Mankind did not tolerate lactose: scientists figured out how and why people learned to digest it


    Humanity was lactose intolerant: scientists figured out how and why people learned to digest it

    If evolution had not intervened in human development, then our future would not be so bright.

    Scientists from the University of Bristol and University College London believe that people began to better tolerate lactose much later than they began to drink milk. This is due to periods of famine and the spread of disease, and if this quality had not developed in humans, then it would be very difficult for our species to survive, writes the Daily Mail.

    People began to domesticate animals and consume their milk for about 10 thousand years back. At that time, all people could not digest lactose, the sugar that is found in milk and dairy products.

    Lactose and lactase

    The enzyme that breaks down lactose is called lactase, and it is produced in the small intestine during fetal development in the womb. The born person stopped digesting lactose immediately after the breastfeeding of the child stopped, because lactase ceased to be produced. Thus, lactose entered the large intestine and lactose intolerance appeared, which caused diarrhea, bloating, flatulence, and even convulsions. Similar troubles can appear in modern people who cannot digest lactose.

    Humanity was lactose intolerant: scientists figured out how and why people learned to digest it

    Lactase persistence

    But some people have a gene that contributes to the continued production of lactase even in adults. This genetic variant is called lactase persistence (PL).

    Previously, scientists believed that the prevalence of PL increased in people after they began to regularly consume milk. It was believed that this gene was passed on to many people from generation to generation as a result of evolution.

    But a new study has shown that before the massive spread of the PL gene, people had been actively drinking milk for thousands of years. The results of the analysis of milk fat residues on earthenware of ancient people showed that people drank milk already 9 thousand years ago, but in different regions of the planet the level of its consumption was different.

    Humanity was lactose intolerant: scientists found , how and why people learned to digest it

    When did people start digesting lactose?

    As a result of studying the DNA of ancient people, scientists found that the PL gene began its active spread among people about 5 thousand years ago.

    As factors that influenced the development of people's ability to tolerate lactose, scientists named hunger and illness. Lactose intolerance could be fatal to a person during periods of crop failure and the development of diseases that provoked lactose intolerance.

    People who began to develop the PL gene were more likely to survive than those who remained lactose intolerant.

    “In lean years, people ate more milk and dairy products, which led to terrible consequences. So evolution took matters into its own hands and lactose intolerance became more common, which was passed on to the next generations. In this way, people could suffer less from diseases that provoked lactase deficiency and survived more often,” says George Davey Smith of the University of Bristol.

    Humanity was lactose intolerant: scientists figured out how and why people learned to digest it

    Lactose intolerance

    According to scientists, milk is an extremely useful product for the body, which is still recommended for use if there are no contraindications.

    Focus already wrote that scientists have found out how herpes spread on Earth With. An important role in this process was played by the mass migration of people and kisses.


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