Nutraceuticals are a loose and ever-expanding group of “natural” substances added to a dog or cat’s diet with the intended purpose of relieving pain and inflammation associated with arthritis (osteoarthritis or OA). Substances such as glucosamine and chondroitin sulfate (G/CS), omega-3 fatty acids, methylsufonylmethane (MSM), avocado-based unsaponifiables, and S-adenosylmethionine (SAM-e) are examples of these products.

Glucosamine/chondroitin sulfate products have long been touted for their ability to reduce joint inflammation and provide cartilage subunits for repair. Despite mixed reviews in the scientific literature and limited insight into the exact mechanism by which these products work, these products continue to be used with anecdotal success. The good news is that these products are seemingly very safe with a mild risk of transient diarrhea reported as the most common side effect. There are a multitude of products available over the counter. Quality, source, and bioavailability of the G/CS varies widely and is only loosely associated with the price of the product. Because it is very hard to predict which dogs will respond to G/CS, beginning therapy with a name brand product helps reduce the possibility that the animal failed to respond to the G/CS because of an inferior product. Generally, a positive effect from G/CS may not be seen for six to eight weeks. If the G/CS appears to have a beneficial effect, the therapy must be continued for life.

The anti-inflammatory effect of omega-3 fatty acids has been touted for some time but only recently have they begun to be incorporated into diets and promoted as supplements. Omega-3 fatty acids are metabolized to a compound called eicosapentanoic acid (EA). The by-products of EA are less inflammatory, cause less damage to the microscopic blood supply to the joint, and cause less joint immune system suppression than inflammatory substances produced by other pathways of joint inflammation. They are seemingly safe but may not be effective unless derived from fish (as opposed to vegetable sources). Further, the optimum Omega 6 to Omega 3 ratio has yet to be determined.

Methylsulfonylmethane is an organic sulfur containing compound similar to dimethyl sulfoxide (DMSO) a chemical long touted for its anti-arthritic effects. Sulfur is necessary for the formation of healthy joint cartilage and supplementing the diet with additional sulfur through MSM is proposed to help diseased joint cartilage avoid further deterioration. Methylsulfonylmethane is reported to reduce inflammation and pain associated with OA. Unfortunately, as with most nutraceuticals, there is little properly done research to support these claims. Few if any side effects have been reported with MSM when given at recommended dosages.

S-adenosyl methionine is another sulfur containing compound required for basic cell growth and repair. Although SAM-e has been promoted as a treatment for arthritis, very little scientific evidence supports the claim.

The latest focus in the dietary approach to treating OA is the avocado-based unsaponifiables. Again, these products reduce inflammation, are reportedly safe, and do not require injection. Many diets and dietary supplements are beginning to incorporate these various products into easy-to-administer formulations. Only time will tell which ones prove to be effective and in what combinations.

This column is provided by the faculty of the OSU Boren Veterinary Medical Teaching Hospital.

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