Chapter 3
Introduction
This raises the question of the healthspan, the period of life spent in good health and free of chronic disease and disability. No wonder people are skeptical of longevity treatments when we see our life expectancy rising but our healthspan shrinking. Or, paraphrasing Jonathan Swift: “Everyone wants to live forever, but no one wants to grow old.”
In the United States, for example, we are sick longer than we are healthy. In 1998, a 20-year-old could expect to have 85 years ahead of them, whereas in 2006 a 20-year-old could look forward to 59 more years. Yet the 20-year-olds of the 1990s would likely face ten years with chronic disease, whereas today it’s more like 13 years. It all feels like one step forward and three steps back. Researchers have also noted that we spend two years not functioning—that is, we are unable to manage basic activities of daily living, such as walking a few hundred meters, standing or sitting for two hours without having to lie down, or standing without assistive devices. In other words, we live longer, but sicker.
For this reason, this book addresses both lifespan and healthspan. What’s the point of living longer if you can’t enjoy it with all your senses? My sincere hope is that this book will not only extend your life by years, but fill those years with life.
Introduction
My book How Not to Die wasn’t about living forever. It wasn’t called How Not to Die. Instead, it dealt with how not to die prematurely, in pain and after a long, chronic illness that robs us of our independence. The good news was that we have enormous power over the course of our health, since we can prevent the great majority of premature deaths and disabilities through a sufficiently healthy diet and a similarly healthy lifestyle. How Not to Age starts from a similar premise. It isn’t about immortality, but rather about aging gracefully and vibrantly instead of suffering from devastating infirmities and frailty. But why can’t we actually stop aging and live forever?
“Man will not be content until he has conquered death” — Bernard Strehler
From the Epic of Gilgamesh more than 4000 years ago to the recent 500th anniversary of Ponce de León’s search for the Fountain of Youth, humanity has always yearned for the mythical elixir of life that would free it from the scourge of aging. And why not? Aging is not, after all, an unchangeable constant in nature. Evolution has produced life spans in animals that differ by a factor of millions, from mayflies, whose adult life may last only a few minutes, to clams that can make it past 500 years. Just as the Wright brothers drew inspiration from birds, we can draw inspiration from animals that age slowly, if at all.
Why can’t we live forever? Some animals can, and I’m not talking about a 200-year-old whale, not even a 1000-year-old tree. There actually are species (with names like “immortal jellyfish”) that apparently don’t age and, technically, could live forever. In a sense, humans are immortal in that some of our cells live on—the sperm or egg cell that is lucky enough to find the other. Every child we have grows from a single one of our cells. The mere fact that a single cell can develop into a complete human should make the idea of keeping our body alive indefinitely seem trivial from a biological standpoint. From a fertilized, microscopically small clump can develop perhaps the most complex object in the known universe, the human brain with its 100 000 miles of 86 billion neurons that create 150 trillion connections. If biology can do that, what can’t it do?
Still, there is great skepticism in the scientific community, and many are convinced that aging is irreversible. “Anti-aging” is compared to “antigravity.” Vocal critics in gerontology accused those who speak of the possibility of a substantially extended human lifespan of being “loathsome … [for] misleading the public.” They claim that “anything over 130 [years] is ridiculous.” As expected, advocates counter such doubts by quoting prominent researchers from the past who made equally absolute claims that have since been disproved. For Nobel Prize–winning physicists, the prospect of nuclear power was “nonsense,” “a completely unscientific utopian dream, a childish bogeyman.” Lord Kelvin, one of the greatest scientists of his time, famously assured people that “machines heavier than air cannot fly,” and as late as 1902, just one year before the first flight at Kitty Hawk, he scoffed at their unreality.
Even now, in the laboratory, genetic mutations can extend lifespan tenfold, at least in a species of small worms. In mice, changing diet and genes yields an increase of 70 percent. Individual interventions such as restricting methionine, which belongs to my Anti-Aging Eight, can increase the average and maximum lifespans of rats by about 40 percent, which, translated to humans, could raise average life expectancy to 110 years, with rare “super-agers” potentially reaching 140 years. The results still need to be replicated in humans, but if we could discover treatments that not only slowed the aging process but actively repaired accumulated damage, then the sky would be the limit.
Idealistic scientists in the field imagine that time could, in a sense, be melted away, as in the surrealist painting with the limp, drooping clocks: a “rejuvenation of the body would eventually lead to an endless summer of literally eternal youth.” People imagine an “escape velocity of longevity,” in which we would only have to live long enough to see treatments that gave us more time than passed—a tipping point at which we could increase life expectancy each year by at least one additional year. In theory, that could grant humanity an essentially unlimited lifespan. Imagine dying in the year before the critical point! I don’t want to commit to whether such a breakthrough is possible, but I hope that this book will still be helpful, whether you are striving to live long enough to become immortal or are only trying to be as young as possible when you die at an advanced age.
Four books in one
When I sat down to write (or rather stood up and started walking, since I type at my treadmill desk), I had to decide. What should I focus on? The more superficial signs of aging that everyone wants to know about, such as wrinkles or gray hair, or the clinical aspects like declining brain performance? Or should I deal with how we might slow the aging process itself? As you may have guessed from the length, if you are reading an old-school printed edition, I decided on everything.
The inspiration for How Not to Age was a consensus paper titled “Interventions to Slow Aging in Humans,” compiled by the leading researchers in anti-aging medicine such as Drs. Fontana, Longo, Sinclair, and dozens of others—almost everyone with a name in the field. They had been brought together to identify the most promising strategies for developing drugs to combat aging, and they drew up a list of “essential pathways,” such as pharmacologically inhibiting the hormone IGF-1 or agents that block the enzyme mTOR. As I looked over the list, I realized: Every single one of these solutions can be achieved through diet. That became the opening section of this book.