Saturday, October 23

Why does the world’s tallest population seem to be getting smaller? | Anthropology


From brutal conflict to periods of prosperity, from pandemics to triumphs for equality, human history is full of ups and downs. But such fluctuations not only affect society: the human body can also be a sign of the times.

Studies have shown that our height is not just a matter of genetics, it is also influenced by the environment we live in, with key factors including our nutrition and experience of illness, such as diarrhea.

According to analysis of bone remains According to researchers at the University of Oxford, the average height of men in England increased after the Norman Conquest, possibly linked to warmer temperatures, but subsequently fluctuated alongside seed shortages and famines, policies to help the poor and changes in the types of work that people did. and the conditions in which they worked.

In recent decades, height has increased in many countries, but not all. In 2016, researchers from Imperial College London revealed that in the 100 years between 1914 and 2014, South Korean women gained more than 20 cm average height and men and women in the UK increased by around 11 cm. But the Imperial study also suggested that heights in some countries, including the United States, had recently stagnated.

Now, experts from Statistics Netherlands (CBS), a Dutch government institution, have said that while the Netherlands remains the highest country in the world, Dutch women born in 2001 are on average 1.4 cm shorter than those born in 1980, while for men the decrease measures 1 cm. So what is going on here?

Prof Majid Ezzati, President of Global Environmental Health at Imperial College London, he said it would take a few more years to confirm whether the Dutch were actually seeing a downward trend. But he added: “If this [Dutch trend in height] it’s real, it’s almost certainly nutrition. “

Ezzati said the Dutch school milk program was thought to be one of the reasons the population had grown so much in recent decades. But changes in nutrition can go both ways, and food on demand has exploded in recent years. What remains unclear from the Dutch data, says Ezzati, is whether poor nutrition is limited to particular demographics due to lack of access to healthier alternatives, or whether the change is at the population level, reflecting new fashions. and social trends.

While CBS has suggested that migration plays a role in the latest Dutch data, Ezzati said it is unlikely to be a key factor given the scale of the migration to the Netherlands and the size of the height change.

Genetics are also unlikely to be an explanation. Ezzati noted that this was an important factor in determining an individual’s height – for example, tall parents likely have tall offspring, but current data suggest that genes related to height are not restricted to particular populations. What’s more, evolutionary changes would take timescales much longer than a couple of decades to take effect.

Ezzati said it was crucial to address inequalities so that all children could reach their full growth potential. In fact, his team’s work previously found that while boys and girls in the UK have gotten taller in recent decades, the rate of increase was not as great for boys in other wealthy countries, a factor which, according to them, is due to poor access to nutritious food. for those who can’t afford it.

Ezzati suggested that the maximum average height for humans would likely not be reached until the entire population had access to good nutrition, possibly for several generations.

“I suspect that the Dutch have, on average, at least a little bit more ahead,” he added. “[But] if that’s one or two centimeters or five centimeters on average, I don’t know. “


www.theguardian.com

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