Early man 'couldn't stomach milk'

[Demi]

BBC News
London, UK
27 February, 2007


Early man 'couldn't stomach milk'

A drink of milk was off the menu for Europeans until only a few thousand years ago, say researchers from London.

Analysis of Neolithic remains, in Proceedings of the National Academy of Sciences, suggests no European adults could digest the drink at that time.

University College London scientists say that the rapid spread of a gene which lets us reap the benefits of milk shows evolution in action.

But intolerance to milk remains common in modern times, say nutritionists.

In order to digest milk, adult humans need to have a gene which produces an enzyme called lactase to break down lactose, one of the main sugars it contains.

Without it, a drink of milk proves an uncomfortable experience, causing bloating, stomach cramps and diarrhoea.

Today, more than 90% of people of northern European origin have the gene.

Skeleton study

Working with scientists from Mainz University in Germany, the UCL team looked for the gene that produces the lactase enzyme in Neolithic skeletons dating between 5480BC and 5000BC.

These are believed to be from some of the earliest farming communities in Europe.

The lactase gene was absent from the DNA extracted from these skeletons, suggesting that these early Europeans would not be tolerant to milk.

Dr Mark Thomas, from UCL, said: "The ability to drink milk is the most advantageous trait that's evolved in Europeans in the recent past.

"Although the benefits of milk tolerance are not fully understood, they probably include the advantage of a continuous supply compared with the 'boom and bust' of seasonal crops, its nourishing qualities, and the fact that, unlike stream water, it's uncontaminated with parasites, making it safer.

"All in all, the ability to drink milk gave some early Europeans a big survival advantage."

Milk exposure

The big question for scientists now is how the human population changed and took advantage of milk consumption.

One theory suggests that small groups who could tolerate lactose became dominant because they could then farm cattle for milk.

But the UCL team says it is more likely that the genetic mutation allowing the digestion of milk arose at some point after dairy farming began.

Dr Thomas says the absence of the gene in the remains studied supports this theory.

If lactose tolerance had come first, the farmers would have already have had the gene.

As they did not, he suggests the genetic mutation took place at a later point.

He added: "It's likely that the gene variant arose in one individual somewhere in northern Europe, and was such an advantage, it spread quickly.

"This is probably the single most advantageous gene trait in humans in the last 30,000 years."

Today's intolerance

Anna Denny, a scientist with the British Nutrition Foundation, said 'lactase deficiency' affected about 5% of white British people, and a larger proportion of those from some ethnic minorities.

In some parts of the world, such as Asia and Africa, the vast majority of people are lactose intolerant to some degree.

Once diagnosed, the usual way to control its symptoms is to restrict the amount of milk products eaten every day, although nutritionists say that eliminating dairy products entirely is usually unnecessary.

Anna Denny said: "Lactose intolerance tends to be dose-related and some people are more sensitive than others, consequently only about a third of the people with lactase deficiency are actually lactose intolerant.

"Patients with severe lactose intolerance can usually eat yogurt, hard cheeses and lactose-reduced milk and all are encouraged to eat these as a source of calcium and other nutrients."


http://news.bbc.co.uk/1/hi/health/6397001.stm

[LondonIan]

Damn, you beat me again! I was just about to post that in the Paleo thread.

[amergin]

There are a number of points in the article worthy of comment.
Firstly, almost all humans of every race are capable of digesting the lactose in milk when they are babies and infants. Human babies share this trait with every mammal, (including whales and dolphins).
The lactose intolerance arises as they grow older and lose the ability to produce the lactase enzyme.
There is an interesting feature to the distribution of adult lactose tolerance. This is that it is common in northern Europe. I have a suspicion that this is not an accident.
When a cow is milked the milk is at blood heat. IN modern dairy farms it is immediately sent down a pipeline to be pastuerised, then to a chiller where it is cooled to 4 degree centigrade, ready to be picked up by the refrigerated truck from the creamery.
Also the milk pipelines are rinsed and sterilised at least once a day.
IF these things were not done then the milk would rapidly sour in a warm climate. This effect is amplified when the milk is gathered in a wooden pail or leather bag that has been used to store milk before and has not been sterilised. When it sours the lactose is all or part fermented to lactic acid, which is digestible, though a little tart. In fact there is a tradition of deliberately allowing or causing milk to sour to produce Yogurt, Kefir, buttermilk, and Kumar from horse milk. There is also fermented camels milk in some regions. These foods are produced generally in more southerly latitudes, or during the summer months in the Asiatic steppes.
The Doctor quoted in the article is slightly off track when he says ""Although the benefits of milk tolerance are not fully understood, they probably include the advantage of a continuous supply compared with the 'boom and bust' of seasonal crops," Presumably the doctor believes iron age Northern Europeans lived near a supermarket with a large dairy section. :)
Cows, sheep and goats in their more primitive state had their calves in the spring and fed them on the rich milk from early summer grass. The calves would be weaned and the cows would have gone dry going into winter as the food supply diminished. Modern cows have been intensively bred to increase the length of lactation post calving. In some countries they are even drugged with hormones to produce milk out of all relation to their natural cycles.
While milk was more constant than crop harvests it would still have a large seasonal variation, both in quantity and quality. The main seasonal stores of dairy food would have been cheese, and butter in northern Europe, Butter oil in southern regions.
I would speculate then that north Europeans pastoralists living in regions with cool summer temperatures had a particular reason to keep their lactase. For other pastoral races who could and did make their milk digestible by deliberately fermenting it there was not the same evolutionary advantage in retaining the lactase enzyme into adulthood.
Though now that both people and food are moving between different climate zones, and chilled fresh milk is appearing in supermarkets in places where it would have been an impossibility in former times, there is more chance of a mismatch between diet and genes giving rise to the problems associated with lactose intolerance.

