When babies eat certain foods early in life—the kinds so many end up allergic to, like eggs and peanuts—they’re less likely to develop allergies to those foods later on, finds a new analysis published in the Journal of the American Medical Association (JAMA).
Increasing attention has focused on the role of timing of introduction of allergenic food into the infant diet and risk of allergic and autoimmune diseases. Infant feeding guidelines have moved away from advising parents to delay the introduction of allergenic food, but most guidelines do not yet advise early feeding of such foods.
In 2000, the American Academy of Pediatrics recommended that allergenic foods be kept away from infants until they were at least a year old, and often older. That warning was especially strong for those with a family history of allergies.
That advice has been amended, and newer evidence has shown that introducing foods earlier is actually better for preventing food allergies. The authors of the just-published study reviewed all of the available evidence on the topic and included 146 studies in their final analysis.
They found evidence of “moderate certainty” that introducing peanuts early, between ages 4 and 11 months, is linked to a reduction in the risk of developing a peanut allergy. Eggs, too, showed this association when they were introduced between ages 4 and 6 months. Early introduction of another common allergen, fish, was also linked to less allergy—possibly due to the anti-inflammatory effects of omega-3s—though evidence for this link wasn’t as certain.
In contrast to egg and peanut allergy, this review found that oral tolerance was not relevant to celiac disease, suggesting that the findings may not be generalizable beyond food allergy mediated by IgE antibodies. Trial sequential analysis of gluten introduction and celiac disease risk found that further trials would not be futile; however, available data show no evidence of an association. Ongoing work is evaluating a potential role for oral tolerance in other autoimmune diseases; for example, the induction of immune tolerance to insulin for preventing type 1 diabetes mellitus.
More research is necessary to figure out the ideal amounts of these allergens, the optimum times of introduction and the reasons behind the link.