Posts Tagged ‘Evolutionary Medicine’

I always get excited when I meet a fellow student in the medical world who has an interest in evolutionary and ancestral thinking. It doesn’t happen often, but I’ve twice run into students who, by subtle hints, have let on that they think our current thoughts on health and nutrition are seriously broken. The back-and-forth as we suss out whether we’re on the same team is like an ever-escalating dance. First someone drops the line “nutrient dense food”, then the other says something along the lines of “I don’t think saturated fats are evil”, and before you know it we’re lauding the benefits of egg yolks and liver. 


In a culture that tends to focus on treating illness rather than preventing it, and in an environment where we’re frequently so busy trying to fix something that we don’t take the time to step back and wonder why it broke in the first place, it is refreshing to find people who like to think deeply about human evolution and ancestry when talking about health and disease. These people are rare in most clinical settings. When I find others who share these interests I generally wish I’d discovered our common interests earlier- I wish we’d had a secret handshake to tip each other off.


In just over a week I’m heading to Atlanta Georgia for the 2013 Ancestral Health Symposium.  There, no secret handshake will be needed to ID those who are interested in evolutionary and ancestral health, as interest in this subject is a prerequisite for attending the symposium.  I’m excited to catch up with old friends, meet new ones, and also to speak at this year’s symposium. 


I’ve written before about alcoholic fatty liver disease (the subject of my PhD research), and I’m looking forward to talking about the role of dietary fats in fatty liver disease at this year’s symposium (though the time slot is shared with some other interesting talks, so I’m not sure I’ll garner much of an audience).  I’m also hosting a panel of ancestrally minded physicians who will be talking about the successes and challenges of using evolutionary and ancestral thinking in their own clinical practice.  They’ll be taking questions from the audience, so if you’re in attendance come prepared- it should be fun!


If you’ll be at the symposium, please say hello!



A good morning of Wilderness Medicine out in Canyonlands National Park,



Here’s the short abstract for my presentation:


Fatty liver disease is a growing epidemic in the developed world, with some estimating that over 40% of the US population have some amount of disease.  The general recommendations for those with fatty liver disease include avoiding saturated fats, though research does not support this recommendation. In fact, saturated fats have been shown to be protective against fatty liver disease with some even having a therapeutic effect. Conversely, consumption of large amounts of polyunsaturated fats that have only recently become abundant in western diets plays a key role in disease development.



Sorry for the slow rate of posts these days.  I’m reaching the end of my final year or medical school (I actually graduate in December), and while fourth year clerkships aren’t nearly as arduous as those undertaken as a third year medical student, all the other loose ends of medical school are piling up on me at the moment. I take the Clinical Skills portion of the boards next week, the Clinical Knowledge portion of the boards at the beginning of September, and I have to get my residency applications ready to go in the near future (which, of course, includes figuring out WHERE I want to submit applications to!).  Of course I also have a presentation to prepare and a trip to Atlanta to plan!  I have a long list of things I want to write about, but at the moment other things are taking precedence.  Thank you for your patience! 


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As an evolutionarily minded medical student, you can sometimes feel a bit alone in the crowd of conventionally minded medical practitioners and students.  I’ll admit that I’ve been repeatedly impressed with the interest that many of my fellow med students (as well as residents and even some attendings) show the ancestral/evolutionary ideas that I sometimes talk about, but most generally find an evolutionary approach to health and wellness interesting, rather than integral, in the consideration of health, wellness, and disease. 


I am not, however, alone.  There are a number of MDs and DOs who are interested in bridging the gap between ancestral health and western medicine.  There is a budding new organization of Physicians and Ancestral Health (with a winter meeting in February that I hope to attend), and there are other medical students who share a passion for thinking about modern medicine in the context of ancestral health. One such medical student is Angela Arbach, a student at Cornell Medical School currently doing research during a year long sabbatical between her third and fourth years of medical school, who I had the pleasure of meeting at the Ancestral Health Symposium in Boston in August.  There we had a long chat about our shared interest in evolutionary and ancestral medicine, as well as our specific areas of focus (she is passionate about women’s health and infectious disease).  I didn’t know it at the time, but Angela would soon be winging her way to Africa, where she would be involved in an international nutrition research project. When we recently caught up over e-mail I asked if she’d be interested in sharing her experience on my blog.  Her travels and observations are something that so few get to experience but so many could benefit from pondering. 


With out further ado: an ancestrally minded med student abroad.

Fresh from the Ancestral Health Symposium (AHS), after several days home in NYC and then a national boards exam in Philly, I was on a 4-hour bus trip to upstate New York to finalize plans for a research project in international nutrition.  A month later, I was on a plane to Northern Uganda: a nation in the global south, devastatingly resource poor, with an uncomfortably recent history of conflict.  [Check out the doc Uganda Rising, on youtube, for more history and a quick but imperative summary of colonialism in Africa].  It’s also a beautiful place.  From polychromatic garb to the giant layered sky underscored by the surrounding savannah, there is no shortage of images to appreciate.  The Acholi people, the dominant ethnic group of Northern Uganda, are still close to their traditional roots despite colonization and the recent influx of modern technologies.  When the English arrived, they left their development plans out of the north, making it easier to forcibly enlist Acholi men in the security forces.  And then, after independence (50 years, last month!), the north remained isolated and underdeveloped due to the LRA insurgency.  The Nile River, separating Acholiland from the rest of the country, only aids in this political and cultural divide.  For these reasons, an AHS-primed brain finds many cultural practices as fodder for rumination, along with prompts for contemplating our role in a global context.  Below, I will describe some of my earliest observations in this complicated milieu.

