Research demonstrates that their nutritional value is raised when they are supplemented together. Numerous factors, including pollution, heavy exercise, pregnancy, lactation, growth and high levels of dietary fat, increase the horse's needs for these nutrients. In the U.S., soils in the East, Northwest, and Great Lakes regions are selenium deficient. In some Midwestern and Southwestern states, local soils may contain excessive amounts of selenium. In these areas, contact your local feed consultant or county extension agent before supplementing selenium.
Antioxidants are natural substances produced by the body or supplied in the diet.
They combine with free radicals to produce water and other stable products, stopping the chain of damaging oxidative reactions. Vitamin E, an essential fat soluble vitamin, is also an important antioxidant defender. Studies of growing and performing horses have led many equine nutritionists to recommend an increased dietary allowance for vitamin E. Selenium, especially as part of glutathione peroxidase, is also a key antioxidant nutrient for many tissues. Esterified forms of vitamin E, on the other hand, are stable outside the body but are converted to the active form as they are absorbed through the intestinal wall. One of these, dl-alpha tocopheryl acetate, has been chosen by the World Health Organization as the universal standard for vitamin E potency.