by Bob Yirka , Medical Xpress

Credit: Pixabay/CC0 Public Domain

A team of pediatricians, and infectious and inflammatory disease specialists at the University of Gothenburg, working with colleagues from Skaraborg Hospital, all in Sweden, has found a lower incidence of allergies in infants born to parents living on farms who are exposed to animals as they age.

In their paper published in the open-access journal PLOS ONE, the group theorizes that exposure to farm animals as infants leads to differences in the gut biome, which in turn leads to reduced likelihood of developing allergies later on.

Over the past several decades, medical researchers have found the gut biome plays a much bigger role in human health than previously thought. In this new effort, the researchers in Sweden found evidence that it might also play a major role in the development of allergies.

Prior research has shown that shortly after birth, the human gut biome is rich in facultative bacteria, which prefer an environment with a lot of oxygen. As the bacteria consume the oxygen in the gut, the proportion of anaerobes grows. Over time, the anaerobes become more diverse and outgrow the facultative bacteria, a sign of a mature gut biome.

In this new effort, the research team wondered if living on a farm during the critical early stages of gut biome development might have an impact. To find out, they collected fecal samples from 65 children during their infancy and later as they grew older. They then compared samples from children born to parents living on a farm with animals, children that did not grow up on a farm, and non-farm children that had a pet. Samples were collected at three days, 18 months, three years and eight years.

Gut microbiota composition in (A–C) children growing up on a farm vs. control children and (D–F) children growing up with pets vs. no pets. Credit: PLOS ONE (2024). DOI: 10.1371/journal.pone.0313078

The researchers found that infants living on a farm had seven times more anaerobes than facultative bacteria compared to infants who did not live on a farm, whether they had a pet or not. They also found that gut biome differences between the two groups shrank as the children aged, but those who lived on a farm as infants had much lower rates of allergies at age 8.

More information: Annika Ljung et al, Gut microbiota markers in early childhood are linked to farm living, pets in household and allergy, PLOS ONE (2024). DOI: 10.1371/journal.pone.0313078

Journal information: PLoS ONE 

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