A 3‐year longitudinal study of zinc status in infants fed human milk (HM), casein‐based (CBF), or soy‐based formula (SBF) in Korea

Abstract

Zinc nutritional status was longitudinally assessed by measuring zinc intakes and serum zinc concentrations from birth to 36 months in 51 infants who were exclusively fed HM (n=20), CBF (n=12), or SBF (n=19) during the first 5 months of life. Zinc contents in milk and formulas were measured, and zinc intake was estimated at 1–36 months of life by weighing infants before and after feeding in the HM group and by collecting formula intake records in the CBF and SBF groups. After solid foods were introduced, all foods consumed were also included to estimate zinc intake. Mean daily zinc intakes were 1.0, 3.8, and 7.0 mg at 5 months and 3.8, 5.8 and 11.6 mg at 12 months and 5.5, 3.7, and 6.0 mg at 36 months in the HM, CBF, and SBF groups, respectively. Although the overall zinc intake in infants fed SBF was higher than those in the HM or CBF groups throughout the study, mean serum zinc concentrations were similar in all groups. The proportions of infants with low serum zinc (< 65 μg/100 mL) were 10%, 17%, and 20% at 5 months, and 42%, 30%, and 12% at 12 months, and 33%, 13%, and 20% at 36 months in the HM, CBF, and SBF groups, respectively, suggesting the presence of inadequate zinc status. The strategies to increase zinc intake in the HM group and to increase bioavailability of zinc in CBF or SBF should be studied. Research Support: Dr. Chung's Food Co.