The Benefits of Selenium and Vitamin E

The benefits of selenium and vitamin E have been understood for many years. Selenium (Se) is an essential micronutrient present in tissues throughout the body. It is important physiologically because it is an integral component of the enzyme, glutathione peroxidase (GSH-px). Tissue concentrations of selenium are highly correlated with GSH-px activity and directly related to selenium intake. (1)

Plants grown on selenium deficient soil do not provide adequate dietary selenium. Depletion occurs naturally geographically and is accelerated under fertilizer stress. Especially noted are poorly drained acid soils. Forages from such soils could comprise two-thirds of the U.S., Canada and Europe.

Selenium, with its enabling enzyme GSH-px and vitamin E function at different cellular levels. GSH-px works in the cytosol of the cell, while vitamin E functions as an integral component of lipid membrane. (2).

Both the GSH-px enzyme with selenium and vitamin E are part of the antioxidant system present in all cells. Optimum cell functioning is supported by both vitamin E and GSH-px because they help reduce and maintain low cell and tissue concentrations of reactive oxygen molecules and lipid peroxides. Large quantities of superoxide and hydrogen peroxide are produced during cellular oxygen metabolism and are severely damaging to enzymes, DNA, cellular proteins and membrane lipids. GSH-px converts hydrogen peroxide to water and lipid peroxides to their corresponding alcohols, while vitamin E converts reactive oxygen and lipid hydroperoxides to non-reactive compounds. (3)

Vitamin E (dl-alpha tocopheryl) defends enzymes and proteins in cell membranes against reactive, free-radical oxygen generated in cell metabolism. Cell tissue high in polyunsaturated fatty acids is especially vulnerable to reactive oxygen. Animals deficient in GSH-px and vitamin E exhibit reduced intercellular pathogen destruction and therefore lower response to peroxide and reactive oxygen invasion.

The typical problems associated with selenium and vitamin E deficiencies are nutritional muscular dystrophy (especially in young foals), tying-up syndrome, elevated SGOT (AST), nutritional muscle myopathy, decreased cardiac efficiency, infertility and impaired kidney and liver functions.

Acceptable serum selenium levels are associated with 180-210 ng/ml, while deficiencies are exhibited when serum selenium levels fall below 150 ng/ml. Variations in vitamin E level adequacy exist but 400 mg/ml appear to be adequate. (4)

(1)   Scholz, R.W. & Hutchinson, L.J. (1979), American Journal of Veterinary Research 40.
(2)   Hoekstra, W.E. (1975), Federation Proceedings 34, 2083
(3)   Putnam, M.E. & Comben, N. (1987), Veterinary Record 121, 541.
(4)   Rotruck, J.T., Pope, A., Ganther, W.E. & Hoekstra, W.G. (1973), Science 179, 558.