Many owners offer their horses antioxidant supplements. In some cases, this might be without a solid understanding of what antioxidants do and how they benefit horses. To better appreciate how oxygen is both vital and dangerous to a horse’s body and the role antioxidants play in combating “oxidative stress,” take this short, 10-point crash course on understanding antioxidants.
1. Oxygen is 100% essential for almost all living creatures. Inhaled oxygen drives metabolic processes and helps cells produce energy.
2. In typical Jekyll and Hyde style, some oxygen molecules form damaging “reactive oxygen species” (ROS) while producing energy. These molecules are also called free radicals.
3. Free radicals are unstable ions that, at a molecular level, have an unpaired electron. Recall that molecules are unhappy until they are paired in some way with other unhappy molecules and form stable compounds. For example, one sodium (Na+) ion combines with one chloride ion (Cl-) to form NaCl or sodium chloride, known commonly as salt.
4. Some of the most common oxygen free radicals include the hydroxyl radical, superoxide anion radical, and hydrogen peroxide.
5. Free radicals bounce around the cell nucleus or cell membrane, much like a ball in a pinball machine, trying to donate or accept electrons from other cellular molecules they encounter during their tirade. Frequently, they react with—and damage—DNA strands, proteins, and the fats found in cell membranes, setting off a chain reaction of other molecules stealing or donating electrons.
6. Damage by free radicals is associated with aging and various diseases, including cancer.
7. Cells have natural defense mechanisms in place to combat free radicals. These natural antioxidants are free-radical scavengers that donate electrons to rampaging free radicals but remain stable themselves with unpaired electrons.
8. Natural antioxidants are either individual molecules like glutathione and uric acid or complex enzymes and enzyme systems (e.g., superoxide dismutase, catalase, and glutathione peroxidase). Many antioxidants can be supplied in the diet. Classic examples of dietary antioxidants include β-carotene, vitamin C, and vitamin E. Various plant or herbal products are also thought to serve as antioxidants, such as turmeric, garlic, and ginger.
9. During exercise, horses inhale more oxygen than usual to meet the oxygen demand of their muscles. Along with supporting the muscular oxygen needs, free radicals are produced and horses suffer “oxidative stress.”
10. Oxidative stress comes from an imbalance between free radical production and antioxidant defenses. Supplementing horses with antioxidants helps alleviate oxidative stress by bringing the environment back into balance.
Committed to research in both nutrition and exercise physiology, Kentucky Equine Research (KER) offers two antioxidant supplements for horses: Nano•E, a water-soluble, natural-source of vitamin E with a unique nanodispersion delivery system that results in superior bioavailability; and Preserve PS (Preserve in Australia) to provide natural-source vitamin E, vitamin C, and other antioxidants.