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Our ancestors also had lactose intolerance but they didn’t milk it, scientists say

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Intolerance to lactose is nothing new, scientists say. Picture posed

Intolerance to lactose is nothing new, scientists say. Picture posed

Intolerance to lactose is nothing new, scientists say. Picture posed

A flat white with soy or oat milk has become a common coffee order among millennials, with many citing lactose intolerance for their dairy avoidance.

But a study shows that lactose-intolerant people have been drinking milk for more than 9,000 years without significant health issues.

Scientists say the inability to digest lactose posed few problems to ancient people in good health, simply causing some minor discomfort.

Researchers from University College London (UCL) and the University of Bristol suggest the ability to tolerate milk developed in healthy people who survived famine and disease.

“It’s probably the most strongly selected single gene trait to have evolved in Europeans and also in many African and Middle Eastern and southern Asian populations over the last 10,000 years,” UCL Prof Mark Thomas said in the journal Nature.

Scientists gathered historical data on how much milk was drunk around the world at various times and compared this to when the lactase gene was common.  

They found there was no link between the two, confirming that drinking milk and being able to digest lactose was of no evolutionary benefit. 

However, the evidence did show that during times of famine and disease the intolerance could prove fatal because severe symptoms caused deadly dehydration and other problems.

It was during these periods that the prevalence of the lactase gene shot up.

The lactase gene was 689 times more likely to be found in a person during times of famine, and 284 times more likely in times of disease.

“If you are healthy and lactase non-persistent, and you drink lots of milk, you may experience some discomfort, but you not going to die of it,” Prof George Davey Smith of Bristol University said. But “ if you are severely malnourished and have diarrhoea, then you’ve got life-threatening problems”.

(© Telegraph Media Group Ltd 2022)

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Telegraph Media Group Limited [2022]


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