Food Allergies Are Influenced by Birth Mode, Ethnicity, Gut Microbiota
Infants born by caesarean section or with low intestinal microbiota are at an increased risk of developing food allergies, according to the results of a recent study. This risk is increased in infants born to mothers of Asian ethnicity.
To explore the associations between infant gut microbiota, method of childbirth, ethnicity, and food sensitivity, the researchers conducted an observational study as well as post hoc analyses. The study included 2844 fecal samples from 1422 full-term infants in Canada. Samples were collected at 3 or 4-months of age, and 1 year.
The fecal microbiota were characterized using 16S rRNA amplicon sequencing to determine developmental trajectories of gut microbiota. Skin prick tests were used at ages 1 year and 3 years to measure atopic sensitization.
The results indicated that birth mode and ethnicity influenced 4 developmental trajectories of gut microbiota. In particular, the trajectory with persistently low Bacteroides abundance and high Enterobacteriaceae/Bacteroidaceae ratio had increased associations of food sensitivity. A deficiency of sphingolipid metabolism and persistent Clostridioides difficile colonization are characteristics of this trajectory.
The increased risk of sensitivity for infants with this trajectory was especially significant for peanut sensitivity, with a 3-fold risk at age 3 years (OR 2.82, 95% CI, 1.13 – 7.01). This peanut sensitivity risk was further increased in infants born with this trajectory to Asian mothers (OR 7.87, 95% CI, 1.13-7.01). Further, the relationship between Asian ethnicity and peanut allergies was mediated by this trajectory.
“This study documented an association between persistently low gut Bacteroides abundance throughout infancy and sensitization to peanut in childhood,” the study authors concluded. “It is the first to show a mediation role for infant gut microbiota in ethnicity associated development of food sensitization.”
Tun HM, Peng Y, Chen B, et al. Ethnicity associations with food sensitivity are mediated by gut microbiota development in the first year of life. Gastroenterology. Published online March 15, 2021. doi: /10.1053/j.gastro.2021.03.016