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Evolving to handle grains?

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  • Evolving to handle grains?



    Ok, so grains are pretty bad for us but since they have been with us since the dawn of civilization I think they're here to stay. If this is indeed the case, how long before we evolve to cope with the anti-nutrients in them and do our systems cope with them any better than the people 10,000 years ago?


  • #2
    1



    Interesting question.


    Thing is, as long as someone survives long enough to reproduce, their genes will be passed on. That's why late-onset diseases such as dementia haven't been selected against. It's also the basis of the claim that humans have stopped evolving due to medicines and fertility treatments, but that's a whole other can of worms!


    It does seem anecdotally that some people are more sensitive than others, but I couldn't tell you if that was genetic, or related to aaaaaall the other differences in life!

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    • #3
      1



      Probably in a million years or so. But do you think we, as a race, will even last that long? No chance.

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      • #4
        1



        From what I&#39;ve read, it takes an organism about 500,000 years to adapt to a new dietary plan. We&#39;ve had maybe 10,000 years. It&#39;s not going to happen anytime soon.

        Primal eating in a nutshell: If you are hungry, eat Primal food until you are satisfied (not stuffed). Then stop. Wait until you're hungry again. Repeat.

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        • #5
          1



          Actually, evolution only occurs when there is some pressure to do so. If there is no pressure forcing a change in the gene pool (where those better suited to survive, do so, and pass on their more-suited genes to their offspring), than there is no shift in the species. Because the cumulative effects of the CW way of eating tends to affect people later in life, after reproduction may have already occurred, chances are that any "favorable" CW-diet genes will not increase within the gene pool.


          And Raphael is right in the sense that very few species really ever last that long. There are some hypotheses that many dinosaur species were eliminated due to their inability to adapt to the angiosperms (flowering plants) that over-ran the planet, pushing the gymnosperms northward. Most dinosaurs couldn&#39;t tolerate the colder temps as well. Before the final hit of possible meteor or volcanic eruptions occurred, the dinos were on their way out anyway.


          It is funny how humans look at the planet as a place to preserve "as is" and "for us." This planet will likely go on without us very easily and species are likely to replace us just as has been done many, many times in the almost 5 billion years of its existence.


          Sorry, I digress, but I do love to talk evolution (and not evolution vs creationism).

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          • #6
            1



            But Griff, what about evolving to digest lactose? That seems to have happened to Europeans in a fairly short time.

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            • #7
              1



              I think it&#39;s because lactose isn&#39;t as bad as what&#39;s in grains... besides, at one point in our lives (as babies) we could handle it very well. It&#39;s only a sugar.


              Anyways, I don&#39;t know much, so I might be wrong. :P

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              • #8
                1



                Yep, the ability that some of us have to tolerate lactose in adulthood was a fairly simple genetic alteration. The changes required to more effectively digest grains would take a lot more time to evolve.


                The gene for lactase, the enzyme that breaks down lactose, is switched on from infancy until sometime in childhood. Then it shuts off, because presumably you are no longer ingesting breastmilk, and your body would rather not waste resources making an enzyme that is not needed. But fairly simple mutations have occurred which can keep the gene from shutting off. Those changes allow some people to continue efficient digestion of lactose in adulthood.


                However, I wouldn&#39;t go so far as to say we&#39;re now perfectly adapted for digesting cow&#39;s milk products. Sure, some of us can handle lactose, and that ability probably conferred a competitive advantage at some point in time. But some humans who have no trouble with lactose DO have significant trouble handling cow&#39;s milk proteins (caseins and/or whey). This can cause true allergies or dairy intolerance/sensitivity. The latter are often milder and may go completely unrecognized, but they can have significant negative impact on health.