[LarryAJ]

Firstly, almost all humans of every race are capable of digesting the lactose in milk when they are babies and infants. Human babies share this trait with every mammal, (including whales and dolphins).
The lactose intolerance arises as they grow older and lose the ability to produce the lactase enzyme. Good catch, amergin!
So ALL mammals MUST have the gene that produces lactase. The mechanism that causes it to slow down and eventually stop production of lactase is unknown according to my biochemistry book (published in 2005). That then begs the question, do all mammals stop producing lactase when they are mature? What about cats that seem to like to drink cows milk? I remember my uncle milking in the barn where there several cats. I was fun to watch them open their mouths so my uncle could give them a squirt direct in their mouths from the cows teat. Yes, I know that some say NOT to give cats cows milk, but the barn cats would come around essentially begging for milk.

Perhaps the researchers doing this study have been in the lab much to long. :D :agree:

[waywardsis]

In order to digest milk, adult humans need to have a gene which produces an enzyme called lactase to break down lactose, one of the main sugars it contains.

Without it, a drink of milk proves an uncomfortable experience, causing bloating, stomach cramps and diarrhoea.

They don't mention casein allergy/intolerance, one of if not the most common food allergy around. It's always lactose lactose lactose...the protein causes far more problems (like gluten and soy). I do wonder if this intolerance is partially due to the lack of "real" milk, such as Amergin was describing. Man, I'd love to find some raw milk products and see how they affected me (or didn't).

[2bthinner!]

I wonder how probiotics fit into this? Off to search..

ETA: A lot of the sites I found are selling probiotics, but this site claims to be an information site for researchers.
http://www.csa.com/discoveryguides/probiotic/review4.php

♦ Lactose Intolerance.

The inability of adults to digest lactose, or milk sugar, is prevalent worldwide. People of northern European descent are unique in retaining the ability to produce the lactose-digesting enzyme, lactase, into adulthood so they can continue to drink milk. Consumption of lactose by those lacking adequate levels of lactase produced in the small intestine can result in diarrhea, bloating, abdominal pain and flatulence. These symptoms are due to the undigested lactose reaching the large intestine and being fermented by the colonic microbes, which can produce gases and products that lead to watery stool (6).

The consumption of dairy products - important for supplying calcium and preventing osteoporosis - by people with lactose intolerance can be facilitated by probiotic bacteria (6).

It has been documented scientifically that many lactose intolerant individuals are better able to consume fermented dairy products, such as yogurt, with fewer symptoms than the same amount of unfermented milk, even though yogurt contains about the same amount of lactose as milk. Yogurt was found to aid digestion of lactose because the lactic acid bacteria used to make yogurt produce lactase and digest the lactose before it reaches the colon. In addition to yogurt starter bacteria, L. acidophilus and bifidobacteria have been shown by several studies to improve digestion of lactose, although generally to a lesser extent than the yogurt starter cultures, Lactobacillus bulgaricus and Streptococcus thermophilus (6).

♦ Hypertension.

