Infant Gut Microbiomes Exhibit Circadian Rhythms Independent of External Cues
Recent research published in the journal Cell Host & Microbe reveals that infant gut microbiomes display circadian rhythms, even when they are cultured outside of the body. The study, conducted by experts from the Technical University of Munich, found that this rhythm is detectable as early as 2 weeks after birth and becomes more pronounced with age.
The senior author and microbiome expert, Dirk Haller, expressed his surprise at the findings, stating, ‘We found that even at very early ages of colonization, the microbial ecosystem develops this circadian rhythmicity. We have shown these rhythms before in adults, but we were not sure when these mechanisms first appear.’
The study also debunked the common belief that diet significantly impacts the development and composition of the infant microbiome. While diet did have some impact, the researchers emphasized that age plays a more crucial role. Haller explained, ‘Diet matters, but less than aging of the gut. When we compared breastfed and formula-fed infants, the differences in microbiome colonization were marginal. Our intestinal system is probably a little bit more flexible in adapting to what the environment has to offer.’
The researchers utilized a randomized controlled trial involving 210 infants to compare microbiome development in exclusively breastfed infants and those who received various types of formula. Stool samples were collected at different ages, ranging from 0.5 months to 24 months, and the time of day was also noted during collection.
Surprisingly, the study found that diet had minimal impact on infant growth or the differences in their microbiomes. Despite some variation, all infants showed a gradual increase in gut microbe diversity, with no observable difference between the groups at 24 months. Additionally, the research revealed that GOS (galacto-oligosaccharides)-supplemented infant formula was more effective at promoting sustained levels of Bifidobacteria compared to formula containing Bifidobacteria.
However, a significant difference in the gut metabolite profile was identified between exclusively breastfed and formula-fed infants. The study sheds light on the intricate development of infant gut microbiomes and emphasizes the influence of age over diet in shaping the microbial ecosystem.
