Vitamin E Status in Preterm Infants: Assessment by Plasma and Erythrocyte Vitamin E‐Lipid Ratios and Hemolysis Tests

Abstract

Background:Vitamin E is an essential component of the antioxidant defenses, but supplementation can have side effects in the preterm infant. Careful monitoring of vitamin E status is thus essential, however no consensus has been reached on the best clinical method.Methods:In 47 healthy preterm infants, several methods for assessment of vitamin E status were evaluated: plasma and erythrocyte vitamin E levels were measured, vitamin E lipid ratios were calculated, and two variations of the hydrogen peroxide hemolysis test were conducted.Results:At birth, the plasma and erythrocyte vitamin E levels were low. After birth, the plasma levels rose gradually, whereas the erythrocyte levels remained low. In contrast, the vitamin E‐total‐lipid ratio was in the low normal range from birth onwards. Vitamin E‐lipid ratios using two lipid components (cholesterol with triglycerides, or cholesterol with phospholipids) or one lipid component (cholesterol) correlated with the vitamin E‐total‐lipid ratio with a good sensitivity and specificity. The susceptibility of erythrocytes to hydrogen peroxide‐induced damage (measured as potassium release or malondialdehyde production) was high at birth and declined after birth. However, this susceptibility did not correlate with plasma or erythrocyte vitamin E levels or vitamin E‐total‐lipid ratio, and the hydrogen peroxide hemolysis test is not a reliable indicator of vitamin E status in preterm infants.Conclusions:Our study indicated that a gold standard for clinical assessment of vitamin E status in preterm infants is yet to be found.