Nutritionists and physicians have started to question milk-drinking, suggesting that many consumers eat far too much dairy. Dr. Michael Klaper has even suggested that milk is just “baby calf growth fluid�, designed to “turn a 65 pound calf into a 400 pound cow�, and that unless you have long ears and a tail, you should never drink the white stuff (https://www.youtube.com/watch?v=toZ7Mr-ClCE).

In other words, Dr. Klaper argues that cow´s milk should be avoided because it was designed as calf food. But his reasoning is absurd reductionism, because most of what humans eat was meant to be something else, not people food. Wheat grains were intended to be seed, not flour. Honey is supposed to tide the hive over the lean season, not to be added to pastry. Fish certainly did not evolve so that people could make sushi.

So why do people eat dairy products?

Before agriculture, all humans were hunters-and-gatherers. They ate meat when they could (but seldom as much as people who get their food from the supermarket). They ate a bit of fat (wild animals can be pretty lean). Fish were part of the diet in many places and so were insects in a few areas where other sources of animal protein were scarce. Honey was occasionally on the menu, but no processed sugar. Some grains were eaten, but not much, because large-seeded grasses were not very common in the wild. The ancestral human diet was mostly fruit, nuts, roots, tubers and vegetables, and no milk.

This began to change about 8500 BC when wheat and a handful of other crops were domesticated in the Near East (Zohary et al. 2012). Studies at the site of Çatal Hüyük, in what is now Turkey, suggest that farmers began to domesticate cattle at that same time. But the transition to agriculture was gradual, and early farmers still hunted; most of their meat still came from the wild. Livestock only began to provide most of the meat for Near Eastern farmers about 7500 BC, around 1000 years after the beginning of animal domestication (Helmer and Vigne 2007). It seems that then as now, farmers were adapting gradually, experimenting as they went.

Daniel Helmer (a specialist in the ancient Near East) and Jean-Denis Vigne (a zoo-archaeologist) suggest that during these early centuries of animal rearing, domestic animals were not kept so much for their meat, but for other products like traction, skin, hair, and manure, but most of all for milk. Archaeological evidence (especially remains of milk residues on pottery sherds) suggests that dairying was established by about 7000 BC in the Near East, and by about 5900-5700 BC in Britain, and in central Europe (Helmer and Vigne 2007).
Over the centuries, ancient farmers selected for cows that gave more milk. The modern dairy cow yields around 40 liters of milk a day during the first month of lactation, far more than the calf can drink. Milking allowed farmers to take food from their livestock every day, without killing the animals. The milk was rich in fat and protein, both of which were scarce in early agricultural diets.

There was one problem with ancient dairying; most people could not digest lactose, the natural sugar in milk. Human babies can digest the lactose in their mothers’ milk, but most lose this ability in adulthood.

Humans managed to eat milk products in two ways. One was to make cheese or other fermented products, where the yeast or lacto-bacteria broke down the lactose. The second way: some peoples evolved a genetic ability to absorb lactose, a trait governed by a single, dominant gene. Anthropologist William Durham asked why people would evolve the ability to digest fresh milk, if they could simply make it into easily digestible cheese. There must be a high adaptive advantage to being able to digest fresh milk, since in some populations, e.g. in Northern Europe, nearly 100% of the population has the genetic ability to digest fresh milk. It turns out that fresh milk is rich in vitamin D, which allows easy absorption of calcium. Durham reasons that this conferred a special advantage on people in cold countries, where they did not always get enough sunlight to synthesize their own vitamin D.

It is also possible that when people had been raising cows for centuries, and milk was abundant, people who could drink fresh milk were better fed than their neighbors, and so the milk-drinking gene spread through the population. That is my guess, but there is no doubt that the modern people who can drink milk are the ones whose ancestors tended cows in ancient Europe, Africa or South Asia.

If your ancestors were not dairying folks, you may be lactose intolerant. If you can drink milk, you can thank your forbearers who herded cows and put milk on the table.

Further reading

Durham, William H. 1991 Coevolution: Genes, Culture and Human Diversity. Stanford: Stanford University Press. Pp. 228-259.

Helmer Daniel and Jean-Denis Vigne 2007 “Was Milk a ‘Secondary Product’ in the Old World Neolithisation Process? Its Role in the Domestication of Cattle, Sheep and Goats.� Anthropozoologica 42(2):9-40.

Zohary, Daniel, Maria Hopf and Ehud Weiss 2012 Domestication of Plants in the Old World: The Origin and Spread of Domesticated Plants in South-west Asia, Europe, and the Mediterranean Basin (Fourth Edition). Oxford: Oxford University Press.

Further viewing

Access Agriculture has a small collection of videos for small-scale dairy farmers.

Pure milk is good milk ; Keeping milk free from antibiotics ;  Managing cattle ticks; Taking milk to the collection center ; Keeping milk clean and fresh ;  Hand milking of dairy cows

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