Plasma vitamin E levels and vitamin E/β-lipoprotein relationships in small preterm infants during the early anemia of prematurity

Abstract

The vitamin E status of AGA preterm infants (birth weights≦1500 g) was studied during the first 10 weeks of life. The total polyunsaturated fatty acid content of the diet was 12%, and medicinal iron was given from 4 weeks of age. Plasma vitamin E concentrations correlated significantly with β-lipoprotein levels in the infants not supplemented with tocopherol. The low plasma vitamin E levels observed in these infants thus reflect the low transport capacity of the plasma, and do not necessarily signify vitamin E deficiency. Erythrocytes from the preterm infants showed increased hemolysis in the hydrogen peroxide hemolysis test, also when the plasma tocopherol levels were above 11.6 μmol/l; and for the same level of tocopherol, the degree of hemolysis varied considerably. This indicates that factors other than the tocopherol concentrations influence this test. When glucose was added to the cells during the test the hemolysis decreased. A group of infants supplemented with 7.5 IU water-soluble tocopherol/day showed satisfactory median levels of the vitamin, both when assessed as plasma vitamin E concentrations and as vitamin E/β-lipoprotein ratios. However, some infants had low plasma concentrations and ratios, particularly at 4 weeks of age. This indicates that this supplementary dose is insufficient when a water-soluble preparation is used. A very wide range of plasma vitamin E concentrations was observed in the supplemented infants. A word of caution against too vigorous supplementation in small preterm infants is therefore warranted.