Gut microbiota responses to complementary food sources differ by milk feeding type

Area of Science:

• Microbiome research
• Infant nutrition
• Host-microbe interactions

Background:

• Early-life nutrition significantly influences the infant gut microbiome and long-term health.
• The impact of different solid food sources (homemade, commercial, mixed) on the infant gut microbiome remains under-investigated.

Purpose of the Study:

• To investigate the relationship between solid food source at 6 months and infant gut microbiome diversity and composition at 1 year.
• To determine if these relationships are modified by milk feeding type.

Main Methods:

• Secondary analysis of the Canadian Healthy Infant Longitudinal Development (CHILD) cohort.
• 16S rRNA sequencing of stool samples at 1 year, with solid food source assessed at 6 months.
• Statistical analyses included generalized linear models, PERMANOVA, and MaAsLin2, adjusting for covariates and examining effect modification by milk feeding type.

Main Results:

• Solid food source explained minimal gut microbiota variability (0.53%).
• Formula-fed infants showed the most significant differences: homemade/mixed foods were linked to higher Firmicutes and Turicibacteraceae at 6 months.
• At 1 year, formula-fed infants on homemade foods had altered microbial diversity (higher richness, lower evenness) compared to those on commercial foods. No significant effects were observed in human milk-fed or weaned infants.

Conclusions:

• Solid food source is an under-recognized factor in infant gut microbiome variability, with effects dependent on milk feeding type.
• Formula-fed infants exhibit greater sensitivity to complementary food source compared to human milk-fed infants.
• Findings support tailored infant nutrition strategies, emphasizing precision nutrition based on feeding type.