About 50-60 million people in United States are estimated to have hypertension, or elevated blood pressure. Antihypertensive effects have been documented in animal models and in mildly hypertensive adults for three compounds derived from the growth of certain lactobacilli: i) fermented milk containing two tripeptides derived from the proteolytic action of L. helveticus on casein in milk; ii) bacterial cell wall components from cell extracts of lactobacilli; and iii) fermented milk containing fermentation-derived gamma amino butyric acid. Systolic blood pressure was decreased on the order of 10-20 mm Hg. These results suggest that consumption of certain lactobacilli, or products made from them, may reduce blood pressure in mildly hypertensive people. Viability of the lactobacillus is not required for the effect. Such fermentation-derived, but nonprobiotic, products have been developed (6). Sounds like a downside to pasturization. Another site stated that no cooked food has the digestive enzymes that raw food does. I guess that's great if it's in your own back yard, but our foods are handled way too much.

Interesting about blood pressure too.

[Angeline]

What about cats that seem to like to drink cows milk? I remember my uncle milking in the barn where there several cats. I was fun to watch them open their mouths so my uncle could give them a squirt direct in their mouths from the cows teat. Yes, I know that some say NOT to give cats cows milk, but the barn cats would come around essentially begging for milk.

They might have liked cow milk, but that doesn't mean that they could easily digest it. I gave my cat milk once and never again. Apart from the mess, it was very guilt-inducing to see my poor kitty being in obvious intestinal distress.

After that, I would occasionally, for a treat, get her special lactose-free milk. She just loved that

[2bthinner!]

They might have liked cow milk, but that doesn't mean that they could easily digest it. I gave my cat milk once and never again. Apart from the mess, it was very guilt-inducing to see my poor kitty being in obvious intestinal distress. From what I'm reading though, raw milk like the barn cats were getting has the necessary enzyme for digestion. Pasturized milk from the store doesn't.

[PlayDoh]

i've had many cats and have not had one yet that cannot digest milk. i have had one that doesn't really seem to care much for any food other than cat chow, but all have been milk drinkers and my one cat is 22? 23? years old now. for some reason, this year, not only has he gotten a little deaf, but he also has started eating every oddball thing under the sun, and the little fart just takes it, it isn't like we gave it to him. things like flax chips, chicken noodle soup, mushroom soup, rice, cookies, pretzels, licorice, bread, bagels, coffee, you name it, he eats it. if anyone leaves any food laying around, he'll find it and eat it. he's been offered meat before, but he grew up mostly on kibble and i can't figure why he's going nuts for human food now. he's always loved milk though.

[ysabella]

Ferrets like milk, too.

They like ice cream even better, though. :D

[glennette]

i've had many cats and have not had one yet that cannot digest milk. i have had one that doesn't really seem to care much for any food other than cat chow, but all have been milk drinkers and my one cat is 22? 23? years old now. for some reason, this year, not only has he gotten a little deaf, but he also has started eating every oddball thing under the sun, and the little fart just takes it, it isn't like we gave it to him. things like flax chips, chicken noodle soup, mushroom soup, rice, cookies, pretzels, licorice, bread, bagels, coffee, you name it, he eats it. if anyone leaves any food laying around, he'll find it and eat it. he's been offered meat before, but he grew up mostly on kibble and i can't figure why he's going nuts for human food now. he's always loved milk though.

Ditto! I used to do a fix and release on strays and their first meal would always be milk. Never had one refuse or have problem after drinking it.

[mike_d]

I would expect lactose intolerance developed because many people that could tolerate animal milk died from disease before they could reproduce. The human genome is not well adapted to refined carbohydrates or even grains because they kill so slowly there is no natural selection.

[Nancy LC]

From what I'm reading though, raw milk like the barn cats were getting has the necessary enzyme for digestion. Pasturized milk from the store doesn't.
I think this has become Internet lore. I've looked into claims that raw milk has enzymes that allow you to digest it versus pastuerized, it is true there is one enzyme, that I could find that is disabled by heat, but it helps break down phosphates, think it was called phosphotase.

So before I'm willing to believe that raw milk, with its risk issues, is easier to digest, someone needs to document what enzyme is in unpasteurized milk that isn't in pastuerized milk... because I sure couldn't find anything. I looked because I wanted to keep having milk products but I have an autoimmune intolerance to them.

As far as something breaking down casein.... I don't think fermenting or anything else affects it, although there is a bacteria with caseii in it's name but I haven't figure out what it eats but the only time that ever gets into milk is when someone sticks it in there on purpose (like making yogurt with special starter).

[2bthinner!]

I don't know exactly what pasturization does to foods, but it does something. My mother gets bad indigestion from pasturized orange juice, but if she makes it herself from her own orange trees, she's fine. :confused:

[ReginaW]

I would expect lactose intolerance developed because many people that could tolerate animal milk died from disease before they could reproduce. The human genome is not well adapted to refined carbohydrates or even grains because they kill so slowly there is no natural selection.

