On lactose intolerance and Asians
I kind of hate that term, because most mammals stop drinking their mother's milk after some time. We humans are the weird ones. The ability to break down lactose comes from the body's production of the enzyme lactase. (Still with me?)
Aside: I'm not certain which causes the other: do infants stop producing lactase because mothers stop producing milk? Or do mothers stop producing milk because infants stop producing lactase? In my mind it makes sense that it should be the former. I can't imagine that a mother would continue to lactate forever after having a baby! Can anyone confirm this?
The theory is that humans (or proto-humans?) were like other mammals: some time after infancy, they stopped producing lactase, and stopped drinking milk.
And then some humans decided drinking the milk of other mammals was a great idea! And they did it so often that a genetic mutation occurred, which allowed lactase production to continue into adulthood. And then natural selection favoured the lactase-persistent mutation in the groups that drank other-mammal milk. Weirdos.
So I'd rather say I'm not lactase-persistent.
Actually, most Asians are not lactase-persistent.
This is probably a good time to remind you that there are 56 recognised ethnicities in mainland China alone.
Han Chinese didn't have a lot of dairy in their diet. (There were of course exceptions, and apparently, introductions to cheesemaking from Italy!) But peoples with nomadic aspects, such as Mongolians and Tibetans, did have cheese, yogurt and milk.
However, it was more common to find fermented or cultured milk such as yogurt and kumis, and I think there are at least two reasons for this. First, it lasts longer; and second, some or all of the lactose gets broken down.
Disclaimer: I'm not an anthropologist. I'm just someone who thinks food is pretty awesome, and who has a lot varied of interests. If I've made any mistakes, feel free to let me know and send me some sources!
