Levels of Silicon in Maternal, Cord, and Newborn Serum and Their Relation With Those of Zinc and Copper.

BACKGROUND: Evidence of silicon's importance to health has been gradually accumulating. Nevertheless, there are few studies comparing serum silicon levels in newborns with maternal levels. Likewise, little is known concerning the inter-relation between silicon and other trace elements. OBJECTIVE: The present study evaluated maternal and newborn levels of serum silicon and their relation to those of zinc and copper. METHODS: We measured serum silicon, copper, and zinc in 66 pregnant women, in the umbilical cord of their infants, and in 44 newborns, by atomic absorption spectrophotometry. All the samples were from fasted subjects. RESULTS: Serum silicon level in term newborns (20.6 ±â€Š13.2 µmol/L) was significantly higher than in umbilical cord (8.9 ±â€Š3.5 µmol/L; P < 0.0001). Mean serum silicon level in maternal vein (7.7 ±â€Š3.4 µmol/L) was lower than that in umbilical cord, although differences were not significant. We also found higher levels of zinc (P = 0.008) and lower levels of copper (P < 0.0001) in cord blood compared with maternal blood. Umbilical venous/maternal venous level ratios of zinc, copper, and silicon were 1.5 ±â€Š0.5, 0.2 ±â€Š0.1, and 1.3 ±â€Š0.7, respectively. There was a positive correlation between silicon and zinc levels (r = 0.32), and a negative correlation between copper and zinc levels (r = -0.35). CONCLUSIONS: It seems that there is a positive gradient of silicon from the mother to her fetus. Silicon levels were higher in newborn than in cord blood, and correlated significantly with that of zinc but not copper. Additional investigations are needed to further define the role of silicon and its interaction with other trace elements during the perinatal period.

Maternal smoking and the vitamin D-parathyroid hormone system during the perinatal period.

OBJECTIVE: To evaluate the effect of smoking on the vitamin D-parathyroid hormone (PTH) system during the perinatal period. STUDY DESIGN: Sixty-one healthy women with singleton pregnancies and their newborns participated in a cohort study. We compared serum PTH and BsmI polymorphism of the vitamin D receptor gene, 25 hydroxyvitamin D (25(OH)D), 1,25 dihydroxyvitamin D, calcium, phosphorus, and bone alkaline phosphatase (bALP) in a smoking group (n = 32) versus a non-smoking group (n = 29), controlling for lifestyle confounders. The mothers were examined at 30 to 32 weeks and 38 to 40 weeks of pregnancy, and the infants were examined at 2 to 3 days of postnatal life. RESULTS: Mothers who smoked and their newborns showed decreased serum PTH (30-32 weeks, 26.9 +/- 10.7 pg/mL versus 37.1+/-19.5 pg/mL; 38-40 weeks, 32.2 +/- 13.5 pg/mL versus 46.2 +/- 21.9 pg/mL, P = .005; newborns, 43.4 +/- 21.8 versus 64.1 +/- 34.2 pg/mL, P = .02) and increased phosphorus. Newborns of mothers who smoked also had significantly lower anthropometric measurements and serum 25(OH)D (14.2 +/- 6.2 ng/mL versus 22.3 +/- 11.3 ng/mL, P = .009). In addition, pregnant women who smoked had lower bALP (30-32 weeks, 31 +/- 15 U/L versus 44+/-29 U/L; 38-40 weeks, 55 +/- 32 U/L versus 97 +/- 62 U/L, P = .005). CONCLUSIONS: Smoking during pregnancy negatively influences calcium-regulating hormones, leading to relative hypoparathyroidism in both the mother and their newborns.

The effect of zinc supplementation on linear growth, body composition, and growth factors in preterm infants.

OBJECTIVE: The aim of our study was to evaluate the effect of zinc supplementation on linear growth, body composition, and growth factors in premature infants. DESIGN: Thirty-six preterm infants (gestational age: 32.0 +/- 2.1 weeks, birth weight: 1704 +/- 364 g) participated in a longitudinal double-blind, randomized clinical trial. They were randomly allocated either to the supplemental (S) group fed with a standard term formula supplemented with zinc (final content 10 mg/L) and a small quantity of copper (final content 0.6 mg/L), or to the placebo group fed with the same formula without supplementation (final content of zinc: 5 mg/L and copper: 0.4 mg/L), from 36 weeks postconceptional age until 6 months corrected postnatal age. At each evaluation, anthropometric variables and bioelectrical impedance were measured, a 3-day dietary record was collected, and a blood sample was taken. We analyzed serum levels of total alkaline phosphatase, skeletal alkaline phosphatase (sALP), insulin growth factor (IGF)-I, IGF binding protein-3, IGF binding protein-1, zinc and copper, and the concentrations of zinc in erythrocytes. RESULTS: The S group had significantly higher zinc levels in serum and erythrocytes and lower serum copper levels with respect to the placebo group. We found that the S group had a greater linear growth (from baseline to 3 months corrected age: Delta score deviation standard length: 1.32 +/-.8 vs.38 +/-.8). The increase in total body water and in serum levels of sALP was also significantly higher in the S group (total body water: 3 months; corrected age: 3.8 +/-.5 vs 3.5 +/-.4 kg, 6 months; corrected age: 4.5 +/-.5 vs 4.2 +/-.4 kg; sALP: 3 months; corrected age: 140.2 +/- 28.7 vs 118.7 +/- 18.8 micro g/L). CONCLUSIONS: Zinc supplementation has a positive effect on linear growth in premature infants.