First, of course, the food.  It starts with starchy staples, mostly sweet potatoes, millet, rice, maize, sorghum, cassava, squash, and plantains.  These starches are used to scoop up, usually by hand, some combination of beans, peas, sesame seed paste, and, if you’re not incredibly food insecure, goat, fish, chicken, beef, or offal. The modicum of nonstarchy vegetables is nearly always cooked: the beans and meat stews are boiled with small pieces of tomato, green pepper, and onion, and a common side dish is boiled leafy greens.  I recently read an account of a Ugandan grandmother’s reaction to Western salads, laughing and asking how people can be healthy eating these raw foods since humans are not goats or cows.  The author explained how cooking all vegetables is a protective tradition, as soil and water is often contaminated by waste, but I wonder if there is more to it.  Fruit is eaten raw, however, and the most common fruits I see are bananas, oranges, jackfruit, mangos, avocado, passion fruit, and watermelons.  In terms of ferments, I’ve only heard of bongo (fermented milk) and the various alcoholic homebrews, usually from banana, maize, sorghum, or millet.

Example meals:  a plate of sweet potato and posho (stiff maize porridge) with a bowl of beans in a sesame paste sauce; kwan kal (stiff millet porridge) with boiled greens, tahini mixed in the green water; rice with a bowl of smoked goat meat stew.

fresh fish, sesame pasted greens, stiff millet porridge, sweet potatoes

One of my favorite meals, also an Acholi staple, is sesame paste mixed with mashed, cooked pigeon peas (dek ngoo) drizzled with dark shea nut oil (moo yaa).  Eat this by dipping in pieces of sweet potato or kwan kal.  These are typical lunches and dinners.

dek gnoo and moo yaa, with stiff maize porridge rice on the right

Breakfast is varied.  Some skip it, especially if they live in poverty and work all day (sure, call it a “feeding window, or just malnutrition).  Milk tea and milk instant coffee are very popular, with a milk-to-water ratio of 1:1 loaded up with table sugar.  The milk here is delicious– largely local and grassfed, it tastes so rich and sweet (a Ugandan colleague’s wife, who lived in the US for a year, told me “American milk doesn’t taste like milk”).  Millet porridge is served in some schools for breakfast.  A popular drink for children is milk, fermented or fresh, mixed with some kind of grain (I’ve heard millet or corn).  More common outside of the north, but still present here, is katogo:  stewed plantain or banana with offal or groundnuts.  Groundnuts are very similar to peanuts, and people buy them roasted for breakfast or snacking.  Groundnut stew (similar to a mild peanut sauce) is common elsewhere, but sesame paste stews are more common here.  Overall, the food variety is less than other places I’ve traveled, and the dishes are quite plain with little spice or herb additions– low food reward, perhaps.

That all sounds wonderful, but I left out a big part of the common diet:  wheat, vegetable oils, and soft drinks.  All new additions to the food tradition, sometimes supplanting old foods.  Indian influence means chapati and samosas are common street foods, cooked in vegetable oils, of course.  Loaves of bread are becoming a staple, as well, and some people eat it with a schmear of sesame seed butter for breakfast.  I was happy to discover how common eggs are, but if I eat out, they are always fried brown in veg oil.  So it goes.  Within the ubiquity of food insufficiency in a context of very limited healthcare, I fear the implications of substituting already meager dietary items with these industrial foods.

Modern staples: vegetable oils, toilet paper, and soda

Walking around, I see people in positions that could be in Gokhale’s book.  The women work hard– constantly bent over to cook, wash dishes, do laundry, and clean floors (brooms are 2-3 feet long and made from reeds, mops are rags that you move with your arms).  They stay bent at the waist with perfectly straight backs, motivating me to keep stretching the hammies…

Women at work

 Some of these chores are done squatting, too.  Otherwise, the women can be seen transporting heavy objects on their heads, from 5 gallon jugs of water to sacks of grain.  This is all done with a baby wrapped to their backs.

I could be wrong, but perhaps these practices are the reason I see less postural kyphosis in the elderly ladies.  Also, I should mention that gyms are nearly nonexistent, and the only time I see running is when people get caught in the rain, are playing football (soccer), or are white people doing aid work or research (that’s me! But my research involves too much time at a desk).  Strenuous jobs are the norm, and most people don’t have cars.  Walking and bicycling are the rule.  Most of the footwear I see are thin sandals (minimalist), and it’s common to see barefooted people walking around, especially outside the towns (poverty).

About 100 years old, but I’m told these are still made in some villages

The lack of street lamps, along with daily power outages, and the fact that the vast majority of homes don’t have access to electricity, means that people generally experience natural darkness as the sun sets.  I’ve been heading to bed much earlier, especially since I cannot sleep past 5 or 6 am due to the roosters.  If I go to bed early enough, I often wake up in the middle of the night for an hour or so before a “second sleep”.  One of my colleagues (a Ugandan) does this, too, but I cannot generalize beyond us.  He and his family sometimes take a little siesta after lunch, too, which I can certainly get behind.  I can also check off items from the recent MDA post on hormesis.  I already mentioned the exercise and calorie restriction, and sunlight exposure is a given in a country on the equator.  Also, without modern conveniences such as electricity and hot water heaters, all showers are cold showers!

