
The lactose-tolerance mutation - MaysonL
http://www.slate.com/articles/health_and_science/human_evolution/2012/10/evolution_of_lactose_tolerance_why_do_humans_keep_drinking_milk.single.html
======
Spooky23
Access to milk is a great thing, because you get the calories and many
nutrients needed to sustain life, and all you need is a cow, goat or sheep
(which is mobile) and pasture.

Compare that to cereal crops like wheat or maize or vegetable crops, which
require long uninterrupted growing seasons and irrigation.

Why is this important? When a troop of rampaging soldiers cuts through your
village and pillages everything in sight, you grab your cows and family and
boogey out of there. Essentially, you have a mobile food supply.

In the event of a drought, you have options as well. With wheat or vegetables,
no rain == no food. With a dairy animal, you go kill the guy who controls the
next pasture and let Old Bessie the cow feast on the grass. (The other key
development was the introduction of potatoes, which remain buried under the
ground safe from the rampaging army above -- my Irish ancestors subsisted on
potatoes hidden from the English taxman and a cow that lived in the house.)

In Europe and the Near East, these things were really important, because there
was always pillaging armies marching across the continent. Today, it's
unlikely that some Mongol horde is going to loot my supermarket, so I drink
milk and eat cheese because they are really tasty.

~~~
pm90
The importance of Milk/Cows has been recognized in other cultures as well. My
ancestors found cows to be so important that they deemed it sacred

Today, India is the largest producer of Milk in the world, and that goes a
long way in providing nutrition to its masses.

~~~
yogrish
In India, Cow is more of divine than Bovine. As author rightly mentioned
"Agriculture-plus-dairying became the backbone", in Indian civilization, it
has been imbibed in culture that they both go hand in hand.Their
interdependence is well known Cow eats Grass/waste crops, Cow dung/urine is
used as manure for the crop and mosquito repellants etc. And outputs of both
are enjoyed by the farmer - Crop and Milk products :)

~~~
mahmud
Why not eat the bulls for meat as well?

~~~
indiecore
Bulls make more cows?

~~~
gadders
You only need one to impregnate lots of cows.

I wonder what happens to the male offspring of Cows in India?

~~~
hnriot
not if you want a reasonably distributed gene pool, diversity of genes is
always a good idea

~~~
gadders
Well, yes. You don't want one bull to do 100% of cows, but one bull can easily
do an entire herd, and using In Vitro methods the most valuable bulls
fertilise thousands of cows.

------
pdog
_> Various ideas are being kicked around to explain why natural selection
promoted milk-drinking, but evolutionary biologists are still puzzled. [...]
Those who couldn't drink milk were apt to die before they could reproduce._

The success of the lactose tolerance mutation may be partly due to sexual
selection[1]. It's been proposed that neoteny[2] is a key feature of human
evolution. The ability to drink milk as an adult is a neotenous trait, and it
may have been "accidentally" selected for when other beautiful features were
sexually selected.

David Rothenberg's book, _Survival of the Beautiful_ [3], argues that
biologists are sometimes "blinded" by natural selection and ignore sexual
selection.

\---

[1] - <http://en.wikipedia.org/wiki/Sexual_selection>

[2] - <http://en.wikipedia.org/wiki/Neoteny>

[3] -
[http://blogs.scientificamerican.com/thoughtomics/2012/10/25/...](http://blogs.scientificamerican.com/thoughtomics/2012/10/25/book-
review-survival-of-the-beautiful/)

~~~
zeteo
How, specifically, can sexual selection operate in this case? It would seem
necessary that the lactase-production gene, which the article mentions, must
have some external effect that's peculiarly attractive. But I don't think it's
possible to tell apart lactose-tolerant people by their appearance.

~~~
nikatwork
Milk consumption makes males taller and broader [1]. So the sheilas want to
breed with the tall milk-fed hottie and not his short, weedy and flatulent
lactose-intolerant friend.

[1]
[http://www.annualreviews.org/doi/abs/10.1146/annurev.nutr.26...](http://www.annualreviews.org/doi/abs/10.1146/annurev.nutr.26.010506.103757)

~~~
enraged_camel
This is incorrect in its context. While milk consumption does aid growth,
lactose intolerance in most cases develops during late adolescence and early
adulthood. By that time, most of the growth in height has stopped.

~~~
nikatwork
You're going to need a citation for "lactose intolerance in most cases
develops during late adolescence and early adulthood".

According to this indirect citation [1], lactose intolerance varies by age and
race, eg 85% of Chinese are lactose intolerant by age 10.

If a significant percentage of a genetic group develops lactose intolerance by
age 10, then yes - it would most definitely affect growth.

[1] <http://boards.straightdope.com/sdmb/showthread.php?t=485313>

