Early life interactions— including environmental and social— play an important role in children’s health and in building up their immune system. Research in this space suggests that these interactions help children develop a more robust and diverse community of microorganisms in their gut, known as the gut microbiome.
But what happens when a pandemic forces everyone to stay indoors, disrupting children’s connection to the outside world? A recent study published in Scientific Reports that examined changes in the microbiomes of infants who spent a year indoors during the COVID-19-induced lockdown offers insights into this question.
The study reveals a decrease in the diversity of certain types of bacteria in the infants’ microbiomes compared to their status before the lockdown. The researchers say this sheds light on the importance of exposing children to their environment and emphasises the significance of diversity in building a stronger and healthier gut microbiome.
“This study contributes to a growing field of literature about how the social environment is associated with the developing gut microbiome and provides additional evidence for associations between environmental disruptions and the composition and diversity of the infant gut microbiome,” says Sarah C Vogel to Happiest Health, the article’s co-lead author, from NYU Steinhardt’s Developmental Psychology programme.
Influence on the gut microbiome
“The COVID-19 pandemic provides a rare natural experiment to help us better understand how the social environment shapes the infant gut microbiome, and this study contributes to a growing field of research about how changes to an infant’s social environment might be associated with changes to the gut microbiome,” says Vogel.
Several studies have shown that early childhood development of the gut microbiome is dependent on their environment. For instance, a 2022 study showed that children in day-care facilities had a more diverse microbial composition in their gut.
Other studies also throw light on the alpha diversity of the gut. Alpha diversity measures the variety and richness of the microbial species within a single individual’s gut. It provides insights into the overall microbial diversity in a specific gut environment.
Findings of the study
In the current study, researchers at NYU collected microbiome data from infants between December 2018 and December 2020. Since the lockdown came into effect in March 2020, they were able to note the difference in microbiome before and after the start of the pandemic.
The team of developmental researchers inferred that the lower alpha diversity in these children was because of reduction in social interactions, increased hygiene and change in interactions with their environment and family.
It also showed a lower abundance of two families of bacteria: Pasteurellaceae and the Haemophilus family, which the authors attribute to more frequent use of cleaning or disinfectant products.
This study is the first of its kind to look at how the COVID-19 pandemic might affect the gut microbiome as it develops in young individuals. It adds to the existing knowledge about how the things we experience in our early years can influence the different types of microorganisms in our gut.
While it is too soon to say that there is a direct health implication caused by lower diversity of certain species of bacteria in the guts of children who were born just before or during the pandemic-induced lockdowns, it will be interesting to see how it affects health across their lifespan.
“In adults we know that lower diversity of the microbiota species in the gut has been linked to poorer physical and mental health,” says Natalie Brito, senior author, and associate professor at NYU Steinhardt in a statement. “But more research is needed on the development of the gut microbiome during infancy and how the early caregiving environment can shape those connections.”
Additionally, the authors also assessed the effect of diet on the microbiome and found that infants ate slightly more fat in their diets, and this higher fat intake was linked to a less diverse gut microbiome. While breastfeeding was associated with lower gut microbiome diversity, it did not vary between the groups studied before and during the pandemic.
To gain a better understanding of how the pandemic may have affected the infants’ gut microbiome, future research must include larger and more diverse samples and look at other measurements.
“Studies that include long-term outcomes, such as additional measures of the gut microbiome or other indices of child development, might help us understand if the associations we identified in our study persisted over time or waned once the world opened back up” concludes Vogel.