Humans are not lactose intolerant at birth, or until after between age two to five or a slow progressive loss of digestion of lactose into adulthood...and many have a "mutated" gene that allows for consumption of dairy into adulthood without problems.

That "mutation" is actually micro-evolution at work, called neoteny - the adaption to maintain a juvenile trait into adulthood.

Examples of populations with this are those with ancestry in Europe, the Middle East, and India; and the Maasai of East Africa - many of these populations have a version of the gene for continued lactase production in adulthood - the ability to make lactase is not disabled after infancy - most probably because it was these peoples long ago who used milk from cattle, goats, and sheep for a source of food. Something important to keep in mind is the milk in these populations is usually raw (thus has lactase in the milk) or minimally processed nowadays (not homogenized and usually low heat pasturized if it's pasturized) and more often than not, in the past it was fermented - yogurt, kefir, cheese - which reduced lactose in the food eaten....these populations simply had no way to keep milk from spoiling rapidly, so fermenting it made it possible to keep it longer.

[Dodger]

I used to take in a lot of milk. When I switched from a low-fat eating style to Atkins, I quit drinking milk. After about three years, I had some milk and discovered that I now seem to be lactose intolerant. I still eat cheese and butter, but I have problems with milk. Milk is an easy thing to avoid so it is not a problem.

[2bthinner!]

I think there's a heredity at work too. My mother has problems with her stomach, my daughter has problems with hers. But, I'm in the middle, generation wise and have the reputation of an "iron stomach". :confused: I mean, there are a few things that bother me. And they are weird things. Aspartame and hot dogs. Although I haven't eaten hot dogs in years, so I'm not really sure they are still a problem.

[mike_d]

Good point Reg ...

I love kefir, I make my own from a culture I bought at Whole Earth Market and have no problems with it-- that skim milk I can't take it :p

Maybe those that are lactose intolerant have the gene, but its switched off?

[ReginaW]

Maybe those that are lactose intolerant have the gene, but its switched off?


From what I've read, for the majority of humans, "switched off" is the default for the gene...as infants we need to be able to digest lactose since it's in breastmilk, but "need" diminishes as we mature and our diet begins to exclude breastmilk....most people lose the ability to make lactase somewhere between two and five...some take longer and it's thought teh ability may be retained in many as long as exposure continues (although that's certainly not true of everyone) and/or if they have the mutation on the gene to allow continued production of lactase.

What I think is pretty interesting is that raw milk (and breastmilk) actually has lactase in it too - so I have to wonder if perhaps how we process milk today might be part of the problem many have with lactose?

I dunno?....

I know a few people who can digest raw milk and/or fermented dairy (even when pasturized) wihtout any overt symptoms of lactose intolerance - even after years of avoiding dairy because they had horrible lactose intolerance....but they still can't tolerate things made from pasturized-homogenized milk like ice cream or liquid milk - even if they add a lactase supplement. Maybe it's the lactose? Maybe the lack of lactase in the product? Maybe a combination of both with the effect from processing? Who knows?

[LC FP]

It seems strange that the human genome would contain the gene for lactase, the default setting would be "switched off", and human breastmilk would contain lactose and lactase.

It's like a poorly designed Microsoft computer system with a couple "patches" installed.

[arc]

There are people that seem to be lactose intolerant who are actually gluten intolerant. Lactase is produced in the tip of the villi in the small intestines. These villi can be wiped out by the autoimmune response of celiac disease (gluten intolerance). My mom has been lactose intolerant for a long time but is now able to slowly bring back in dairy, the longer she is on a gluten free diet.

[ReginaW]

It seems strange that the human genome would contain the gene for lactase, the default setting would be "switched off", and human breastmilk would contain lactose and lactase.

It's like a poorly designed Microsoft computer system with a couple "patches" installed.

Actually, it's a pretty efficient way to utilize nutrients as needed - lactase produced in infancy (required to ensure survival) then kept on later as one matures means the body is still making something it no longer needs if the diet no longer contains much lactose (which is how the diet is for many in the world - not much dairy); so the gene switches off and production for lactase dimishes because there is no longer a need (declining exposure during weaning for example) and now those building blocks to make lactase go to another process to make something else needed.

Makes sense to me anyway.