~~~
enraged_camel
Citation: <http://en.wikipedia.org/wiki/Lactose_intolerance#Terminology>

Relevant quote - emphasis mine: "Primary lactase deficiency is genetic, _only
affects adults_ and is caused by the absence of a lactase persistence
allele.[9][10] It is the most common cause of lactose intolerance as a
majority of the world's population lacks these alleles.[11]"

edit: Also, I can't believe you linked to some forum called "The Straight
Dope" as your citation.

~~~
nikatwork
Did you even bother to follow the link? Here, I extracted the reference for
you [1].

"Chinese and Japanese populations typically lose between 80 and 90 percent of
their ability to digest lactose within three to four years of weaning."
(Swagerty et al, 2002)

Ergo, lactose intolerance is a factor in children in some genetic groups. Your
citation (sourced from the same wikipedia page) does not refute that.

[1]
[http://en.wikipedia.org/w/index.php?title=Lactose_intoleranc...](http://en.wikipedia.org/w/index.php?title=Lactose_intolerance&oldid=236949155#Lactose_intolerance_by_group)

------
ImprovedSilence
I don't know what it is, but I frickin love milk. It's one of my 4 main
liquids (water, milk, coffee, beer) I put down a gallon about every 4 days. In
college, I'd drink a half gallon a day. Usually when I eat anything that makes
me thristy/is a little salty, like red meat, I"ll crush the milk too. Pasta?
it's so carby, I've got to have milk to get some protein to level out the
glucose release. Hungover? not only does milk rehydrate me, it gives me much
needed calories/energy. Why I'm so dependent, I have no idea. Friends and
family know to stock up on extra milk when I visit. It's like water to me. I
can't explain why, or how I got to this point.

edit: Growing up, we always had 2% in the house. From college on I drink skim,
occasionally (once every few months) I get 1 or 2%, just to up the fat content
(I'm a runner, not terribly concerned with weight gain, more or less trying to
maintain body mass...)

~~~
dizzystar
Why did you convert to skim? I don't have any viable sources, but I thought
skim was not only tasteless, but not any more healthy than other milk. At
least one study has shown skim increases cardiovascular plaque.

I don't really like to stand on the stump of "nutritional science," but I
always find food choices interesting.

~~~
troels
In general, reducing fat (especially the animal kind) is good for modern
people, since we tend to get too much of it.

~~~
gamache
What you said was gospel in 1990, but nowadays there is much dispute over the
role of fat in a healthy diet.

~~~
ImprovedSilence
Agreed, I thought the optimal ratios of calorie intake is 30% from fat, 30%
from protein, and 40% from carbs. fat is 9 calories/gram, and 4 calories/gram
for carbs and fat. At least that's what I try to go by when backpacking. but
still, at the rate I drink milk, I'd be consuming way too much fat if I upped
it to whole...

~~~
seestheday
I believe that the 30/30/40 ratio comes from the zone diet. To my knowledge
there hasn't been any scientific verification on why this is the desired
ratio. I've seen lots of other people claiming different ratios work better
(e.g. some people claiming that 60%+ fat is best). I'm of the opinion that the
ratios don't matter nearly as much as food quality. Does anyone have
studies/references that can prove me wrong?

Eating non-sick/happy animals and animal products just seems to make more
sense to me. Garbage in garbage out.

------
zeteo
I guess I must be missing something, because there's a rather obvious
explanation of the article's central paradox: lactose has calories. To wit, it
takes about 10kg of milk to make 1kg of hard cheese, i.e. 6000 vs 4000
calories. So if you have milk directly, instead of cheese, you get ~50% more
calories. This would presumably make quite a difference for semi-starving
pastoral populations in 10,000 BC.

~~~
kamaal
Sorry didn't understand your statement. If it takes 10kg of milk to make 1 kg
of cheese. Than eating 1 kg cheese is like drinking 10kgs of milk. How then
does milk give you more calories than equivalent quantity(in kgs) of cheese?

