Vitamin E: Natural vs. Synthetic
Vitamin E is the most powerful antioxidant in the equine diet. But not all forms of the vitamin are created equally. Most supplements contain synthetic vitamin E (dl-alpha-tocopherol acetate), which is not as potent as natural vitamin E (d-alpha-tocopherol acetate). Compared with synthetic vitamin E, the body can more efficiently transport and deliver natural vitamin E to target tissues. Current research in several species, including horses, shows that natural vitamin E is two to three times more potent than synthetic.
Water-Soluble Vitamin E Is Most Effective
Water-soluble vitamin E can be absorbed efficiently from the gastrointestinal tract. Because of this rapid absorption, vitamin E is readily dispersed into the blood and to outlying tissues. When other forms of vitamin E are fed (e.g., oil-based or emulsified forms), the digestive system must break down the vitamin E before it can be used, thus delaying absorption.
Research Shows How Different Types of Vitamin E Are Absorbed
Assessment of vitamin E status is accomplished by measuring levels in plasma. In a recent study, plasma levels of horses consuming three types of vitamin E were compared: synthetic vitamin E acetate powder, natural vitamin E acetate powder (Elevate Maintenance Powder), and natural, water-soluble vitamin E liquid (Elevate W.S.). Dramatic increases were noted in horses fed natural, water-soluble vitamin E liquid (Elevate W.S.). From baseline values, blood levels rose an astonishing 207% when horses were given 8,000 IU of water-soluble vitamin E liquid (Elevate W.S). Blood levels of natural vitamin E acetate powder (Elevate Maintenance Powder) also increased, but not as quickly. This study did show that plasma levels fell slightly when horses were fed synthetic vitamin E powder.