Milk Monday: Lactose and Evolution

I think it is funny how lactose intolerance is referred to as a “condition”, and that to not have the lactase enzmes required to digest the lactose sugar found in milk is called a “deficiency” in medical circles. In fact, the condition of lactose intolerance has been normal for adult humans for most of our history and is still the case for a large proportion of the global population.

Lactose Intolerance by Region (African countri...

Estimated Lactose Intolerance by Region

Most people on the planet lose their ability to make lactase as they mature and transition from mother’s milk to other foods. However, in the last 5,000-10,000 years in the dairy farming populations of Europe, East Africa and Asia, some real live evolution has gone on, as noted by professor Jonathan K. Pritchard in this month’s edition of Scientific American magazine. These populations appear to have bred more selectively in favour of a gene that has no built in lactase timer, allowing most adults to go on consuming milk for the rest of their lives.

However, if you suffer from this “digestive disorder” which can cause symptoms such as bloating, nausea and gas after consuming dairy products (remember Meg Ryan in French Kiss?) take comfort from the fact that you share it with most humans past, present and (hopefully) future on this planet. A lot of people actually experience mild lactose intolerance but tend to ignore and become innured to the uncomfortable feeling they get from dairy – testimony to the fact that we are quite used to experiencing wind, bloating and indigestion from our diets and think nothing of it.


How We Are Evolving –  in Scientific American (subscription required to view full article)


One Response

  1. Interesting. So, I’m normal. I like that. Thanks mate.

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