Newborn babies are prone to allergic reactions by physical contact to various allergy-triggering substances, especially those present in different foods and specific infant formulas; therefore, breastfeeding is openly recommended to avoid allergic reactions; however, good literature is not current to support this hypothesis. Researchers conducted this study to perform a nonsystematic review of the literature on breastfeeding as a primary prevention tool for allergic diseases.

Human milk contains vast amounts of biologically active components that significantly impact the development of the gut microbiota. Exclusively breastfed infants show a different microbiota, with a predominance of Bifidobacterium species in their intestines.

The mechanisms underlying the antiallergic effects of human milk are most probably complex, as human milk contains not only nutritional substances but also functional molecules including polysaccharides, cytokines, proteins, and other components which can produce an epigenetic modulation of the innate and adaptive immune responses of the infant in very early life.

Currently, there is not sufficiently substantial evidence to guarantee its effectiveness in allergy prevention. Therefore the leading international scientific societies still do not count it among the recognized primary prevention strategies of allergy.

Reference: https://journals.lww.com/co-allergy/Abstract/2021/04000/Allergy_prevention_through_breastfeeding.18.aspx