1164-P: Associations of Human Milk Metabolites with Infant Adiposity and Body Composition Measures

Introduction and Objective: Breast milk is a dynamic substance rich in both nutritive and nonnutritive compounds that may influence infant growth, development, and obesity risk. We aimed to identify metabolites in human milk that are associated with infant growth and body composition. Methods: We analyzed breast milk metabolomics from 350 mother-infant pairs at 1 month postpartum using high-sensitivity LC/GC-MS and assessed infant anthropometrics (BMI percentile) and body composition [percent body fat (%BF), Fat Free Mass Index (FFMI)] using air displacement plethysmography (at 1-month) and DXA (at 6-months). We tested associations between milk metabolites and infant anthropometric and body composition measures using linear regressions adjusting for covariates including maternal age, parity, delivery mode, gestational age, infant sex, birth weight, race, ethnicity, and enrollment site. We used Benjamini-Hochberg procedure to adjust for multiple comparisons (FDR <0.05). Results: Semi-quantitative concentrations were obtained for 458 metabolites. A greater number of milk metabolites were associated with %BF (9 with FDR<0.05) and BMI percentile (4 with FDR <0.05) than with FFMI (0 with FDR <0.05). Highest ranking metabolites associated with %BF included gamma-glutamylglutamine (beta=0.056, FDR=0.004) and 7-methylguanine (beta=0.061, FDR=0.03) while docosahexaenoate (beta = -0.020, FDR= 0.02) and p-hydroxybenzoate (beta = -0.012, FDR= 0.02) were the highest ranking metabolites associated with BMI percentile. The purine metabolite 7-methylguanine has been implicated previously in adipogenesis. Conclusion: Infant adiposity measures, but not measures of fat free mass, are associated with differences in the human milk metabolome. Further studies are needed to determine whether differences in human milk metabolites play a mechanistic role in infant growth and obesity risk. Disclosure A. Uniyal: None. C. Lu: None. J.M. Dreyfuss: None. E.M. Nagel: None. A. Pena: None. M. Rudolph: None. D.A. Fields: None. E.W. Demerath: None. E.M. Isganaitis: None. Funding NIH/NICHD (R01HD080444, R01HD109830)