Milk may have fueled a growth spurt thousands of years ago

By Stephen Beech via SWNS

Milk may have fueled a growth spurt in Europe thousands of years ago, suggests a new study.

Scientists say that the evolution of lactose tolerance may explain why people in northern and central Europe increased in size between 7,000 and 4,000 years ago, while people elsewhere - including Britain - stayed the same height or even got smaller.

To examine how human body size has changed, anthropologist Professor Jay Stock and his colleagues collated data from more than 3,500 skeletons from 366 archaeological sites in seven regions stretching back to 30,000 years ago.

They used skeletal measurements to estimate each individual’s height and the size of weight-bearing joints to estimate their weight.

They found that the global mean height for men and women declined from 30,000 years ago onwards, reaching its minimum between 8,000 and 6,000 years ago.

However, in central Europe, stature rose between 7,000 and 4,000 years ago, while in northern Europe, it increased between 8,000 and 2,000 years ago. Similar trends were seen for body mass.

Prof Stock, of Western University in Canada, said: "The earliest evidence of dairy production is from around 9,000 years ago in western Asia, from where it spread around the world, reaching central Europe at least 7,400 years ago."

The research team believes that the "exceptional" growth resulted from those Europeans producing the enzyme lactase into adulthood, which allowed them to gain more nutrition from lactose, a sugar found in milk.

But the study, published in the journal Proceedings of the National Academy of Sciences (PNAS), found that people in Britain got smaller in the same period, despite being early milk drinkers.

Professor Mark Thomas, at University College London (UCL), said: “I see no systematic, numerical analysis to suggest it is much more than a guess that selection was stronger on lactase at this time when we see increases in body mass."