to cover the needs of 97 to 98 percent of the individuals in the group (therefore, for vitamin E the RDA is 120 percent of the EAR). The calculated RDA in milligrams is rounded up.

As indicated earlier in the section on infants, the estimated average amount of α-tocopherol secreted daily in human milk in the first 6 months of life is 4 mg (9.3 µmol). Thus, addition of this figure to the EAR for α-tocopherol for women, 12 mg (28.2 µmol)/day, would provide an EAR of 16 mg (37.5 µmol)/day of α-tocopherol in a lactating female.

The EAR is in excess of the median intake of 8.4 mg (19.5 µmol)/day for lactating women reported in the U.S. Department of Agriculture Continuing Survey of Food Intake by Individuals (CSFII) (Appendix Table D-2). Because estimates of vitamin E intake are underreported and vitamin E deficiency in infants receiving human milk is extremely rare, it is logical to postulate that lactating women are consuming more vitamin E than reported and that ingestion of supplements is unnecessary during lactation.

To estimate the EAR for lactation, the average vitamin E secreted in human milk, 4 mg (9.3 µmol) of α-tocopherol, is added to the EAR for the nonlactating woman, giving an EAR of 16 mg (37.2 µmol)/day of α-tocopherol.

The RDA for vitamin E is set by assuming a coefficient of variation (CV) of 10 percent (see Chapter 1) because information is not available on the standard deviation of the requirement for vitamin E; the RDA is defined as equal to the EAR plus twice the assumed CV to cover the needs of 97 to 98 percent of the individuals in the