Another topic I want to touch on is Acholiland’s continued tribal culture.  Traditional dance and music is at the heart of this.  I frequently hear drums in the distance as I walk, and I’ve seen groups of students in universities meet up for dances in the grass.  For more on the healing power of traditional music and dance, track down the 2007 film War Dance, an incredibly beautiful but heartbreaking story about school children in Northern Uganda.  I have yet to read my book on the history of the Acholi tribes, so the majority of my info is from conversations with Ugandan friends, one of whom is the designated leader of his clan.  The presence of tribal culture is strong, the sense of belonging is crucial, and excommunication from your clan is considered a punishment worse than death.  Clan leaders are still called upon to resolve disputes or offer advice.  [See the Al Jazeera documentary, Bitter Root, for how these traditional practices lead to reconciliation, rather than retribution, for former abducted-children-turned-rebel-soldiers, taking the justice system from the hands of the government to the realm of tradition].  Distant relatives are sometimes described using nuclear family nouns– the son of your grandpa’s cousin’s kid is your brother– and everyone feels a sense of responsibility and goodwill towards other members of their clan.  This sounds like ubuntu, the topic of Frank Forencich’s talk (Africa reference?) at AHS, which I missed because I had to run back to New York that day.  I should mention that everyone here was thrilled when Obama won, and they often cite that sense of brotherhood they get from him, along with his more skillful way of taking care of the poor.

That’s my account so far, but remember that some of this information came from people who may want to tell the foreigner something interesting, rather than common, and then that data is filtered through my biased brain.  And of course, I can’t talk about these things without sprinkling in some political, economic, and social issues facing the Acholi.  An ancestral health picture is nice, but it’s not complete.  Acholi tradition has been undermined by forced migration into internally displaced peoples camps for over a decade, ending merely a few years ago, preventing the practice of many cultural rituals.  They were without land, independence, and other means to continue traditional livelihoods.  On a few occasions, I’ve been able to informally talk with Acholi elders.  They never fail to remind me how the IDP camps destroyed their peoples’ culture and morals, as well as fostering drug abuse, rape, and disease.  And yes, the foodways and hormesis sound great, but people are starving here.  Naturally active livelihoods are awesome, but not when they are the result of extreme gender inequality where women have no choice.  It’s sweet and heartwarming that man-on-man handholding is so common– brotherhood, right?  But it’s scary that the same affection towards your wife is risqué, or that you could be killed or imprisoned if you engage in love outside the bounds of heteronormativity.  Blame it on the proximate lack of education, former colonialism, or widespread Christianity, but it’s happening.  And let’s not start on the infectious diseases, government corruption, illiteracy rates, motor vehicle accidents, and lack of good healthcare.

So what can we learn from these people, a group so geographically close to the Hadza, Batwa, and Karamojong, close to some of the earliest human remains in the archaeological record?  The answer seems largely irrelevant.  We have a lot of the answers we need about diet and lifestyle.  Perhaps this is a case where we should ask:  what can we give of ourselves?  The ancestral health community has gained a lot from the study of indigenous groups, so what can we do in return?  How will we enable empowerment and protect culture?  American health trends have a global effect, so how can we be the example of doing this in a positive way?  Why was the apropos panel on Reclaiming Latino Health so under-attended, compared to the lamentable, stale debate on… potatoes?  Were we fighting with the Pima to protect their water?  Has anyone heard of the Decolonizing Diet Project?  And for the egocentric: more preservation of cultural heritage means more research opportunities to figure out the perfect post-workout meal…  I mentioned missing Forencichs’ talk, but when I read how greatly he inspired people, I looked him up and found this relevant post.  Adele Hite, a speaker at the symposium, gave a list of ways to become more involved than just frequently-commenting-on-blogs.  Her examples largely involve the USA, but I don’t see why our scope cannot transcend self-created national borders.  This already happens in research and blogging, so why not in action?  Involvement in other cultures demands care and scrutiny (you want to avoid dead aid), but I think this community is smart and thoughtful enough to create a significantly net-positive effect.  We’re crafty people, and we’ve already accomplished so much.  Some organizations are doing exciting, ancestral-health-minded things, like this medical clinic in Burundi.  They started a native foods garden, along with the administration of agriculture education programs, to combat widespread food insecurity that took place after the civil war and genocide– a nice solution to what many food aid programs stick a bandaid on by creating relationships of dependency using their culturally inappropriate bags of wheat and jugs of vegetable oil.

I’m merely a student, so I cannot provide all the answers, but I hope the bulk of my career will work on these issues.  I think this community is also up for the challenge, as evidenced by the last symposium.  The blogging about micro/macronutrients is dying down, and our focus is getting bigger:  public policy, remarkable research projects, interventions, activism, creation of med student electives, and the introduction of evolutionary health into workplaces and grand rounds.  I’m not saying that global issues and cultural preservation need to supplant the other amazing endeavors born from the synergy in the ancestral community, but I look forward to more attention to these topics.  They are not tangential, but fundamental, to progress for us all.

Angela is a medical student at Cornell in NYC. If you’d like to read more of her observations (with less focus on ancestral health) you can check out her travel blog, I highly recommend it!  

