There is enormous enthusiasm to try to protect horses from arthritis using medicinal products and nutritional. Recent human studies suggest there may be benefits in terms of reducing joint pain, but the exact mechanisms are unclear. This has served to boost interest in equine products — if they work on me, they must work on my horse.
In fact, only about 50 percent of humans respond in controlled, blinded studies. In horses, there is not enough objective evidence to show that joint protective ("chondroprotective") agents actually reduce cartilage wear, inflammation, or pain, but many swear by these products and there is evidence in humans to support those claims.
Recently, at the American Association of Equine Practitioners in San Antonio, Texas (Nov. 2000) equine surgeon Dr. Larry Bramlage (Rood and Riddle, Lexington, Kentucky) cautioned veterinarians about aspects of the "nutraceutical" industry, the corner of the industry that develops and markets oral preparations that are supposed to protect joints.
Overall, he was positive about their potential benefits, but he made some cautionary points about the way they are formulated and marketed. For orientation, the four major agents and their putative effects that Dr. Bramlage discussed include the following:
Nutraceuticals Are Not Regulated Or Tested
There are no requirements for safety, efficacy, or quality control of these products if they are labeled as nutraceuticals. This reduces the cost of development for these products, but reduces our confidence in their consistency and reliability to deliver what is claimed on the label. No endorsements were given, but CosequinR (glucosamine and chondroitin sulfate) received an honorable mention for quality assurance and reliable documentation of its constituents.
There are many formulations for the same product. For example, glucosamines, which are supposed to reduce the wear and tear (degradation) by reducing inflammation, are formulated as several derivatives, such as glucosamine-sulfate, N-acetylglucosamine, and glucosamine-HCl. There is a vast difference between the effects of each. N-acetyl glucosamine had no effect on cartilage, but glucosamine-sulfate was effective in laboratory cultures of cartilage.
One Product Cannnot Solve Every Horse's Joint Ailments
The specific need for these agents varies with discipline, intensity of training and the current status of the joint. For example, if you have a normal horse undergoing intense training, a combination of agents may be used in a preventative fashion, but in the horse with signs of arthritis, an entirely different approach may be taken, and this may not involve the use of nutraceuticals.
It should be noted that products that contain multiple agents may compromise on quality. A number of companies make products containing multiple agents, but the quantity and quality of active ingredients may be compromised unless they are tested and well-documented. Few products have gone this route, and we should remain leery of products that have not been tested. There should be a guaranteed analysis on the product for quality assurance.
Furthermore, not all products are well-absorbed by the horse's intestine. For example, glucosamines are well absorbed from the horse's intestine, whereas chondroitin sulfates are not. Combined products may compromise on the effective dose of one or another of the constituents because one is absorbed better. In addition, it is unknown how well the different chemical derivatives of glucosamine are absorbed in the horse's intestine. Therefore, we don't know how much of each derivative affects the joint.
Not All Formulations Of The Same Product (Glucosamines) Have The Same Effect
The different derivatives of glucosamines also have different effects. For example, a recent study showed that glucosamine sulfate, but not N-acetyl glucosamine reduced the effects of inflammatory substances fed to cartilage cells in culture.
In summary, Dr. Bramlage suggested that, although there are benefits to these agents, it's a "buyer beware" scenario, with potential problems in the areas of quality assurance, intestinal absorption, and the questionable effects of certain derivatives, that may run counter to the way they are marketed. Cheap is definitely not better, and claims of multiple constituents must be questioned for quality and actual benefit. Keep an open mind, and don't spend a lot of money on products with unproven benefit.