Digestion of milk a relatively new adaptation for humans

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Digestion of milk a relatively new adaptation for humans

February 27, 2007
Not Milk? Neolithic Europeans Couldn't Stomach the Stuff
DNA analysis of nine prehistoric skeletons finds no sign of a gene variant conferring the ability to digest milk
By Nikhil Swaminathan

In what they claim is the first direct evidence of the evolution of lactase-persistence (the ability to digest milk and other dairy foods), German and British researchers came up empty in their search for the gene variant that allows over 90 percent of northern Europeans to gulp down and properly digest milk. In many others around the world, lactose causes diarrhea and bloating, especially in adulthood.

Lactase persistence (also called lactose tolerance), the continued production of the enzyme lactase that breaks down the sugar lactose in milk, correlates heavily with populations currently or once based on dairy farming, estimated to have begun in Europe roughly 8,000 to 9,000 years ago. (Populations in the Middle East and northeastern Africa also have the ability to digest milk.) "There's pretty good evidence that it's the most strongly selected single gene variant in Europeans in the last 30,000 years," says Mark Thomas, a genetic anthropologist at University College London and co-author of a new study in this week's Proceedings of the National Academy of Sciences.

Thomas, along with a team of scientists from the University of Mainz in Germany led by paleogeneticist Joachim Burger, searched for the gene variant that confers lactase persistence in most modern-day Europeans in eight samples from the skeletal remains of Europeans who lived during the Neolithic era along with one sample from the Mesolithic era. The Neolithic relics were carbon dated to between 5,000 and 5,840 years ago, while the Mesolithic remains date back almost 4,000 years. The samples were found in locations ranging from Germany to Lithuania.
According to the study, the ability to process lactose was not highly prevalent in the Neolithic era. In fact, the researchers did not find any trace of the gene variant in their samples. The total absence suggests that no more than about 40 percent of the population could possibly have been lactose tolerant 5,000 years ago—indicating that the ability to digest the milk sugar probably resulted from the advent of dairy farming.


"Eight thousand years, in evolutionary terms, is nothing, especially when a genotype frequency raises from close to 0 up to more then 70 percent and, in some areas of northern Europe, [to] even more than 90 percent," Burger says, adding he expected to find that some individuals were lactase-persistent. "The fact that we have found none demonstrates that positive selection was acting massively on prehistoric European populations and that the speed of the spread of the allele (gene variant) was enormous."
About 80 percent of the people in southern Europe now are lactose intolerant, which means that there was a relatively small window for the gene variant to have come into prevalence in northern Europe. Burger says he will study more populations in Eurasia to try to determine when the gene variant spiked in frequency. Thomas, on the other hand, plans to integrate these findings "into a full population computer simulation to try to understand the spread of farming, dairying and other population movement."

Sarah Tishkoff, an evolutionary geneticist at the University of Maryland, says that the new work highlights the potential of tying the findings of genetics and archeology together. She warns, however, that, "one of the limitations of doing ancient DNA work is the difficulty of obtaining enough nuclear DNA to look at large numbers of samples to determine differences among populations." She adds that going forward, analyzing a few samples from the same area and period of time may better hone the ancestral frequency of this gene variant.

http://www.sciam.com/article.cfm?articleid=048C5C9D-E7F2-99DF-3ED2616E392893DB&chanId=sa027

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milk

briefly, what is this saying about evolution? Europeans are more lactose intolerant? Non Europeans? Who comsumes more dairy products?

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naomi94 wrote: briefly,

naomi94 wrote:
briefly, what is this saying about evolution?

Nothing really. Just that we have recently evolved to consume milk, or at least portions of our society have.

Conn_in_Brooklyn wrote:
Europeans are more lactose intolerant?

Southern europeans are more intolerant than northern. Though I don't know the specifics of the demographics. I've only seen this news article, not the study itself.

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Our body still has trouble

Our body still has trouble digesting milk, even if you are lactose tolerant.  It takes alot of energy to break down, and most of the calcium it gives you is wasted...you can get more calcium from vegetables.  There are strong arguments that suggest drinking milk as an adult may do more harm than good.

 

Hopefully ShadowofMan will log in and see this topic, he knows much more about this stuff than I do.  I get most of my evolutionary diet information from him. 


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From: http://www.wrongdiagno

From:

http://www.wrongdiagnosis.com/l/lactose_intolerance/stats.htm


Prevelance statistics about Lactose Intolerance: The following statistics relate to the prevalence of Lactose Intolerance:

  • 90% of Asian American adults have lactose intolerance (NIDDK 1994)
  • 70% of African-American adults have lactose intolerance (NIDDK 1994)
  • 74% of Native American adults have lactose intolerance (NIDDK 1994)
  • 53% of Mexican-American adults have lactose intolerance (NIDDK 1994)
  • 15% Caucasian adults have lactose intolerance (NIDDK 1994)


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kriz wrote: There are

kriz wrote:

There are strong arguments that suggest drinking milk as an adult may do more harm than good.



DAMN! I drink between 12 and 16 pints a week... (i have an empty pint glass of milk next to me as i type) What harm does it do?

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Does this include milk from

Does this include milk from our species? Or is this a case of "DEATH BY DAIRY COW!"?


