Avocado Soybean Unsaponifiable (ASU) Extracts Earn a Passing Grade for Equine Osteoarthritis

Avocado and soybean unsaponifiable (ASU) extracts--the fraction of oil that does not form soap after hydrolysis--are some of the newest joint products to grace the equine nutritional supplement shelves. The beneficial effects of ASU for horses with osteoarthritis were reported in a new study by David Frisbie, DVM, PhD and colleagues from the Gail Holmes Equine Orthopaedic Research Center at Colorado State University.

The researchers evaluated ASU in horses with experimentally-induced osteoarthritis. This clinical trial concluded that ASU significantly reduced the severity of joint damage and significantly increased the synthesis of cartilage glycosaminoglycans (i.e., the "building blocks" of articular cartilage) in joints with osteoarthritis, compared to horses treated with a placebo.

In this study, 16 horses with osteoarthritis were divided into two groups: eight horses received ASU extracts in molasses and eight received only molasses for 70 days. During the study, the horses were exercised on a treadmill and the researchers measured the horses' lameness, joint swelling, and various gross, microscopic, and biochemical parameters.

"While ASU did not decrease clinical signs of pain in horses with osteoarthritis, a disease-modifying effect was identified suggesting that oral administration of ASU can be useful in the management of horses with osteoarthritis," Frisbie reported.

Despite the need for further research to identify the exact cause of the observed beneficial effects of ASU, the ramifications of this landmark trial are potentially far-reaching. According to Frisbie, this is the first peer-reviewed, placebo-controlled study evaluating an oral nutritional supplement conducted in live horses with osteoarthritis.

The next step, suggested Frisbie, is to hold other supplement companies to higher standards to prove that their products also are effective.

The study, "Evaluation of avocado soybean unsaponifiable extracts for treatment of horses with experimentally induced osteoarthritis" was published in the June 2007 edition of the American Journal of Veterinary Research. Contributing researchers were Frisbie, Kawcak, DVM, PhD; McIlwraith BVSc, PhD; Werby DVM; and Park DVM, PhD.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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