Vitamin E as an antioxidant

Vitamin E – A major antioxidant

Vitamin E is a term used to describe a group of very potent, fat soluble antioxidants.   Vitamin E occurs naturally in foods and can be available in dietary supplements. Naturally vitamin E exits in eight chemical forms.

Vitamin E functions as a chain-breaking antioxidant that prevents the propagation of free radical reactions (Tappel, A. L. (1962) Vitamin E as the biological lipid antioxidant.Vitam. Horm. 20,493-510).    

Antioxidants have a protective action against the damaging effects of free radicals. Normally vitamin E is absorbed from the intestine and enters the lymphatic system and transported to the liver.

Vitamin E is a one of the major antioxidants that is available as micronutrients. It is the principal fat-soluble vitamin in our body. It is strengthen the cell membrane against the possible dangerous effects of free radicals. This will help in preventing or delaying the degenerative diseases associated with the free radicals.

In addition to its activities as an antioxidant, vitamin E is involved in immune function and, as shown primarily by in vitro studies of cells, cell signaling, regulation of gene expression, and other metabolic processes (Traber MG. Vitamin E. Modern Nutrition in Health and Disease. 10th ed. Baltimore, MD: Lippincott Williams & Wilkins, 2006;396-411)

Studies have shown that antioxidant status reflects the immunocompetence of a person. It also reflects the risk of age related degenerative diseases in the person. Recent clinical studies have shown that Vitamin E have a beneficial effect in slowing the progression of Alzheimer’s disease.

 Another neurodegenerative disease that may be linked to increased free radical damage is Parkinson’s(Halliwell B. Antioxidants and human disease: A general introduction. Nutr Rev. 1997;55:(II)S44-S52).

Vitamin E also helps in controlling the side effects of non –insulin dependent diabetes mellitus. Aging is associated with slow immune response. Vitamin E improves immune responsiveness to certain diseases.

Recommended dose of Vitamin E?

Intake recommendations for vitamin E and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of The National Academies (formerly National Academy of Sciences) (Institute of Medicine. Food and Nutrition Board.  National Academy Press, 2000).

Recommended daily allowance (RDA) for a healthy adult is 1500 international units(IU). There is no increase in the supplemental doses pregnant or lactating mothers.

Toxicity can occur with doses higher that 4,000 IU. There are symptoms of elevated blood pressure if used at higher doses for long.

Natural food sources of Vitamin E

Vitamin E naturally occurs in vegetable oils, whole grain wheat, and green vegetables especially with leaves, cereals, soybeans, whole raw seeds, sardines and nuts.

When the body do not get enough vitamin E, it is more susceptible to age related disease like cancer, Alzheimer’s and diabetes.

Reference:

Tappel, A. L. (1962) Vitamin E as the biological lipid antioxidant.Vitam. Horm. 20,493-510

Traber MG. Vitamin E. In: Shils ME, Shike M, Ross AC, Caballero B, Cousins R, eds. Modern Nutrition in Health and Disease. 10th ed. Baltimore, MD: Lippincott Williams & Wilkins, 2006;396-411.

Halliwell B. Antioxidants and human disease: A general introduction. Nutr Rev. 1997;55:(II)S44-S52.

Author: Dr Rubina Mushtaq

 

 

 

 

 

 

 

 

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