The popsci rags like to push a lot of junk science. Apparently this phenomenon has even taken root among white supremacist communities (I guess white supremacy is when you tacitly admit your lactase inferiority to Pakistanis, Arabs, and Black Africans from the Sahel)
Anyway, here are the three main points of interest:
1) Only testing the European alleles. Looking for a lactase allele in Europe, and then extrapolating that to the rest of the world, is a bit like finding the light skin mutation in Japan, and then saying that Germans must be Black because they lack it. Admittedly this has improved a little bit in recent years with the study of African and Arab-specific alleles, but
2) Sampling bias in the tests. Even if you look at the idiotproof lactose digestion blood tests, you’ll see that there is massive sampling bias. For one, non-europeans are atrociously undersampled; I’m counting over 40 samples for Europe and only 4 or 5 for any other equigeographic region. Secondly, even within Europe, the lactose intolerant populations are undersampled. There are plenty of samples in the British isles and central Europe, where tolerance is high; but very few samples in the Balkans, Slavic, and Uralic lands, where tolerance is much lower. This overestimates European lactose tolerance.
3) Lactose tolerance isn’t even a real term in the first place. Japanese people, who are inarguably very unable to digest lactose, are 80-90% lactose tolerant. That’s right, when given 1 to 2 standard glasses of milk, the vast majority of Japanese indicate no ill gastrointestinal effects. If the Japanese are okay with milk, I guarantee that your ethnic group is also, whatever that may be.
The third point is evident from basic nutritional science, which I guess the average person has no knowledge of these days. Sugars that don’t get digested get broken down by bacteria. Sometimes, this can cause gas, usually not, when the individual has a healthy microbiome. 100% of whites are unable to digest cellulose, which is a sugar found in all plant foods. If we used popular logic, all whites should thus become carnivores.
So all ethnic groups are lactose tolerant, but only a few (NW Indians, Arabs, NW Europeans, and various African groups) are lactase persistent. So what exactly is lactase persistence, and why does it matter?
Lactase persistence is important because it allows you to unlock more calories. In standard cow’s milk, lactose contains 33% of the total calories, meaning that an LP person would access 50% more calories than a LNP individual.
Further supporting this is the genetic analysis of over 20 Yamnaya Caspian steppe males. These guys were totally lacking the “Indoeuropean” LP allele, and thus could not digest lactose.
“But wait, couldn’t they have had different unknown LP alleles too?”, you might ask. The answer is no, because Yamnaya people contributed ancestry to modern Europeans. If the Yamnaya had an LP allele, it would have made it into modern Europeans and undergone selection, and we would know about it today. But that didn’t happen.
In the Indoeuropean Yamnaya steppe times, population densities were a lot lower, and thus access to calories was considerably higher; this meant that people were generally less wanting for basic sustenance. This is further supported by the fact that Yamnaya men had some of the tallest genetic height potentials known, taller than modern north Europeans. This indicates that they were not starved for calories.
The evolution of lactose digestion was likely mostly due to starvation conditions. There is also a slight trend of obesity with lactase persistence; the Brits are the most lactose digestive in Europe, and they are also some of the fattest. It makes sense intuitively that a population that would need to digest the smatter of calories in lactose would also evolve thriftier genes to hold onto calories.
Little White Lies 