Summary: Vitamin E Requirements, Supplementation and Disorders

Carey Williams, PhD
Associate Professor / Equine Extension Specialist
Department of Animal Sciences
Rutgers University, New Brunswick, NJ

Vitamin E is a fat soluble vitamin that is present in nature as four tocopherols: alpha, beta, gamma and delta, and four tocotrienols: alpha, beta, gamma and delta. Of all the forms, α-tocopherol was found to be the most biologically active. Vitamin E can be found in many types of forage and pasture grasses, especially orchard grass, alfalfa, fescue, and timothy. This decreases with the age of the plant, as well as with processing (heat, bailing, grinding, etc.). Sun-curing hay also decreases the content of vitamin E in the forage. Vitamin E supplements are useful if unable to have a source of fresh forage. Besides being a dietary necessity, vitamin E is also recognized as an important antioxidant. Vitamin E is a fat-soluble vitamin, and it protects cell membranes from damage. It is especially important for exercising horses, as exercise can induce oxidative stress and reactive oxygen species damage to cells, as well as decrease circulating vitamin E levels. In turn can cause muscle problems and an overall decrease in endurance capacity and performance. Building up stores of vitamin E before stressing the horse (e.g. traveling, competition) can be beneficial. Like any other essential part of diet, there are negative side effects associated with vitamin E deficiency. Deficiency can cause uncoordination and various muscle and nervous disorders. Examples of diseases associated with vitamin E deficiency are white muscle disease, equine degenerative myeloencephalopathy (EDM), and equine motor neuron disease (EMND). High amounts of vitamin E are not toxic to horses, however, large doses should be carefully monitored as they may interact with other nutrients in the diet. This presentation will cover more details on all aspects of vitamin E.