If the lactose intolerance is common for the vast majority of people of non-European descent, then why is milk drinking so common in certain African and Asian cultures?

Question

A lot of pasotoralkst and hisforically pastoralist peoples like the Maasai, Mongolians, Tibetans have a prominent milk drinking culture that existed before European influence. How’d groups like these get by for so long if lactose intolerance is so universal.

In: 23

Answer 1

Lactose intolerance is only an issue in infants who cannot digest breast milk. Mammals including humans lose the ability to produce lactase to digest milk around the time of weening. That changed when humans domesticated animals. Humans with persistent lactase production could continue feeding on a unique, highly nutrient dense food source. This advantaged those traits in reproduction over thousands of years, allowing those with persistent lactase to survive and reproduce in some environments to the point it became part of that ethnic background.