Zinc status of Indian children

Zinc is a trace metal essential for human health and its deficiency is found to cause severe growth retardation in children. Information on the zinc status of Indian children is meagre perhaps due to lack of a reliable parameter. However, in view of the role of zinc in promoting growth, it has become common practice to prescribe zinc supplements to young children and newborns, particularly preterm infants. It is now clearly established that zinc confers no additional benefits to an individual with adequate zinc status while it can potentially lead to harmful effects by disturbing the milieu of other trace metals in the body. Estimation of thymulin levels in circulation is found to be a sensitive indicator of zinc status and using this parameter we found that apparently normal children have adequate zinc status. Children suffering from severe protein energy malnutrition however had very low levels of the hormone besides low leukocyte and plasma zinc levels indicating zinc deficiency. Such children showed improvement in their zinc status when zinc supplements were provided along with rehabilitation diets. Pregnant women and term newborns showed no evidence of zinc deficiency. Preterm infants had higher leukocyte zinc levels during early infancy and the breast milk of their mothers also had higher zinc content which could cater to the higher requirements of the rapidly growing preterm infant. All breast-fed infants showed decline in the zinc status gradually over the initial 4 months of life and regained adequate zinc status after appropriate weaning. These studies thus do not support the view of routine zinc supplements to pregnant women or children. However, Infants solely fed formula milk from birth had significantly impaired zinc status till the time of weaning. The functional significance of severe zinc inadequacy in such infants needs to be established.