Developmental Deficiency and Age
Some babies that are born prematurely, may suffer a condition known as developmental lactase deficiency. It is when the babies have temporary lactose intolerance because their small intestine hadn’t fully developed at the time of birth.
The symptoms include flatulence and loose stools, which usually improve as the babies get older.
Some persons have adequate levels of lactase in their bodies all through childhood, only to develop a deficiency during adulthood. Studies have shown that lactase production reduces as you get older without any underlying condition to trigger it.