Glucosamine and chondroitin have gained such a following
in recent years that US authorities have undertaken the
largest-ever study on them and we now have the first
results...
Glucosamine has a very special role in combating joint problems.
In the last few months, further scientific support for this
supplement in combination with chondroitin has emerged from the
prestigious American Glucosamine/chondroitin Arthritis Intervention
Trial (known to doctors as GAIT).
WHAT DO WE KNOW ALREADY?
Osteoarthritis is the most common joint problem suffered by
millions in the Western world; it commonly affects knees, hips,
spine or hands. The signs and symptoms are well known: pain,
stiffness and decreased mobility. In the past, OA was considered
irreversible - due to progressive ‘wearing-out’ of the
joint - but new research is changing our thinking. We now know
that, at least in the early stages of OA, the cartilage cells in
the joint are very active, with mechanisms operating against
destructive breakdown. These repair mechanisms could account for
reports of people in whom OA has halted or even
reversed1, once thought to be impossible.
By June 2001, enough evidence had accumulated in clinical trials
for the erstwhile conservative American Arthritis Foundation to
issue a statement declaring glucosamine to be ‘an appropriate
treatment’ for osteoarthritis. As far as chondroitin is
concerned, the development of its evidence base for efficacy in
treating OA has lagged behind that of glucosamine. In the past few
years, several small but welldesigned double-blind clinical studies
have shown positive benefits of chondroitin supplementation for the
alleviation of knee arthritis compared with placebo treatment.
SCIENTIFIC RESEARCH
The National Institutes of Health in the USA decided to invest
substantial amounts of public funds in the GAIT study - the largest
on these supplements ever undertaken. The study involves thirteen
research centres across the United States. The work is ongoing, but
results of the first phase were reported in November. They showed a
positive effect of glucosamine in combination with chrondroitin for
treatment of OA of the knee and strongly supported the previous
positive outcomes for these supplements.
At the start of the GAIT study, about 1,500 volunteers were
randomly assigned to take, on a daily basis for six months, either
(1) 1,500 mg of glucosamine, (2) 1,200 mg of chondroitin, (3) a
combination of both, (4) an orthodox painkiller called Celebrex or
(5) a placebo. Patients were included in the trial only if they had
had knee pain for at least six months before it began and showed
arthritic changes of the knee under X-ray. Success in the trial was
measured by a 20 per cent improvement from baseline in a
well-established pain score after six months of treatment. In the
second, long-term phase of GAIT, half the volunteers will continue
their treatments for a further 18 months to ascertain whether
glucosamine and chondroitin really do support joint-repair
mechanisms and can halt the progression of this debilitating
disease.
The volunteers who benefited most in the GAIT study had the
highest knee pain scores at the beginning. For this subgroup, it
was found that glucosamine plus chondroitin was more effective than
Celebrex in reducing pain. However, for people with mild knee pain,
only Celebrex showed a significant improvement compared to the
placebo. The authors suggested that the reason why the combined
supplement was found more effective for greater initial pain may be
because those suffering from milder forms had more difficulty in
accurately assessing changes in their condition.
CONCLUSIONS
While orthodox medication for OA with non-steroidal
antiinflammatory drugs reduces pain, it does nothing to enhance
joint-repair mechanisms and reverse the degeneration process. This
contrasts with what has been reported to happen to OA patients
receiving glucosamine and chondroitin. Not only was the progression
of the disease halted, but it was reversed. It is hoped the second
phase of the GAIT study - to be completed in 2008 - will provide
scientific support to underpin these clinical observations.
1 Bland JH (1983). Am J Med 74, 16.
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