... and I wonder why that would be?
The National Institute for Health and Clinical Excellence published a handy guide with its recommendations for health professionals - the information above is taken from it.
The NHS on its NHS Direct page "Osteoarthritis - Self help" has this to say:
...there is very little medical evidence to back up the effectiveness of supplements, such as chondroitin and glucosamine. Although there is little medical evidence to back up the effectiveness of glucosamine hydrochloride, recent research has shown that taking glucosamine sulphate (which is found in healthy cartilage), or fish oils, may have positive results. However, the NHS cannot recommend, or prescribe, the use of glucosamine sulphate because it does not often prove to [be] cost-effective.
Hardly a resounding endorsement. So what is that "recent research"? Well, unfortunately, the NHS page doesn't give the reference, but I'll bet that it is probably the GAIT trial - The Glucosamine/Chondroitin Arthritis Intervention Trial, which was a large randomized, placebo-controlled trial conducted at several sites across the USA. The National Centre for Complementary & Alternative medicine (NCCAM, who were involved in the trial) in the US has an excellent Q&A.
The research has been going on for a number of years, and the first stage of the trial was published in 2006 in The New England Journal of Medicine which concluded:
Glucosamine and chondroitin sulfate alone or in combination did not reduce pain effectively in the overall group of patients with osteoarthritis of the knee. Exploratory analyses suggest that the combination of glucosamine and chondroitin sulfate may be effective in the subgroup of patients with moderate-to-severe knee pain
They freely admit that because of the small numbers in this subgroup, they were unable to to demonstrate statistical benefits, and requested further research.
In a funny "who do you believe?"-type story, Dr Trish MacNair was dealing out Doctor's advice on the BBC's Health Pages and in October 2007 (after this study came out, here advice was (in direct opposition to GAIT, the largest and most relevant study on the supplements):
Glucosamine seems to be less useful when a person has more severe pain from arthritis.(As an aside, I found this line from the GAIT publication fascinating:
...the high rate of response to placebo (60.1 percent) and the relatively mild degree of pain from osteoarthritis among the participants may have limited our ability to detect benefits of the treatments. Elevated rates of response to placebo have been reported in other osteoarthritis trials and may relate, in part, to patients' biases and expectations and to the enrollment of patients with relatively mild symptoms of osteoarthritis.
I'm pretty sure we all know of people who have arthritis who swear by some secret natural pain-reliever such as honey & ginger hot drinks or cider vinegar - this study seems to suggest that we arthrites will respond well to a raft of placebos; anything to numb the pain! If it "works", that's excellent - stick with it. I have my own placebo, and I know it's a placebo, but a double of Highland Park Whisky with one piece of ice (just one, mind) seems to do the trick and it's more fun than cider vinegar).
Anyway, I'm rambling.
The next stage of the trial has now been released - it is due to be published in Arthritis & Rheumatism (paywalled, although Abstract here), and NCCAM's press release is here, and was interpreted by Reuters here. The results were as follows:
Dietary Supplements Glucosamine and/or Chondroitin Fare No Better than Placebo in Slowing Structural Damage of Knee Osteoarthritis
The researchers looked at the reduction in joint space width and found it had decreased less than they had expected which made the analysis more complicated. It's fair to say though that the scientific self-criticism that the press release acknowledges is something that we could do with seeing a lot more of in the CAM world this side of the pond.
They had 572 people for the study and it ran for a further 18 months after the first observation, giving a 2 year study span altogether. Director of the co-funder of the study, National Institute of Arthritis and Musculoskeletal & Skin Diseases, very sensibly said:
Research continues to reveal that osteoarthritis, the most common form of arthritis, appears to be the result of an array of factors including age, gender, genetics, obesity, and joint injuries.or in other words "It's probably a bit more complicated than that", a phrase which should be used much, much more than it is.
At this point in time, none of the UK newspapers have picked up the story (from credit crunch to bone crunch?), although I did find out that Chesney Hawkes had some cartilege removed from his hip and guess what? He now takes glucosamine.