• Ephera@lemmy.mlEnglish
    5·
    4 months ago

    Yes, except that you don’t gain tolerance simply from continuing to drink milk. It’s a regional evolutionary change from many generations continuing to drink milk and the majority of adults across the globe are actually lactose intolerant.

    Worldwide, around 65% of adults are affected by lactose malabsorption. Other mammals usually lose the ability to digest lactose after weaning. Lactose intolerance is the ancestral state of all humans before the recent evolution of lactase persistence in some populations, which extends lactose tolerance into adulthood.

    (Lactase is the enzyme for breaking down lactose.)

    Map showing "An estimate of the percentage of adults that can digest lactose in the indigenous population of the Old World". Europe and parts of Africa as well as the Middle East have higher percentages of tolerance. Asia and Australia are largely intolerant.

    https://en.wikipedia.org/wiki/Lactose_intolerance

    • Panini@lemmy.blahaj.zoneEnglish
      1·
      4 months ago

      I’m surprised the middle east doesn’t have a higher concentration of lactase producers. I was under the impression that’s where the Aurochs was first domesticated into cattle.

      • Ephera@lemmy.mlEnglish
        2·
        4 months ago

        Wikipedia has a decent summary in the History section here: https://en.wikipedia.org/wiki/Milk#History

        Key points, if I’m understanding things correctly:

        • Early domestication was for meat, leather and draft animals, not for milk.
        • Milk consumption started in South West Asia and later stuck around in Europe, because people there had already settled for agriculture. I think, Middle East was more nomadic?
        • The Middle East also had camels as an alternative milk source, and camel milk contains somewhat less lactose (4.6% vs. 3.5–4.5%), according to this: https://pmc.ncbi.nlm.nih.gov/articles/PMC8117040/
          So that might’ve also affected things somewhat? 🫠