MattShizzle
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I hate milk. Milk sucks!

I hate milk. Milk sucks!


kriz
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Well, from what I

Well, from what I understand, milk from humans or a cow isnt too different.  Lactose-Intolerance is actually the norm amongst most animals...it arrises to wean the young off of their mothers and to eat other foods.

 As far as the harm Milk can do, obviously its not that grave as people drink Milk all the time.  But it takes alot of energy to digest and absorbs alot of calcium and other nutrients in your system (so much of the calcium in milk is burned off by digesting it).  Theres also something about the acidity of foods, either very acidic or basic are good for you, I cant remember.  There are many studies that show many diseases (most notably cancer) cannot survive in a body thats has either a basic or acidic pH, I cant remember.  Anyway, Milk puts your pH in the wrong direction.

 

I wish someone with more knowledge on this could come and clear it up, I really only know all this stuff through second hand sources...and am not clear on specifics. 


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gobaskof wrote: kriz

gobaskof wrote:
kriz wrote:

There are strong arguments that suggest drinking milk as an adult may do more harm than good.



DAMN! I drink between 12 and 16 pints a week... (i have an empty pint glass of milk next to me as i type) What harm does it do?

I've read that your body has trouble absorbing calcium from milk (from calcium lactate) and digesting the proteins in milk requires calcium, so you end up with a net loss in calcium when you drink milk.

-Triften 


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There are still benefits to

There are still benefits to milk consumption however. It's a lot safer than say McDonalds. I drink at least as much of it as Gobaskof. I love milk.

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HealingBlight
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You knowledge people ruin

You knowledge people ruin all the drinks on me! First it was coke, now its milk! D: What are you going to do about filtered water then now? It has satan in it? Sad

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kriz
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HealingBlight wrote: You

HealingBlight wrote:
You knowledge people ruin all the drinks on me! First it was coke, now its milk! D: What are you going to do about filtered water then now? It has satan in it? Sad

 

Sorry about that.  Sticking out tongue

Filtered water is great, but if you're talking about bottled water that is something different.  Bottled water wastes huge amounts of resources, from the gas it takes to truck it all over the place to the creation and disposal of millions of plastic bottles.  A country with as good of a tap water infrastructure as the US, bottled water is ridiculous.

Sorry, but raining on parades is all the rage on this forum.  I don't think sodas, milk, or bottled water are in any way good for individuals or society, but I use all of them...especially milk.  I'll usually have a couple of bowls of cereal a week.  And I'll drink a 2 or 3 sodas a month.  And I'll buy bottled water at a gas station when I'm driving somewhere or something occasionally.  I used to drink soad almost every day, and you don't realize how addicting it is until you try to cut it out of your diet.  I also used to drink alot of milk.  I was never into bottled water though.  :P 


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"Oui, oui! No milk for me!"

"Oui, oui! No milk for me!"


triften
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kriz wrote: HealingBlight

kriz wrote:

HealingBlight wrote:
You knowledge people ruin all the drinks on me! First it was coke, now its milk! D: What are you going to do about filtered water then now? It has satan in it? Sad

 

Sorry about that. Sticking out tongue

Filtered water is great, but if you're talking about bottled water that is something different. Bottled water wastes huge amounts of resources, from the gas it takes to truck it all over the place to the creation and disposal of millions of plastic bottles. A country with as good of a tap water infrastructure as the US, bottled water is ridiculous.

Not to mention the fact that bottled water has fewer regulations on it than tap water. Ick.

(Plus, a little flouride now and then helps your teeth.)

-Triften 


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If anyone wants an

If anyone wants an evolutionary perspective on diet, you should read Dr. Loren Cordain's The Paleodiet. 

www.thepaleodiet.com 

From his research, dairy (as awesome as it tastes) is one of the worst things to put in your body.  Very high in saturated fats (not bad in it's self, but we consume way too much).  We should be getting a better balance of mono and polyunsaturated, omega-3 and omega-6.  While milk is a good source of calcium, your body doesn't get any of it.  You need a net calcium balance (more calcium consumed than excreted).  When something is consumed, it reports to the kidney with an acidity.  If your kidneys senses to much acid it will take a source of alkalinity from the body.  Calcium in the bones is the first to go.  Foods that contrubute to net acidity are:  Meats, grains, beans, and dairy (especially hard cheeses).  Alkaline foods include:  Fruits and Vegetables (especially raisins and spinach).   

The dairy lobby in the US is obsene.  They make a ton of money getting their milk sold to the school system and getting the daily recommended dose increased on the new pyramid, all the while funding science that perpetuates the myth that milk is "wholesome".  Even though the U.S. has the highest consumption of calcium (from milk), they also have the highest rates of bones deteriorating deseases like osteoporosis.  There is even some research linking autism to dairy consumption.   

Seriously, if you have any interest in the diet that humans evolved to eat, check out www.thepaleodiet.com

 

A daughter of hope and fear, religion explains to Ignorance the nature of the unknowable. -Ambrose Bierce


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Wait!...Stop the press...how

Wait!...Stop the press...how did coke get killed by the smart ones?!!!


ShadowOfMan
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Coke or coca?  What?

Coke or coca?  What?