so don't they realize that when they tell you to cut the fat/dairy and meat, they themselves are advocating cutting out major food groups for millions, if not billions?- how hypocritical!



because that would mean that they spent thousands of $$$ and several years training themselves to be dead wrong! Where would their sense of superiority over the rest of mankind be if they had to admit they know less than the average well-informed internet user? Their self-esteem would surely take a beating! Of course they are not going to change their views or their stance...in spite of the evidence!

I must disagree somewhat with your conclusion. Although humans "originally" came out of Africa, there was clearly enough separate evolution and development to give people in Europe and Asia different traits. My ancestors having been in Europe for 30,000 years or so DOES make a difference to my physiology. My people adapted to lactose, for example, as well as having blue eyes for vitamin D absorption.

Sorry, but tracing your ancestry back to Europe instead of Nigeria is an important clue as to what foods you deal better with.

Don't get me started


Lee

I was trying to go with a tree analogy with branches off branches off brances off branches etc. Sounded silly when I wrote it down.

Lee

I think blue eyes have been traced to a single ancestor who had a mutation. If you know someone with blue eyes, you both have that ancestor in common - my mother had blue eyes, so nice to meet you, cousin!

And yes small changes in genetics according to how long ago your ancestors took up agriculture do have an effect on tolerance to certain foods - those with only a few generations of agriculture do worse than those with many generations when eating westernized food. People with darker skin do worse for vitamin D in the northern hemisphere, because white skin is an adaptation to allow more vitamin d to be absorbed.

Lee

Yeah I read that about the blue eyes too, but they were "selected" in certain parts of the world all the same.

I want to make something clear: I am well-educated and understand human evolution and the out of Africa theory. However, I disagree that just because we all "originally" came out of Africa we are all the same when it comes to food tolerance and food adaptability. The reason many people of African descent, and almost no people of Nordic descent, cannot tolerate lactose is because something changed in those two ethnic groups AFTER they split up.

BTW, I normally do not get annoyed with disagreements here (in fact I encourage them), but NancyLC, when you responded to what I said, you added a little "laughing at you" icon. I sort of don't get that. Is it supposed to make me look/feel stupid?

Do you have any supporting evidence for this statement? This sounds a lot like the blood type theory.

I don't explode from lactose when I eat dairy and I definitely know it isn't a good food for me. It probably wouldn't kill me off or shorten my life by too many years, but it makes me feel miserable and I'm much better off eliminating it. Blue eyes, fair skin, European... I do better modeling my eating like the humans responsible for most of my genes, the Africans.

AFAIK there's no advantage to having blue eyes. It is the skin where D is manufactured. Funny thing is, the folks native to the arctic circle have rather dark skin. So, as long as populations are eating vitamin D rich foods they hunted, why would light skin even be necessary? Nowadays people rarely eat liver.

It works out because they eat a lot of vit. d rich foods. The selection pressure might have gone the other way. People with fair skin got skin cancer and died in the tropics, before clothes were available.

Here's an article about why light colored skin might have evolved that suggests vitamin D wouldn't even have been a factor until agriculture became predominant.
http://www.livescience.com/7863-people-white.html

I thought the lactose example was decent evidence. Not proof, of course, but evidence nonetheless.

I certainly would not dismiss ancestral heritage when it comes to what we should or should not be eating. You laughed at me when I claimed 100% Northern European heritage. I am still not sure what is incorrect about that (or why it's funny). If I were to say I were 100% homo sapien, would that be incorrect because technically I descended from homo habilus at some point? Aye, we're all "human beings," but there are racial and ethnic differences among people. I think it is perfectly reasonable in light of the fact that some food intolerances, diseases, etc. tend to predominate in certain ethnic groups, to keep that in mind when we choose our individual diets.

And, BTW, as someone who grew up in Alaska, I can attest that the Natives from Barrow at least, were very pale.

It just seems rather arbitrary to me to draw the boundaries at the point where they left Asia to come to Europe. Maybe it's because people get caught up in their race/skin color. It seems as arbitrary to me as someone deciding that 10,000 years of eating grains is enough time for us to fully adapt to it.

Biological differences among races do not exist, WU research shows


Lactose tolerance is evidence of lactose tolerance. *shrug* Does it mean we're okay with everything in dairy products? I would say "no".

I would think the selection pressure on adequate vitamin D from either nutrition or absorption would have been dramatic. Those with vitamin D issues because of darker skin and poor diet in northern latitudes would start to develop issues in childhood. Ricketts can be fatal, and even when not can lead to significant disease and deformity, meaning that those with these issues would be far less likely to procreate. Once disabled, I suspect that these people would have been considered less worthy of the prized parts of the animal which would most likely be given in preference to hunters and fertile women. Without very good dietary sources and unable to get enough via sunlight, it would be likely that over not very many generations, only those with good vitamin D absorption would be having offspring. Those with lighter skin would be at an advantage.

