Vitamin E status in preterm infants: assessment by plasma and erythrocyte vitamin E-lipid ratios and hemolysis tests.
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.
van Zoeren-Grobben
D
D
Department of Pediatrics, University Hospital Leiden, The Netherlands.
Jacobs
N J
NJ
Houdkamp
E
E
Lindeman
J H
JH
Drejer
D F
DF
Berger
H M
HM
D004912:Erythrocytes / Q000378:metabolism*; D006461:Hemolysis; D006801:Humans; D006861:Hydrogen Peroxide; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood*; D008055:Lipids / Q000097:blood*; D008315:Malondialdehyde / Q000097:blood; D009752:Nutritional Status; D011188:Potassium / Q000097:blood; D014810:Vitamin E / Q000097:blood*
D008055:Lipids; D014810:Vitamin E; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D011188:Potassium