Milk — whether from a cow, plant, or nut — is often said to do a body good, but would you believe it also may have helped build civilizations?
That’s according to new findings published Wednesday in the journal Science Advances looking at the teeth of ancient humans living on the Tibetan Plateau, also known as the “roof of the world” for being the highest and largest plateau on Earth. The study found that drinking milk — particularly, it seems, from sheep and goat — was a key component of the ancient Tibetan diet dating back at least 3,500 years, likely helping these individuals thrive thousands of meters above sea level where agricultural and other natural resources were extraordinarily scarce.
Was it barley or dairy farming?
Thousands of years ago, as humans traded in their hunter-gatherer lifestyles for more permanent settlements, cultivating a reliable food source with both crop and animal farming was crucial to increasing the life expectancy of our prehistoric ancestors, not to mention boosting population growth.
The first documented instance of dairy farming itself dates back to over 6,000 years ago in Western Asia, where it appears to have spread to on either side of the continent to Europe and Africa and to China, Mongolia, and presumably, the Tibetan Plateau.
This idea that ancient humans of the plateau were guzzling down nutrient-rich milk like the rest of the world has largely been based on historical Chinese records and inferred from ruminant bones or traces of dairy-related foods found in excavations sites — not actual, direct archaeological evidence, Li Tang, the lead author of the new study and a doctoral candidate at the Max Planck Institute for the Science of Human History in Berlin, tells Inverse.
To add to that, a prevailing thought of how ancient Tibetans managed to put down roots in their inhospitable, high-altitude environs has been attributed to barley farming. That’s because barley is a cool-season crop that can tolerate frost and some freezing temperatures, but Tang says most of the evidence for this is based on regions of the Tibetan Plateau below 3,500 meters sea level where it was a bit more arable than higher up.
“Recently, we’ve [developed] advanced farming techniques where we can make hybrid species to make some barley better adapted to the cold or the Tibetan environment,” she says. “But in the past, we didn’t have such techniques to [bolster] high-altitude adaptability… and also farming management techniques like irrigation, those were maybe less advanced than current times, so it was even more challenging for [ancient Tibetans] to farm.”
Ancient tartar reveals all
If barley farming wasn’t what was keeping ancient Tibetans afloat, what was? Tang wanted to see if milk was actually the real MVP. Investigating that required a bit of dental work and some ancient tartar.
Tang and her team, which included archaeologists and scientists from across Europe, the U.S., Australia, and China, looked at teeth collected from past and recent archaeological digs on the Tibetan Plateau. They specifically searched for milk proteins contained in a hard mineral deposit that forms on the teeth when plaque — a sticky film of bacteria and food particles — is left for a prolonged period of time. The minerals in saliva, such as calcium and phosphate, combine with the plaque and harden, forming dental calculus, which can’t be removed without a professional dental cleaning (definitely not a service available to ancient Tibetans).
Using a cutting-edge analysis tool called paleoproteomics that’s been used to reveal long-gone information about ancient diets, including dairy consumption, the researchers examined the dental calculus of 40 individuals collected from 15 sites across the interior of the plateau. The earliest dates back to the late Neolithic period (so around 4,500 to 3,000 years ago), and the latest from the Tibetan Empire around 1,200 years ago.
Tang and her colleagues found milk proteins in the ancient tartar as far back as 3,500 years ago, suggesting that’s when dairy farming was first introduced or picked up practice on the plateau. While it was hard to identify exactly which proteins came from which dairy animal (such as whether cow, yak, or goat) because they all share similar proteins, Tang was able to definitively pin down a Tibetan fondness for sheep and goat milk.
“I actually only found 100 percent [certainty for] sheep and goat milk,” says Tang. “There are several potential milk [proteins] from cow or yak, but I wouldn’t say it’s 100 percent for sure.”
Not only that, the dental calculus from ancient Tibetans living higher up the plateau toward the western and northern steppes 3,700 meters above sea level (even as high as 4,654 meters) had more of these milk proteins than those living below in the southern-central and south-eastern Tibet where there’s plenty more arable land. Tang believes this pattern shows how nutritiously critical milk and milk products like butter, cheese, and yogurt were to the highland Tibetan diet compared to the rest of the region.
This, however, doesn’t conclusively mean ancient Tibetans living at lower elevations didn’t consume dairy. It could have been they were eating more grains like barley or they just didn’t have the means, especially those living in the warmer valleys, to preserve milk compared to their highland relatives.
Tracing the origins of dairy farming
Tang says this is just the beginning of uncovering the role dairy had in the ancient Tibetan lifestyle, and there’s much more research that needs to be done. One avenue she hopes to explore is what kind of livestock these hardy people relied upon. For example, it’s long been recognized that yaks, a mammal native to the Himalayan region of Central Asia that look like a very cute, shaggy mix between a bison and a cow, have long been revered in Tibet, both as a food source and in spiritual practices. Given their place in Tibetan culture and the fact these animals can produce up to half a gallon of milk a day (for reference, dairy cows produce eight to 10 gallons), Tang hopes that with further research and more sensitive tools, she’ll be able more clearly resolve the role yaks and other dairy animals played in ancient Tibetan society.
While 3,500 years ago is the earliest instance of dairy farming Tang and her colleagues uncovered, she’s hoping to go back even farther in history to trace how and which groups were involved in getting milk drinking off the ground into the highlands.
“We see dairy pastoralism as a powerful cultural adaptation that helped ancient Tibetans settle down on the highlands,” she says. “Because without dairy, how could they get access to reliable food resources in order to stay when they were really far away from the villages they could trade with.”
If that’s got you hankering for a glass of milk, better thank the ancient Tibetans.
