Zinc supplementation does not affect growth, morbidity, or motor development of US term breastfed infants at 4-10 mo of age.
What this study found
Zinc supplementation did not improve growth, gross motor development, or morbidity in these healthy term breastfed infants. In the zinc group, mean weight gain was 348 +/- 75 g/mo and mean length gain was 1.48 +/- 0.15 cm/mo, but these outcomes did not differ significantly from placebo; attained weight and length at 10 months were also not significantly different. Gross motor development on the AIMS was not significantly different between groups, and incidence or prevalence of diarrhea, otitis media, respiratory illness, fever only, and total illness also did not differ significantly. Plasma…
- Study & population
- Randomized, double-blind, placebo-controlled trial in healthy term breastfed infants in the United States.
- Intervention
- The active intervention was 5 mg elemental zinc daily as zinc sulfate, given orally as drops each morning from ages 4 to 10 months.
- Key limitation
- Primary analyses were based on a reduced active-arm sample rather than all randomized infants, and the biochemical subset was very small.
View source
Open PDFOriginal abstract
BACKGROUND It has been documented that growth patterns differ between breastfed and formula-fed infants. Some investigators have suggested that these differences may be related to differences in zinc nutriture. OBJECTIVE The objective of this study was to examine the effect of zinc supplementation on growth, morbidity, and motor development in healthy, term, breastfed infants. DESIGN We conducted a randomized double-blind intervention comparing zinc supplementation (5 mg/d as zinc sulfate) with placebo in breastfed infants aged 4-10 mo. Growth and indexes of body composition and gross motor development were measured monthly from 3 to 10 mo. Morbidity data were collected weekly. RESULTS Eighty-five infants were enrolled, and 70 completed the study. The baseline characteristics, attained weight or length at 10 mo, growth velocity, gross motor development, and morbidity did not differ significantly between groups, even after control for potentially confounding variables. CONCLUSIONS The dietary zinc intake of these breastfed infants appeared to be adequate, given that zinc supplementation did not affect growth, development, or risk of infection (although sample size for detection of differences in development or infection was limited). Previously described differences in growth between breastfed and formula-fed infants in such populations do not appear to be due to differences in zinc nutriture.