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                • #9
                  1



                  You don&#39;t really evolve to digest lactose. All mammal babies are born with the ability to produce lactase, the enzyme to digest lactose. But the gene that makes the instructions for making lactase is turned off around the age of weaning in most mammals, probably triggered by the transition to other foods. We humans have decided to continue drinking/eating OTHER mammals&#39; milk, so many of us keep producing the enzyme. This is more of a case of an environmental trigger (continuing to drink the milk) affecting the gene&#39;s expression. We don&#39;t have to develop new gene instructions to drink milk - just keep the ones we have working. My guess, and it is truly a guess, is that some cultures use dairy so prevalently that the gene mechanism to shut down may have been altered some, IF it gave those who could tolerate milk longer a reproductive capacity edge. This might be true in northern clime cultures who may have depended on milk products to get them through hard winters or through drought periods, etc. If children died early because they could not tolerate other mammal milk, then it is possible that there was some selection for those that kept the enzyme working longer.


                  Evolution can work quickly, but it can be harsh - you either survive or don&#39;t and you better hope there are some members in the group that will be able to pass on those survival genes to the next generation. If no one has the genes, the species is out of luck. Just ask the several million species or more that are long gone from this planet. Cheetahs, for example, are so genetically similar that if something comes along like a virus that kills one, it will most likely wipe the remaining population out because they have no genetic diversity.

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                  • #10
                    1



                    Anyone interested in the genetics of lactase persistence can read all about it here -


                    http://www.ncbi.nlm.nih.gov/entrez/d....cgi?id=223100

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                    • #11
                      1



                      There is some really need speculation that Europeans white skin is a genetic adaptaion to drinking milk - here is a portion of a writing by Loren Cordain:Prevalence of Lactase in Northern Europeans


                      Northern Europeans and their descendants are unusual amongst the world’s peoples in that they maintain the ability to consume cow’s milk without digestive discomfort because their guts produce lactase, the enzyme necessary to digest lactose, the sugar found in milk. Between 70 to 90% of Northern Europeans maintain the adult lactase persistence (ALP) gene, whereas the presence of ALP in most of the world’s people is much lower, ranging from approximately 3 to 25 % (Figure 1)28.


                      Figure 1. The percentage of some world’s people with the ability to digest lactose in milk.


                      The standard evolutionary explanation for the presence of ALP in Northern Europeans is that once they had adopted dairying, selection for the ALP genes allowed lactose in milk to be digested without gastrointestinal disturbances and diarrhea. Consequently, ALP enabled calcium and other nutrients in milk to be readily digested, thereby enhancing nutrition and increasing survival28. One of the problems with this explanation is that many of the world’s societies with long histories of dairying, such as the Mongols, the Herero, the Nuer, the Dinka, the Zulu and the Xhosa have low levels of the ALP gene and are generally lactase deficient28, 29. These people have taken a behavioral approach to reduce the lactose in milk by consuming it as fermented products (sour milk, kumis, and yogurt) or as cheese. Certainly, Northern Europeans could have taken this approach. So the evidence suggests that the selection for ALP in Northern Europeans must have occurred for reasons other than the additional calcium and food calories found in fermented milk products.


                      Extreme Dermal Depigmentation in Northern Europeans


                      In addition to maintaining a high frequency of ALP, Northern Europeans are unique amongst the world’s people in that they exhibit extreme dermal de-pigmentation. Blond or red hair, very light skin and blue or gray irises are external characteristics that rarely occur together in any other people of the world. The standard evolutionary explanation for extreme dermal de-pigmentation is that Northern Europeans resided at high latitudes where sunlight was seasonally restricted causing impaired vitamin D metabolism30, 31. Accordingly, the selection for light skin enhanced vitamin D synthesis during brief periods of sunlight exposure in these high latitude, sunlight compromised people. The problem with this explanation, as has been previously pointed out, is that other world’s people living at similar or higher latitudes have not evolved extreme dermal depigmentation32 as depicted from the Biasutti map below (Figure 2).


                      Figure 2. The Biasutti map depicting skin pigmentation in the world’s peoples29.


                      Putting It All Together: The Bigger Picture


                      The reason why Northern Europeans evolved extreme dermal de-pigmentation was two fold. First vitamin D metabolism was slightly compromised in these people from reduced sunlight exposure by living at higher latitudes. But more importantly, regular consumption of whole wheat, because of its high WGA content, pushed vitamin D metabolism to the breaking point, likely causing an epidemic of rickets during the Neolithic. Remember that WGA gets into the bloodstream by binding the EGF-R, and then impairs vitamin D metabolism by blocking the nuclear pore, thereby preventing vitamin D from doing its job. So, one evolutionary strategy employed to overcome WGA’s deleterious effect upon vitamin D metabolism was to select genes coding for lighter skin so that more vitamin D could be synthesized during intermittent sunlight exposure.


