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Polyphenols in Horse DietsBy Kentucky Equine Research Staff · February 9, 2017

Horses generally consume bland diets, especially if offered only hay and pasture. Tasty treats spice up the menu. Instead of reaching for peppermints, though, consider brightly colored fruits, vegetables, and even berries so horses reap the rewards of a class of compounds called polyphenols.

“Polyphenols are natural plant products that not only give plants their vibrant color but also exert an array of biological activities when consumed by animals,” explained Kathleen Crandell, Ph.D., a nutritionist with Kentucky Equine Research (KER).

The term “polyphenol” refers to a group of molecules that share similar chemical structures. In this case, all polyphenols must have two or more six-carbon rings. Examples of polyphenolic compounds include both flavonoids (flavonols, flavanones, isoflavones, and flavans) as well as non-flavonoid polyphenols, including curcumin and resveratrol. Grape seed extract provides a great source of flavonoids and other polyphenolics.

Previous research on curcumin, obtained from the brightly colored spice turmeric, shows various medical benefits, including helping patients with osteoarthritis and supporting immunity. Other benefits of polyphenolic compounds include antibacterial, antiviral, anticancer, and antiallergic properties.

Studies in horses suggest that polyphenols such as curcumin and resveratrol can help fight inflammation and the natural ageing process, referred to as inflammaging. As horses age, a generalized increase in inflammation occurs, contributing to the development of chronic diseases such as laminitis and osteoarthritis. Many experts, including Siard and colleagues*, suggest that adding polyphenols to the diet reduces inflammation. In turn, polyphenol supplementation could decrease the amount of nonsteroidal anti-inflammatory drugs administered to older horses, potentially reducing the risk of adverse reactions to such drugs, including diarrhea, kidney disease, and gastric ulcers. Anecdotal information from New Zealand suggests that flavonoids also help muscle recovery in endurance horses.

“Vitamin E supplements such as Nano•E also possess antioxidative properties, protecting against a variety of free radicals produced during exercise and natural inflammatory processes,” Crandell shared.

*Siard, M.H., K.E. McMurry, A.A. Adams. 2016. Effects of polyphenols including curcuminoids, resveratrol, quercetin, pterostilbene, and hydroxypterostilbene on lymphocyte pro-inflammatory cytokine production of senior horses in vitro. Veterinary Immunology and Immunopathology. 173:50-59.