Lactose is essential
Lactose is a milk sugar naturally occurring in all milks (including breast milk), that provides fuel and energy to all the cells of the body, and is critical for optimal growth and development. It is made up of two simple sugars: glucose and galactose. Lactose is molecularly identical regardless of the source (goat's milk, cow's milk or breast milk).

Research shows lactose may also contribute to the absorption of calcium, help regulate gut microbiota and support immune function.
What is lactose intolerance?
Lactase is the enzyme responsible for the breakdown of lactose. As we age, lactase may be deficient or lacking altogether. Lactose intolerance is associated with inadequate breakdown and malabsorption of lactose. When this occurs, bacteria in the colon ferment the undigested lactose, leading to digestive discomfort with symptoms such as diarrhea, abdominal pain, gas, and bloating.
Congenital lactose intolerance is rare in young children
While there are rare disorders in which infants are unable to break down lactose in breast milk or formula, most infants produce lactase to digest lactose provided by their mother's breast milk.
Lactose intolerance may be a common problem in older children and adults, but it is uncommon before 2 or 3 years of age.
What else may cause digestive discomfort?