International Units of Vitamin E

The vitamin-E content of a food or recipe is sometimes measured in milligrams of alpha-tocopherol (often written as "a-tocopherol"), and sometimes in International Units (IUs). There is a mathematical relationship between the two measures: one IU is 0.67 milligram of alpha-tocopherol. Hence:

• To convert IUs of vitamin E into milligrams of alpha-tocopherol: multiply the number of IUs by 0.67.
   

• To convert milligrams of alpha-tocopherol to IUs: multiply the number of milligrams by 1.5.

(These conversion factors are for natural vitamin E, which is technically called d-alpha-tocopherol. For the synthetic form of the vitamin, called dl-alpha-tocopherol, the conversion factors are 0.45 and 2.2, respectively.)