Dietary zinc intake and growth during infancy.

Energy, protein, zinc intake, and weight and length were monitored at 3, 6, and 12 months in 50 preterm infants (corrected for gestational age) (mean birthweight, 1,054 +/- 234 g; mean gestation, 29 +/- 2.5 weeks) and 60 full-term infants (mean birthweight, 3,509 +/- 269 g; mean gestation, 40 +/- 1 weeks). Mean energy and protein intake (per kilogram body weight) was higher (p less than 0.05) for the preterm infants at all times and met the recommended levels for preterm infants. No significant differences in zinc intake (per kilogram body weight) between the two groups existed, and at 3 months, mean zinc intake in the preterm group (per kilogram body weight) was below the recommended level for full-term infants. At no time were the growth percentiles of the preterm group equal to those of the full-term group. Multiple regression equations predicting length at 3 months and weight at 12 months for all the infants were significant, the significant variables being length at birth and zinc intake (milligrams per day) at 3 months, and weight at birth and dietary zinc intake (milligrams per day) at 12 months, respectively. Results indicate that zinc intake played a more important role in explaining the length at 3 months and weight at 12 months than did any other variables, including intakes of protein and energy, gestational age, socioeconomic index of the father, midparent height, sex, and age of introduction of solid foods. Results thus support the suggestion that infants, especially those born prematurely, are at risk for inadequate intake of dietary zinc.