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Many people get their start in the ancestral health/evolutionary wellness world through food.  Be it “paleo” or “primal” (or perhaps the ever practical advice of Dr. Emily Deans: “Don’t eat like a Jerk”), most people start this journey with food, and then start to apply the evolutionary mindset to other aspects of life. Once the logic of “eating evolutionarily” sets in (and once you realize how good you look and feel while doing it), you might start to apply the evolutionary approach to other aspects of your life.

Once you’ve been at this long enough, you start to think about the evolutionary aspects of everything- food, movement, socialization, sex, sun, stress, and sleep (so many s’s!)- but it seems that the two that most frequently go together are food and feet.  The exact timeframe may vary, but there’s usually not a huge gap between someone adopting a “primal” or “paleo” diet, and someone purchasing their first pair of Vibram Five Fingers– and so your migration to the fringe begins…

The jump from an evolutionary approach to food to barefoot running is an appropriate one.  The evolution of the foot (and our ability to run) is often traced to the human ability to run down prey, and thus the evolutionary argument that meat is an important part of an appropriate human diet. From an evolutionary health perspective, the argument that “these feet were made for moving” (without the help of massive rocker-bottom shoes) just starts to make sense, and might just prevent (or explain) injury.

If you’re not familiar with the arguments for a barefoot approach (or if you are, but haven’t seen this video), I highly recommend the following brief video, made to accompany this paper [1], in the eminent journal Nature*.

It certainly makes sense that a forefoot foot strike pattern inline with our evolutionary “design” might be protective against running-induced injury.  Indeed, a small retrospective study that was published this July showed exactly that.  In cross-country runners, those with a forefoot foot strike had significantly less repetitive stress injuries than their rearfoot-striking counterparts [2].

Embracing the barefoot message does not mean you have to embrace actually going barefoot.  You can see from the VFF link above that there are options for those who want the barefoot experience without the unpleasant effects of doggie-doo.  For those worried about being labeled part of the monkey-foot army, have no fear- there are minimalist options out there that are relatively indistinguishable from *regular* footwear.

In the last few years there’s been an explosion of minimalist or “barefoot” shoes. Those in the market can chose from a number of mainstream or more esoteric brands.  From New Balance Minimus Zeroes and Merrel Gloves to Vivobarefoot and some of the Inov-8 options, there are many options for the barefoot enthusiast to try.

I’ve gone through a number of pairs of VFF at this point, with the rather simple KSOs being my style of choice.  I’ve endured the occasional joshing from friends and entertained many questions from strangers out on trails, and am generally enthusiastic about VFFs, but they’re definitely not a “stealth” minimalist shoe.  On the other hand, the Vivobarefoot sneakers that I wear in the hospital look like totally normal sneakers. [I’ll admit my favorite hospital “outfit” is the 4 S’s- Scrubs, Sneakers, Sweatshirt, and Stethoscope]

I’m not here to write a review of the Vivos I’ve been wearing (though they’ve been great for me). My advice for anyone looking to explore minimalist shoes is to go to a store and try on the different options. I know some people love the Merrel line, but they’re definitely too narrow in the arch area for me (they leave me feeling like I’m in shoes with big arch support).  I want to try the NB Mimimus Zeroes (the newest NB “barefoot” option with no heel drop) before I purchase my next pair of sneakers.

Shopping for a new pair of sneakers is definitely on my mind, as I’ve recently realized that my original pair of Vivos is on the way out. They’re had a good run, but some of the luggs are now totally worn down, and the sole is starting to erode too. I hadn’t noticed in the way they wore, but when I flipped them over I was initially surprised to see where there was wear.

Ever since I was a kid I’ve been “hard” on sneakers. I’ve worn through the soles of many shoes (and stomped down the back of many an unlaced sneaker- much to my parents chagrin). In the past, I’ve always noticed that it was the heels of my sneakers’ soles that went first.  With my Vivobarefoots, the wear is only prominent at the ball of my feet. I dug up an old pair of sneakers (not worn out, as I switched over to minimalist options before these were done) and you can clearly see that the greatest wear is in the heel areas. Yes- there is some wear in the toes, but not much. For contrast, look at my ailing Vivos.

The different wear patterns in my last pair of normal Merrels and my minimalist Vivobarefoots.

For me, this is pretty convincing evidence that minimalist shoes do, in fact, encourage the midfoot strike that is desired by those that go barefoot. That’s not to say that minimalist shoes are a cure-all for heel striking. You can check out this video from the 2011 NYC barefoot run to see the variety of footfall patterns- many of those with minimalist shoes have a different footfall from the truly barefoot, with a couple examples of heel-striking in minimalist shoes… ouch!

Some technical difficulties aside, minimalist shoes are definitely a step in the right direction (pun intended?) for those wishing to get a more “evolutionarily appropriate” footfall, without going truly barefoot (or for those who might like to go barefoot, but are constrained by social norms (or hospital policy!))

Lunch/sun break on a sunny day on my surgery clerkship.

Usual disclaimers apply- minimalist shoes are not for everyone. Getting accustomed to minimalist shoes can take time. Consult a medical professional before starting any exercise regime. Go in search of the Wizard of Oz (NOT DOCTOR OZ!) if you are in need of your own brain.

*For those keen on reading more about evolutionary medicine, Daniel Lieberman published an article on evolutionary medicine and barefoot running in April [3].

1.         Lieberman, D.E., M. Venkadesan, W.A. Werbel, A.I. Daoud, S. D’Andrea, I.S. Davis, R.O. Mang’eni, and Y. Pitsiladis, Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature, 2010. 463(7280): p. 531-5.

