Popular Science - USA (2020 - Spring)

intolerant. Yet, in the frost-free summer

months, she believes they may be getting up

to half their calories from milk products.

Scientists once thought dairying and the

ability to drink milk went hand in hand.

What she found in Mongolia has pushed

Warinner to posit a new explanation. On her

visit to Khatgal, she says, the answer was all

around her, even if she couldn’t see it.

Sitting, transfixed, in homes made from

wool, leather, and wood, she was struck

by the contrast with the plastic and steel

kitchens she was familiar with in the US

and Europe. Mongolians are surrounded

by microscopic organisms: the bacteria

that ferment the milk into their assorted

foodstuffs, the microbes in their guts and

on the dairy-soaked felt of their yurts. The

way these invisible

creatures interact with

each other, with the en-

vironment, and with

our bodies creates a

dynamic ecosystem.

That’s not unique. Everyone lives with a billions-

strong universe of microbes in, on, and around

them. Several pounds’ worth thrive in our guts

alone. Researchers have dubbed this wee world the

micro biome and are just beginning to understand

the role it plays in our health.

Some of these colonies, though, are more diverse

than others: Warinner is still working on sam-

pling the Khatgal herders’ microbiomes, but

another team has already gathered evidence that

the Mongolian bacterial makeup differs from

those found in more-industrial areas of the world.

Charting the ecosystem they are a part of might

someday help explain why the population is able to

eat so much dairy— and offer clues to help people

everywhere who are lactose intolerant.

Warinner argues that a better understanding of the

complex microbial universe inhabiting every Mon-

golian yurt could also provide insight into a problem

that goes far beyond helping folks eat more brie. As

communities around the world abandon traditional

lifestyles, so-called diseases of civilization, like demen-

tia, diabetes, and food intolerances, are on the rise.

Warinner is convinced that the Mongolian affinity

Mongolians

subsist on a

dairy-heavy diet,

even though

most are lactose

intolerant.

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IN SEARCH OF THE MISSING MICROBE