International Board of Certified Lactation Consultant (IBCLC) Practice Exam

Which nutrient is present in human milk in the highest quantity, although it supplies less of the infant's energy needs?

1. Protein

2. Carbohydrates

3. Lactose

4. Vitamins

The correct answer is: Lactose

Human milk is composed of various nutrients that contribute to an infant's growth and development, with carbohydrates being the most abundant component present in significant quantities. Among the carbohydrates in human milk, lactose is the primary sugar, making up the largest portion. Lactose serves multiple critical functions for infants; it not only provides some energy but also plays a vital role in calcium absorption, which is essential for bone development. However, despite being the most prevalent nutrient in human milk, lactose supplies less energy compared to fats and proteins, which are also present in lower quantities. While proteins and vitamins are crucial for overall health and development, their quantities in milk do not surpass that of carbohydrates. Lactose's presence in high amounts emphasizes its importance, even though it contributes less to the total energy content necessary for infants. This characteristic highlights the unique nutritional composition of human milk tailored specifically to meet an infant's needs.