2.         Daoud, A.I., G.J. Geissler, F. Wang, J. Saretsky, Y.A. Daoud, and D.E. Lieberman, Foot strike and injury rates in endurance runners: a retrospective study. Med Sci Sports Exerc, 2012. 44(7): p. 1325-34.

3.         Lieberman, D.E., What we can learn about running from barefoot running: an evolutionary medical perspective. Exerc Sport Sci Rev, 2012. 40(2): p. 63-72.

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Last week I gave a talk on evolutionary medicine to a group of ~50 medical students at my school. I really enjoy public speaking and I love talking about evolutionary medicine, so I had a blast (and the talk seemed to be well received).  I won’t try and recount exactly what I said in my talk, but as people seem to be interested in what I had to say I’ll try and provide a general idea of how the talk flowed, sharing the things that I think medical students should keep in the back of their mind as they go through their medical training.

I started with an introduction to evolutionary medicine…

An image from a 2010 Nature article on Evolutionary Medicine. (Particularly fun as Darwin did start to train as a physician at one point!) 

The term “Evolutionary Medicine” is rather broad, and can mean anything from how and why our enzymes work a specific way to why we respond to our modern environment (or a medicine, stress, or toxin) the way we do.  It stresses (to me at least) the fact that natural selection is everywhere, and we would do well to remember this (in medicine, business, policy, and life!). The term “Evolutionary Medicine” is sometimes used interchangeably with “Darwinian Medicine”, and is often mentioned during the discussion of “Ancestral Health”. These are all terms I hope that we will hear more of as medical education continues to evolve (selection pressure is everywhere, right?)

Speaking of med schools- I just read that the first lecture new med students get at UCSD is a lecture on evolutionary medicine [1]. Very cool! I like the idea of introducing the subject to med students before the onset of clinical training, as it offers a paradigm in which to think about health and disease, instead of trying to learn everything from a purely mechanistic perspective.

As med students, we are already familiar with some selective pressures that alter human health. Microbial resistance to antibiotics, sickle cell anemia, and lactose intolerance (though perhaps more accurately, “lactase persistence”) are all things we learn about, and are probably (hopefully?) taught with an emphasis on the selection pressures that brought these things to prevalence. These three examples, however, are just the tip of the iceberg.

We can use evolutionary medicine (and indeed I think we should) at all levels of human health and disease, but I think that an excellent starting point for this discussion is to take a step back and look at the bigger picture of “what it is to be human”.

So what is “being human”?

I find the easiest way to look at this question is to ask “how does a human live ‘in the wild’”. I’m not talking about a weekend camping trip, or even a half-year adventure through the rugged arctic, but rather, what can we glean from archeological evidence, our closest hominid relatives, and native peoples about how humans evolved? Alas, many native cultures are converting (or already have converted) to a more modern lifestyle, but there is a lot that we can learn from the lifestyle of people such as the Australian Aboriginals, the New Zealand Maori, Native Americans, Kitavans, Inuit, Maasai, and others.  Even though much cultural identity has been lost in recent generations, memories and documentation exist that we can use to better understand traditionally living humans.

I should say, at the outset, that this is not a plea to return to a traditional lifestyle (nor do I think people living in traditional cultures should be barred the opportunity to adopt aspects of our modern life). This isn’t about “going back” or recreating a specific lifestyle. Instead, this is about understanding our past so we can thrive in the present (and beyond).

Perhaps first and foremost (and indeed, my starting point into evolutionary wellness (there I go using yet another term)) is the food that humans thrive on. It is increasingly evident that there is not one “perfect human diet” that we evolved to thrive on. Rather, there are a number of foods that nourish and sustain our body in a healthy way. Humans evolved eating (and indeed some of these things truly ‘made us human’) meat, seafood, eggs, vegetables, fruits, nuts, and tubers.

What about grains and dairy? This is inevitably the cry we will hear from patients, friends, family, and hospital nutritionists! To hear these people talk is to think that humans cannot exist without these two staves of life. As much as people think of these things as staples of the human diet, the reality is that they were most likely not consumed in any real quantity until the agricultural revolution, a mere 10,000 years ago (not much time when you consider the span of human evolution). While it is true some people do well on these foods (and indeed, lactase persistence gave some a significant reproductive advantage at some point in the last 10,000 years), many people do not. Even those that seem to tolerate these things well are often surprised by the benefits they experience when these things are eliminated from the diet. Not everyone does poorly on these foods, but it definitely seems that many have not evolved to thrive on them.

Perhaps more important than thinking about what humans evolved to eat is thinking about what is truly novel in our modern diet. Unnatural trans-fats (not all trans-fats, as there are natural ones such as conjugated linoleic acid (CLA), which appears to have significant health benefits) have been shown to be particularly evil, and a campaign has been waged (mostly successfully) to rid them from our modern diet. With unnatural trans-fats mostly out of the way, the worst of our modern novelties (in my opinion) is the excessive amount of linoleic acid (found in vegetable oils such as corn oil and soybean oil) in our modern diet. I could write a book about the evils of linoleic acid (who knows, maybe one day I will), but without going into detail, excess linoleic acid is associated with increased gut permeability, increased inflammation, and increased fatty liver, just to name a few conditions off the top of my head.  I think the westernized world would be a much healthier place if we would eliminate all the modern sources of linoleic acid and again embrace sources of omega-3 fats such as fatty fish and grass-fed meats (but that is enough information for another talk entirely!).

