Human Milk. Human milk is recognized as the optimal milk source for infants throughout at least the first year of life and is recommended as the sole nutritional milk source for infants during the first 4 to 6 months of life (IOM, 1991). Therefore, determination of the AI for vitamin E for infants is based on data from infants fed human milk as the principal fluid during the periods 0 through 6 and 7 through 12 months of age. The AI is set for ages 0 through 6 months at the mean value calculated from studies in which the intake of human milk was measured by test weighing volume, and the average concentration of the nutrient in human milk was determined using average values from several reported studies.
In general, the total vitamin E content of colostrum is high (average content ranges from 6.8–23 mg/L) (Ali et al., 1986; Boersma et al., 1991; Chappell et al., 1985; Jansson et al., 1981; Kobayashi et al., 1975; Thomas et al., 1981); the concentration decreases in transitional milk, sampled at 6–10 days, and further decreases in mature milk, as shown in Table 6-4. The range of vitamin E concentrations in mature human milk after approximately 30 days of lactation varies from 1.8 mg/L (Kobayashi et al., 1975) to approximately 9 mg/L (Thomas et al., 1981).
Vitamin E concentrations are most accurately analyzed by high-performance liquid chromatography (HPLC). Therefore, reports of vitamin E concentrations in human milk utilizing non-HPLC methods (Ali et al., 1986; Kobayashi et al., 1975; and Thomas et al., 1981) are not used in this assessment. HPLC measurements of the average α-tocopherol content of mature human milk have yielded values of 2.3 (Lammi-Keefe et al., 1990), 3.5 (Chappell et al., 1985), 3.7 ± 0.6 (SD) (Lammi-Keefe et al., 1985), 7.2 ± 3.9 (SD) (Jansson et al., 1981), and 8 ± 5 mg/L (SD) (Boersma et al., 1991). The latter authors reported that the α-tocopherol amounts in human milk were nearly identical to the α-tocopherol equivalent amounts.
Data suggest that there is no difference in milk vitamin E content between mothers with preterm and term births (Lammi-Keefe et al., 1985; Thomas et al., 1981). In addition, there is no significant diurnal variation in the vitamin E content of human milk (Chappell et al., 1985).
Ages 0 through 6 Months. This recommendation is based on the mean volume of human milk intake of 0.78 L/day (Allen et al., 1991; Butte et al., 1984; Heinig et al., 1993), consumed by infants ages 0 through 6 months. The average concentration of α-tocopherol in human milk is approximately 4.9 mg/L as assessed by HPLC in the five studies cited above. If this amount is multiplied by the aver-