[apotheosis]

Children create lactase to process milk (lactose) until around puberty, then they stop creating it. I learned in college that studies have shown that a lot of people of Northern European descent continue to create lactase into adulthood, and thus can continue to break down milk and cheeses without issue.

There is still a percentage of non-European population that can consume lactose into adulthood, and not break it down without any external symptoms.

[braindeath]

There are plenty of non-Europeans that can digest lactose. Think middle-easterners and Mediterraneans and their consumption of sheep and goat milk. Central and East africans too. The trait has incomplete (variable) penetrance.

Lactose tolerance is estimated at 30-45 percent.. So it's a substantial non-European population. The intolerance is heavily skewed toward East and South Asia -- though a lot of South Asians consume milk and paneer.