Joint Supplement Choices

Joint Supplement Choices

Owners and veterinarians are constantly in search of methods to prevent the onset of osteoarthritis, reduce its severity, or halt its progression. Nutraceuticals such as joint supplements have become popular preventative therapies.

Photo: The Horse Staff

Osteoarthritis (OA) remains one of the most important yet incurable causes of lameness in our equine athletes. Owners and veterinarians are constantly in search of methods to prevent the onset of osteoarthritis, reduce its severity, or halt its progression.

Although non-steroidal anti-inflammatory drugs and intra-articular corticosteroids are still important for treating clinical lameness associated with OA, nutraceuticals such as joint supplements have become popular prophylactic (preventive) and conjunctive osteoarthritis therapies. These products, however, are not subject to the same extensive efficacy testing requirements as pharmaceuticals.

One of the largest obstacles veterinarians face when recommending joint supplementation is the lack of adequate research surrounding these products. When choosing a supplement it is important to understand the ingredients. Most joint supplements contain glucosamine and/or chondroitin sulfate. Chondroitin sulfate is an important structural component of articular (joint) cartilage. The chondroitin is most often extracted from cow, pig, or marine cartilaginous tissues. The substance is believed to possess anti-inflammatory properties as well as promote the synthesis of other articular cartilage components such as proteoglycans and hyaluronic acid (HA). Glucosamine, another common ingredient, is most often produced by the breakdown of shellfish exoskeleton. It is a precursor to a major component of articular cartilage, glycosaminoglycans. However, researchers have not shown supplementing with glucosamine alone to be efficacious in horses, and the majority of support for its use remains anecdotal.

Other proposed active ingredients in joint supplements might include HA, omega-3 fatty acid sources, or unsaponified avocado soy. Hyaluronic acid is a major component of articular cartilage and synovial (inside the joint) fluid, but the benefits of oral HA administration remain controversial. In a 2006 study, Bergin et al. reported findings suggesting oral HA administration might result in decreased joint effusion (swelling) after surgery. However, results from a recent study by Carmona et al. (2009) indicated no benefit to oral HA administration in horses with cartilage defects.

Unsaponified avocado soy, an ingredient of recent interest, showed promise in a 2007 study conducted by Kawcak et al. at Colorado State University's Equine Orthopaedic Research Center. The researchers found decreased cartilage damage and increased articular cartilage glycosaminoglycan content with unsaponified avocado soy administration. It is one of few joint supplement ingredients for which a controlled equine study demonstrated efficacy.

Other supplements contain omega-3 fatty acids, which have multiple anti-inflammatory properties as shown in clinical trials of dogs with OA (Vandeweerd et al., 2012). However, researchers have not yet studied these effects exclusively in horses, and further research is indicated.

The efficacy of oral joint supplement formulations depends on the ingredients' absorption within the gastrointestinal tract. Chondroitin sulfate might be more biologically available than glucosamine (Du et al., 2002), but glucosamine and chondroitin sulfate levels in individual supplements vary. In a 2010 study, Oke et al. evaluated the glucosamine levels in 23 commercially available supplements and found marked variability in the amount of glucosamine the products contained when compared to the labels. In addition, only a small amount (approximately 6%) of the glucosamine administered becomes biologically available (Du et al., 2004). Some study results have suggested that the average adult horse should receive approximately 10 grams of glucosamine orally per day (Laverty et al., 2005). Further research is needed to determine the ideal dose and frequency of administration of chondroitin sulfate, glucosamine, and other joint supplement components.

Although a wide variety of joint supplements are available, few companies provide significant proof of efficacy. Research in joint supplementation is advancing slowly with some support for ingredients such as chondroitin sulfate, unsaponified avocado soy, and omega-3 fatty acids. When choosing a product the veterinarian and horse owner must rely on limited research in combination with anecdotal support and personal experience.


About the Author

Aimee C. Colbath, VMD

Aimee C. Colbath, VMD, is a resident in equine surgery and lameness at Colorado State University.

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