Red blood cell tocopherol concentrations in a normal population of Japanese children and premature infants in relation to the assessment of vitamin E status.

To determine the normal range of red blood cell (RBC) tocopherol as an assessment of vitamin E nutritional status, 261 apparently healthy children, 3 to 16 years old, including 160 males and 101 females, were investigated and this population was compared with premature infants and adults. In the children, the mean plasma tocopherol was 682 micrograms/100 ml, ranging from 309 to 1,442 micrograms/100 ml. Plasma tocopherol expressed in terms of total lipids (tocopherol/lipid ratio) was generally within accepted value (greater than 0.8). Only one had a value below 0.8. The mean RBC tocopherol was 179 micrograms/100 ml packed cells ranging from 79 to 320 micrograms/100 ml. When the cumulative percentage frequency was examined, the value of 115 micrograms/100 ml corresponded to the fifth percentile of the population of RBC. Thirteen of 90 premature infants (14.4%) less than 24-hours-old and 9 of 48 at 7 days of age (18.8%) had values of less than 115 micrograms/100 ml packed RBCs, while on the basis of the tocopherol/lipid ratio, 44.8% of the infants less than 24-hours-old and 22.2% of those 7 days old had values below 0.8. No adult was below the accepted values of either RBC tocopherol or the tocopherol/lipid ratio.