Zinc Supplementation and Growth of the Fetus and Low Birth Weight Infant

Abstract

Zinc deficiency limits growth in young children, and in animal models it also affects fetal growth. In animals, the effect of severe zinc deficiency on growth is evident. However, controlled trials of zinc supplementation during pregnancy in humans have not demonstrated consistent effects on weight at birth and/or duration of gestation. Those studies that have identified a positive effect of zinc on fetal growth were performed on low-socioeconomic or migrant groups in industrialized countries or in countries where diet and living conditions are improving. In contrast, in studies conducted either on populations with minimal risk of zinc deficiency or those suffering from multiple and severe nutritional deficiencies, no effects have been found. The potential confounding factors that may help explain the contradictory results include the following: age of pregnant women; presence of digestive diseases, other nutritional deficiencies, phytates or other factors that affect bioavailability; timing and duration of zinc supplementation and compliance with supplements. Few studies of zinc supplementation were conducted on infants that were born small for their gestational age or preterm; in this case, a positive effect on growth was shown. A study of zinc supplementation during pregnancy found reduced risk of diseases (diarrhea or impetigo) in small-for-gestational-age but not preterm infants. A second study demonstrated reduced mortality in small-for-gestational-age infants. We conclude that supplementation trials during human pregnancy do not provide conclusive evidence for a beneficial effect of zinc supplementation despite the experimental evidence that zinc deficiency may retard fetal growth or shorten pregnancy. However, early zinc supplementation in low birth weight or small-for-gestational-age infants reveals an effective improvement in growth, which suggests a prenatal depletion or insufficient zinc intake to support catch-up growth postnatally.

The Production of Child Health in Kenya: A Structural Model of Birth Weight

“…Although it can be reasonably associated with mother's intake of nutrients, and with the prenatal care received during pregnancy, consistent effect of nutrition on birth weight has been difficult to establish in experimental studies. In some cases, zinc supplementation of diet during pregnancy was found to increase birth weight in randomized trials but in other cases it had no effect (see Castillo-Duran and Weisstaub (2003). This point is echoed by Costello and Osrin (2003) when they note that practicalities of increasing birth weight at the population level remain questionable.…”

Inadequate intakes of dietary zinc among pregnant women from subsistence households in Sidama, Southern Ethiopia

“…Whether the dietary zinc intakes of women in rural Southern Ethiopia are sufficient to meet these high requirements during pregnancy has not yet been established. Zinc deficiency has been associated with adverse effects on both maternal health and pregnancy outcome in some studies, specifically pregnancy complications, reduced birth weight and congenital anomalies [8][9][10] .…”

Reference Range for Zinc Level in Young Healthy Population in Southeast of Iran

“…High level of Zinc is found in Oysters, Red meat, poultry, beans, nuts, certain seafood, whole grains, fortified breakfast cereals, and dairy products. Low level of Zinc is found in vegetable, fruits, tea, coffee, rice, and bread (6). Zinc deficiency usually occurs in negative history of Zinc intake or any zinc-containing supplement intake and is commonly related to nutritional deficiency, but sometimes stems from malignant condition, diabetes mellitus, malabsorption, or other chronic illnesses (7,8).…”