~~~
aptwebapps
The weight difference is water. But if you loose a third of the calories when
converting to cheese then I assume they're in the whey. I doubt that people
who were hard up for calories would discard the whey unless they had some
cultural objection or superstition.

~~~
gliese1337
That may be part of it, but another large part of the difference is that, as
previously stated, turning milk into cheese _destroys lactose_. You get fewer
calories from the cheese because microbes already used up some of the calories
that were originally in the milk in order to turn it into cheese, and thus
those calories are no longer available for you.

------
edanm
I'm slightly lactose intolerant.

Here's a tip for others - you can buy Lactase pills at a pharmacy and take
them just before you eat any meal that contains milk. This gives you the
enzymes you need without your body producing in it.

And it's really awesome. I only started doing this a year ago, but now I can
eat many more cheeses, drink milkshakes, etc., without feeling bad. And it
happens surprisingly often - every time you want to eat pizza, pastas, etc.

Seriously, is you're lactose intolerant, give it a try - it improved my life
considerably.

~~~
enraged_camel
There are also brands of milk that include the enzyme. Even easier.

------
arn
Well, as another datapoint to study, asians are said to have a near 90% adult
lactose intolerance rate. So whatever beneficial natural selection for
Europeans that propagated the always-on lactase mutation, the same
cultural/agricultural circumstances didn't hold true for asians.

~~~
potatolicious
> _"asians are said to have a near 90% adult lactose intolerance rate"_

I'm very skeptical of this. I was born and raised in Asia, and all of my peers
were raised on a diet with regular milk consumption. So either we were a huge
cohort of statistical outliers or that number is way, way off.

I do know that lactose intolerance rates for Asians is much higher (and
consequently, less socially troublesome due to the fact that dairy is
generally not a core part of cuisine), but 90% is way, way, way out there.

~~~
gingerjoos
+1 to that. Among all the people I've ever known (in India) only 2 people are
lactose intolerant. Indian society has, historically, placed a lot of
importance on the cow and milk. Indian mythology has rich references to milk
and other dairy products for eg. Samudra Manthan [1], Krishna the cowherd [2].
If we were to consider the level of medicine practiced in India (see [3] and
[4], for eg.), one would imagine that any real problem of such widespread
nature would be heavily studied and discussed about.

[1] <http://en.wikipedia.org/wiki/Samudra_manthan>

[2] <http://en.wikipedia.org/wiki/File:Krishna_with_flute.jpg>

[3] <http://en.wikipedia.org/wiki/Charaka_Samhita>

[4] <http://en.wikipedia.org/wiki/Sushruta_Samhita>

~~~
kingsley_20
This is an American usage of the word "asian", which excludes subcontinentals.

Interestingly, my wife and I grew up on milk in India (to adulthood), but
found ourselves mildly lactose-intolerant to American milk.

Edit: changed "includes" to "excludes".

~~~
whatusername
And Australian. "Asian" to me has always meant:
China/Japan/Malaysia/Indonesia/Korea(s)/Thailand/Vietnam/Phillipines/PNG/Timor/Laos/Cambodia
and maybe Burma.

------
6ren
> Everywhere that agriculture and civilization went, lactose tolerance came
> along.

Odd that they don't mention physical displacement: invasion, dispossession,
death. The gene would likely have coincided with other developments of
civilization, such as weapon technology, greater numbers, greater cooperation,
specialised soldiers etc. Maybe there's evidence against it, but odd it's not
addressed, with a puzzlingly high "selection differential". Another factor
might have been sexual selection, if the new folk were healthier looking etc.

Note they are talking specifically about the West - agriculture and
civilization spread throughout the East without this gene.

------
brc
It's an interesting article, on a topic I've read about before. I think the
answer is that is no one answer - maybe milk became fashionable, and the guys
who had a regular supply of milk attracted more females, and thus more
offspring. Maybe it was fashionable and, if being consumed as yoghurt, somehow
acted as medicine to a bacteria getting around at the time. Maybe it was
fasionable, had medicinal qualities and gave you stronger bones, so you were
more able to survive childbirth and things like battles or hardships.

I'm just glad I'm not lactose intolerant, so thanks to whoever in my billions
of ancestors decided to keep at it.

~~~
maxerickson
I wonder how much of it is due to having cows and harsh winters.

(as someone with lots of northern European ancestry and lactose intolerance,
it's a fun subject. I can still eat cheese and yoghurt and half-digested milk,
so it isn't much bother)

~~~
brc
Well, the start of dairy wasn't in a cold climate, so I don't know about that.
There was clearly some advantage in being able to digest lactose. Maybe it was
the occasional winter that had to be lasted through, and having a cow or goat
to milk helped out. Anything that weeded out the competition would have done.

~~~
maxerickson
I was thinking about it in two stages; among the people that are using dairy,
the ones that can easily consume fresh milk have better access to calories
during a cold winter (which might be a difficult time to make yoghurt or
such).

------
dave1619
_> Heart disease, diabetes, alcoholism, celiac disease, and perhaps even acne
are direct results of the switch to agriculture._

Really? A plant-based whole foods diet is probably the best cure out there for
heart disease and type 2 diabetes. (google Dean Ornish, Neil Barnard, John
McDougall)

The author tells a good story but his bashing of agriculture is unsupported.