[ysabella]

I think this has become Internet lore. I've looked into claims that raw milk has enzymes that allow you to digest it versus pastuerized, it is true there is one enzyme, that I could find that is disabled by heat, but it helps break down phosphates, think it was called phosphotase.
I posted once here where I looked up all about pasteurization - after that outbreak of E.coli at a raw milk dairy here in Washington state - in case that's interesting to you, the post is here (http://forum.lowcarber.org/showpost.php?p=5834284&postcount=22), with a follow-up here (http://forum.lowcarber.org/showpost.php?p=5834295&postcount=23). I also said in another short post, "What I saw in my various searches is, milk in the States that is labeled "pasteurized" is mostly done using the HTST method - as [username] grandpa stated, 72 degrees C for 15 seconds.
More than that is usually labeled "ultra-pasteurized." And of course there's UHT milk that doesn't have to be refrigerated, although I've seen that more in Europe than the States."

So before I'm willing to believe that raw milk, with its risk issues, is easier to digest, someone needs to document what enzyme is in unpasteurized milk that isn't in pastuerized milk... because I sure couldn't find anything. I looked because I wanted to keep having milk products but I have an autoimmune intolerance to them.
As I pointed out in the above-linked posts, pasteurization doesn't necessarily kill off even those enzymes that are present. It will deactivate some, but not all, in general. Not that it matters, because enzymes are something we just digest as proteins.
Plus that, raw milk and pasteurized milk sour the exact same way, so I don't think raw milk somehow digests itself.

As far as something breaking down casein.... I don't think fermenting or anything else affects it, although there is a bacteria with caseii in it's name but I haven't figure out what it eats but the only time that ever gets into milk is when someone sticks it in there on purpose (like making yogurt with special starter).
A quick search: Wikipedia page for Lactobacillus casei (http://en.wikipedia.org/wiki/Lactobacillus_casei). Used in the making of sour cream and cream cheese, and present in human mouths and intestines. I know some people here on the boards say they can't handle casein, I wonder if they have less of this, or something?
Yeah, I don't know what it really does, except produce acid. Huh.

[ysabella]

Ooh, NancyLC, interesting thing on http://en.wikipedia.org/wiki/Raw_milk :

Some people say that pasteurized milk converts the protein casein into beta-casomorphin-7, which some in turn link to autism. This argument is based on incorrect knowledge of casein digestion. The process of human digestion, not pasteurization, converts casein into casomorphins (including beta-casomorphin-7) regardless of whether the consumed milk product was pasteurized. Since a person's body creates these byproducts from any casein it encounters, it makes no difference as to the source of the casein, be it from raw or pasteurized milk, cheese, yogurt, etc. In addition, casein and casein micelles are not degraded by pasteurization temperatures [3], but are coagulated upon boiling, which explains the different consistency of boiled milk. In regard to total elimination of casein from a person's diet, see gluten-free, casein-free diet for more information on reported effects of this particular diet.

So then on http://en.wikipedia.org/wiki/Gluten-free%2C_casein-free_diet :
The molecular structure of the partially undigested proteins, known as peptides, resemble opiates. It is thought that such peptides have an effect much like opiates in the brain and nervous system. From this premise it follows that long term exposure to these opiate peptides can have many damaging effects on the developing brain and also affects behavior, just as any narcotic would.

The opioid peptides involved are identified as casomorphines from casein, and gluten exorphines and gliadorphin from gluten.

There's a Wikipedia page on 'Casomorphine' but it's totally unsupported. It mentions supposed opiates from casein, gluten, and...spinach.
I remember someone on this board haranguing me that whey protein and MSG act "just like cocaine" on the brain. So people really have a thing about foods turning into opiates, apparently. Which is far from proven, apparently.

Interesting stuff! But I should get back to work.

[waywardsis]

Ysa, I've noticed a big change in my mental state having given up gluten and casein, two proteins that I have autoimmune reactions to. I didn't realize I was low-level depressed much of the time, bc I'd always felt that way. Moods are different, I'm less irritable, more optimistic, etc. I no longer lapse into dark broodiness or have crying jags for no reason...I could go on. I ahd no idea that g or c could even affect anyone in that way; these improvements were a total surprise. So something's going on neurologically with this stuff, at least for some of us.

[ysabella]

waywardsis, glad you're feeling better!

I'm not saying casein/gluten can't have any neurological effects. I couldn't possibly. It's just that for all we know, neurological effects could be via some other pathway, not this opioid idea. It isn't proven. The blood/brain barrier is complicated (http://jn.nutrition.org/cgi/content/full/130/4/1016S), after all.

Edited to add, if casein is a problem, raw milk will not be any better than pasteurized, apparently. And I guess maybe boiled milk will be different, although I'm not sure what it means to digestion and so on if the caseins coagulate. :confused: