Childhood Food Allergies and the Role of Early Diet

Food allergies are a growing food safety and public health concern that affect an estimated 8% of children in the United States . . . Although the immune system normally protects people from germs, in people with food allergies, the immune system mistakenly responds to food as if it were harmful.

Centers for Disease Control and Prevention, (2022)

Food allergies are immunologic reactions in response to certain foods. Food allergies generally involve immunoglobulin E (IgE), an antibody that plays a central role in allergy sensitization and atopic disorders such as allergic rhinitis, asthma and atopic dermatitis. These conditions are hypersensitivity reactions of IgE and other immune cells to an allergen that produce the clinical symptoms seen in those disorders, such as congestion, sore throat, and itchy eyes or skin.

“A food allergy can happen at any age but occurs most often in infants and children younger than 6 years,” according to the American Academy of Pediatrics (AAP, 2021). Some studies show that the incidence of childhood food allergy reported by parents is greater than the incidence of confirmed food allergy, perhaps in part because of confusion about what defines a food allergy and actual symptoms. This discrepancy suggests a need for pediatricians and other primary care clinicians to provide parents and caregivers with timely and accurate information about food allergies and to obtain accurate diagnoses. Such efforts could prevent unnecessary restriction of an infant’s diet. Unneeded food restrictions may result in inadequate nutrition during an important period of childhood growth and development.

Infants with at least one parent or sibling diagnosed with allergies are more likely to have atopic disease and develop food allergies.

Prevention of food allergies is key because, at present, there is no cure once food allergies develop. After a food allergy develops, avoiding the food that triggers a reaction is the only way to safely avoid symptoms.

It is possible for almost any food to cause an allergic reaction, but the following foods are associated with up to 90 percent of allergic reactions:

• Cow’s milk
• Eggs
• Fish
• Peanuts
• Shellfish
• Soy
• Tree nuts
• Wheat

Current evidence does not indicate that maternal dietary restrictions during pregnancy or lactation help prevent development of food allergies in the child, according to a 2019 AAP clinical report about atopic disease.

The role of breastfeeding in either preventing or delaying the onset of specific food allergies is not clear. “It has been suggested that the early introduction of allergenic foods while breastfeeding might be protective against development of food allergy” (Ibid.).

While the AAP previously recommended delaying the introduction of certain foods to children at high risk for developing food allergies, the 2019 AAP clinical report about early nutrition and atopic disease noted that there is no evidence that delaying the introduction of highly allergenic foods such as peanuts, eggs and fish beyond age 4 to 6 months prevents atopic disease. In fact, recent evidence shows that early introduction of allergenic foods may prevent allergies. Guidelines for this early introduction are covered in the tab Recommendations for Introducing Highly Allergenic Foods.