Microbiota and Body Composition During the Period of Complementary Feeding.

OBJECTIVES This study aimed to explore the associations between food group intake, faecal microbiota profile and body composition during the period of complementary feeding. METHODS Diet was assessed using a quantitative food frequency questionnaire, faecal microbiota profile was assessed using 16S rRNA gene sequencing and body composition was assessed using bioelectrical impedance analysis and dual energy X-ray absorptiometry, in a cohort of 50 infants aged 6 to 24 months of age. RESULTS During this critical period of microbiota development, age was the strongest predictor of microbiota composition with network analysis revealing a cluster of genera positively associated with age. A separate cluster comprised genera associated with Fat Mass Index with Bifidobacterium showing the strongest correlation with Fat Mass Index (rho = 0.55, p = 0.001, FDR = 0.018). Dairy intake was both negatively correlated with Bacteroides (rho = -0.49, p < 0.001, FDR = 0.024) and positively correlated with Lean Mass Index (rho = 0.44, p = 0.007, FDR = 0.024). Antibiotics use in the first month of life had the most striking influence on body composition and was associated with an increase in mean BMI (Body Mass Index) Z score of 1.17 (p = 0.001) and body fat of 3.5% (p = 0.001). CONCLUSIONS Our results suggested that antibiotics use in the first month of life had the most striking influence on body composition in this cohort of infants aged 6 to 24 months while dairy intake interacted with both microbiota and body composition in early life.