International Board of Certified Lactation Consultant (IBCLC) Practice Exam

What are the three most abundant components in human milk, in order?

1. Lactose, proteins, fats

2. Lipids, proteins, HMOs

3. Lactose, lipids, HMOs

4. Proteins, carbohydrates, vitamins

The correct answer is: Lactose, lipids, HMOs

Human milk is a complex and dynamic substance formulated specifically to meet the nutritional needs of infants. The three most abundant components of human milk, in order, are lactose, lipids, and human milk oligosaccharides (HMOs). Lactose is the primary carbohydrate found in human milk, making up about 7% of its composition. It plays a crucial role in energy provision for infants and also aids in the absorption of calcium and other minerals. Lipids are the major source of calories in human milk, comprising about 3.5 to 5% of its content. They are essential for infant growth and development, especially for brain development, as they contain essential fatty acids necessary for neurological functions. Human milk oligosaccharides (HMOs) are a significant component of human milk, representing the third most abundant component. They contribute to the development of a healthy gut microbiome and provide prebiotic benefits, which enhance the growth of beneficial bacteria in the infant’s gut. Understanding these components reinforces their importance in infant health and nutrition, emphasizing how human milk is optimized for an infant's developmental needs. The other answer choices inaccurately prioritize or identify components that do not match the established abundance and roles of key components in human milk.