~~~
gnufied
I am no expert but another linked story
([http://discovermagazine.com/1987/may/02-the-worst-mistake-
in...](http://discovermagazine.com/1987/may/02-the-worst-mistake-in-the-
history-of-the-human-race/article_view?b_start:int=1&-C=)) explains it better
why Agriculture had overall deteriorating effect on human health:

1\. Early farmers had less access to variety of diet compared to hunter-
gatherers. It is hard to disagree with this one. For a lot of Asia, Rice is
still the main food and rice on its own contain little more than
carbohydrates.

2\. Risk of starvation if crops failed.

3\. Encouraged crowded societies and deterioration in position of Women.
Agriculture forced women to have children often and that in turn impacted
their health. I don't know much about Europe but in India Govt. still runs
advertisement encouraging Women to have kids at a gap of 3 years or more. I
think it is widely held that healthier Mother in general means healthier baby.

~~~
moheeb
There is no way 'Agriculture' has had an " _overall deteriorating effect on
human health_ ".

I believe the massive population explosion of humans can not be explained
without agriculture.

~~~
realitygrill
Think about this. Those two statements are not mutually exclusive.

~~~
moheeb
Think about what? Your sentence ends right there.

So billions more people are able to survive somehow now...but our "health" has
gone down?

There is the health of the human species...which has gone up undeniably,
evidenced by the billions more people being fed...and then there is the health
of the individual human.

So you were referring to the health of an individual when discussing
agriculture's impact? Sample size seems kinda small. Also...seems that most of
us wouldn't be around for that discussion as the non-agricultural food supply
would not allow us to be born.

------
bane
It's because it's delicious and goes really well in lots of foods.

It moderates strong flavors, smooths out acidic drinks, fluffs up eggs among
many other thousands of beneficial food uses.

Other dairy products like butter and cheese are key to an immense palette of
flavors and cooking techniques.

Dairy is so delicious that I've even seen people with violent milk allergies
put up with the consequences just to scarf down a few bites of custard or ice
cream.

~~~
TazeTSchnitzel
They can get Lactase pills...

------
thalecress
Calories. Cheese has only about 60% the calories of a starting volume of milk.
[1]

Plus, animals can graze on land you can't farm, and they're very portable.

[1] [http://westhunt.wordpress.com/2012/01/21/the-indo-
european-a...](http://westhunt.wordpress.com/2012/01/21/the-indo-european-
advantage/)

------
WA
I read once a theory that the enzyme that splits lactose in the body is
destroyed by sunlight. People living near the equator have a much higher
lactose intolerance because the constant sunshine destroys the enzyme.

Likewise, people in Sweden for example have a 100x higher lactose tolerance,
because there's less sunlight throughout the year.

------
zaroth
Wow, mampires...

"We became, in the coinage of one paleoanthropologist, “mampires” who feed on
the fluids of other animals."

~~~
feintruled
The real irony for me is the instinctual revulsion that many feel about
drinking human milk! (As adults, of course, babies sure seem to love it)

------
thomasfl
It really sucks living in norway with lactose intolerance. Just about every
kind of processed food got milk in some form or another in it. Bread, hot
dogs, caviar, potati chips. It's mad cow milk disease!

------
josephjrobison
I do value the importance of milk from a survival standpoint, but I think
today's milk is a bastardized version of milk our ancestors survived on that
they drank directly from the cow. With the whole factory farm system and
terrible diets most (American) cows eat, not to mention the steroids and
antibiotics that a lot of cows are given, I don't believe the idea that milk
is a nutrient packed elixir.

Not hating for those who want to feel good about their love for milk, but I
don't think today's milk is much more than a treat and baking ingredient.

------
ekm2
Man was drinking milk long before there was a western civilization.

------
teyc
Perhaps people who tolerated milk reared cows. Given that those who were
exposed to cowpox survive smallpox, the advantage conferred would have been
huge.

------
hcarvalhoalves
The ties between agriculture and herding are not clear. Mongols are nomads and
have a diet that is basically just milk.

I believe the benefit of drinking milk is obvious. A herd can take calories
from grass and drink mud, while the human enjoys a source of clean, caloric,
nutrient rich drink that can go anywhere. Farmers, on the other hand, can just
be ran over, pilled or sieged by enemies.

------
robmcm
It could be a lot more simple, such as a bacteria that grew on cheese, or a
virus that milk protected you from.

This would support massive switch to tolerance (simple survival of the
fittest).

It also supports the spread, as a bacteria or virus would not have made it out
of the "islands" (himalayas, oceans) and so tolerance wouldn't have been an
advantage.

------
Shenglong
_though not in the Americas, Australia, or the Far East._

Does anyone know why some East Asians (such as myself) are lactose tolerant?
Is that evidence of interbreeding in the past?

