As if Breastfeeding Weren't Badass Enough, It Helped Us Survive the Ice Age

From boosting baby’s brain development to supporting a healthy immune system, breast milk is capable of some pretty powerful stuff. But what if we told you it was responsible for keeping the human species from extinction? New research presented in the Proceedings of the National Academy of Sciences suggests breast milk helped our ancestors survive some incredibly adverse conditions.

Specifically, researchers are looking at a gene mutation called EDAR that is still detectable in ancient teeth, manifesting itself as shovel-shaped incisors (your top and bottom front four teeth). This gene, found predominantly in Native Americans and Asians, is also linked to thicker hair shafts and more sweat glands, and most recently, enhanced development in the milk ducts of women’s breasts.

The new study says a variant of the gene, called V370A, was likely carried by a group of people who split off from Asian groups 25,000 years ago and eventually settled in the Americas 15,000 years ago. For the 10,000 years in between, the last Ice Age allowed this group to inhabit a land bridge between Siberia and Alaska. That’s an area that, for much of the year, doesn’t get a lot of sunlight. And the lack of vitamin D exposure should’ve led to problems with bone development, fat regulation and immune system function in babies. (Adults, on the other hand, could get their vitamin D from the animals they hunted.) But it didn’t.

Leslea Hlusko, associate professor of integrative biology at the University of California, Berkeley, thinks breastfeeding is the population-sustaining answer, giving babies the nutrients and fat they were missing out on.

“This highlights the importance of the mother-infant relationship and how essential it has been for human survival,” she says.

Assuming that the spread of the gene mutation is for the sake of improving milk ducts to pass more nutrients to babies, this marks the first evidence of selection due to a maternal-infant bond.

There you have it: Your bond with baby could save the world.

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