Vitamin E Deficiency and Toxicity
Cellular vitamin E deficiency leads to an increase in peroxidation of membrane lipids. This often results in abnormalities in membrane transport, a decrease in mitochondrial energy production. An increased mutation rate due to oxidation of DNA is also commonly observed in deficient cells.In animals, vitamin E deficiency has been associated with a number of problems:
- Impaired fertility in both sexes. This is observed particularly in rodents, and resulted in vitamin E sometimes being called the "fertility vitamin".
- Muscle disease. Vitamin E deficiency is a well known cause of nutritional myopathy (white muscle disease) in a variety of animals. This disorder is most commonly seen in pigs, cattle and sheep, and is characterized by cardiac and skeletal muscle necrosis and calcification, sometimes observed shortly after birth. In many cases, there is a clear interaction between vitamin E and selenium deficiency in the pathogenesis of this syndrome.
- Degeneration of central nervous system and peripheral nerves. This is a primary manifestation of vitamin E deficiency in humans, where it is seen predominantly and most severely in children.
- Accelerated destruction of red blood cells.
Due to the widespread occurance of vitamin E, deficiency is relatively rare. In humans in is most commonly associated with lipid malabsorption syndromes, which can occur with genetic or acquired diseases affecting the intestine, pancreas or liver.
Recognition of the antioxidant properties of vitamin E have led to a rather huge interest in its use to reducing the risk of many degenerative diseases, including cancer, atherosclerosis, chronic inflammation and cataracts. At this time it seems fair to state that, other than consuming a balanced diet that would be expected to provide adequate vitamin E, there is little indication that vitamin E supplementation will provide substantive protection from such diseases.
The risk of overconsuming vitamin E appears to be low, but the effects of prolonged, high dose supplementation is not known.
(published with permission in writing from:http://www.vivo.colostate.edu)