~~~
robmcm
Could be the same mutation, or lack of mutation (depending on the original
state of tolerance). However if there is no advantage/disadvantage at a
certain point (such as our brains taking over to stop young suckling too long,
or ample supply of other foods) then it would remain relatively rare in the
gene pool.

Perhaps the opposite was true in Asia and your genes managed to survive where
the tolerance was an disadvantage?

------
bifrost
I have an obvious bias here (I have a cow milk allergy) but I will be very
happy when the use of cow milk becomes nonexistant!

~~~
bmelton
Not trying to be obnoxious, but why?

I'm allergic to cats, and while I might often joke that they're beasts from
hell (seriously, have you ever paid attention to cats? They're preternaturally
Satanic,) I don't actually wish them any harm.

I know nothing of milk allergies or their severity -- is it so bad that just
being _near_ milk will cause you troubles, or is it only ingestion/contact. If
the former, I suppose I get it. If the latter, why would it bother you that
other people choose to consume it?

~~~
Anechoic
As one of the 75% of blacks who is lactose intolerant, I can certainly
sympathize with bifrost's post, although I don't want to deprive others of
milk products if they enjoy it.

As I was growing up, milk, being recognized as healthy part of a diet, was
basically forced on me during school - okay, not literally, but the school
lunches only provided milk or chocolate milk, the water fountains didn't work
reliability, and the cafeteria staff would always look down on my if I brought
my own juice. Sometimes it was easier to just gulp down the milk and then deal
with stomach cramps/diarrhea during my afternoon classes followed by rushing
home to use the bathroom before I exploded.

One of the best parts about going away to college was being able to select my
own beverages with my meal. If you want to have milk, that's fine with me,
just don't force me to have to consume it.

------
mitchi
I hate the taste of milk. Pour yourself a glass of milk and drink some of it.
Now go away and come back 5 minutes later. Drink again. It tastes bad now. I
quickly changed to Soy Milk and I drank a lot of that instead. However,
recently I have stopped all soy products because of the estrogen catalysers in
them. I'm now on Almond Milk, I hope I'm good now.

~~~
joesb
Then why not finish the whole glass?

------
zacharyvoase
Would pasteurization (or lack thereof pre-1862) have any effect on the
research?

------
ckdarby
I feel a little odd drinking this while I drink a glass of milk >_>

------
finnw
The title sounds like the name of a Big Bang Theory episode

------
krob
I'm lactose intolerant. I guess I'm a caveman :(

------
goggles99
WOW - I cannot believe the false premise this entire article is based on. This
is Epigenetics, not mutation or evolution!!!
<http://en.wikipedia.org/wiki/Epigenetics>
<http://www.pbs.org/wgbh/nova/body/epigenetics.html>

The article itself says _> Two hundred thousand years later, around 10,000
B.C., this began to change. A genetic mutation appeared, somewhere near
modern-day Turkey, that jammed the lactase-production gene permanently in the
“on” position._

This is NOT a genetic mutation. The gene was already there but not turned on
past the toddler years. I searched this entire page of comments and no one
knows or points this out?

------
ck2
Because cereal tastes terrible with water?

Because the dairy industry in the US alone gets $4 billion per year in
subsidies from taxpayers?

~~~
_neil
I've found almond milk to be an excellent replacement for cereal. Better than
soy anyways.

~~~
dhughes
It's weird how almond, soy or coconut liquids can legally be called "milk"
none of those sources have nipples. Coffee is liquid from fermented beans
similar to soy it's no more milk than soy is.

I know here in Canada for decades margarine had to be smuggled into the
country, when it was legal it couldn't be yellow like butter (but even butter
has artificial yellow colour added), it certainly couldn't be called butter.

~~~
colanderman
> I know here in Canada for decades margarine had to be smuggled into the
> country

Sounds like anticompetitive political corruption by the dairy industry; I
can't imagine how that protects consumers.

Do you also have a problem with ground peanut spread being called "peanut
butter"?

~~~
dhughes
I don't think it was anticompetitive reasons although the end result was that
I believe it was farmers created a market for butter that margarine would
benefit from.

As for PB I'm not a dairy farmer.

