Sunday, August 22, 2010

Zombieland

Back in the day, we ate a lot of brains.  Stands to reason.  All animals come with one, after all.  And we certainly wouldn't leave behind such a great source of important fat.  

Have you seen the movie Zombieland?  I highly recommend it if you're into gore and fun, and while the dietary advice isn't necessarily paleo, the exercise discussions take a functional fitness turn... (link is not "safe for work," as they say).

Zombies might be lacking in variety with their chosen food, but they certainly wouldn't be lacking in micronutrients and omega 3s!  Brains are also an especially rich source of phospholipids, one of which, phosphatidylserine, was mentioned in a comment on Friday's post by Sue.  She seems to have had luck with it helping her joint pain and fatigue.  Terrific!  But why?

Well, phospholipids are found in many foods, but the highest concentrations are in brains and seafood.  When one looks back at different hunter-gatherers roaming the world, they would tend to eat a lot of seafood, or they ate a lot of large land-roving mammals, or both.  It would make sense that today we might have a lot less phospholipid intake compared to our evolutionary past.   In fact, today's foods contain about 1/3 the amount of phospholipids they did even at the beginning of the 20th century (1). 

Research in phospholipids was heating up in the 80s and 90s, but then a little illness came along called mad cow disease, and since the major source of phospholipids for supplements was cow brain, things slowed down for a while until an alternative soy source was found.  Not surprisingly, the soy sourced supplement is somewhat different than the animal sourced one, but looks like from perusing pubmed that almost all the latest research was done with the soy version.  If you are not fond of soy, krill oil combines omega 3 and phospholipids, and since krill (or the algae they eat) are the food for marine animals from which many ancient humans got their phospholipids, it would certainly be a more evolutionarily pedigreed source than soy.

But what does the research show?  Do we suffer as human beings because we've greatly reduced our phospholipid intake?  Well, in sports performance studies, phospholipids can help reduce pain and speed up recovery (1).  And supplementation can result in a statistically significant improvement in your golf shot (2).   This study of memory and cognition in the elderly didn't show any improvement using the soy-derived versions (3), though other earlier studies showed positive effects.  But the most intriguing part of the research is when you find out that ingestion of phospholipids has been found to reduce increases in ACTH and cortisol in response to stress (4).

I've always wondered why we modern humans are considered so "stressed."  I mean, sure, we are probably way more stressed than the majority of our ancestors who worked obtaining food 17 hours a week and otherwise hung out and told stories and played games.  But the most accepted pathophysiologic model for major depressive disorder and other mental illness is the stress diathesis model.  Meaning stress combined with genetic vulnerability changes your brain and causes your symptoms.  There's a lot of research support for this model and it makes a great deal of sense.  BUT.  Mental illness has been increasing over the 20th and 21st centuries, especially depression.  Maurizio Fava said in a lecture it is increasing 10% in each generation since the 1950s.  That is HUGE.  We know this (in America at least) from epidemiological catchment studies (5) done since the beginning of the 20th century.

But are we really more and more stressed?  In the first 50 years of the 20th century, there were two huge world wars.  Millions of people died from huge flu epidemics, and when my mother was a child, there was still constant fear of polio.  By the 60s we were worried about global nuclear annihilation.  Sure, now I have to remember 40 different passwords and traffic is pretty rotten, and we worry about terrorism and relatives with chronic illness and young men and women are still fighting wars, but is that more stressful than what families faced in the last century?

I don't think stress has changed so much, at least from the last century to now.  Agricultural humans have always been unhealthy and stressed, and I don't see how increases in cardiovascular disease and mental illness over the past 100 years could be explained *strictly* by a stress (cortisol) model.

I contend (as many do) that the MAJOR change in the last 100 years has been our industrialized diets.  Agriculture is one thing, and not good for human health (though it did beef up human fertility).  But industrialization of the food supply, I believe, is the primary causative factor in our modern physical diseases and our modern decline in mental health.

And here we have a bit of evidence that may bring diet and stress together at last.  Phospholipid supplementation, in a few studies, decreases our stress response, especially to emotional stress.  (No one had a clear idea why, unfortunately, in the studies I looked at, but as usual, I'll keep an eye out!).  Imagine day after day of munching on mammal brains or atlantic herring, rich in phopholipids, and thus (if one believes the research) having a blunted hormonal response to emotional and physical stressors, compared to our relatively phospholipid deficient diets of today.  Modern disease pathology is all about the cortisol, as much as it is all about the insulin.

We are built for eating brains and seafood.  The farther we stray from our ancestral diets, the more we seem to suffer.

(Thanks to Sue and Geoff and other commenters for your thoughts and ideas on these topics!)

9 comments:

  1. "atlantic herring, rich in phopholipids" that explains A LOT. i often wondered why my brain goes into overdrive when eating some herrings, so that i at times even had a hard time going to bed. the effect indeed was exactly as if i had taken a PS pill. funny :)

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  2. Thanks for bringing phospholipids to my attention. Since going primal, I've been eating a lot of sardines and smoked oysters. And my wife often asks me why I never seem to be stressed out. My 2 year old at her first smoked oyster on Friday and liked it! There's hope for her future afterall.

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  3. Egg yolks are a good source too! Can't believe I used to throw away the yolks in my BFL days...

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  4. When I was a kid back in the 60's, crumbed lambs brains were served regularly for dinner (as were tripe, tongue, liver, heart and kidneys)

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  5. Thanks, Doc! That makes a great deal of sense.

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  6. one thing you said, that agriculture beefed up fertlity... my generation however is the resulting baby boomers from agricultural monkey-like-reproducers.... the offspring of this baby boom from agriculture has an infertility rate out the wazoo... its like 1 in 8 women are infertile. everyone has something wrong with them it is rididculous.

    youre spot on about the stress and food connection, i really wish i could get my dad to understand this. i watch him down a candy bar, get his serotonin, fall asleep, then wae up grumpy and do it again. not overweight at all but his brain has this NEED for carbs and crap

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  7. Julianne - I know someone who fed brains to her kids and told them it was chicken! It was a common meal anyway where she came from...

    Malpaz - My speculation is that the hyper-industrialization has begun to cause infertility (perhaps not just through the obvious mechanisms such as metabolic syndrome leading to PCOS and infertility). But no one can argue that the human population hasn't ballooned with agriculture itself, from 10,000 years ago to today!

    Sue - thanks to you! I was looking for a direct link from diet to cortisol and you found one. Wouldn't it be nice if we could design large, thoughtful prospective controlled trials to prove all this stuff, though?

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  8. Another fascinating post! Thank you. I have tried to get our various farmers to include the brain in our beef/lamb/bison orders, but there isn't a butcher in site willing to take his/her chances with the health inspector. I will be looking for a decent supply of herring. I do have plenty of tongue and heart in my freezer. Do you know how they compare to brain in regards to Phospholipid count?

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  9. Hi Tara - chicken heart is apparently a very good source, but I don't know about other hearts or tongue. The wikipedia article has a good list:

    http://en.wikipedia.org/wiki/Phosphatidylserine

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