[Medical Q&A] Can babies who are exclusively breastfed also have food allergies?

Author: Zhu Weiwei Peking University Third Hospital

Reviewer: Li Zailing, Chief Physician, Peking University Third Hospital

Babies who are exclusively breastfed can also develop food allergies.

Some babies who are exclusively breastfed will still have allergic symptoms even though they do not consume milk and other foods. This is because repeated stimulation by allergens in the womb or early after birth can delay or inhibit the development of Th1 cells in the infant immune system, leaving Th2 cells in a state of continuous dominance. The imbalance in the development of these two cells can lead to allergies. The mother's serum antibodies may also accidentally pass through the placenta to passively sensitize the fetus, or large molecular food antigens may accidentally pass through the placenta to sensitize the fetus. When the baby ingests the same allergen again after birth, allergic symptoms will occur. This can explain why babies who are exclusively breastfed will have allergic symptoms even though they have not yet accepted foods such as milk and eggs. The mother consumes food during lactation, and the active fragments of some of these foods can be passed to the baby through the mother's milk secretion, causing an immune response. Therefore, it is an important measure for mothers and babies to jointly avoid diets that may cause allergies to reduce the occurrence of allergic symptoms.