{Ed. Note- I can find it difficult to keep myself on task as I talk about evolutionary health. Since it really gives you a paradigm in which to think, it is so easy to branch off at any place to explore other venues that benefit from an evolutionary approach.}

When considering the declining health of the western world, other culprits in our modern diet are likely excessive sugars, additives and preservatives, soy, hyper-palitable processes foods, a host of other things I can’t think to list right now and, though it is debatable for some as mentioned above, grains and dairy.

Going beyond food- what else makes us human?

A topic that I have been meaning to write on for ages, but that “That Paleo Guy” Jamie Scott has recently been writing quite a bit about, is Sun.

Humans evolved outside, under the sun. Our lives, both daily and seasonally, were controlled by the rising and setting of the sun. Most of us know that UV radiation from the sun is responsible for starting the conversion of precursor compounds into active vitamin D, but how many of us actually get enough sun to be replete in vitamin D, and how much do we actually need? Looking at this from the evolutionary standpoint, we can determine that appropriate vitamin D levels are extremely important for human health and survival. Indeed- it is believed that the drive for adequate vitamin D levels is what drove lighter skin pigmentation in humans as they migrated away from the equator (lighter skin meant that people could still make adequate vitamin D despite the decreased UVB exposure at northern latitudes and the decreased skin exposure due to increased clothes in colder climates).

Vitamin D is also a great opportunity to tap into Ancestral Health as a way to guide modern medicine. For lack of a better description, we in the western world are shooting blind when trying to figure out what is an appropriate target for blood levels of vitamin D. We currently base our studies off of epidemiological studies of humans living well-outside their evolutionary niche and laboratory studies using isolated cells and models quite distant from a living, breathing, human.  While these studies can provide us with interesting information (and quite a bit of garbage), can it really give us a good idea of what is optimal for human health? Might information from people living in a traditional lifestyle give us a better idea of how humans have evolved to thrive? A paper recently came out that looked at vitamin D levels in groups of Maasai and Hadzabe and found that the mean Vitamin D concentrations in these population is 115nmol/L (~46ug/L) [2]. Whether this level is “ideal” is uncertain, but it’s an interesting (and arguably more reasonable) place to get started than trying to tease out a reasonable target from the varying levels of insufficiency in most modern civilizations.

The benefits of sunlight aren’t limited to vitamin D. The sun plays other roles in human health, and I will make a strong (personal) argument that sun exposure does wonders for psychological wellbeing!

Humans were meant to move

This is, perhaps, something that everyone can agree upon. This, like food and sun, is something that can be looked at from many different angles under the lens of evolution. How has our body evolved as we became bipeds, and where are the weaknesses in our constitution? Bipedalism changed the shape of our hips, and with it the risks of childbirth. Our shoulders are wonderfully mobile joints, but with mobility comes potential weakness (hello rotator cuff injuries!). And what about feet? Through feats (heh- couldn’t help myself!) of natural selection, our feet have been crafted over millennia to support and move us unassisted, yet now we want to rely on highly engineered shoes to cushion, balance, and protect our feet. Interesting research our of Harvard by Daniel Lieberman’s lab shows some of the effects shoes have on the forces exerted on our knees (cliff notes versions- shoes aren’t doing us any favors). Furthermore, recently the floodgates have opened letting loose a stream of research showing the “dangers of sitting”. These are all elements of human health that can be  more easily understood when placed in the context of an evolutionary paradigm.

Humans sleep

This seems like such an obvious statement, but it’s probably one of the hardest things for people to implement. As budding health professionals, we are rarely able to set a good example in this aspect, yet we should realize that cutting short on sleep is detrimental to more than just our coffee budgets. As I mentioned above, until recently, our lives were controlled by the rising and setting of the sun- now we are able to extend our hours (not just of waking, but also working), probably at great expense to our health. Here, as in other aspects of evolutionary health, I’m not recommending that we shun our modern world, but instead that we should understand our modern situation in the light of our evolutionary past and our biology. An interesting evo-health aspect to consider here is the effect of blue light on melatonin production (melatonin is a hormone important in controlling our circadian rhythm). Exposure to blue light decreases the production of melatonin in the brain, thereby affecting our sleep-wake cycle. While we’re unlikely to convince many (indeed you won’t convince me!) to turn my computer off after sunset, we should consider reasonable “hacks” to work around it. For this example, the cool free program f.lux is available, which alters the amount of blue light emitted from your display based on the time of day and your local sunset and sunrise time.  If you don’t have it already, check it out!

Humans have friends, not “friends”

I’m not going to waste much time on this one, but real, legitimate human interactions are an important part of being human. I’m not saying you can’t make great friends on the internet- one of my best friends is an internet friend- but a real social bonds take more time and effort than a 140 character message or the occasional “poke”.  Meaningful relationships take time, which is something many are painfully short of these days.  Alas, the same modern life stresses that make strong social bonds hard to forge and maintain also make such support even more necessary.


Evolutionary Medicine isn’t just about preventative health.

I won’t go into it here, but in the closing minutes of my talk I went on to talk about some of the evo-med examples I have written about here before. First I discussed the likely role of the appendix (and why we should care) and then I talked about an alternative perspective on the etiology of diverticulitis. I also stressed that this talk wasn’t meant to be an all inclusive “this is evolutionary medicine” talk, but more of an opportunity to introduce a subject that I hope my peers will start to consider as they continue their medical education and eventually head off to their specialty of choice.

