Research has shown a strong link between gut microbiota and allergic diseases, which impacts microbial diversity and specific strains.
The study offers a new perspective on the impact of social isolation in early life on the gut microbiome. (Shutterstock)
Lockdowns enforced during the Covid-19 pandemic had a notable effect on the gut microbiome development in babies born during this time. The gut microbiome, which comprises a community of microorganisms residing in our digestive tract, holds crucial significance for human health.
A recent study, published in Allergy, marks the first comprehensive exploration into the gut health of newborns during the pandemic. Interestingly, those born during lockdowns also exhibited lower-than-expected rates of allergic conditions, including food allergies.
The study found notable differences in the microbiome development of infants born during lockdowns compared to those born before the pandemic.
These distinctions were associated with a positive impact on gut health for pandemic-born infants, attributed to the unique lockdown environment. Reduced infection rates, lower antibiotic use, and prolonged breastfeeding were identified as contributing factors.
Infants born during this period also exhibited a higher presence of beneficial microbes acquired from their mothers postnatally, potentially offering protection against the development of allergic diseases.
Research has shown a significant relationship between gut microbiota and allergic diseases. Alterations in gut microbiota have been observed in allergic individuals, impacting microbial diversity and specific bacterial strains.
“Allergies, which are prevalent in humans, are known to have a significant connection with gut microbiota. The gut microbiota plays a substantial role in various aspects of human health, including inflammation, immune system function, and metabolism,” Kochi-based gastroenterologist Dr Rajeev Jayadevan tell South First.
Studies indicate that dysbiosis in the gut microbiota, characterised by an imbalance, can lead to allergic diseases like food allergy and respiratory allergies.
The composition of the gut microbiome has been associated with food allergy susceptibility, with certain bacterial strains linked to food allergy progression.
Additionally, impaired microbiota maturation in early life has been linked to an increased risk of developing allergic diseases later on. The gut microbiota plays a crucial role in modulating immune responses and influencing the development of allergic disorders.
Babies born in the early stages of the pandemic, when the Irish population diligently followed guidelines, were primarily confined to their own families. As a result, they had limited external contact, and mothers took on the primary caregiving role, leading to increased breastfeeding compared to pre-pandemic levels.
“Due to their secluded lifestyle, these infants were spared the usual infections common among young children, such as respiratory viruses (RSV infections) and common colds. Typically, these minor infections resolve on their own without medical intervention. However, in routine medical visits, doctors often prescribe antibiotics, a common practice worldwide,” says Dr Jayadevan.
Remarkably, the babies in this specific cohort, observed over the first year of their lives, did not receive antibiotics as frequently. Only 17 percent of them were exposed to antibiotics, a stark contrast to the expected 80 percent exposure rate based on pre-pandemic standards.
The study focused on the gut flora or microbiome of these babies during the six to twelve-month period.
The babies born during the pandemic, referred to as the CORAL group, exhibited notable differences in their gut microbiome compared to the historical norm.
“It’s crucial to understand that a baby’s gut starts as essentially sterile at birth, primarily hosting the mother’s bacteria in the initial weeks, which then permanently colonises the gut. Subsequently, exposure to other family members and the broader environment contributes to what is termed ‘horizontal transmission’ of bacteria,” says Dr Jayadevan.
However, during a lockdown, the mother becomes the exclusive source of bacteria for the baby. This primarily involves beneficial bacteria known as bifidobacteria, essential for a healthy gut.
Another category of bacteria is clostridia, which encompasses various types, including both beneficial and potentially harmful ones. The balance and types of these bacteria significantly differed in the babies born during the pandemic compared to the conventional pattern.
The study also found that infants with siblings had higher levels of bifidobacteria, providing a potential explanation for why having siblings is linked to a lower risk of allergies.
“This particular study yields a couple of significant findings. Firstly, it suggests that proper breastfeeding practices and protecting the baby from infections, along with avoiding antibiotics in the first year, seem to result in a healthier gut microbiome in infants. The causal relationship between these factors is not established; the observation is based on the association of these three variables,” explains Dr Jayadevan.
He adds that secondly, understanding how these relationships evolve beyond the age of 12 months requires a more extended period of observation. Only through continued study of the same group of babies over time can researchers uncover the dynamics of these equations.
“The study reinforces the benefits of breastfeeding, emphasising that a longer duration is preferable. Weaning habits should be developed with professional advice, considering that the baby interacts with the environment. Paediatricians play a crucial role in educating parents about appropriate weaning practice,” says Dr Jayadevan.
The prudent use of antibiotics is highlighted. While antibiotics are essential in treating infections, their use should be limited to cases where necessary. Preventing infections early in life seems to carry benefits, but it’s essential to strike a balance.
“These insights offer valuable considerations for parents and caregivers in promoting the health and well-being of infants,” adds Dr Jayadevan.
The study offers a new perspective on the impact of social isolation in early life on the gut microbiome.
“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,” author of the study Jonathan Hourihane said in a statement.
“We hope to re-examine these children when they are 5 years old to see if there are longer term impacts of these interesting changes in early gut microbiome,” he added.
“While we all start life sterile, communities of beneficial microbes that inhabit our gut develop over the first years of life. 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,” said Professor Liam O’Mahony, another author of the study in a statement.
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