicate that a mixture of
glucosamine and chondroitin (pronounced Kondroytin) are the most
effective. Glucosamine in its natural form exists in all our joints
and muscles, playing a role in the everyday mobility and smooth
working of cartilage, tendons and ligaments. It is a major building
block of the complex proteins called glycosaminoglycans that in
turn form part of the structure of cartilage. It is essential for
the production of new cartilage and synthesis of the joint’s
oil (synovial fluid), helping to make it thicker and more
cushioning. It strengthens the jelly-like centre of intervertebral
discs and is also needed for healthy formation of nails, tendons,
skin, eyes, bone, ligaments and mucous membranes. Glucosamine
sulphate is a substance that is naturally made in the body from a
sugar (glucose) and an amino acid (glutamine). Larger quantities
are needed when damaged joints are healing and, as production of
glucosamine is normally a slow process, it is often in short
supply. It is therefore frequently taken orally as a nutritional
supplement.
Research
Glucosamine sulphate can improve joint symptoms associated with
sports injuries and arthritis by at least 40% and often up to 70%
compared with an inactive placebo. A landmark clinical trial
compared the effects of glucosamine sulphate (1500mg once daily for
three years) versus placebo on the long-term progression of knee
osteoarthritis in 212 patients. Those taking placebo showed
progressive narrowing of the knee joint space over the three year
trial period, while those taking glucosamine sulphate showed no
significant loss of joint space. Those receiving glucosamine
sulphate enjoyed significant improvements in pain and disability,
which was sustained for the three-year duration of the trial; in
contrast, those taking placebo experienced a significant worsening
of symptoms. The authors concluded that ‘The long-term
structure-modifying and symptom-modifying effects of glucosamine
sulphate suggest that it could be a disease modifying agent in
osteoarthritis’.1
Glucosamine sulphate appears to be at least as effective in
reducing joint pain as non-steroidal anti-inflammatory painkillers
such as ibuprofen. In a study involving 178 people with
osteoarthritis of the knee, those taking glucosamine 1500mg daily
for four weeks showed improvements similar to those seen with
ibuprofen 1200mg daily, but with fewer side effects. Two weeks
after stopping treatment, those who had taken glucosamine had a
better residual therapeutic effect than those taking the
non-steroidal anti-inflammatory drug.2
safety
No significant side effects were reported. It should not, however,
be used in pregnancy, as its effects have not yet been
investigated.
Chondroitin
Chondroitin sulphate is closely related to glucosamine and is
usually combined with it for additional benefit. The former
supplies building blocks for making structural substances known as
glycosaminoglycans in joints. It attracts water into joints, which
acts as a shock absorber as well as a nutrient transport system.
Chondroitin sulphate inhibits enzymes that break down cartilage,
while stimulating those involved in the production of structural
substances such as proteoglycans, glycosaminoglycans and collagen.
Chondroitin sulphate helps to raise blood levels of hyaluronan, a
sticky gel that cements joint tissues together.
1Long-term
effects of glucosamine sulphate on osteoarthritis progression: a
randomised, placebo-controlled clinical trial, Jean Yves Reginster,
Rita Deroisy, Lucio C Rovati, Richard L Lee, Eric Lejeune, O L
Bruyere, Giampaolo Giacovelli, Yves Henrotin, Jane E Dacre,
Christiane Gossett: Lancet 2001; 357: 251-5.
2Efficacy and safety of glucosamine
sulphate versus ibuprofen in patients with knee osteoarthritis, Qiu
G X, Gao S N, Giacovelli G, Rovati L, Setnikar I:
Arzneimittelforschung. 1998 May; 48(5): 469-74.
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