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

Vitamin A and E supplementation in breast-fed newborns

BACKGROUND

Vitamins A and E are two potent antioxidant nutrients that play a significant role in immune function. In contrast to the numerous studies of vitamin A and E status in children, adolescents, and adults, information on term infants, particularly breast-fed infants, is scarce. The goals of the present investigation were to examine the vitamins A and E nutritional status of term breast-fed infants at birth and to assess retinol and tocopherol plasma levels during a 3-month supplementation trial.

METHODS

The study was a prospective, blinded comparison of a supplementation protocol with a placebo in a group of consecutively recruited term newborns. The supplemented group received 3000 IU vitamin A and 5 IU vitamin E orally. The placebo group received a solution of similar viscosity and organoleptic characteristics. Vitamin A and E were separated by reverse-phase high-performance liquid chromatography on a C18 Spectrasyl column and quantified by ultraviolet spectrophotometry.

RESULTS

Vitamin A and E levels steadily increased with age in both groups of infants. However, levels at 3 months were higher in the supplemented than in the control group.

CONCLUSION

The data show that supplementation with 3000 IU vitamin A and 5 IU vitamin E for 3 months increases circulating vitamin levels in newborn term babies compared with those in nonsupplemented infants.

Red blood cell tocopherol and liver tocopherol in hyperlipemic rats as compared with plasma tocopherol

In rats with hyperlipemia induced by Triton WR-1339, changes in tocopherol concentrations in plasma and RBC were compared with those in the liver and its subcellular fractions, microsomes and mitochondria. After daily injection with Triton, plasma total lipids at 3 days and 7 days, respectively, showed elevations 6.5 times and 15 times as high as those in the control rats, and triglycerides showed the most predominant elevation. With the hyperlipemia, the concentrations of tocopherol in RBC and the subcellular fractions decreased, as plasma lipids and plasma tocopherol increased, while no change occurred in tocopherol concentrations in liver homogenates. The changes in the ratio of tocopherol to total lipids in plasma coincided with changes in tocopherol concentrations in the RBC and subcellular fractions.

Plasma erythropoietin concentrations during the early anemia of prematurity

Plasma erythropoietin concentrations were studied in 11 preterm appropriate for gestational age infants at the age of 3-14 weeks. Their birth weights ranged from 860-1 690 g. Erythropoietin was measured by a cell culture technique. Significant concentrations of erythropoietin was detected in 18 out of 29 samples, at all stages of the early anemia. The highest levels were found at 3-9 weeks. Individual erythropoietin values did not correlate with hemoglobin concentrations, hematocrit levels or 'corrected' reticulocyte counts, nor did the 'corrected' reticulocyte count correlate with hemoglobin or hematocrit. The lack of correlation with hemoglobin concentration most likely reflects the importance of other factors as well as the hemoglobin in determining the oxygenation status of the infant. A significant positive correlation (r = 0.60, p less than 0.01) was found between erythropoietin concentration and weight gain in the preceding week. The study shows that small preterm infants are capable of erythropoietin production during their early anemia, and indicates that the hormone plays a role in the regulation of erythropoiesis also at this time of life.

Influence of plasma lipids and adiposity on red blood cell tocopherol level

The influence of plasma lipids and the degree of adiposity on red blood cell (RBC) tocopherol levels was investigated in children. In the first study of nonobese children with a wide range of plasma lipid values, the correlation coefficient between RBC tocopherol levels and plasma tocopherol levels was 0.39 (P less than 0.001, n = 195) but when RBC tocopherol was compared with plasma tocopherol based on plasma total lipids, the coefficient increased to 0.69. From this finding it is assumed that RBC tocopherol levels are governed by the tocopherol concentration in plasma lipids. In the second study of obese children, RBC tocopherol levels decreased in the children with 30% or more excess weight, as compared with those of control children and those with less than 30% obesity, while plasma tocopherol levels were unrelated to obesity grades. Because of no significant difference in plasma total lipid levels among these three groups of children, decreased RBC tocopherol in children with 30% or more obesity is probably attributable to their adiposity.