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.

Reference values for serum silicon in adults.

Silicon is an essential nutrient of fundamental importance to human biology. It has been shown that silicon is required for bone, cartilage, and connective tissue formation. However, the assessment of silicon concentration is difficult as reference values are lacking. The aim of the present study was to establish reference values for apparently healthy individuals. Silicon concentrations were determined in serum of 1325 healthy subjects 18-91 years of age using atomic absorption spectrometry. Medians for serum silicon concentrations showed a statistically significant age and sex dependency. In men 18-59 years of age the median was 9.5 micromol/L and decreased to 8.5 micromol/L at 60-74 years of age. In women there was an increase in the median from age 18-29 years (10.00 micromol/L) to 30-44 years (11.10 micromol/L) followed by a decrease in the age group of 45-59 years (9.23 micromol/L). In subjects aged over 74 years the median serum silicon values were 7.70 micromol/L for men and 8.00 micromol/L for women. The most important findings in this study are the decrease of silicon and the course of the silicon concentrations with age, especially in women. The present study is an important prerequisite for studies that aim to identify the health effects and medical implications of silicon.