Should Adults Really Be Drinking Milk? Studying Neolithic Ancestors Suggests Not
Is drinking cow’s milk healthy for humans? Many remember the rush to get to the head of the line for milk at morning recess in elementary school and TV ads showing healthy kids running around the playground accompanied by the message that milk helps build healthy bones. But scientific research now questions if drinking milk is really a good idea. The answer may be found by studying the Neolithic humans who first started to practice dairy-related animal husbandry.
A multidisciplinary team of researchers discovered that until 8,000 years ago only children were able to digest lactose (a form of sugar present in milk); adults could not produce endogenous lactase, the enzyme required to break down lactose.
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Old Egyptian painting showing an early instance of a domesticated animal (the cow being milked). ( Public Domain )
But a genetic mutation occurred before the first farmers settled in Europe - humans began to be able to produce lactase their whole lives. Since then, most adults in Central and Northern Europe have been able to digest milk. It was less than 5000 years ago when this event occurred. Positive selection and recurrent waves of migration likely combined forces to make this happen.
Krishna milking a cow while the calf looks. (Wellcome Images/ CC BY 4.0 )
Anthropologist Professor Joachim Burger of Johannes Gutenberg University Mainz (JGU) explained the ability to digest milk was a genetic adaptation:
"To appreciate the significance of our findings, it is important to realize that a major proportion of present-day central and northern Europeans descend from just a small group of Neolithic farmers who happened to be able to digest fresh milk, even after weaning.”
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Sujatha milking the cow, Mahavehera Temple. ( CC BY SA 4.0 )
Nonetheless, 60% of people living in the world today still lack the enzyme necessary to break down lactose – but many of them don’t know it and suffer from digestive and allergy issues related to milk consumption.
Okay, but we still need to drink milk to have strong bones and prevent osteoporosis, right? Maybe not. Our paleolithic ancestors didn’t drink milk, but they were stronger and more muscular than most people today. There is also no indication suggesting that advanced osteoporosis was a problem for them. This suggests that eating grains and vegetables may be enough to provide the necessary amount of calcium for adults to be healthy.
Apart from humans, no other mammal species continues to drink milk after infancy. A growing body of research suggests we should consider stopping the practice as well.
"The Milkmaid" (1657-1658), painting by the Dutch artist Johannes Vermeer. Rijksmuseum in Amsterdam, Netherlands. ( Public Domain )
Top Image: Detail of ‘A Maid Milking a Cow in a Barn’ (1652-1654) by Gerard ter Borch. Source: Public Domain