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Joint Supplements for Dogs

by Jeff Grognet, DVM, BSc (Agr) and Louise Janes, BSc(Agr), DVM

Your dog (or cat) has been lame on and off for months. Recently, his limp wouldn’t go away. After taking x-rays, your veterinarian has diagnosed arthritis. What can you do to give him comfort?

 

You may choose to give your companion painkillers – either steroidal medication such as cortisone or nonsteroidal anti-inflammatory tablets – or you might consider the benefits of acupuncture, chiropractic, or laser. But, what about supplements? Will they help your arthritic friend?

Just as there is a plethora of approaches to arthritis management, there is a wide variety of joint support supplements. The terms nutraceuticals (purified substances that help body function) and chondroprotectants (substances that specifically protect cartilage) are commonly used to categorize these products. More recently, the acronym DMOA (disease-modifying osteoarthritic agent) has been coined. Substances included in this group nourish joints and relieve inflammation and pain.

The most widely used DMOA is glucosamine. Given orally, it is broken down by the body to glycosaminoglycan (GAG), a normal constituent in collagen and proteoglycans, which are the building blocks of cartilage. GAG also helps boost the amount of joint-nourishing hyaluronic acid produced by the cells lining the joint capsule. Glucosamine enhances cartilage repair, but it also retards the damaging effects of inflammation in the joint. The end result is less pain and more mobility.

There is disagreement over whether the hydrochloride (HCl) or the sulfate form is best suited for pets. Some sources claim that the HCl salt is better absorbed while others suggest there is equal absorption of both. Another source suggests that the HCl form provides more glucosamine per unit weight than the sulfate form.

Chondroitin sulfate is frequently added to glucosamine products. It reduces the breakdown of cartilage by decreasing the activity of the inflammatory enzymes that cause cartilage destruction. The actions of glucosamine and chondroitin are sufficiently different that their effect is synergistic. Together, they form a potent pair.

The most commonly used nutraceutical in dogs is CosequinR (Nutramax Laboratories). Besides glucosamine and chondriotin, it also contains manganese, a cofactor in GAG synthesis. Studies prove it increases the activity of cartilage-producing cells, decreases the action of cartilage-damaging enzymes, lessens pain, and increases mobility.

A debate continues on whether or not the beneficial claims attached to specific brand names can be extrapolated to other products containing the same ingredients in different forms, from different sources, and in different amounts and combinations. In other words, a generic brand may not be equivalent to a brand name.

Antioxidants such as vitamins E and C, selenium, and dimethylsulfoxide (DMSO) supposedly help protect cartilage by reducing oxidative cell damage. Unfortunately, information on the efficacy of these products is scarce. There is also an ongoing concern regarding the quality control of these products.

Methylsulfonylmethane (MSM) can help arthritic joints, but unfortunately, it has a drawback. It has an innate ability to transport molecules across cell membranes. Besides carrying medications, it can also carry toxins directly into the body. Studies in animals suggest that it can cause changes in the lens of the eye. Human rheumatologists (arthritis experts) consider MSM an unproven remedy.

Recently, many dog food manufacturers have started including chondroprotectants in their products. Most add glucosamine and some also add chondroitin. There are several unanswered questions about this practice. Is the amount added therapeutic? And how does food processing affect the bioavailability of these substances?

Several prescription diet companies have formulated products that research shows are beneficial to joint health. These diets contain many additives, including antioxidants and such ingredients as green-lipped muscle. Much of their efficacy is derived from their high omega-3 fatty acid content. These specific fatty acids decrease joint inflammation and subsequent joint degeneration. Because of this positive effect, many veterinarians prescribe omega fatty acids as a supplement for their arthritis patients.

Injectable Chondroprotectant

Not all chondroprotectants are administered orally. Cartrophen-VetR, produced from beech hemicellulose, is given to dogs and cats by injection. Both of these substances reduce the breakdown of cartilage, increase cartilage repair, and improve circulation to the joints so they are beneficial to pets with arthritis.

For more information contact Dr. Jeff Grognet or Dr. Louise Janes at

Mid-Isle Veterinary Hospital
5-161 Fern Road West
Qualicum Beach, B.C.
Tel (250) 752-8969

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