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For thousands of years, in order to survive, humans had to store fat efficiently, take in salt to help prevent dehydration, be vigilant against threats of physical harm, and clot blood to prevent blood loss. But, as a new book argues, in modern times, food and salt are more readily available and physical threats and blood loss aren't nearly as dangerous as they used to be. However our bodies are still operating as they did hundreds of years ago. The result is a host of modern ills: obesity, high blood pressure, depression, anxiety, heart attacks and strokes.
Here & Now's Jeremy Hobson talks with cardiologist Dr. Lee Goldman, a dean at the Columbia University medical school and author of "Too Much of a Good Thing: How Four Key Survival Traits Are Now Killing Us."
Book Excerpt: 'Too Much Of A Good Thing'
By Lee Goldman, MD
Ever since I began practicing medicine, my family and friends have inevitably asked me about real and perceived health problems. Common questions always include: “Why is it so hard for me to lose weight?” “Do I really need to take my blood pressure medicine even if I feel okay?” “Should I take an aspirin every day?”
In thinking about these questions and others, I began to appreciate what seems to be a peculiar conundrum. Some of the key protective strategies our bodies have used to assure the survival of our human species for tens of thousands of years now cause many of the major diseases of modern industrialized societies.
In writing this book, my first goal is to emphasize the historical fragility of the human species and why we wouldn’t be here today, let alone dominate the world, if it were not for fundamental survival traits such as hunger, thirst, fear, and our blood’s ability to clot. My second goal is to explain why these hardwired survival traits are often now “too good” — not only more powerful than we need them to be to survive in the modern world but also so strong that, paradoxically, they’ve become major causes of human disease and death. My third and perhaps most important goal is to explain how the future may play out, including how we can continue to use our brains to influence that outcome.
Too Much of a Good Thing focuses on the four key human survival traits, without which we wouldn’t be here today:
- Appetite and the imperative for calories. Early humans avoided starvation by being able to gorge themselves whenever food was available. Now that same tendency to eat more than our bodies really need explains why 35 percent of Americans are obese and have an increased risk of developing dia- betes, heart disease, and even cancer.
- Our need for water and salt. Our ancestors continually faced the possibility of fatal dehydration, especially if they exercised and sweated, so their bodies had to crave and conserve both water and salt. Today, many Americans consume far more salt than they need, and this excess salt combined with the same internal hormones that conserve salt and water are the reasons why 30 percent of us have high blood pressure — significantly increasing our risks of heart disease, stroke, and kidney failure.
- Knowing when to fight, when to flee, and when to be submissive. In prehistoric societies, up to 25 percent of deaths were caused by violence, so it was critical to be hypervigilant, always worrying about potentially getting killed. But as the world got safer, violence declined. Suicide is now much more common in the United States than murder and fatal animal attacks. Why? Our hypervigilance, fears, and worrying contribute to a growing epidemic of anxiety, depression, and post-traumatic stress — and the suicides that can result.
- The ability to form blood clots so we won’t bleed to death. Because of their considerable risk of bleeding from trauma and childbirth, early humans needed to be able to clot quickly and efficiently. Now, with the advent of everything from bandages to blood transfusions, blood clots are more likely to kill us than excessive bleeding. Most heart attacks and strokes — the leading causes of death in today’s society — are a direct result of blood clots that block the flow of arterial blood to our hearts and brains. And long car rides and plane trips, unknown to our distant ancestors, can cause dangerous and sometimes fatal clots in our veins.
Well into the nineteenth century, each of these four traits specifically helped our ancestors survive as they tried to avoid starvation, dehydration, violence, and bleeding — which have been among the leading causes of death throughout human history. But now, amazingly, these same four traits collectively explain more than 40 percent of deaths in the United States, including four of the eight leading causes of mortality, and are directly responsible for more than six times the number of deaths they prevent. How could the very same attributes that helped humans not only survive but also dominate the earth now be so counterproductive?
This paradox is the essence of Too Much of a Good Thing. For more than 200,000 years and perhaps 10,000 generations, the world of our ancestors changed very gradually. Our genes, which define who we are, also evolved more or less on a parallel path, so our ancestors could adapt and thrive. Then, barely 200 years ago, human brainpower began to change our world dramatically, as the Industrial Revolution signaled the beginning of an entirely new era of transportation, electricity, supermarkets, and medical care. The good news is that life expectancy, which was little different in the early 1800s from what it was tens of thousands of years ago, has just about doubled since then, including more than a six-year gain just since 1990. But the bad news is that our bodies have had only about 10 generations to try to adapt to this new world. Our genes simply can’t change that fast, and, as a result, our bodies are lagging behind our environment. Instead of dying from challenges against which our bodies were designed to protect us, we’re now more likely to die from the protective traits themselves.
So what will happen next? There are three major possibilities.
One is that everything gets worse — more obesity, diabetes, high blood pressure, anxiety, depression, suicides, heart attacks, and strokes — until those of us with these diseases don’t live long enough to have children. Although this possibility may seem far-fetched, we already see obese children becoming diabetic adolescents who will be less likely to have children — let alone healthy children — than their nondiabetic counterparts. But somehow, we should be more than smart enough to avoid this doomsday scenario.
A second possibility is that we collectively will devote more time and effort to being healthier. We’ll all eat better, exercise more, and embrace other virtuous lifestyle changes. Unfortunately, these self-help approaches, though sometimes successful on an individual basis, are notoriously unsuccessful across populations. The term “yo-yo dieting” — a reference to the fact that most people who lose weight usually gain it right back — is just one example of the tendency for many short-term successes to be counterbalanced by long-term failures.
The third possibility is that we’ll take advantage of modern science — not in isolation but as a key complement to continued attempts to improve our lifestyles. High blood pressure requires medication; stomach surgery is the most successful way to deal with refractory extreme obesity; the chemical imbalances that cause depression often respond best to antidepressant medications; and an aspirin a day really does make sense for some of us. Ongoing scientific advances also hold great promise for future medications that could control our appetites for food and salt or that could safely reset our clotting systems. And with the decoding of the human genome, we’re entering an era in which the specific genetic causes of modern diseases may be treated with medicines that target only the responsible gene. These advances augur a new era of personalized precision medicine: treatment specifically designed to address each individual’s needs. This growing reliance on medications or even surgery shouldn’t be dismissed as moral weakness but rather recognized as the sometimes necessary way to do what we can’t do on our own — because our genes simply aren’t built that way and can’t change fast enough.
Too Much of a Good Thing addresses all these possible outcomes and potential solutions to our present predicament. Each of the first five chapters begins with a story that helps frame the modern situation, and then explains how our current health challenges are the direct result of historically successful human attributes. The final three chapters provide a blueprint for how we can and must continue to use our brains to get our genes and our bodies back into sync with the environment we’ve created.
- Lee Goldman, MD, dean of the faculties of health sciences and medicine at Columbia University Medical Center.
This segment aired on December 15, 2015.
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