Vitamin E Supplements

Posted by Blog Friday, March 4, 2011

Vitamin E supplements must be taken with food for proper absorption. Natural vitamin E in supplements is designated by a d as in d-alpha-tocopherol. Synthetic vitamin E is designated with a dl as in dl-alpha-tocopherol. The newer and more accurate designations differentiate between R for natural and S for synthetic. As seen in Figure 5-7, the synthetic forms are different from the natural forms.

 There are eight possible isomers: RRR (natural), SRR, SSR, SRS, SSS, RSR, RRS, and RSS. Synthetic vitamin E is a mix of eight isomers, of which only one is natural. Half of the synthetic forms (SRR, SSR, SRS, and SSS) do not function as vitamin E in the body at all.

The correct, current way to describe natural alpha-tocopherol is RRR-alphatocopherol. When vitamin E is synthesized, all eight isomers are made and the result is called “racemic,” as in all-rac-alpha-tocopherol. This synthetic mix is the most common form used in medical studies.

Figure 5-7 Natural and synthetic alpha-tocopherol.

There are two ways of stating the potency of vitamin E, in International Units (IU) and in milligrams (mg). The acetate form of synthetic alpha-tocopherol was arbitrarily chosen to have one IU per mg. Natural RRR-alpha-tocopherol has a biological activity of at least 1.49 IU per mg. Continuing research is indicating that the biological activity of natural vitamin E (RRR-alpha-tocopherol) may be 2 IU per mg or more. Natural vitamin E has more activity because it is not diluted with synthetic isomers. In synthetic all-rac-alpha-tocopherol, only half of the isomers are usable by the body, so it is less potent. Only one of the eight isomers in synthetic alpha-tocopherol is found in natural food.

There are two common forms of synthetic alpha-tocopherol used in supplements: the acetate ester form and the succinate ester form. Both forms are broken apart into alpha-tocopherol in the intestines. Acetate ester and succinate ester are more stable in storage because they are not antioxidants until they are de-esterified in the intestines.

Both of these synthetic forms contain one natural form of alpha-tocopherol and seven isomers of alpha-tocopherol that are not found in nature. These synthetic supplements also differ from natural vitamin E because they are missing all other tocopherols and tocotrienols. The inconsistent results in medical studies with these synthetic supplements may be partially due to these differences between vitamin E found in food and vitamin E found in synthetic supplements.

More about E-Vitamin:

Vitamin E

Antioxidant Activity

Cholesterol and Vitamin E

Vitamin E and Blood Circulation

Food Sources of Vitamin E

Vitamin E Supplements

Toxicity of Vitamin E


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