I’ve only referenced a couple papers in this post, but I did put up a number of papers throughout my talk to show that this is science. There is a growing body of evidence to support the importance of evolutionary thinking in modern medicine, and an increasing interest in teaching evolutionary principles to medical students. As for me- I continue to find great excitement and joy (two wonderful human pleasures) in thinking about these evolutionary principles and how we can utilize them in practice.

1.            Varki, A., Nothing in medicine makes sense, except in the light of evolution. J Mol Med (Berl), 2012. 90(5): p. 481-94.

2.            Luxwolda, M.F., R.S. Kuipers, I.P. Kema, D.A. Janneke Dijck-Brouwer, and F.A. Muskiet, Traditionally living populations in East Africa have a mean serum 25-hydroxyvitamin D concentration of 115 nmol/l. Br J Nutr, 2012: p. 1-5.

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No- this isn’t an addendum to the “spring mating games” I mentioned in my last post.  (I feel like I might have just lost half my readers…)

The third year of medical school is a hectic one.  For those that aren’t familiar with the system, the first 2 years of medical school (in the US at least) are “pre-clinical” years, where future physicians learn the ‘basic science’ behind medicine. The foundations of our clinical knowledge are fields such as anatomy, embryology, biochemistry, pharmacology, physiology, pathology, microbiology, immunology, and, at least in my school, some basic biostatistics.  The end of second year culminates with the first step of the USMLE Boards.  Those that aren’t daft enough to take a hiatus to do a PhD (and when those of us that were daft enough finally come back) then start clinical clerkships in the third year.

For lack of a better description- 3rd year medical school is like speed dating for future physicians, but we’re looking for a career not a partner.  There’s a lot to be learned in third year (there is a very steep learning curve when you finally step foot on the floors), and each clerkship (Psychiatry, Neurology, General Medicine, Surgery, Obstetrics and Gynecology, Family Medicine, and Pediatrics) requires the acquisition of new clinical skills and knowledge.  The idea, obviously, isn’t to make you a surgeon in 2 months, but to give you some basic knowledge in these fields and to give you an idea of what it is like to be a physician in each of these specialties.

Some students come into medical school knowing what they want to be (though even the most determined often change paths), but many (myself included- more so at the beginning of medical school than now) really have no idea.  Over the course of a clerkship you not only get the basic clinical knowledge of a specialty, but you also get a feel for the specialty itself. These clerkships are short- I had a month on both Psychiatry and Neurology, and two months on Surgery.  This is barely enough time to figure out what a specialty is all about, and of course your experience is very much determined by the hospital you work at and the people you work with, yet this is the system in which we work (and in this instance I’m not sure there’s a better option).  By the end of third year, medical students need to know what they want to be “when they grow up”.  That’s when you have to start getting ready for “The Match”, the process in which medical students and residency programs rank their respective top picks and a computer determines their destiny (think of it as speed dating meets arranged marriage).

As I come off my surgery rotation, now a third of the way through my third year of medical school, it seems like an appropriate time to take a look at the clerkships past, and to glance forward to those awaiting me.

I started with Neurology- a very cerebral specialty (pun intended), where, at least when I spent my time with the stoke team, we spent a lot of time doing very thorough histories and physicals, teasing out the specific deficits and abnormalities of a patient’s presentation to determine (“localize” is the medical term) where in the brain there was an issue.  This is a wonderful exercise, and a skilled neurologist can take a thorough physical and, based on presentation, precisely localize where in the brain the problem has occurred… Now a day, this is frequently done as somewhat of an academic exercise after the determination has already been made by a CT scan and/or MRI. While there definitely is space for aspects of neurology to be explored with an ancestral/evolutionary health gaze (more hemorrhagic strokes during the winter? Maybe there’s a role for Vitamin D?), for me I found the specialty one of “a lot of thought, not much action”. Engaging as the thought process is, and as cool as some of the physical-exam detective work can be, I’m fairly sure that on my speed-dating card, Neurology is a “No”.

I was surprised by my Psychiatry clerkship. I wrote about my experience previously and, from the assessment of the clinicians I worked with and my own thoughts, I’d say Psychiatry is a mutual “Maybe”.

As I reach the end of my two-month trial on surgery, I will mark, without hesitation but with definite heartache, “No”.  Had my surgical rotation ended after my first month, when I had experienced only general surgery, there would have been no hesitation nor heartache.  General surgery is, without a doubt, not for me.  Over that month I saw many surgical revisions of the human body that were necessary, almost exclusively, because humans are living outside of an evolutionary appropriate lifestyle.  The removal of large portions of bowel because of diverticulitis, appendices and gallbladders removed around the clock, amputations because of uncontrolled diabetes… It all seems so unnecessary (for the most part) if we figured out how to live within the confines of how our body evolved to thrive.  In many of these cases, surgery is a (hopefully) definitive treatment for a preventable disease that I would rather just see prevented.  Other specialties within surgery- such as vascular, transplant, and cardiothoracic, or totally different training programs such as neurosurgery or orthopedics- all have their place, but none of them enthralled me. The other major issue with surgery is the toll it takes on your body and your life.  Surgery is physically demanding, not just for the hours of standing in one place, sometimes hunched precariously or stooped over a microscope, but also for the hours it requires.  Surgical training requires residents spend very long hours in the hospital, and to be honest, it’s not a price I am willing to pay.

