Paleo/NT, Is Eating Dairy Natural? - Page 5 - Mothering Forums
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#121 of 127 Old 11-05-2006, 08:23 AM
 
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Originally Posted by Ravin View Post
This totally ignores the reality that we've been undergoing natural selection in relation to those foods we've adopted over the last ten thousand years. Lactase persistence, for example, can be traced to 2 mutations, one found in highest concentration in Northern Europe, the other in West Africa (if I remember correctly). That 13% of the human population with a mutation for lactase persistence have it because under conditions of dietary inclusion of dairy products, it has a selective advantage. In populations that don't eat dairy, there's no advantage to such a mutation so it would be unlikely to become widespread, and in populations that haven't had a mutation that results in lactase persistence enter their gene pool, it won't matter how much dairy they eat, they still won't have lactase as adults.
I guess the question that I continue to have throughout this thread is whether human adults need to be able to produce their own lactase in order to benefit nutritionally from dairy.

I'm Asian, so probably very unlikely to carry any genetic ability to continue to produce lactase into adulthood, yet I can drink milk (even pasteurized) quite comfortably. My dh (Jewish with roots in Northern and Eastern Europe) is um... noticeably lactose intolerant , yet even he isn't so uncomfortable that he will avoid dairy. And he tolerates yogurt and cheese without a problem at all. Of course, there are those who really can't drink milk, but I'm wondering if they are perhaps the exception rather than the rule.

So I guess the question that I have to answer for myself is whether dairy is more of a benefit than not.

The implication made by Marie, Metasequoia and others that dairy and grains, in and of themselves, are a root cause of the decline in health among neolithic people seems too far a stretch to me. Nevertheless, I would be really interested in seeing some arguments that are more about the direct links between milk and disease. (I'm not saying this in a snarky "prove it to me" kind of way; I really would like to understand this. Is it a protein-fat-carbohydrate ratio, as some have suggested? Some immunofactor that is good for cows, but maybe not humans?)

And although I have not yet read NPD :, I'm pretty fascinated by all the references people keep making to those fabulously healthy cheese-eating, milk-swigging Swiss. And the Masai. And the yogurt-eating, long-lived folks in western Asia. And all of Weston Price's results with high vitamin butter oil. Of course, other groups make it clear that one does not need to have milk in order to have a healthy, long life. But still, if milk is genetically inappropriate for humans, I'm having a hard time understanding these reports.

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#122 of 127 Old 11-05-2006, 12:29 PM
 
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Last post on this thread...I will reiterate, as I have before:

Eating grains and milk is small quantities is NOT the problem. We are omnivores and can handle small amounts of almost any food that is not poisonous.

It is the LARGE quantities that is the problem. To the exclusion of other foods. This is our diet today. Take a careful look at your own diet and examine ingredients. How much dairy and/or grains/legumes do you eat every day. I did this for myself two years ago, and it is SHOCKING what is added to processed foods.

I do not argue that humans have not gone through small genetic variations in the last 10,000 years. Of course they have. SMALL ONES. No extra organs, for instance, that would help us digest dairy in the quantities that some cultures (ours) consume it.

My guess is that the cultures cited above eat far less dairy than we do on a daily basis, and eat more variety of other foods. It is a guess, but I'd one I'd wager on.

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#123 of 127 Old 11-05-2006, 02:46 PM
 
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Ravin, thanks for your posts. I've been reading with interest. I wanted to back up Marie a little bit. From my understanding of evolution, the basis of changes on the scale of species is random genetic mutations that find support in the environment. Because these mutations are so rare, such wide-scale changes are measured by the millions of years, not just the 10,000's. If there was a genetic mutation that allowed humans to produce lactase (considering it was not possible before), 10,000 years is not enough time to have affected the human species universally. Also, mutations must also give the individual an advantage somehow, increasing the chances that the mutation will be passed on. If, for example, milk was the major source of food, the individual with the mutation would have an advantage over the one who did not. However, in places where there is variety, the advantage would be almost nil.

It must be remembered that Lamarck's "functional" adaptation was debunked. The idea is that giraffes stretch their necks to get at trees. The neck stretches according to function. That change enters into the reproductive cells somehow. Environment does not change the gene directly.

According to one source, http://www.nutritionreporter.com/stone_age_diet.html, we are 99.9% similar to our paleolithic ancestors. So I do agree that evolution is dynamic and always in affect. However the preponderance of genetic similarity remains true and will for a long time. We are 99% the same as the homo species before we became sapiens. Millions and millions of years produced changes to the tune of a mere 1%. That is much more compelling to me than possible changes that could have occured over the last thousands of years.

