Infants and young children with good gut flora at an early stage of life particularly, aged one year, had a lower risk of developing lung diseases such as allergy-related wheeze or asthma, according to researchers from Deakin University in Australia.

The study, which was recently presented at the European Respiratory Society International Congress in Milan, Italy, established a link between gut microbiota maturation and allergy-related wheezing (atopic wheeze). The study looked at the gut microbes development in children and general population. However, this study has certain drawbacks, including the DNA technique employed to identify the gut microbiota does not provide information about the microbial functions.

 The intestinal flora, or gut microbiota, are communities of microorganisms occurring naturally in the intestine that play a crucial role in the developmental processes of the body, including vitamin synthesis and boosting immunity. Children inherit some microbiota from their mothers at the time of birth. 

Researchers investigated the data obtained from a cohort study known as the Barwon Infant Study (BIS), which involved 1074 babies from the Barwon region of Australia between 2010 and 2013.

 During the study, they tracked the babies for three years and examined the microorganisms in faecal samples collected at various postnatal reviews. They asked parents about atopic wheeze or asthma in the preceding 12 months, and skin-prick tests were conducted to determine whether the children had any allergies to any food or airborne particles (like ryegrass or dust).

 In a subgroup involving 323 children, researchers from the BIS team identified and characterised gut flora using a mathematical estimation of the maturity of the children’s microbiota, known as the microbiota-by-age score (MAZs).

 Lead author Dr Yuan Gao, Deakin University, Geelong, Australia, said, "Our studies on the Barwon Infant Study showed that a more mature infant gut microbiota at one year of age was associated with a lower chance of developing food allergies and asthma in childhood."

Pointing out that mature gut microbiota reduces the chances of children suffering from allergy-related wheeze, she added, "If MAZ increased within a certain range, known as the standard deviation, it halved the risk of allergy-related wheeze at both of these ages."

"In other words, the more mature the gut microbiota, the less likely the children were to have allergy-related wheeze. We did not find a similar association with MAZ scores at one or six months," Dr Gao said. 

 She further mentioned that a clinical trial is being planned with a target to involve 2000 children from Australia and New Zealand to investigate whether an oral mixture of dead bacteria can increase the immunity against viral infection in babies.

"ARROW has the potential to dramatically improve the health of children with recurrent wheezing and asthma," Dr Gao added.

 According to Dr Erol Gaillard, Secretary of the European Respiratory Society group and professor at the University of Leicester and Leicester Royal Infirmary in Leicester, UK, allergy-related health issues impact children worldwide and due to fewer families, limited food options, and limited exposure to farm animals, the conditions are deteriorating.

Dr Gaillard emphasised that Dr Gao and their team suggest that healthy gut flora may be beneficial in preventing allergies and asthma. This is consistent with other views suggesting that early exposure to a wide range of microorganisms is probable due to frequent contact with children, animals, and a variety of foods.

He said, "If we can find ways to boost the maturity of gut microbiota, this could have a significant effect on the incidence of allergies, and so it will be interesting to see the results of the ARROW study."