Absorption, Transport and Distribution of Vitamin E

Abstract

Vitamin E is the term used for eight naturally occurring fat-soluble nutrients called tocopherols. alpha-Tocopherol is essential, has the highest biological activity and predominates in many species. In humans vitamin E is the most important lipid soluble antioxidant and deficiency may cause neurological dysfunction, myopathies and diminished erythrocyte life span. alpha-Tocopherol is absorbed via the lymphatic pathway and transported in association with chylomicrons. In plasma, alpha-tocopherol is found in all lipoprotein fractions but mostly is associated with apo B-containing lipoproteins. alpha-Tocopherol is associated with very-low-density lipoprotein when it is secreted from the liver. In the rat, about 90% of total body mass of alpha-tocopherol is recovered in the liver, skeletal muscle and adipose tissue. Most alpha-tocopherol is located in the mitochondrial fractions and in the endoplasmic reticulum, whereas little is found in cytosol and peroxisomes. New clinical evidence from heavy drinkers and from experimental work in rats suggests that alcohol may increase oxidation of alpha-tocopherol. Increased demand for vitamin E has also been observed in premature infants and patients with malabsorption, but there is little evidence that the healthy population requires supplementation of vitamin E to a well-balanced diet.

Influence of the antioxidants vitamin E and idebenone on retinal cell injury mediated by chemical ischemia, hypoglycemia, or oxidative stress

“…Vitamin E is a potent scavenger of peroxyl radicals within the membranes [45,46]. The polar ␣-tocopheryl esters, namely vitamin E succinate, have proven valuable tools for supplementing ␣-tocopherol to isolated cells, increasing the resistance of cells to oxidative damage [47].…”

“…Vitamin E distributes to cellular membranes and is located in the mitochondrial fractions and in the endoplasmic reticulum [45]. Ray and Fariss [53] proposed the accumulation of vitamin E succinate at the level of mitochondria, where it could exert its antioxidant activity.…”

Antioxidants and Their Importance During Muscular Exercise: A Review

“…These enzymes are responsible for removing superoxide radicals, H 2 O 2 and organic hydroperoxides. Additional antioxidant enzymes such as thioredoxin, glutaredoxin, and peroxiredoxin reductase also contribute to cellular protection against oxidation [13,18]. An acute exercise or longer term exercise result in increased activities of superoxide dismutase, catalase or glutathione peroxidase in animal and human muscles [6 Superoxide dismutase must work with enzymes that remove H 2 O 2, that is with catalase.…”

“…Supplementation with tocotrienol-rich fractions (TRF) from palm oil, a potent antioxidant from the natural Vitamin E family, may help in the prevention or treatment of several diseases [45]. Studies have shown vitamin E supplementation as an efficient means of reducing exercise-induced muscle damage due to free radical formation [18].…”

“…Beside several anti-oxidant enzyme systems and vitamins, cells contain endogenous non-enzymic anti-oxidants and naturally dietary compounds, to be used as scavenger free radicals molecules and to work against cellular damage [18].…”