New Research Shows Why Humans Developed the Ability to Drink Milk

Hi, it’s Naomi in Berlin. When I was a suburban American kid in the 1980s, my mom used to buy milk five gallons at a time. New research this week had some surprising insights about what we had in common with our Stone Age ancestors. But before we get to that...

Thousands of years ago, a genetic mutation spread across Europe to allow humans to absorb the sugar in milk. Babies have a gut enzyme called lactase that breaks down that sugar, called lactose. But without the mutation, humans lose the ability to make lactase and take in lactose after they’re weaned.