Influence of Singular First Foods on the Infant Gut Microbiome: A Randomized Controlled Trial

Area of Science:

• Microbiology
• Pediatrics
• Nutrition Science

Background:

• The infant gut microbiome is crucial for immune function, inflammation, and metabolism.
• Microbiome malleability decreases with age, highlighting the importance of early dietary exposures.
• First complementary foods (CFs) significantly influence the developing infant gut microbiome.

Purpose of the Study:

• To investigate the impact of different first complementary foods (CFs) on the infant gut microbiome.
• To conduct a pilot randomized controlled trial evaluating CF effects on microbial diversity and composition.
• To compare the effects of oatmeal cereal, beef, carrot, and prune as initial CFs.

Main Methods:

• A pilot randomized controlled trial involving 43 exclusively human milk-fed infants.
• Infants were assigned to receive one of four CFs (oatmeal, beef, carrot, prune) for one week, followed by oatmeal.
• Stool samples were collected daily and analyzed using full-length 16S rRNA gene amplicon sequencing.

Main Results:

• Oatmeal cereal increased observed amplicon sequence variants (ASVs) compared to beef in phase 1.
• Prune introduction led to increases in specific bacteria (Bacteroides ovatus, Klebsiella pneumoniae), while oatmeal increased Enterococcus spp. relative to beef.
• In phase 2, oatmeal cereal after beef or prune enhanced microbial diversity (Shannon and Faith's PD).

Conclusions:

• Beef provides essential minerals but may lead to a less diverse gut microbiome compared to other CFs.
• Fruits and vegetables showed comparable diversity to cereals, suggesting potential for balanced introductions.
• Future research should explore combining meat with fruits/vegetables and detailed impacts on microbial taxa and host pathways.