What is the primary function of lactose in milk?

Lactose, a disaccharide sugar found in milk, primarily serves as a source of energy. When consumed, lactose is broken down by the enzyme lactase into two simpler sugars, glucose and galactose. These sugars can then be metabolized by the body to produce energy. This energy provision is essential for many physiological functions and is particularly important for infants, who rely on milk as their primary source of nutrition.

While lactose does play a role in influencing the flavor of milk and can have some minimal impact on texture, these are not its primary functions. Additionally, lactose does not provide fat—this is primarily the role of milk fats, which contribute to the creaminess and richness of dairy products. Therefore, understanding the energy-providing characteristics of lactose highlights its crucial role in nutrition and physiological energy needs.