Lockdowns affected gut microbiome, allergies in newborns

Lockdowns imposed during the COVID-19 pandemic had a surprisingly beneficial impact on the gut microbiome development of babies born during these periods, according to a new study led by Irish researchers. Published in the journal Allergy, the study is said to be the first to specifically explore the gut health of newborns in the pandemic.

“While we all start life sterile, communities of beneficial microbes that inhabit our gut develop over the first years of life,” explained joint senior author Professor Liam O’Mahony, from APC Microbiome Ireland at University College Cork.

“We took the opportunity to study microbiome development in infants raised during the early COVID-19 era when strict social distancing restrictions were in place, as the complexity of early life exposures was reduced and this facilitated a more accurate identification of the key early life exposures.

“Prior to this study, it has been difficult to fully determine the relative contribution of these multiple environmental exposures and dietary factors on early-life microbiome development.

The researchers analysed faecal samples from 351 babies born in the first three months of the pandemic, comparing these with pre-pandemic cohorts. Online questionnaires were used to collect information on diet, home environment and health. Stool samples were collected at six, 12 and 24 months, while allergy testing was performed at 12 and 24 months.

Their findings highlighted gut health benefits for ‘pandemic babies’ arising from the unique environment of lockdown, including lower rates of infection and consequent antibiotic use, and increased duration of breastfeeding. Babies born during lockdown were also found to have more of the beneficial microbes acquired after birth from their mother, which may have played a protective role resulting in lower-than-expected rates of allergic conditions, such as food allergies.

“One fascinating outcome is that due to reduced human exposures and protection from infection, only 17% of infants required an antibiotic by one year of age, which correlated with higher levels of beneficial bacteria such as bifidobacteria,” O’Mahony said.

“This study offers a new perspective on the impact of social isolation in early life on the gut microbiome,” added joint senior author Professor Jonathan Hourihane, from the Royal College of Surgeons in Ireland (RCSI) and Children’s Health Ireland at Temple Street. “Notably, the lower allergy rates among newborns during the lockdown could highlight the impact of lifestyle and environmental factors, such as frequent antibiotic use, on the rise of allergic diseases.”

Image credit: iStock.com/SDI Productions