As others have mentioned, most Asian people are lactose intolerant. From a western perspective this seems odd, but is actually the “normal” human condition. Everything that follows is from Marvin Harris’s book Our Kind, which I’m trying to simplify into ELI5 style.
Lactose is the sugar in milk. Your body can’t use lactose, and has to break it down into simpler sugars. This is done by the enzyme lactase. “Naturally” mammals produce lactase while they are nursing from their mothers, but then stop producing it as they grow older because “naturally” they won’t ever consume milk again.
I say “naturally” and “normal” because humans are different, we developed agriculture and domesticated other animals. This takes us out of the natural cycle a bit, allows us to do things our biology wasn’t really intended for. However, natural selection still applies – if we do something that increases our survival rate and success at reproducing, that trait will be selected and pass on to the next generation, propagate and become “normal”. These traits can be genetic (genes, like being strong or fast) or cultural (memes, like wearing makeup).
When we started domesticating milk-producing animals such as goats or cows, we gained the option to consume milk as adults. Our natural state does not allow us to do that, but some individuals would be different and possess a mutation wherein they would continue producing lactase as adults, allowing them to consume milk. In some cultures that trait was very valuable, resulting in increased survival and reproduction, thus the trait became very common and eventually the “normal”. In other cultures the trait had no net gain and therefore does not propagate, and so not the “normal”.
So what’s the difference in the cultures? What makes adult lactase production a big win for those of Northern European descent, but pretty worthless for East Asians? It has to do with geography and available sources of calcium and vitamin D.
You need calcium in your diet. You can get that calcium a few different ways – milk being one, leafy green vegetables being another. To make use of calcium your body also needs either vitamin D or lactose. You can get vitamin D from seafood, or your body can make it when exposed to sunlight. Without vitamin D, lactose assists with the use of calcium. So, cultures with easy access to leafy greens plus sunlight or fish, calcium is taken care of and milk has no advantage. Cultures without access to leafy greens – or without access to sunlight or seafood – need dairy either as a source of calcium, or a source of lactose to use the calcium, or both.
This leads to the difference between dairy that’s fermented (yogurt or most cheese) or unfermented (straight up milk). Fermented dairy products still have the calcium, but the lactose is broken down into simpler sugars, so lactase is not necessary to digest it. Therefore a culture with access to fish or sunlight but not leafy greens would benefit greatly from keeping dairy animals, but don’t benefit from still creating lactase as adults – they consume the milk as yogurt or cheese to get all the calcium they need and make use of that calcium thanks to vitamin D.
So now finally, enter the Northern Europeans – the people that would eventually become western society as we know it today – developed in a climate that required them to bundle up most of the time due to extreme cold, so no sunlight to make vitamin D. They also had very little seafood in their diets at the time (~12,000 years ago), and limited access to leafy green vegetables. Calcium and vitamin D are lacking. So, those individuals who possessed the ability to consume unfermented dairy as adults had an advantage. They survived and bred more frequently, thus passing the trait on and making it “normal”. Within 5000 years after the domestication of dairy animals, 90% of northern Europeans possessed the ability to produce lactase into adulthood and dairy of all types was commonplace.
Meanwhile let’s consider China ~12,000 years ago. Leafy greens were a major part of the diet, so calcium is not an issue. Those in coastal areas developed fishing techniques much earlier than Europeans, as well as a trade infrastructure to transport that seafood pretty far into the mainland, so vitamin D is not an issue. Thus no advantage to unfermented dairy consumption among the bulk of Chinese. Only those far inland and to the north would have an issue – those peoples who became the Mongols, who did consume dairy. Furthermore even fermented dairy never took hold in Chinese culture because of their trade networks – the Chinese were able to obtain their labor animals from other cultures (tibetans, mongols, etc) – therefore did not breed their own cows or goats. Pigs were the primary meat animal raised. With no need for dairy, and without really having it around in the first place, they developed into a culture with virtually zero dairy of any type. And much like the Northern Europeans went on to culturally dominate western civilization, Chinese culture influenced many others in Asia.
So… in summary (TL;DR): Dairy consumption has 2 extremes produced by geography and available diets: Lots of dairy including raw milk driven by Northern Europeans, and virtually zero dairy of any kind driven by the Chinese. Between those extremes are everybody else, who for the most part made use of fermented dairy for its calcium, but remain lactose intolerant.
When Martin Cohn passed through airport security at Ronald Reagan Airport, he figured that he’d probably get some questions about the 3-D-printed model of a mouse penis in his bag.
The model is 15 centimeters long, made of clear translucent plastic, and indisputably phallic— like the dismembered member of some monstrous, transparent, 11-foot rodent. One of Cohn’s colleagues had already been questioned about it when she carried it on an outward flight from Gainesville to Washington D.C. She put it through the security scanner, and the bag got pulled. A TSA official looked inside, winked at her, and let her go. She was amused but embarrassed, so Cohn offered to take the model home on the return flight.
Once again, the bag was pulled. A TSA officer asked if Cohn had anything sharp or fragile inside. Yes, he said, some 3-D-printed anatomical models. They’re pretty fragile. The officer pulled out two models of mouse embryos, nodded to herself, and moved on. “And then,” Cohn recalls, “she pulled out this mouse penis by its base, like it was Excalibur.”
What is this?
“Do you need to know or do you want to know?” said Cohn.
I’m curious, she replied.
“It’s a 3-D print-out of an adult mouse penis.”
“A 3-D print-out of an adult mouse penis.”
Oh no it isn’t.
The officer called over three of her colleagues and asked them to guess what it is. No one said anything, so Cohn told them. They fell apart laughing.
“Technically it’s not even my dolphin vagina mold. I was carrying it for someone.”
Continue at the Atlantic