Cheese changed the course of Western civilization

Lots of "likelihood," "probablilities" and "maybes" floating around in that article, and not a lot of certainty. I find the article scant on proof, and speclative at best.

In particular, there's this:

  What this meant, says Kindstedt, is that “children 
  and newborns would be exposed to milk frequently, 
  which ultimately through random mutations selected 
  for children who could tolerate lactose later into 
  adulthood.”

Explain to me how childhood exposure to milk (the period when humans tolerate lactose) selects against lactose intolerance in adulthood?

For example, so let's say you have a mixed population of families, where initially there's a prevaling majority of hereditary lactose intolerance, but with a minority of the new mutants present, who decades later will comfortably continue to consume dairy.

Mutations are typically recessive so you might have households where one parent is lactose tolerant, and none of the children are, due to the lottery of gene expression in sexual reproduction. Maybe some intolerant children are carriers and some aren't, but it's still a roll of the dice.

How does consuming dairy products as a child select for this trait which will not be expressed until years later? What obvious mechanism of selection am I failing to understand here?

Are medieval societies filled with stories of the lactose intolerant humilating themselves with dairrhea on prom night and reducing themselves to social pariahs, doomed to die childless and alone? I mean really.

Is lactose tolerance purely genetic, or is there an element of exposure that causes it?

The reason I ask is funnily enough that I've made the same observation as xiaq: I'm Chinese. There's no suggestion of any other ancestry than far eastern, yet I can still drink milk.

My mom is lactose intolerant but my dad seems to be able to process it. Though he doesn't expose himself much; it's just not that big a part of Chinese diets. I grew up in the West, where kids get milk all the time.

I guess another way to say it is if a kid drinks milk and keeps doing it, will he suddenly get the squits from it one day?

Interesting. As a Chinese I have always wondered why lactose intolerance is so common in China but not in the west. Turns out I asked the wrong question :)

This rapid evolutionary change is one reason why much of the reasoning for "Paleo" diets is flawed. Humans have changed since Paleo times.

I can't see how the article justifies its title. Did the (comparatively) lower level of adult lactose intolerance in the West have social, cultural, economic or other effects significant enough to be described as a change in the course of civilisation? If so, what were those changes?

EDIT: s/tolerance/intolerance/

I remember reading about American Indians killing nursing buffalo calves and cutting open the stomachs to feed the curdled milk to their children as a special treat (almost like ice cream). Surely hunters of mammals throughout the ages were familiar with this delicacy. Why isn't this considered the 'discovery' of cheese?

One thing that's missing from this is a more nuanced discussion of lactose intolerance. It's not a simple binary thing like celiac disease or an allergy. It's possible to consume around a cup (250ml) of milk per meal for lactose intolerant people, but doing so without experiencing typical lactose intolerance symptoms requires regular exposure and building up to those levels (possibly due to micro-biome effects). What that means is that a group of people that started introducing animal milk consumption with infants might also begin consuming milk through adulthood in small quantities. That would provide the sort of situation that would make it easy for adult lactose tolerance to have a major evolutionary advantage.

If teens and adults are drinking small amounts of milk regularly as well as some amount of cheese then those who are lactose intolerant (the common case) will only be able to get calories from the fat and proteins. But anyone who has acquired lactose tolerance will be able to consume an unlimited amount of dairy products and will also gain around 40% more calories from the lactose. That's an enormous dietary boost especially for people who are struggling at the margins of livelihood and malnutrition. More calories means less stunted growth, which means stronger bodies, and a greater ability to survive through harsh winters or lean times.

And cheese is a marvelous invention.

Pajata [1] is unweaned veal intestines, and contain a cheese-like substance. It's one possible source of cheese invention.

[1] https://en.wikipedia.org/wiki/Rigatoni_con_la_Pajata

I'm a blue-eyed, blond, cheese eating adult and I like it.

That reminds me of something I read about blond, fair people and milk I didn't see it mentioned in the article about vitamin D which is added to milk these days but I don't know if it has any naturally. People with fair skin, blond hair in northern climates helps in the dim sunlight to get enough vitamin D.

I also recall reading that people living in a northern climate who have access to large amounts of fish allowed generations of that group of people to retain a darker skin colour since the vitamin D from fish meant people didn't need fair skin to get as much vitamin D from the sun.

Cheese is an awesome food. It's high-protein and high-fat and is perfect if you're a farmer or in some other way burning a lot of calories.

Where I live (switzerland) we eat a ton of cheese and it's seasonal, with Spring/Summer cheese being when the cows are in the mountains eating clover, herbs, and grass, versus in the Fall and Winter when the cows are in the valleys eating hay. There are something like 5000 varieties of cheese in Switzerland if you include every village and farmer and their sub-varieties in the list, but for mainstream cheeses there's something like 500 varieties. You can get unusual different cheeses every weekend if you're willing to take a trip to some random village in a tucked-away valley. (sausage too! especially if you're willing to eat sausages made with horse, deer, dog, etc.)

I'm not Swiss but my wife and I still eat a ton of cheese. It's so good here and such a part of the culture that you can't help but take to it. We burn off the calories like the Swiss do with hiking and skiing every weekend.

I don't like the term "lactose intolerant". It implies that having difficulty digesting lactose is differentiating you from some loosely defined norm.

In fact, the opposite is true[1]. As the article states, being able to digest lactose is a recent genetic adaption. What it doesn't state is that still, even in the West, a lot of people experience lower tolerance to lactose as a natural process of aging.

I would therefore say that the correct way of labeling it is that adults in general have different levels of _lactose tolerance_.

Anecdotally, I can add that my level of lactose tolerance was very low for two years after drinking half a liter of milk that was two weeks old (don't ask). I assume that it severely messed up my small intestine. After I cut carbs and gluten from my diet for a month and a half, I could suddenly digest lactose again. As with lactose intolerance, I believe gluten intolerance is a misnomer, as all people are sensitive to excessive amounts of gluten, though here the case is not nearly as clear cut. My intestine finally being able to repair itself might instead be due to the fact that I didn't eat many carbs at all during this period, and so avoided the gastro-intestinal allergens known as FODMAPs[2]. Wheat contains the FODMAP fructan, which might be the reason many people say they feel better on a gluten free diet[3].

[1]: http://www.collective-evolution.com/2013/04/03/over-75-of-ea...

[2]: http://en.wikipedia.org/wiki/FODMAP

[3]: http://www.npr.org/blogs/thesalt/2014/05/22/314287321/sensit...