I don't doubt that intelligent homo sapiens would see a pattern in northern latitudes that those with darker skin were more likely to get certain diseases and deformities, making lighter skin a more popular choice when procreating in order to have healthier offspring. Probably compounding the problem.

In communities where there was an abundance of vitamin D containing foods, I would have thought the selection pressure to be far less - but the ancestors of people in those communities would have travelled through different places and lived in other areas where there may have been famines or less food availability, and I think it would only take hundreds of years, not thousands for the evolution of whiter skin.

Regarding whether genetics is important for diet - I think yes. A natural unprocessed diet is probably best for most, and without dairy. But I do believe that there are varying tolerances to different foods due to tiny genetic variations. The longer your ancestors were eating a certain food, the more chance you've developed a tolerance for it - for instance for lactose, due to some genetic adaptation.

Lee

No, we all have tiny genetic differences. Otherwise we'd be clones. There are normal inherited differences and spontaneous mutations that if not detrimental will become inherited. Certain differences due to interbreeding in communities, become associated with those communities.

I find it really reassuring that unless you come from some isolated tribe, we all share a quite recent common ancestor, only a few thousand years ago - kind of makes all those stupid cosmetic and social differences seem less important.....well, to me anyway .


Lee

How do you account for the inuits and native americans that are in very cloudy/cold environments? Peruvians in the Andies... etc.

I think that the issue with D wouldn't have been an issue until people stopped relying on hunting and eating D rich liver. It seems like that would only be an important trait for neolithic cultures.

I think these societies became isolated pretty late on, considering the Inuits didn't cross over from asia until about 1000BC - some selection pressure could well have happened way before then, but the Inuit's skin stopped lightening as they get huge amounts of Vit D from their food - therfore from that point on - no selective breeding due to disease, deformity or death. For all we know, their diet was heavy in vitamin D even before they made the move from Asia.

Cultures that came later to agriculture, and relied heavily on hunting and fishing also tend to have slightly darker skin - probably because of higher vitamin D content in the diet and less need to adapt. The tribes in the Americas were hunting and fishing until a few hundred years ago when their populations took a nose dive due to us diseased Europeans.

I suspect in times of famine, ricketts would often be fatal in the northern hemisphere, and would sadly have affected the darkest skinned worst. Remember the last ice age glaciation didn't recede until about 10000 years ago, there would have been depletion of species numbers, huge competition with other homo sapiens and also neaderthals and other homo species in Europe. Food may well have been scarce, at least some of the time.

The lightening of skin colour issue doesn't make sense until taking into account both sunlight and dietary vit d levels.


Lee

Please. It is NOT arbitrary when it comes to what we should or should not be eating. It makes sense that we would be genetically better suited to certain foods based upon our ancestry.

This is a forum where we discuss nutrition, not a diversity workshop. There is absolutely nothing racist of ethnocentric about discussing this. In fact, I often wonder if one of the reasons blacks in the US have much higher obesity rate than whites IS something genetic. Sadly, we are no longer allowed to talk about such matters frankly without getting called racist, or basically having the conversation shut down. Sadder still, it's entirely possible that raising that question and searching for answers could potentially lead to much healthier people. Oh, but wait, that would be racist. Never mind!

Yeah, yeah, yeah...we all originally came from Africa so we're all the "same" so please, let's not say we're different. Dude, we ARE different in some ways. There are genetic traits which differ among the races and ethnicities. Sadly, nature did not get the memo that "we're all the same" and made some of us different. It's okay. It's okay that we're different.


Not necessarily, but it is evidence that we likely tolerate dairy much more than the person who is lactose intolerant. It is also good evidence that my ancestors had many thousands of years of pastoral living and dairy consumption, and that those who could thrive on dairy were selected and were more likely to reproduce, thus eventually leaving that gene in me.

I'm also more into celebrating the differences in society than trying to pretend we're all the same - we're not clones.

I love getting to know people with different cultures and religions, learning about their history and way of life. I think history shows a pattern of westerners out exploring, trying to inflict their way of life and practices on native peoples all over the world when they weren't ready for it, and who the hell decided our way of living was superior anyway. Not acknowledging and accepting differences has caused untold harm around the world.

Acknowledging, learning about and understanding our differences does more for race relations, and enables us to learn how to best assist those in different communities - especially with things like diet. 90-100% of east asians are lactose intolerant, as well as more than 80% of native americans. Many communities have religious or cultural practices involving food, not anything to do with genetics necessarily, but just as important to each community.

I have to say, I get a far warmer reception when I tell someone I don't know a lot about their culture or religion, but I'd love to learn, than those who just say 'it doesn't matter, we're all the same', which in my experience is met by frowns and head shaking - because the differences do matter to others, when its part of their culture and history or deeply held religious beliefs, sometimes saying 'we're all the same' can be a tad upsetting to some.

Sorry got a bit off topic talking about culture and religion when we were discussing genetics, but there is some relevance, as just as some will have some genetic issues meaning certain foods aren't ideal, there will also be cultural and religious reasons why certain foods aren't accepted.

Lee