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November 5, 1973

Natural vs Synthetic Vitamin E

Author Affiliations

Mallard, Inc. Detroit

JAMA. 1973;226(6):672. doi:10.1001/jama.1973.03230060048020

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To the Editor.—  Dr. Ayers questioned (225:1124, 1973) Nagy's reply to the question of natural vs synthetic vitamins as being biologically equivalent. He referred to the difference in optical rotation of vitamin E derived from natural vs synthetic sources and their difference in potency on a milligram-for-milligram basis.Many substances that are identical chemically except for optical activity (dextro [d] vs levo [1] form) are not biologically equivalent. Further, there are a variety of officially recognized forms of vitamin E listed in the National Formulary: α-D or α-dextrolevo (DL) tocopherol, α-D or α-DL tocopheryl acetate, α-D or α-DL tocopheryl acid succinate, mixed tocopheryls concentrate, and α-D tocopheryl acetate concentrate. The concentrates are obtained from edible vegetable oils or from the by-products of their refining. The National Formulary (NF XIII) establishes appropriate standards of purity for each and requires vitamin E products to be labeled in terms of international units as