A new paper, published in the journal of the American Gastroenterological Association, has found a causal link between cesarean section (C-section) birth, low intestinal microbiota, and peanut allergies in infants.

The study researchers reported the effect is more pronounced in kids of Asian descent than others, according to Science Daily.

Principal investigator Dr. Anita Kozyrskyj of the University of Alberta said, “It’s important to know what predicts or increases the risk of food sensitivities because they predict which infants will go on to develop asthma and other types of allergies.”

The researchers looked at the gut bacteria of more than 1,400 infants and found that babies born through C-section had low levels of Bacteroides, a type of bacteria known to be critical to immune system development, which increased their risk of developing a peanut allergy by age three.

“In this case, we observed that there was an association between Asian ethnicity and peanut sensitivity, and then the mediation analysis provided additional evidence for the causal association with cesarean section,” Dr. Kozyrskyj explained.

“As the gut microbiota are developing so is the gut’s immune system,” she added, “training the gut to react to pathogens and to be tolerant of the food that we require.”

The study investigators reported that babies with food allergies are more likely to develop asthma, eczema, and allergic rhinitis later in life.

Dr. Kozyrskyj said the overall rate of allergies is increasing in western countries and is likely linked to environmental factors, according to Science Daily.

“In China, food allergies are uncommon, but those who immigrate to Canada face a higher risk and more severe form of allergic disease,” she noted. “It’s likely related to a change in diet and environment.” To prevent such association, it is better to avoid C-section birth unless it is medically necessary. Dr. Kozyrskyj, “With this evidence at hand, the parent and the obstetrician might choose a different birth mode.”