Vitamin E (α-tocopherol)

Vitamin E (α-tocopherol)

1. both .... are each composed of α, β, γ, and δ vitamins having unique biological effects (8 compounds).

   • The tocopherol
   • and tocotrienol subfamilies

2. α-tocopherol is the most active form

3. One of body’s primary defenders against oxidation, protecting lipids and other vulnerable components of cells and their membranes against destruction

4. Vitamin E protects lungs from air pollutants, such as ozone and nitric oxide that can initiate damaging reactions

5. While it has been found to improve physical performance and to enhance sexual performance → it does not slow or prevent process of aging!!

6. Functions

   • Antioxidant in prevention against oxidation of cell components by free radicals. Tocopherols protect PUFA (Polyunsaturated fatty acid) in cellular membranes and circulating LDL and VLDL from peroxidative damage. Thus, its function is complementary to GPx (Se containing) in cytoplasm.
     • Ascorbic acid may reduce tocopheroxyl radicals back to tocopherol and may recycle the vitamin.
       • High intake of vitamin E is associated with lower incidence of CVD (cardiovascular disease)
         • Participates in body’s immune defense by protecting blood cells

7. Deficiency

   • Very rare except in people with fat malabsorption diseases such as:
     • cystic fibrosis
     • Crohn’s disease
   • Premature, low birth weight and bottle-fed infants (cow’s milk is poor in vitamin E) are predisposed to vitamin E deficiency (inadequate reserve )
   • Prolonged deficiency causes neuromuscular dysfunction
   • Hemolytic anemia is a classic sign of vitamin E deficiency due to disruption of RBC membranes. Symptoms include neuromuscular weakness, ataxia, impaired vision and speech.
   • Vitamin E supplementation can be given to premature infants to protect against hemolytic anemia

8. Toxicity

   • Vitamin E, like other antioxidants, also have pro-oxidant actions at high cencentrations
     • The least toxic fat-soluble vitamin.
       • The use of vitamin E supplements may help to protect against the development of heart disease by protecting LDL from oxidation by free radicals
         • Large doses can be used in the treatment of rare inborn error of metabolism that result in hemolytic anemia (e.g.) G6P DH deficiency, GPx deficiency. Large doses may interfere with vitamin K metabolism and should be avoided during anticoagulant therapy.

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