Coffee with milk?

You may have heard the following comment: "Why do you drink milk? What are you? A calf?” To those of us who love cows for their meat, milk, and derivatives such as cheese, butter and yogurt, the remark upsets us a little, because our black coffee is delicious, but with milk, we find it even better. Another comment that makes any scientist cringe in disbelief is "the human being hasn't changed in the last 10,000 years." We affirm that we can drink milk without this being an aberration and that in fact, our genes have changed in many ways, although here we will only mention one. 

First, let's go back to our 400th great-great-grandfather, that is, 400 generations ago or 10,000 years. If we could meet this character we would find a shepherd who has just arrived at a wild Europe, possibly to the territory that today is Poland, carrying his flock of sheep, goats or perhaps cows. His wife or mother knows that the milk is indigestible to all but young children. However, they have learned to make cheese and yogurt. These contain less lactose than liquid milk and can be used by the whole family. How did they learn it? We always affirm that history is not linear, and the discovery possibly occurred in several places, at different times and by hundreds of people. The human being has always been very sharp-eyed and diligent, especially in relation to food because their life goes on in it. It is possible that someone inadvertently left milk in a clay container and the milk got fermented, or sour, or who knows what else happened, but the combination of hunger and intelligence showed that person that it was edible. And unlike pure milk, it did not cause diarrhea.

Of course, 10,000 years ago nobody knew about lactase, lactose or why a child could drink milk but when grown up it produced diarrhea to the same person. Lactose is a disaccharide (a type of sugar) contained in milk that the enzyme called lactase allows to digest. However, the gene that controls lactase deactivates its production when the child grows. But, about 7,500 years ago, or with our great-great-grandfather No.300 (note that 100 great-grandparents have passed), there was an explosive appearance of a mutation that made lactase to be produced throughout life. Now an adult can drink milk and not spend the night outdoors (we doubt that our great-great-grandfather 300 had a toilet).

This mutation gave a significant advantage to shepherd tribes over hunter-gatherer tribes. In winter, when the harvests were bad or in periods of famine, you could survive daily with milk and cheese, while the cow or goat barbecue would only last a couple of days. In addition, you can store cheese for long periods of time and nothing is more delicious than a well matured cheese. This mutation is found mainly in Europe, West Africa, the Middle East and India. In America, lactose itolerance depends on your origin. The majority of Native Americans, Asian and African Americans are lactose intolerant, while the descendants of Europeans are less prone to have this condition.

In summary, drinking milk and its derivatives until adulthood is due to a highly beneficial mutation. Unless you are lactose intolerant, you do not have to deprive yourself of milk. Today we can use substitutes, but for our great-great-grandfather 300 and his family, it could be a matter of life or death. Unfortunately, it would be several centuries before they could have enjoyed milk with their coffee.