Last Updated on April 5, 2022 by Allison Price
Vitamin E (tocopherol), a fat-soluble vitamin, plays many roles in the body. Vitamin E’s main role is to act as an antioxidant. It works in close collaboration with Vitamin C and Selenium to protect the body against oxidative stress from illness, exercise and other medical conditions. Vitamin E helps maintain normal neuromuscular function by this mechanism. Vitamin E is also important in maintaining a strong immune system. Vitamin E helps maintain blood viscosity by assisting the body to properly use vitamin K. A high intake of vitamin E (more than 10,000 IU/day) can be dangerous. It may also increase the risk of Vitamin A deficiency and interfere with Vitamin A’s uptake. Fresh green grass and other supplemental sources are the main sources of vitamin E in a diet. Below is a table listing the required Vitamin E levels for a 1100lb horse.
The following are the normal reference ranges for horse plasma/serum levels of a-tocopherol:
More than 2 mg/mL. – Adequate 1.5-2 mg/mL. – Marginal
1.5 mg/mL or less – Deficient
Vitamin E is naturally found in eight forms: alpha-, beta, gamma, delta-tocopherols, tocotrienols, and gamma. Each of these has slightly different activities in the body. Although there are eight forms of vitamin E available, alpha-tocopherol is the most active. Alpha-tocopherol, the preferred form of vitamin A transported and used in the liver, is considered to be the most active natural form.
Synthetic vitamin E is not derived from natural food sources and is usually derived from petroleum products. Synthetic vitamin E (dlalpha-tocopherol, or any variant starting with dl) can be found in many supplemental vitamin e products fed to horses. Because of its chemical structure, synthetic vitamin E is not as potent as natural vitamin. This decreases overall absorption and utilization. Studies have shown that synthetic vitamin E needs to be three times as potent to equal natural vitamin E. It is also excreted more quickly than natural vitamin E, which means it takes less time to reach the tissues.
The most common names for natural vitamin E are d–alphatocopherol, D-alphatocopherol acetate or d–alphatocopherol succinate. However, mixed tocopherols (mixed vitamins) can also be used. These contain not only d–alphatocopherol but natural mixtures beta, gamma and delta tocopherols. Plant oils are the best source of natural vitamin E. Natural vitamin E is more easily absorbed by the body because of its molecular structure. Natural vitamin E is bound to certain transport proteins in the liver that are more effective at binding to it. This allows it to be transported to other parts of the body for its important functions, such as antioxidants. The natural and synthetic versions of most vitamins are very similar. However, vitamin E is much more natural.
