A large analysis has found that the risk of food allergies in children isn’t tied to a single cause, but rather a combination of factors present early in life, even during the first year.
Researchers at McMaster University in Canada analyzed data from nearly 2.8 million children worldwide and determined that approximately 5% will develop a food allergy by age six. Understanding these early-life factors is crucial for developing preventative strategies and improving child health outcomes.
The research, published in JAMA Pediatrics, involved a systematic review and meta-analysis of 190 studies on food allergies in children.
The authors evaluated over 340 potential factors that could influence allergy risk. The primary conclusion is that allergies aren’t solely explained by genetic predisposition, but result from the interplay between heredity, skin health, the microbiome and environmental exposures.
Eczema appearing in the first year of life was identified as a significant risk factor. Infants with eczema were found to be three to four times more likely to develop food allergies.
The presence of wheezing or nasal allergies was also associated with a higher risk.
Family history also plays a role: children with parents or siblings who have allergies are more likely to develop food allergies, especially when both parents are allergic, according to a report on the university’s website.
The timing of introducing potentially allergenic foods into a child’s diet is also relevant. The study showed that delaying the introduction of foods like peanuts, tree nuts, or eggs could increase allergy risk. Children exposed to peanuts after 12 months of age had more than double the risk of developing a peanut allergy.
Antibiotic leverage in early infancy was identified as another factor associated with increased risk. Antibiotic administration in the first month of life was linked to a higher probability of food allergies. Antibiotic use later in childhood or during pregnancy was associated with an increased risk, but to a lesser extent than exposure within the first month after birth.
What Doesn’t Influence a Child’s Food Allergy Risk
The analysis did not locate an association between food allergies and several commonly cited factors, including low birth weight, post-term birth, partial breastfeeding (mixed feeding), maternal diet, or stress during pregnancy.