                      The second evolutionary strategy taken by natural selection was to reduce or impair the uptake of any WGA that was ingested from wheat. This is where the selection for the adult lactase persistence (ALP) gene comes in. Raw cow’s milk is a rich source of epidermal growth factor (EGF) and contains 325ng per ml33. In contrast, the processing of milk to make fermented milk products will greatly reduce or destroy EGF as it is unstable when exposed to heat, light and acidity33-35. By ingesting raw cow’s milk Neolithic people would be directly dosing themselves with EGF which then could compete with and displace WGA for the EGF-R. Further, EGF from cow’s milk would facilitate gut healing to reduce the number of EGF receptors elicited by the destructive effect of WGA on the gut lining. The net effect of additional EGF from cow’s milk would be to impede entry of WGA into the bloodstream thereby improving vitamin D metabolism, which in turn would reduce the incidence of rickets.


                      Neolithic individuals bearing the ALP genes would gain selective advantage over those who didn’t have this gene because they could drink EGF containing cow’s milk without gastrointestinal discomfort. Consequently, over the course of hundred of generations, there would have been a rapid selection for the ALP genes, not because the calcium and food calories in milk provided crucial nutrition, but rather because the EGF in milk countered the rickets producing effects of WGA from whole wheat consumption. Thus, the extreme dermal depigmentation and high prevalence of the lactase enzyme in Northern Europeans were caused by the same negative selective pressure: high consumption of WGA containing whole wheat. Perhaps there are additional lessons to be learned by us all from this 10,000 year evolutionary experiment in eating whole grains.

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                      • #12
                        1



                        "Perhaps there are additional lessons to be learned by us all from this 10,000 year evolutionary experiment in eating whole grains."


                        Yes, don&#39;t eat them. Or if you are going to eat them, drink raw milk?

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                        • #13
                          1



                          Cordain&#39;s thoughts are very interesting. I had been under the impression that latitude was sufficient to explain lightened skin color. It would have been helpful to see Figure 2, but I think I&#39;d need more detail than that to be convinced. I&#39;d want to know, for example, how long the non-depigmented populations have been living at northern latitudes, how their lifestyles compared to those of lighter-skinned Northern Europeans, how their diets compared, etc.


                          However, he&#39;s making me cringe with all the "ALP gene" talk. He means adult lactase persistence allele, not gene. Alleles are forms of genes. People who can digest lactose in adulthood don&#39;t have extra copies of a modified lactase gene. They simply have a variation of the gene (an allele) that allows continued production of lactase in adulthood.

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                          • #14
                            1



                            The use of fermented dairy makes sense to me. Seems that fermented/sprouted/soaked grains are more tolerable to many human&#39;s as well. Weston A Price Foundation stuff all around!


                            I experimented with soaked/sprouted/fermented grains in the past, and had success with it, no real obvious pitfalls. But a bit more reading on grains&#39; potential harm to our auto-immune system and gut had me swear off them. Once I did, I had a marked elimination of joint pains AND my seasonal hay fever/allergies vanished. It&#39;s all stayed that way for quite some time now, so I&#39;m taking it as cause and effect.


                            That, and all that prep time to use grains in the WAPF manner is too much for me. I&#39;m too lazy it would seem.


                            Thanks for the bit about "alleles vs. genes" Pikala. Seems I learned that back in high school? but forgot. Details like this are pretty important it would seem. It shows the step to utilize lactose late in life is NOT a huge evolutionary step as evolving to grains might one day require! If we should ever get there.....

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                            • #15
                              1



                              Thanks, Pikaia - you did a better job than I did explaining the lactase enzyme allele. I am used to explaining evolution to 10th graders and sometimes I have to start simply than add the details later. Love your posting name, by the way. I wonder how many know what Pikaia is? One of my favorite Cambrians

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