Infant Microbiome Development Minimally Affected by Diet
TOPLINE:
Diet has only a marginal impact on microbiome development in infancy, although metabolite profiles differ between breast- and formula-fed infants; circadian rhythm of the gut microbiome is detectable as early as 2 weeks after birth.
METHODOLOGY:
- A randomized, controlled interventional trial compared microbiota development in 210 newborns who were exclusively breastfed or received one of four formulas: Un-supplemented formula, Bifidobacterium-supplemented formula, galacto-oligosaccharide (GOS)-supplemented, or formula containing GOSs and bifidobacteria. Exclusively breastfed infants served as a reference group to evaluate the impact of infant formula feeding.
- Researchers tracked the infants’ microbiota and metabolite profiles in response to the different feeding modes via stool samples collected periodically during the first 1-2 years of life.
- They also made note of the time of day that the stool sample was collected to assess 24-hour oscillations of the microbiome in relation to dietary exposure.
TAKEAWAY:
- Global microbiota assembly of infants is primarily affected by age and less so by diet. All infants showed a gradual increase in gut microbe diversity, and at 24 months, there was no observable difference between the groups.
- However, gut metabolite profiles differed significantly between exclusively formula-fed and exclusively breastfed infants. None of the supplemented formulas were able to fully recreate the breast milk-related microbial environment.
- GOS-supplemented formula was more effective at promoting sustained levels of bifidobacteria than formula containing bifidobacteria.
- Metabolic and bacterial profiling revealed 24-hour fluctuations and circadian networks as early as 2 weeks after birth. Infant microbes maintained circadian rhythms when grown in continuous culture, even in the absence of external light or host cues, suggesting an intrinsic clock mechanism in bacteria.
IN PRACTICE:
“Our findings warrant the need for further analysis of circadian fluctuations of both bacteria and metabolites and their functional role in contributing to the benefits of infant nutrition,” the study authors wrote.
SOURCE:
The study was published online on April 2 in Cell Host & Microbe.
LIMITATIONS:
The group size for exclusively formula-fed infants was limited, and the explicit contribution of breast milk, relative to infant formula, to bacterial rhythms remains unclear. A possible limitation of the circadian analysis is that the number of fecal samples collected during the night was lower than during the daytime and decreased with age.
DISCLOSURES:
This research was supported by Töpfer GmbH, the German Research Foundation, the Joint Programming Initiative of the European Union, and the German Ministry of Education and Research. The authors had disclosed no relevant conflicts of interest.
