Has milk ever won any wars?

Lactose tolerance may have proven advantageous for particular cultures

A great understanding of how our genes evolve and mutate have led some scientists to look at the link between domestic farming and lactose tolerance. Photograph: Getty Images
A great understanding of how our genes evolve and mutate have led some scientists to look at the link between domestic farming and lactose tolerance. Photograph: Getty Images

Spare a thought for evolution, and its impact on what we are able to eat. Our food has been evolving alongside the changes to our environment and how we live, and has even been the catalyst for great change in our civilisation. Richard Wrangham, a renowned primatologist, argued in his 2013 book Catching Fire that it was learning how to cook that made us truly human. He argues that not only did being able to eat cooked food allow our brains to grow but that cooking around a fire provided a social space and a focal point for early communities.

One such evolutionary strain was the emergence of lactose tolerance, and it’s thought that this ability may have even won wars. Anthropologists believe that before the rise of agriculture about 10,000 years ago, humans didn’t really drink milk beyond infancy, and probably didn’t drink the milk of other mammals. In the last 20 years, a great understanding of how our genes evolve and mutate have led some scientists to look at the link between domestic farming and lactose tolerance. There is a theory that this genetic mutation may have proven advantageous for particular cultures.

In their book The 10,000 Year Explosion: How Civilization Accelerated Human Evolution, anthropologists Gregory Cochran and Henry Harpending point to lactose as a possible stepping stone to the success of certain civilizations over others. "The Proto-Indo-Europeans were rather backward in the realms of technology and social complexity," they write in the 2009 book. "Sumerians invented the wheel, writing, and arithmetic and had cities and extensive irrigation systems at a time when the Proto-Indo-Europeans had, at most, domesticated the horse. We suggest that the advantage driving those Indo-European expansions was biological – a high frequency of the European lactose-tolerance mutation."

Genetic mutations

The Evolution Of Us is a two-part Netflix documentary looking for clues in the genome to understand humankind's evolution. "Many genetic mutations affect our ability to digest food and some may have changed the course of history," states the narrator. In the early 13th century the Jin Dynasty boasted perhaps the largest army in the word. In neighbouring Mongolia, Genghis Khan's army would have been tiny by comparison yet they would go on to conquer the Jin Dynasty's giant army. The Mongolian warriors may have had "a secret weapon hidden in their DNA" – their ability to drink large quantities of horse's milk and cheese made them leaner and stronger fighting machines.

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This genetic mutation brought practical advantages, too. Jack Weatherford, author of Genghis Khan and The Making of the Modern World, explains in the documentary that the Mongol army's horses doubled up as transport and food source, giving them a huge advantage over their Chinese neighbours who relied on a diet of carbohydrates which had to be carried around with them. "They may have only had 100,000 soldiers," says Weatherford, "but every soldier was a warrior."