• diet & genes: take two

    August 12, 2009

    In June I wrote about the impact of evolution and migration patterns on diet.  The post came after I attended an event at the Science Museum called “Moving Genes,” and it featured Dr. Mark Thomas, professor of Evolutionary Genetics at University College London.

    Whenever I write about someone, I like to send them a link to the post; and I was delighted when Dr. Thomas replied right away.  He attached a couple of relevant scientific papers, which admittedly gave me a minor headache as it has been quite a while since university.  He also very kindly let me know that I had misquoted him!

    Now, I actually love it when I’m wrong; because it means I’ll learn something, and in this case it also meant I’d have another post for you.  We agreed to talk the following week to clear things up.

    I wish I had hours and hours to speak with Dr. Thomas; his subject matter is so interesting to me it almost makes me want to go back to school.  I’ll try to sum up our conversation:

    The human species

    In comparison to other species, our biological difference are mostly skin deep.  The operative word here is “mostly”, which I had left out of my previous post.

    We all share a common ancestor that lived around 2,500 years ago.  It’s possible that some or many of us do not carry any genes that were inherited from this common ancestor.

    If we go back 4,000 years, everybody that was alive was either a common ancestor of everybody alive today or not an ancestor of anybody alive today.  I had to read that one several times, and I’m still not sure what it means.  Dr. Thomas clarified that it’s these points that many geneticists found hard to understand – not the general information I had related earlier.

    Milk tolerance

    As I learned during out call, just one word can throw off an entire scientific conclusion.  Dr. Thomas corrected my previous assertion about the digestibility of milk amongst Europeans: some of them have only been able to digest milk for 7,000-8,000 years.

    During times of drought and famine, populations that had access to cow’s milk – and could digest the sugar in milk – could ride out crop failure by drinking this (relatively) uncontaminated fluid.  Therefore, these groups would survive and reproduce whereas others could not.

    Frugivorous origins?

    As I mentioned before, I’ve been reading Dr. Douglas Graham’s 80 10 10 Diet – an intriguing read that makes a good case for how humans are designed to obtain the majority of our calories from fruit.  Dr. Thomas said that the best evidence for a frugivorous past is the color receptors in our eyes.  The majority of mammals have two receptors, whereas we and many of our primate cousins have three – the better to identify fruit with.

    Meat heads

    Again, a clarification:  Populations who ate meat must have had a major advantage, and we can measure this by looking at their genes.

    Dr. Thomas says:  “Our brains could not have evolved to be so big unless we had a high-quality diet with a high meat component.  Big brains are just too energetically expensive to maintain without rich food.”  However, he adds that we would have started out as scavengers, not hunters, until we developed tools 2.5 – 1.5 million years ago.

    I was in error when I stated, “our brains would not have evolved had we remained at the hunter-gatherer stage.”  Actually, we’ve all been at this stage our entire history up to 10,000 years ago.

    I learned a great deal during our call and was of course curious about Dr. Thomas’ vegetarian origins.  He said he went veggie at two-and-a-half years old when he saw his mother plucking a chicken and made the connection between the bird and his dinner.  He says, quite candidly, that he simply finds the idea of eating poultry and seafood disgusting.

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  • is diet coded in our genes?

    June 26, 2009

    Oooh, I have so much up my sleeve!

    First, I’m really excited to be doing my first round of videos for the blog, a series taking you inside my kitchen so you can see where I come up with the recipes on the site and how everything is set up.  I’ll be posting them within the next few days.

    Tomorrow I’ll also be attending a daylong event all about living foods given by Dr. Brian Clement of the Hippocrates Institute in Florida.  Full report to follow.

    But today I wanted to share what I learned last night at an event at the Dana Centre, part of the Science Museum in London.  I love, love the Dana Centre because, like TED – my other freebie favorite – I always come away with new knowledge that keeps ticking over in my brain long after the lecture is over.

    Last night’s topic was “Moving Genes,” a fascinating (albeit all too brief) look at where the human species comes from and how, despite appearances, we’re not all that different.  I thought this fit in beautifully with the idea that we are all fundamentally the same on a spiritual level, how we all spring from the same consciousness.  But here was evidence that we are even more similar than we think, even if we do think quite similarly.

    By far the most intriguing speaker of the night was Dr. Mark Thomas, a senior lecturer in genetics at University College London.

    With obvious zest for his subject, Dr. Thomas explained why all of us are, almost certainly, an African species.  Here are some of his supporting points as noted on his slides:

    • We are not a very diverse species; our differences are only skin deep
    • We all share a common female-line ancestor around 170,000 – she was African!
    • We all share a common male-line ancestor around 70,000 – he was African!
    • So, Adam never met Eve

    Now, I get the African part, but how the above numbers work out is totally beyond me; and, according to Dr. Thomas, even certain genius geneticists can’t make sense of it.

    Of course, my mind started thinking about food, and how these findings line up with 80 10 10 which I’m currently reading.  One of the most intriguing aspects of the book for me is that we originated and evolved in the tropics, hence we are designed to eat a diet based on the fruit that grew there.  The author, Dr. Douglas Graham, goes on to say that we create a “mini tropics” wherever we migrate via artificial means such as central heating and clothing.

    So, when Dr. Thomas said that Europeans have only been able to digest milk for the past 1000 years, I made note and asked him to elaborate during the Q&A session.  I asked him if he has found similar patterns for digesting grains and whether our African ancestry indicates we should consume a certain diet.

    Dr. Thomas was adamant that the amount of nutrition information out there has created an “ideas salad” and that theories such as the blood-type diet are utter garbage. Dr. Thomas is a vegetarian, yet he also stressed that those groups who evolved to drink milk had a major advantage and that our brains would not have evolved had we remained at the hunter-gatherer stage.

    I like the term “ideas salad”, and my take is that we each have a responsibility to take a good look at the providence of all the ingredients in that salad, if you get my drift.  Every theory is worth examining, if only to broaden and challenge your own.  I know that my diet keeps changing the more I learn and the more I evolve.

    If the consumption of meat catapulted our evolution on a physical level, might not the current global shift towards a plant-based diet propel us towards an evolution of a different kind?

    I debated this and other questions after the event with a rather vociferous and interesting gentleman who accused me of having an agenda…stay tuned for all the gory details!  Have a great weekend.

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