(P27-041-24) Infant Gut Microbiota Changed Over Time and in Response to Different Complementary Diets: Results From an On-Going Clinical Trial

Objectives: To determine gut microbiota development during early complementary feeding.

Methods: This randomized controlled trial compares the effects of dietary patterns with common protein-rich foods on gut microbiota development during early complementary feeding in both breast- and formula-fed infants. Five-month-old infants are randomized to three common protein-rich complementary diet groups or an ad lib group (standard of care) from 5 to 12 months of age. Infants are matched for sex, mode of delivery and mode of feeding using stratified randomization. Weighed 3-day diet records were collected at baseline, 9 and 12 months of age and analyzed using NDSR. Stool samples were collected every month during the intervention and 16S rRNA gene profiling was conducted. Because the trial is still ongoing, group assignment is blinded for this preliminary report.

Results: A subgroup (n=100) of participants who completed this on-going randomized controlled feeding trial was included in this interim analysis. Diet records showed no difference in total energy (kcal/kg/d) or protein intakes (g/kg/d) between groups at any time point. From 5 to 12 months, as complementary foods were gradually introduced, alpha-diversity increased in all participants without differences between groups (effect of time p< 1e-06). Gut microbiota profiles also changed significantly over time (PERMANOVA p< 1e-05) with less Bifidobacterium and more Blautia and Roseburia. Beta-diversity as well as the abundances of individual bacterial taxa also differed significantly in association with complementary diet group comparisons.

Conclusions: With the introduction of complementary foods, alpha-diversity increased, and gut microbial composition changed in infants. Gut microbiota composition changes were also dependent on the type of protein-rich foods infants consumed.

Funding Sources: NIDDK, Mead Johnson Nutrition