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The case for evolution in public health policy

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There’s an age-old argument that goes like this: We were never intended to self-isolate with technology, which has lead to social dysfunction, particularly amongst the youth. While I cannot say when this idea originated, it has persisted because it represents a more general sentiment that we’ve overstepped the boundaries of what is naturally good for human beings. Of course, to determine what is indeed natural to us, we must look to human evolutionary history.

Regardless of if technology has actually created some social malaise, the idea is a step towards understanding the modern implications of ancestral human lifestyles. Many evolutionary biologists claim that we underestimate the current relevance of those lifestyles. For example, the recently created journal Evolutionary Applications tries to use our understanding of human evolution to reform public health practices. In one article, researchers Randolph Nesse and Stephen Stearn find “a gulf between evolution and medicine” that they argue must be closed for the public good.

Their call is made especially relevant by the growing field of epigenetics. Though epigenetics can’t quite be called new — it has been studied for at least a quarter of a century — the reader may not yet be familiar with it, because it is incredibly complex and so progress within the field has been slow. Nonetheless, what we do know has added a new dimension to evolution that actively affects our health.

To explain: Epigenetics is concerned with how a person’s chemical environment can affect their development by modifying their gene expression. This mostly occurs in the womb, though it also takes place throughout development. The benefit, with regards to survival, is that specific chemical “cues” are predictive of a certain future environment. When exposed to them, the body alters the course of its physiological development — through modifying its gene expression — to better fit that environment.

The ability to respond to certain cues is the result of long-term evolution. The reception of those cues, though, occurs at the individual level, and many are received from the previous generation, generally via the fetal environment.

Epigenetics and evolution, when taken together, help to explain certain conditions and diseases. Two outcomes of human adaptation are most relevant to personal wellness and public health policy:

  1. Evolution makes frequent errors in what is known as mismatch.
  2. Some negative health factors can be passed on epigenetically.

As to not turn this into a technical report, I’ll go through each briefly, mostly focusing on their consequences rather than their mechanisms.

First is the concept of evolutionary mismatch. This is a phenomenon that results when a species is not fit to its environment, either as the result of a mutation or a significant change to its environment. What then happens is analogous to trying to fit a square peg into a round hole: The species either doesn’t fit its environment and dies off, or fits it poorly. Pertinently, it’s what happens when climate change drastically alters many species’ habitats.

For humans, the most commonly cited example of mismatch is our stress response. Chronic stress has long-term negative health effects, but that’s largely irrelevant from an evolutionary point of view. Stress just had to keep proto-humans alive until they reproduced and perhaps took care of a few children. Now, however, we’re living much longer lives, and so stress is mostly negative. Nonetheless, the APA reports that American’s stress levels are 1.6 points higher, on a 10-point scale, than it believes to be healthy.

The idea of an outdated stress response is not a novel concept, but it has been cast in a new light by epigenetics. At the beginning of 2016, a crucial report demonstrated that chronic stress is passed on to one’s children through epigenetic mechanisms. That means that not only is many people’s stress response mismatched to modern life, but this mismatch transfers to the next generation. A cyclical problem results, which predisposes each subsequent generation to chronic stress.

This, I believe, is the most crucial outcome of recent research on human adaptive mechanisms. To have our decisions directly affect the health of our children demands a new way of thinking about health. An immediate conclusion might be that we place greater responsibility upon parents for the health of their children, but that’s hardly fair. While some transferable health choices are more clearly avoidable, like the effect of smoking during pregnancy, others are so complex that it would be a full-time job for anyone to worry about all of them. It doesn’t make sense to leave the responsibilities of a epigenetics, a highly technical field, entirely to the individual.

Instead, we need a new approach to public health that reflects recent developments in our understanding of adaptive mechanisms and mismatch.

The primary policy difference would be that we more proactively intervene in the development of problems to which people are epigenetically predisposed. There is now a new level of ethical responsibility to public health. Not only should we reform it for our own good, but we must also do so for the next generation, as our health will directly impact theirs. Epigenetic studies inform us that this bioethical argument applies to all sorts of health and lifestyle components including nutrition and weight management (if the mother is obese, the child is more likely to be). Scientists believe, too, that a father’s health affects that of his child.

Of course we can’t just immediately get rid of these health problems to help the next generation. I do think, however, that we could take them more seriously and these findings are reason to do so. There are already known solutions to reducing stress, including community support. Yet, as the Harvard Business Review has recently shown, loneliness is in epidemic proportions and is itself a common cause of chronic stress. Moreover, as I’ve highlighted, Americans increasingly feel unsupported in dealing with health issues.

Perhaps, then, one solution to reduce chronic stress would a public health policy focused more upon outreach and community-based solutions to stress. For example, local governments could hold initiatives to get more people to exercise or fund more fitness resources. Exercise reduces stress, and people are more likely to exercise if others get them to do so. That’s a brief example, but the premise of using community support to promote stress-reducing activities is well-supported by the evidence cited.

However, chronic stress is just one example of evolutionary mismatch which, when left untreated, is inherited by the next generation. There are many others, partially due to the fact that society acts as a rapidly changing environment. Resultantly, one of the best things you can personally do is to learn more about the modern impacts of human evolution.

Unless you are an evolutionary biologist, you won’t be able to learn it all. You can, however, build an understanding of what is generally good for people as a result of our evolutionary history. More importantly, scientific literacy, as has been highlighted for the policy battle over climate change in America, is key to reaching public policy informed by science.

It’s crucial that we act to change that policy soon. The APA warns that chronic stress “has the potential to become the country’s next public health crisis.” Evolutionary science helps us to gauge the severity of the problem, in terms of mismatch, and warns us of its transgenerational effects. We now need to use that knowledge to raise support for the issue and to advocate for smarter health policies to deal with chronic stress and other cases of mismatch.

 

Contact Noah Louis-Ferdinand at nlouisfe ‘at’ stanford.edu.

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Noah Louis-Ferdinand is a freshman from Bloomfield Hills, Michigan. He studies Human Biology and Anthropology. Noah is also an avid reader of philosophy and enjoys contemporary fiction. When not studying or writing, he loves to run trail races throughout the United States.