I'm still confused though about whether we do or don't have lactase. I'm asian too, and mostly lactose intolerant. I don't understand why I would be and others would not. Maybe the production of lactase is determined by some form of recessive/dominant gene?

ETA: If I had read your post in full, I would have seen that you already addressed some of the things I posted about. But I think my point about how wide-spread this mutation could be remains.
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#124 of 127 Old 11-05-2006, 03:15 PM
 
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Small changes are generally all it takes. Certainly one needn't be a lactase persister to gain benefit from milk. It just gives a bit of an advantage, a case of cultural practice being part of the environment in which selective pressure works.

The question becomes, is milk good for you, as an individual, given the variety of food available to you and your body's individual tolerance of it? That is highly variable.

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#125 of 127 Old 11-05-2006, 03:34 PM
 
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Mommay,

The thing of it is, changes relative to the healthfulness of what we eat ARE subtle changes. Producing lactase isn't actually a human novelty. All mammals produce lactase during infancy, it's needed to digest milk of our own species. It's the developmental quirk of continuing to express the lactase gene and produce the enzyme past the age of weaning that is the human novelty.

It doesn't take a major speciation event for evolutionary change to take place. The kinds of things I'm talking about are what's called micro-evolution, changes in gene frequencies within populations. We're a young species, our genome isn't very diverse. But of the diversity that is there, some of it is because of a history of regional natural selective pressures in different environments. Those environments are partly physical, partly cultural. Indeed, at this point they may well be primarily cultural. Strong selective forces can change gene frequencies drastically in just a few generations, if a gene is under selective pressure. And heritable changes in gene expression patterns are even harder to track than simple mutations. It's something we're still learning about.

As cultural beings, the effects of the physical environment on us, and thus its selective pressures, is modified. But, as cultural beings our culture can become a selective pressure as well. In our modern Western culture, selective pressure is modified still more thanks to reproductive technology, modern medicine, and the plentiful, varied food available to us. That's not the case in many parts of the world (such as places where endemic disease kills many people, or where having a cow to get milk from may make the difference between good health and protein malnutrition). We have more cultural options, and therefore less need to eat food we can't digest easily, or more ways to help us digest it if we want to eat it anyway (allergic? take an antihistamine. Lactose intolerant? Drink raw milk or lactaid or take an acidophilus supplement).

We do, however, have our own endemic problems which may well stem from poor choices of diet, novel, evolutionarily untried modern food processing methods, lack of exercise, and chemical exposures no previous human population has dealt with. Our reproductive behavior patterns have changed in major ways as well. What sort of evolutionary effect all this could be having on us in the long term is something we simply can't know in the short term. I'm not talking speciation. I'm talking subtle changes that help us adapt to the world we live in.

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#126 of 127 Old 11-05-2006, 04:50 PM
 
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I did mean "lactase persistence" rather than lactase production at all, which wouldn't make sense given we all need bm.

Yes, micro-changes are all it takes. I'm just surprised that two such mutations occured within a relatively short time. I have always wondered why mutations seem to take hold across the board in certain cases within human evolution, even in populations that are not related to each other. Makes one wonder about functional adaptation. For example, gigantism across the board (amongst animals as well).

I think we agree that if we're still in process, we won't know where we will ultimately end up. Am I the only geek who wishes she could see the universe from the big bang forward in super-sonic speed?
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#127 of 127 Old 11-05-2006, 07:34 PM - Thread Starter
 
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Interesting...

Quote:
MILK

Many hypers find that milk increases hyper symptoms. The high amounts of calcium versus magnesium in milk may be the reason for this observation but there may be another reason: estrogen.

Estrogen is found in milk and studies have shown that estrogen increases cadmium absorption. I believe that cadmium is a major promoter of Graves' disease and TED and the effects of estrogen on cadmium (and possibly other metal) absorption may be the major factor explaining why women get thyroid disease at a much higher rate than men.

Following is a study which states that cadmium toxicity causes anemia, a condition highly associated with thyroid disease. As the article states, cadmium "absorption is increased by co-administration of milk and in conjunction with iron deficiency."

Quoting the study, "Hg++ accumulation in the brains of suckling rats is approx. 10 times higher than in grown animals. Milk increases the bioavailability of Hg++." Does this "10 times" strike a bell for you as it does for me? This is the factor by which women (high in estrogen) are more likely to get hyperthyroidism than men.

The evidence is clearly pointing to heavy metal toxicity from cadmium and mercury which is accelerated by estrogen as the causative factor for hyperthyroidism and hypothyroidism. Milk consumption may be one of the ways that estrogen levels are increased in the body and cadmium absorption is magnified.
Source

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