Diseases and health problems such as breast cancer, heart disease, type-2 diabetes, and AIDS claim millions of lives every year. Darwinian theories can not only help us understand these types of conditions; they can also help us prevent and treat them. By incorporating Darwinian logic into health policy making and medical care, a number of premature deaths can potentially be avoided.
We’re worse off than we think
We loudly praise ourselves on the basis that we live longer than our ancestors. The fact that the average life expectancy in many parts of the world is higher today than ever before has led some people to think that we’re healthier than ever before. What’s often overlooked is that our history extends a lot further back than to the Middle Ages, a time when infectious illnesses of various kinds claimed many lives; that a lot of people in the “underdeveloped” world live under extremely harsh conditions; and that the reason we on average live longer than our hunter-gatherer forebears isn’t that we’re healthier, but rather that we don’t face the same perils of nature, have access to modern medical innovations, and have managed to severely reduce infant mortality rates, particularly in industrialized nations. When it comes to our general health, however, all indices point to the conclusion that we’re worse off than our preagricultural forebears, as I’ve extensively outlined here on the site. Truly healthy people are unicorns these days.
We could certainly be doing a lot better!
The historical rise and fall of different diseases and health problems is rooted in environmental fluctuations that alter the conditions under which genes operate. These shifts can be understood through Darwinian thinking. To a Darwinist such as myself, it’s not surprising that a number of chronic health disorders have become more common as of late, nor that we’re having trouble winning the war we recently waged against the microbial kingdom of the earth. In our haste to make our lives more comfortable and kill the things that cause us harm, we forgot that we’re like all other life forms in that we’re creations of evolution that fall under Darwinian jurisdiction.
How Darwinian medicine can save lives
The life-saving potential of Darwinian medicine is enormous. The fundamental causes and properties of all of the ills that plague humanity, as well as the other organisms we share this planet with, can be deciphered via Darwinian thinking. This may sound extreme or unrealistic, but really, it’s not. Each organism on this planet is a product of an evolutionary process; the implication being that all diseases can somehow be understood on the basis of evolutionary theory.
Let’s pick a random health disorder out of the hat to check and see if this statement holds true….
And the winner is… Oral trush.
Oral thrush is a condition that’s characterized by an overgrowth of Candida yeasts within the oral cavity, most commonly Candida albicans. This yeast is kept in check by friendly bugs inside the mouths of healthy people who harbor a balanced oral microbiota; however, within the mouths and bodies of people who for example eat a lot of sugar and/or have recently taken antibiotics, it can rise to dominance.
This can all be understood through Darwinian thinking. In this scenario, from a human perspective, there is a mismatch between the human body and its microbial environment, triggered by exposure to evolutionarily novel agents, such as for example sugary chocolate and tetracycline. From the perspective of the Candida yeast, however, the change is beneficial, in the sense that the new conditions are conducive to its reproductive success.
By itself, oral thrush is not a life-threatening condition; however, via Darwinian thinking it can be deduced that oral thrush is unlikely to be an isolated disorder. Microbes are as much a part of our environment as the foods we eat and the water we drink. A major change in any aspect of this milieu will bring about gene-environment dissonance. Such a dissonance is unlikely to affect just a single part of the body; rather, the effects are going to be widespread, for the simple reason that no part of the body operates in isolation.
It’s well-established that microbes profoundly influence our health, immune function, behavior, and well-being. Moreover, we know that our health and immune function affect the composition of the microbial communities we harbor. Hence, a condition like oral thrush, which involves a major alteration of the relationship between man and microbes, which was shaped over evolutionary time, is not going to be an isolated condition; rather, it’ll somehow affect and be affected by what goes on in the body of the afflicted person. Chances are it’ll contribute to causing a number of diseases and health problems, some of which could prove deadly.
Similar thought processes can be used to deduce what the causes of other health disorders are, and can thereby also inform as about what we need to do to avoid disease and save as many lives as possible.
For example, through Darwinian thinking it can be deduced that the modern epidemics of heart disease, obesity, and type-2 diabetes emerged largely as a result of changes in the human diet that have occurred in recent evolutionary times, and that the principle reasons why a lot of people are killed by pathogenic microbes and parasites such as Clostridium difficile and Plasmodium falciparum every year are that it’s common these days to be somewhat immunocompromised, that smaller life forms evolve at a different pace than we do, and that we, unlike our hunter-gatherer forebears, live in settled communities of high population densities.
We humans have a tendency to forget that we are not separated from the rest of the living organisms on this planet. Rather, we evolved in the presence of life. Every organism on this planet is a product of a Darwinian process and is a part of an evolutionary arms race. These simple, basic facts are extremely powerful and relevant to medicine, in the sense that they can help us make sense of a wide variety of phenomena, ranging from why so many people die of malaria every year to why we appear to be losing many of the battles we’ve waged against microbes to why heart disease claims millions of lives every year.