How Our Stone Age Bodies Struggle To Stay Healthy In Modern Times

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If you got sick, you probably wouldn't go to an evolutionary biologist to get treated. But Daniel Lieberman, professor of evolutionary biology at Harvard University, says that his field can help you understand why you got sick, and make you more aware of healthy and harmful behaviors.

He joins Fresh Air's Terry Gross to talk about some of the noninfectious diseases that may result from our Paleolithic bodies not being well-adapted to modern conditions. It's a list of ailments big and small, including acid reflux, acne, anxiety, asthma, certain cancers, depression, Type 2 diabetes, flat feet, high blood pressure, irritable bowel syndrome, lower back pain and osteoporosis. In his new book, The Story of the Human Body: Evolution, Health and Disease, Lieberman traces these troubles back to their origins


Interview Highlights

On "mismatch diseases"

Many of the illnesses that we confront today are what evolutionary biologists called "mismatch diseases": … Diseases that occur because our bodies are poorly or inadequately adapted to environments in which we now live. An example would be eating large amounts of sugar or being very physically inactive leads to problems like diabetes or heart disease that then make us sick. So mismatched diseases are diseases that are more modern in the sense that they're more prevalent, or even novel or more severe, because we don't live in the way in which our bodies are adapted.

Written By: NPR – Fresh Air
continue to source article at npr.org

5 COMMENTS

  1. Along with dietary disadvantages I often thought that depression is a modern symptom of settled agricultural society….in that people are generally confined to one place and don’t get to travel around much like our nomadic ancesors did – they responded naturally to seasons, plants and animals available and were fully engaged with their changing environment and not tied to one place….in modern society in stead of physically migrating our thoughts go round and round looking for simple meaning among all the complexity and pressure of modern lives…if there is no escape from the pressures we all shut down a little…

  2. Randolph Nesse is another go to guy for more information on this sort of thing. Depression is explained in some ways by the functional aspects of mood. If one is performing a task with little or no reward, the concomitant bad mood that would go with it acts as a signal to stop whatever it is you are doing and have a think. Many people are stuck in undesirable jobs or relationships that can bring about a drastic reduction in our quality of mood, yet they may not be able to do anything about due to financial or other reasons. Without feeling some sort of reward for actions (at a personal level), we are predisposed to developing conditions (such as depression) that manifest as a body of symptoms that are recognised clinically and treated as such.

  3. Averages and other statistics can sometimes be misleading. Sometimes you need to look into the factors that contribute to the averages. As in the classic example of the man with head in the oven and feet in the freezer.

    I think the point of this article is that seeing as our world isn’t dominated by tigers or violent thugs then we should expect to live at least as long and as well as those relatively few stone age humans who managed to successfully avoid being murdered or eaten in their youth.

    There is evidence that stone age humans who survived early infancy, and who also didn’t die violently in early adulthood, tended to remain reasonably healthy well into old age, despite the absence of modern medical science. Presumably they were the ones who were killing the tigers and the other violent thugs, rather than the other way around. And presumably we are descended from these more violently effective specimens among them. In contrast many people today who don’t die violently in their youth suffer from diseases that greatly reduce their quality of life from around early to late middle age, despite the availability of modern medical science.

    I don’t think this idea is a statistical artefact of assumptions about infant mortality or similar factors. They’ve presumably made relevant adjustments to estimated causes of death and have concluded that there really are non infectious disease burdens afflicting modern humans but which were relatively rare in stone age humans.

    Not all examples of these diseases are significant today, so we tend to underestimate their significance. E.g. bad eyesight and tooth decay might have been debilitating in the stone age, but are minor irritants today, owing to medical technology. The cause of tooth decay and bad eyesight may yet turn out to be a consequence of excessive consumption of fructose and glucose. Something which may have only occurred in many humans since Neolithic times. Now we’re at the point in places like Singapore where most people have bad eyesight. A cultural distinction of Singapore seems to be a leisure preference for shopping and playing computer games – indoor sports with relatively little physical activity.

    The essential aspect of the proposed idea is that this difference in non-infectious disease between stone age and modern humans is not entirely attributable to inequitable access to government subsidised medical care or an indirect consequence of AGE-inducing cigarettes and alcohol. There is a real signal under this noise that is discernible when comparing stone age versus modern humans. It’s not just a matter of diet or stress hormones causing harm, it’s AGE and allergy inducing diets and stress hormone secretions that aren’t associated with physical activity.

    Assuming the signal is real then there’s a few implications for a long and healthy lifespan:

    You can ignore it, and assume that evolution isn’t true, or isn’t relevant to nutrition, lifestyle, or exercise recommendations – as seems to be the approach taken by mainstream nutrition science and the fitness industry. Though you’ll probably need to replace the lack of belief in evolution with a substitute belief in the efficacy of various pharmaceuticals and insurance policies as a means of mitigating a sedentary lifestyle.

    Or you can partly emulate aspects of the lifestyle of your stone age ancestors by experiencing similar stresses from killing tigers and violent thugs or, more practically, find other sources of regular exercise and food that doesn’t involve sitting in front of electronic displays and absorbing huge amounts of fructose and glucose.

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