Abstract
Objectives
Determine if type of protein or carbohydrate source in infant formula (IF) was associated with infant anthropometric outcomes in a nationally representative cohort.
Methods
NHANES 2015–2016 data from infants ≤ 12 months were utilized. Anthropometric Z-scores were calculated. IF ingredient data was retrieved from individual companies. Cross-sectional relationships between protein and carbohydrate source of IF consumed and infant Z-scores were examined, controlling for breastfeeding exclusivity and birth weight category (low vs normal birth weight vs large for gestational age).
Results
416 infants ≤ 12 months participated; 355 had 24-hour dietary recall data. 17 infants were excluded for consuming unspecified store-brand IF for a final sample size of 338.
Considering only breast milk and IF intake, 30% of infants were exclusively breastfed, 56% were exclusively formula fed, and 14% were mixed fed.
Of infants consuming IF (n = 234): 71.8% consumed intact protein and 23% consumed partially hydrolyzed protein IF. 6.8% consumed soy IF. Cohort average carbohydrate consumption from IF consisted of: 64.5% lactose and 31.9% glucose-based sugars. 15% of infants consumed IF containing sucrose.
Consumption of whey protein, lactose, and degree of protein hydrolysis were not associated with any z-scores.
In a multivariable model controlling for birth weight category, exclusive formula feeding was associated with higher weight-for-length Z-scores (P = 0.04).
In a multivariable model of length-for-age Z-score (P < 0.0001), controlling for amount of IF consumed and birth weight category, consumption of a higher percentage of casein (as opposed to whey) protein in IF was associated with lower Z-scores.
In a multivariable model of mid-arm-circumference (MUAC) Z-score (P = 0.032), controlling for amount of IF consumed and birth weight category, consumption of an IF containing sucrose was associated with higher Z-scores.
All of these relationships were strengthened when limiting analysis to infants ≤ 6 months (n = 185).
Conclusions
These data suggest a novel association between infant casein and sucrose intake and growth outcomes. Given the range and prevalence of these ingredients in IF, both feeding researchers and FDA regulation need to consider the potential impact of IF protein and carbohydrate source on the developing infant.
Funding Sources
Internally Funded.