The reason my rejection of surgery turned from an adamant “No” to a sorrowful one is because of Trauma.  My second month of surgery was spent with the Trauma team at my university’s hospital, a level 1 trauma center in a very rough inner city.  In many ways, Trauma surgery is the antithesis of neurology.  No- the people I was working with are not “just dumb trauma surgeons” as one of our attending physicians liked to self-deprecatingly refer to he and his collegues, but they are men (and women) of action.  There is a standard protocol that you run through when a trauma comes in, the “ABCs” (Airway, Breathing, Circulation, Disability, Exposure (yes, if you come into the trauma bay, you will lose your clothes)), but when something needs to be done, a trauma surgeon does not stand on protocol and wait for the final assessment. Many of the cases we saw in the trauma bay were definitely not “traumas” (simple falls, bar fights and assaults are generally things that should be taken care of in the Emergency Department), but many were full of the excitement and noise that years of watching ‘ER’ might have you come to believe is the norm.  One night on call I was part of the team that picked up a Motor Vehicle Crash (MVC) patient from the helipad on the hospital roof.  I’ve now seen gunshot wounds to all different parts of the body.  Trauma surgeons (or the good ones, as I witnessed in our hospital) know when to let assessment carry on, and when they’ve seen enough and something needs to be done NOW.

There is an urgency to trauma surgery, an element of intuitive action, that is lacking in other fields of medicine.  When you go to the operating room with a trauma patient you will see things you’ll never see in a hospital surgery patient, like the milky lymphatic ducts of the intestines (in all other surgery cases, patients are kept without food for many hours before surgery so their bowels (and the lymphatics which carry the emulsified fats we eat) are empty.). In trauma surgery, you’re working on a running engine.  Also, there’s often a significant element of “unknown” when you go to the OR with a trauma patient. These cases are time critical, and often the only imaging study you’ll have is a simple X-ray (no CT scan or MRI to tell you exactly what’s going on- there’s just no time).  A quick ultrasound may tell you there’s fluid in the belly, but you don’t know what that fluid is until you see it, and you don’t know where it’s coming from until you poke around for the source.  Trauma surgeons live in the moment- identifying, controlling, and treating acute injuries at times when minutes can make all the difference.

Another thing I like about trauma surgery, which is so different from general surgery, is that you are treating an acute incident that brings your patient to the table, not a chronic lifestyle (though one can argue that the lifestyle that many of our patients live is what is responsible for their trauma.  This is undoubtedly true for many or our MVC patients (please people- DO NOT DRINK AND DRIVE!) and some of our gun shot wounds and stabbings (we have quite a few repeat customers coming into our hospital for these injuries…).  There’s something about taking an acutely injured patient and ‘fixing them’ (or I prefer ‘putting them back together so they can heal’) that I enjoy that is missing in general surgery.

This feeling, however, comes at a cost.  The hours for any surgeon are long and arduous, but those of a trauma surgeon are longer and harder.  Yes, general surgeons get 3am consults, but a gunshot would to the chest is a lot more time-sensitive than an acute appendix or an obstructed bowel.  The lifestyle of a trauma surgeon is hard and it is wearing, and it obviously takes its toll.

Not surprisingly, trauma calls to a certain type of person… I loved the trauma surgeons- they were all so different: unique in their own ways and so obviously Trauma surgeons. During the last week (prior to my surgery exam) all the students (from all the different teams, about 30 of us in all- 5 had been on Trauma) were lectured by a number of surgical faculty.  You could always tell the trauma surgeons (even if they didn’t introduce themselves as such).  They lectured off the cuff- dynamic and fast.  None of them sat or stood by the computer flipping slides (if they used them)- they paced, gesticulated, called people out and made bold statements… They’re a little wild, often quick to act, and if I ever need a trauma surgeon, I’m really glad they are the way they are.

It was my experience on trauma, and with the trauma surgeons, that makes my heart ache a little bit as I check “No” for surgery. I know I could not mentally or emotionally hack the surgical residency (the hours and the years of all the other surgical specialties that you have to endure in order to do a fellowship in trauma). I also know that I will not put my body and my mind through the rollercoaster ride that is the call schedule of a trauma surgeon.  I know I need sleep. I know I need good food. I know I need sun and socialization.  But I will miss Trauma…

With 4 months and three specialties down, I look forward to my remaining 8 months and 4 specialties of third year.  As far as my speed-dating card goes, I think the best is yet to come. I don’t think Pediatrics, my next clerkship, will be the right fit, but I’m optimistic for the Family Medicine clerkship that follows and then the tour-de-force that is the Internal Medicine 4-month marathon.

When it comes down to it, I don’t think I’m going to find my perfect match in the speed-dating clerkships of medical school. Evolutionary medicine is a yet-to-be-defined specialty, and no residency program offers training in this field (though I have hopes for a fourth year elective in this area!). Indeed- just yesterday NPR mentioned evolutionary medicine and somewhat scathingly pointed out that it was not a practical discipline and at this point “only a theory”.

Actually, when it comes down to it, I don’t really think evolutionary medicine should be its own specialty… Much as it has been said that “nothing in biology makes sense except in the light of evolution”, I think “most (dare I say all?) issues of human health are best understood in the light of evolution”. You can find aspects of each specialty that would benefit from the keen focus of evolutionary minded individuals who, with careful thought, research, and synthesis of new ideas, could push the standards of medicine to new heights.

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