Comparison of growth indices in breast-fed and formula-fed infants and their correlation with zinc status

Abstract

Introduction: Zinc has many effects on human’s multiple systems in the body, including gastrointestinal tract. It is essential for normal development, immune system and growth of an infant. Zinc deficiency increases the chances and severity of gastrointestinal tract and respiratory infections. Children are at high risk of zinc deficiency as their requirements increases with growth. The amount of zinc absorbed from infant formulae is considerably lesser than that absorbed from mother’s milk. The aim was to study the differences in the growth indices of breast-fed and formula-fed infants and also to look for the association of zinc, if any, with these indices.

Methodology: This cross-sectional study was performed from October 2017 to March 2018 in Peshawar, on 50 healthy infants {25 breast-fed infants (BFI) and 25 formula-fed infants (FFI)}. The infants' weight, height, BMI, head circumference and skinfolds (biceps and triceps) were recorded. Blood samples of all the infants were collected for zinc assay. Data were collected in an MS Excel sheet and descriptive data analysis was done by Minitab version 16.

Results: It was observed that the head circumference (cm) of FFI was significantly higher (40.32± 2.34) in comparison to BFI (38.12±4.46) whereas SDS weight, SDS BMI, biceps and triceps measurements did not reveal any significant difference in the two groups. The variables showing a significant positive correlation with zinc were age (r = 0.328, p=0.02) and SDS height (r= 0.274, p= 0.05) while SDS weight, SDS BMI, biceps and triceps measurements were not correlated with zinc status.

Conclusion: All the growth indices except head circumference of both breast-fed and formula-fed infants were comparable. Similarly, all these indices except SDS height were not associated with the levels of zinc during early infancy showing that zinc status does not affect the growth of infants at least in the early phase of life.

Keywords: Zinc, Growth indices, Breast-feeding, Formula feeding