The infant gut microbiome develops in response to dietary exposure, environmental factors, and genetic influences. Breastfeeding is known to promote beneficial bacterial colonisation, particularly bifidobacteria, through human milk oligosaccharides (HMOs). Infant formulas supplemented with bifidobacteria or prebiotics such as galacto-oligosaccharides (GOS) aim to replicate the composition of breastmilk. This study investigates how different feeding regimens influence the development of the infant microbiome and examines the presence of diurnal rhythms in bacterial populations and metabolite profiles.
Methods A randomised controlled trial was conducted involving 210 infants who were allocated to one of four formula groups or an exclusively breastfed reference group. Stool samples were collected longitudinally over 24 months to assess bacterial composition and metabolite profiles. The study also examined whether circadian rhythmicity in the microbiome persisted ex vivo using a chemostat model.
Findings The microbiota of infants was primarily influenced by age rather than diet. Formula-fed and breastfed infants exhibited similar microbial diversity, but metabolite compositions differed significantly. Bifidobacteria abundance was highest in infants receiving GOS-supplemented formula, while those receiving bifidobacteria-supplemented formula did not show the same increase. Notably, the infant gut microbiome displayed diurnal oscillations, with bacterial rhythmicity increasing with age. These oscillations were independent of host influence and persisted in controlled ex vivo conditions.
Implications The findings highlight the dynamic nature of early gut microbiota and its response to dietary interventions. GOS supplementation appears to sustain bifidobacteria levels more effectively than direct bifidobacteria addition. The presence of circadian rhythms in the microbiome suggests potential links between gut bacterial activity and host metabolism. Understanding these rhythms could inform feeding practices and optimise early-life nutrition.
Key Takeaways
· Age has a greater influence on microbiota composition than diet.
· Formula-fed and breastfed infants have similar microbial diversity but different metabolite profiles.
· GOS supplementation sustains bifidobacteria levels better than bifidobacteria supplementation alone.
· Infant microbiota exhibit diurnal oscillations, which increase with age.
· Circadian rhythms in the microbiome persist outside the host, indicating intrinsic bacterial rhythmicity.
· Understanding these rhythms may inform feeding strategies to support early-life gut health.
Conclusion The early-life gut microbiome is shaped by both age and diet, with significant implications for health and development. The discovery of bacterial circadian rhythms highlights a new dimension of microbiome regulation. Supporting microbial diversity and rhythmicity through targeted nutritional strategies may enhance long-term gut health.
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References Heppner N, Reitmeier S, Heddes M, et al. Diurnal rhythmicity of infant fecal microbiota and metabolites: A randomised controlled interventional trial with infant formula. Cell Host & Microbe. 2024;32(4):573-587. doi: 10.1016/j.chom.2024.02.015. https://pubmed.ncbi.nlm.nih.gov/38569545/
