Zinc status and growth of Korean infants fed human milk, casein-based, or soy-based formula: three-year longitudinal study

To evaluate the effect of feeding methods on growth and zinc nutritional status of infants early in life, we monitored from birth to 36 months in 51 infants who were exclusively fed human milk (HM, n = 20), casein-based formula (CBF, n = 12), or soy-based formula (SBF, n = 19) during the first five months of life. Zinc status was assessed by analyzing serum zinc concentrations and zinc intakes. Zinc contents in HM and formulas were measured. Zinc intake was estimated by weighing infants before and after feeding in the HM group and by collecting formula-intake records in the CBF and SBF groups. After solid foods were introduced, all foods consumed were also included to estimate zinc intake. The growth of infants in all groups was similar to that established for normal Korean infants. Human milk zinc concentrations declined as lactation progressed. Zinc concentrations in all formulas tested in this study were higher than HM and were also higher than those claimed by the manufacturers. During the first twelve months, mean serum zinc concentrations of infants were similar in all groups, although infants in the HM group consistently had the lowest zinc intake among the groups, and the overall zinc intake in infants fed SBF was highest. This finding could be explained by the different zinc bioavailability of HM and formulas. In conclusion, infants fed HM, CBF or SBF has normal growth up to three years of age, although HM contained the lowest zinc concentration followed by CBF, then SBF.

Effect of paternal folate deficiency on placental folate content and folate receptor alpha expression in rats

We investigated the effect of paternal folate status on folate content and expression of the folate transporter folate receptor alpha (FRalpha) in rat placental tissues. Rats were mated after males were fed a diet containing 0 mg of folic acid/kg of diet (paternal folate-deficient, PD) or 8 mg folic acid/kg of diet (paternal folate-supplemented, PS) for 4 weeks. At 20 days of gestation, the litter size, placental weight, and fetal weight were measured, and placental folate content (n = 8/group) and expression of FRalpha (n = 10/group) were analyzed by microbiological assay and Western blot analysis, respectively. Although there was no difference observed in litter size or fetal weight, but significant reduction (10%) in the weight of the placenta was observed in the PD group compared to that in the PS group. In the PD group, placental folate content was significantly lower (by 35%), whereas FRalpha expression was higher (by 130%) compared to the PS group. Our results suggest that paternal folate status plays a critical role in regulating placental folate metabolism and transport.