Evolutionary Biology And Good Medicine

“Nothing in biology makes sense except in the light of evolution”. Theodosius Dobzhansky

I often wonder why evolutionary biology isn’t taught more in medical school, and doesn’t underlie our “healthcare” model more. Sure, we learn about the workings and intricacies of the human body, and may encounter evolutionary biology in the Embryology module, but otherwise, the evolutionary reasons as to why disease happens is usually missing from medical education. Perhaps if doctors long ago stopped to think about WHY we have appendices for example, they wouldn’t have assumed they don’t have a purpose in humans just because nobody could find one. Maybe they would have asked why natural selection favoured the sticking around of an organ that was expensive to maintain and appeared to cause more harm than good. We now know the appendix acts as a harbour of vital gut bacteria that can replenish the colon in case of gastric illnesses. While easy to survive without it, it is by no means “useless”.

Evolutionary biology underscores the entire way I think about the human body and is paramount now more than ever. MOST chronic disease today, the things that kill the vast majority of people in Western societies (such as heart disease, cancer, diabetes, etc) have an underlying basis in the fact that our bodies are totally mismatched to the environment. Homo Sapiens evolved for millions of years as hunter gatherers, and the tiny snippet of our lives after agriculture where our environment totally changed (and continues to change) accounts for less than 1% of our history as a species. Our minds may have adapted to the modern world (though arguably, many haven’t, as can be seen by the high and rising rates of mental illness), but our bodies most certainly haven’t. Poor diets, sedentary lifestyles, lack of community, etc lead to poor health, because our bodies expect a certain environment; the one that created our bodies in the first place. Unfortunately this world no longer exists. People like myself spend an extraordinary amount of time, money and effort simply to recreate as close to an environment that our ancestors evolved in, such as eating whole organic food in it’s natural state, lifting heavy things, doing aerobic exercise, intermittent fasting, cleaning the air with an air purifier, the water with a water purifier, and so on. It’s almost comical that I have to exert so much effort just to recreate an environment my body expects, that it takes for granted. Since becoming a mother, I have learnt even more how mismatched our culture’s views and behaviours are, for example around birth, motherhood and parenting. If modern day hunter gatherers are any semblance of what our ancient ancestors were like, it should be normal for women to give birth in quiet, peaceful dark surroundings, squatting and with trusted, familiar women around, for alloparenting to be ubiquitous (the nuclear family is very novel), childcare to be abundant, attachment parenting to be the norm, social life and community to be a standard, and treatment of children as autonomous individuals as an obvious. Not only have our physical surroundings changed dramatically, but so have our social systems. And it is well known, that these factors (junk food, toxic air and water, sedentary jobs under fluorescent lights, loneliness, and poverty ) are some of the biggest determinants of health. While genes confer susceptibilities, like a loaded gun, it’s the environment that pulls the trigger. Human genes haven’t changed much over the past few thousand years but our environments certainly have. As a doctor, I simply cannot heal a patient unless at least some of these environmental factors are addressed. While conventional medicine recognizes this truth, the system mostly favours quick fixes when people are already sick, rather than prevention of sickness in the first place.

I like Functional medicine because it does take efforts to focus on underlying causes and recognizes that our modern environment is a HUGE factor in most illness. We cannot understand ourselves without knowing where we came from, and evolutionary biology teaches us about our past, which created our present. Scientific research usually affirms what evolutionary biology makes obvious; that our bodies are adapted to a certain environment, and only bad things happen when we veer away from that. This is why plenty of research has confirmed the importance of living aligned with our circadian rhythms, moving our bodies a lot, building strong communities and being sociable, eating meat and vegetables, fasting, being in nature, and more. Before these things were understood, we thought they didn’t matter. The lessons of evolutionary biology were not heeded.

This way of thinking is evident in Chesterton’s fence, a heuristic inspired by a quote from G.K Chesterton “There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, “I don’t see the use of this; let us clear it away.” To which the more intelligent type of reformer will do well to answer: “If you don’t see the use of it, I certainly won’t let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it.”

The point being, you must try to understand why something is there before demolishing it. If we look at the habits and lifestyles of hunter gatherers, we must ask WHY those evolved over millions of years before we destroy them in the name of “progress”. It forces one to think about the potential unseen consequences from changing things and deviating from the “natural order”. Our society is so disconnected from the natural world and our hunter gatherer bodies because we have failed to heed Chesterton’s advice. We have taken away, and we have also added nefarious things to the environment without a thought of the second order effects. I have hope that we can reconnect to nature and our lineages, learn where we came from, and as a result positively influence where we are going.

To good health and happiness!


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