What is the primary carbohydrate found in breast milk and commercial infant formulas?

The primary carbohydrate found in breast milk and commercial infant formulas is lactose. Lactose is a disaccharide composed of glucose and galactose, and it plays an essential role in the nutrition and growth of infants. It not only provides energy but also aids in the absorption of calcium, promoting the development of healthy bones and teeth. The presence of lactose in breast milk contributes to the sweet flavor that infants generally prefer, encouraging them to feed.

Additionally, lactose supports the growth of beneficial gut bacteria, which is crucial for the development of a healthy microbiome. This is one of the reasons why breast milk is often recommended over formulas for infants. While other carbohydrates like glucose and fructose are found in various foods, they do not serve as the primary carbohydrate in either breast milk or infant formulas, and sucrose is not naturally present in significant amounts in breast milk, making lactose the correct choice for this question.