IBCLC Practice Exam 2025 – Complete Preparation Guide

Lactose is the primary carbohydrate found in human milk and is present in the highest quantity compared to other nutrients. While it plays a crucial role in providing energy for infants, its caloric contribution is less significant than that of fats, which supply the majority of energy. Lactose is essential for the absorption of calcium, magnesium, and phosphorus in the infant's gastrointestinal tract, further underscoring its importance.

In addition to its role as a carbohydrate, lactose serves as a prebiotic, promoting the growth of beneficial bacteria in the gut, which aids in digestion and overall gut health. This function is vital for the development of a healthy microbiome in infants. The balance of nutrients in human milk is carefully calibrated to support infants' growth and development, making lactose a key player despite its lower contribution to immediate energy needs when compared to fats.

Other options, such as protein and vitamins, while important, are present in lesser quantities than lactose in human milk, and carbohydrates as a category include lactose but do not specify its predominant presence. Thus, the focus on lactose in the context of this question highlights its unique position as the most abundant carbohydrate in human milk.