Lactose intolerance is generally a condition that affects adults as the normal decline of lactase occurs. Lactase is the enzyme that breaks down lactose and allows the small intestine to absorb it. Babies normally have the highest production of lactase as milk is their primary food. There is a considerable amount of confusion about babies, lactose, and whether babies can experience lactose intolerance.

Human breast milk has the highest content of lactose in the mammalian world so despite the rumor that babies that are breast fed could not be lactose intolerant because they do not get cow’s milk even breast fed baby’s primary food source contains lactose.

Lactose intolerance is unusual in babies but not unheard of. Congenital lactose intolerance is a genetic condition that was known to be fatal before the production of non- milk formulas. Congenital lactose intolerance is very rare, usually diagnosed right after birth and most babies recover quickly from this condition which is characterized by severe diarrhea, vomiting, dehydration, irritability, and failure to thrive. If congenital lactose intolerance is not caught quickly it can result in developmental delays and problems with the liver and kidneys.

The other type of lactose intolerance that a baby may suffer from is secondary lactose intolerance that has been caused by some sort of damage to the intestines or it can be a result of premature birth.  Infections or conditions that cause inflammation such as celiac disease are the most common causes of secondary lactose intolerance. Most often once the primary infection or disease is treated the secondary lactose intolerance will also heal itself.

Sometimes secondary lactose intolerance can be misdiagnosed as congenital lactose intolerance in this case often the lactose intolerance resolves itself by the time the child is six months old and most babies will either be able to tolerate lactose or can tolerate it in small amounts.