Scientists say that the answer to the enigma of why humans are getting taller and reaching puberty at an earlier age may lie in a receptor in the brain.
Average height in the UK increased to centimeters during the 20th century, and until 20 in other countries , as nutritional health improved.
But the exact mechanism by which this happened was not known.
The new discovery could lead to the development of substances to improve muscle mass and treatments against growth delays, according to a group of British researchers.
Scientists have long known that people with adequate diets and sufficient and stable access to food grow larger and mature more quickly.
South Korea, for example, has seen the height of its inhabitants skyrocket to me As the country went from being a backward society to a developed one. There are still places in Africa and South Asia where people are only slightly taller than they are 100 years.
“Make a lot of children”
It is known that food signals reach the hypothalamus, a part of the brain, informing the body about its nutritional health and triggering growth.
A new study published in the journal Nature, led by researchers from the University of Cambridge, together with teams from Queen Mary University of London, the University of Bristol, the University of Michigan and Vanderbilt University, sheds light on the brain receptor behind this process.
It has been called MC3R and it is en the crucial link between food and sexual development and growth.
“It tells the body that we are fine, that we have lots of food , so ‘have puberty soon and make a lot of babies,’ ”explains Professor Stephen O’Rahilly of the University of Cambridge and one of the study’s authors.
“It’s not just magic; we have the complete wiring diagram of how this happens. ”
Scientists found that when brain receptors do not function normally, people tend to be shorter and have a later onset of puberty.
The team studied the genetic design of half a million volunteers registered in the UK Biobank, a huge database of genetic and health information, to confirm their hypothesis.
The children who showed genetic mutations that altered the functioning of the brain receptor were all shorter and weighed less than the other minors studied, which reveals that the effects of the action of the receptor begin in the first years of life.
The researchers found a person who had mutations in both copies of the gene MC3R, which is extremely rare and harmful. This person was very short and did not begin puberty until after 20 years.
Drugs for the future
But the Humans are no exception in this. The experts studied mice and found that a similar mechanism operates in animals.
This discovery could benefit children with severe delays in their growth and those weakened by chronic diseases who need to develop their muscles.
“Future research should study whether drugs that activate MC3R could help redirect calories to muscles and other non-fat tissues to improve physical functionality in these patients,” says Professor O’Rahilly.
Scientists have already identified another brain receptor that controls appetite, called MC4R, and those who lack it are often obese.
How far can people grow?
There is a ceiling for growth and it is reached when people reach their genetic potential.
Factors such as diet and health have a huge impact on if that happens.
When children from families with fewer resources receive enough food and calories can grow to the height they inherited from their parents and grandparents.
Taller people generally live longer and are less likely to suffer from heart problems . Statistics show that they also tend to have higher income.
Humans cannot keep growing forever.
As in many other European countries, the average height of the population has skyrocketed in the UK in the last century, but there are indications that in the last 10 years has slowed.
The largest increases in height in the last century were recorded among women South Koreans and Iranian men.
The tallest people in the world are men born in the Netherlands, (1, 82 m.). At the other extreme are women born in Guatemala (1, 40).
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