Ok, maybe not. But still, any sign that folks are questioning this ubiquitous practice is a good thing.
I have written a number of times about the question of whether or not oral glucosamine and chondroitin are useful for arthritis in dogs and cats. Overall, the evidence in humans suggests it is likely no better than a placebo, and the much more limited evidence concerning veterinary uses is no better. Despite this, many veterinarians refuse to acknowledge the lack of support for their assumptions that glucosamine is beneficial. In looking for any skeptical perspectives on this subject, I was only able to find a couple.
A recent short feature in the Journal of the American Veterinary Medical Association posed the clinical question,
Would treatment with a supplement containing glucosamine and chondroitin be likely to yield a clinically meaningful improvement in the signs of chronic osteoarthritis in a dog without unacceptable adverse effects, either as an alternative or adjunct to NSAID treatment?
The answer, based on a brief review of the limited available literature was,
there was insufficient evidence to support a recommendation of glucosamine and chondroitin as an alternative to NSAID medication for treatment of clinical signs attributed to osteoarthritis in dogs…No literature addressing the possible use of a glucosamine-chondroitin product as an adjunct to NSAID treatment was identified.
A popular veterinary blog has also commented on recent studies in humans showing oral glucosamine to be no better than placebo for arthritis. The author expresses succinctly my own feelings on the subject:
I wish oral glucosamine worked. I want it to work. But I want many things that I cannot have. Effective arthritis treatment with oral glucosamine evidently is one of them.
Interestingly, the only other critical comments on veterinary glucosamine use I found was from a decidedly unscientific perspective. A proponent of BARF diets (which, as I’ve discussed previously, is even less rational a practice than using glucosamine) turns the unscientific and evidence-free arguments for raw diets against glucosamine supplements, He claims that,
glucosamine for dogs cannot work for any canine on a commercial dog food diet when the cocktail of chemicals they are comprised of routinely strip bones and joints of much needed nutrients…Only dogs on a diet of raw meat and bone have the proper balance of nutrients to ensure good bone and joint health throughout life.
Not exactly a position I can endorse, even if it sounds on the surface like it leads to the same conclusion on joint supplements. Glucosamine may not have significant proven benefits, but the risks are also apparently negligible. While the evidence does not suggest raw diets are beneficial, the evidence of potential harm is certainly greater than that for glucosamine, although still apparently quite small.
Obviously, the majority of veterinarians and pet owners are still more influenced by personal experiences and anecdotes that suggest glucosamine is beneficial than by the solid research data that shows it is not. Hopefully, the presence of at least a few skeptical voices will motivate more people to question the hype surrounding this supplement and to look closely at the evidence.
If anyone finds any additional skeptical points of view on this subject, please let me know!