IBCLC Exam 2026 – 400 Free Practice Questions to Pass the Exam

Lactose serves as a major osmole in human milk, which is crucial in maintaining osmotic balance within the lactocyte, the milk-producing cell in the mammary gland. As an osmole, lactose attracts water to the lactocyte due to its osmotic properties. This is essential for the secretion of milk since it ensures that the milk has the proper consistency and hydration, which is necessary for effective breastfeeding.

Moreover, the presence of lactose not only contributes to the volume of milk produced but also plays a pivotal role in promoting a healthy gut microbiome in infants. This helps in the digestion and absorption of nutrients, enhancing overall infant health.

While other substances in breast milk contribute to fat, protein, and mineral absorption, their primary roles do not directly relate to the osmotic function that lactose fulfills. Therefore, highlighting lactose as a major osmole in human milk provides a clear understanding of its significance in drawing water into the lactocyte.