International Board of Certified Lactation Consultant (IBCLC) Practice Exam

What role does secretory IgA play in human milk?

1. Promotes digestion

2. Coats mucosal surfaces

3. Enhances fat absorption

4. Regulates hormones

The correct answer is: Coats mucosal surfaces

Secretory immunoglobulin A (IgA) plays a crucial role in enhancing the immune function of human milk. Its primary function is to coat mucosal surfaces in the infant’s gastrointestinal tract and respiratory system. This coating action helps to prevent the binding of pathogens, such as bacteria and viruses, to these surfaces, thereby reducing the risk of infections. By forming a protective barrier, secretory IgA contributes to the infant's immune defense, particularly during the early months of life when their immune system is still developing. While other components of human milk do support digestion, fat absorption, and even have hormonal influences, secretory IgA's specific role in mucosal coating is vital for infant immunity. This protective function emphasizes the importance of breastfeeding, as it provides infants with crucial antibodies that help both in the prevention of illness and the establishment of their immune systems.