Humans were drinking milk before they could digest it

Study of ancient Africans suggests dairy consumption predated evolution of lactase persistence genes

Our history with milk presents a chicken-or-egg conundrum: Humans couldn’t digest the beverage before they evolved mutations that helped them do so, yet they had to already be consuming milk to change their DNA. “There’s always been the question of which came first,” says University of Pennsylvania geneticist Sarah Tishkoff. “The cultural practice or the mutation.”

Now, scientists have found some of the oldest evidence yet for dairy drinking: People in modern Kenya and Sudan were ingesting milk products beginning at least 6000 years ago. That’s before humans evolved the “milk gene,” suggesting we were drinking the liquid before we had the genetic tools to properly digest it.

All humans can digest milk in infancy. But the ability to do so as an adult developed fairly recently, likely in the past 6000 years. A handful of mutations allows adults to produce the enzyme lactase, which can break down the milk sugar lactose. Genes that enable what’s called lactase persistence are widespread in modern Africa, which has four known lactase persistence mutations. (European populations rely on just one.)

When these lactase mutations evolved, they spread rapidly—evidence that people who carried them had a big advantage. “It’s one of the strongest signals of natural selection ever observed,” says Tishkoff, who was not involved with the study.

To peer into our milk-drinking past, researchers turned to Africa, where societies have herded domesticated cows, sheep, and goats for at least 8000 years. The scientists examined eight skeletons excavated in Sudan and Kenya, which were between 2000 and 6000 years old. They scraped hardened dental calculus from their teeth and looked for known milk-specific proteins trapped inside.

The findings revealed these people were consuming some sort of dairy product at least 6000 years ago, the team reports today in Nature Communications. That makes this the earliest known direct evidence for dairy consumption in Africa, and perhaps the world.

The research also shows dairying in Africa goes back just as far as it does in Europe—perhaps longer. That undercuts a myth, propagated by white supremacists, that lactase persistence and milk drinking are somehow associated with white Europeans.

What’s more, ancient Africans don’t appear to have evolved any milk digesting genes, according to a study of some of their skeletal DNA published in 2020. “It looks like the community was drinking milk before they had lactase persistence,” says Madeleine Bleasdale, a co-author of the new work and a specialist in ancient proteins at the Max Planck Institute for the Science of Human History.

The proteins could have come from milk, cheese, or fermented milk products like yogurt, which are common in Africa today. Fermentation is a strategy some cultures use to break down milk sugars before [ … ]

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enjoin
1 month ago

It is not your imagination: dairy IS addictive to the brain.

“Cheese contains casein, a dairy protein that releases casomorphins, which are plant compounds that trigger dopamine production in your brain. This makes cheese mildly addictive.”

https://www.healthline.com/nutrition/is-cheese-addictive#:~:text=Cheese%20contains%20casein%2C%20a%20dairy,This%20makes%20cheese%20mildly%20addictive.

efferent
1 month ago

I never quite understood how adults can “lose” the ability to digest dairy. If it is available to babies … why does it go away?

bolide
1 month ago

Makes complete sense to me. Dairy is extremely yummy and addictive. As an adult, it doesn’t like me and my intestinal tract but that doesn’t stop me from downing it … with lactaid.

turnkey
1 month ago

I can’t believe they managed to insert “white supremacy” into this information. It’s like a sickness … everything must be white supremacist. For shame!

Toni
1 month ago

The first person who would have found milk must have been very thirsty. just saying.

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