Change Your Mindset is a monthly series from CNN’s Mindfulness, But Better team. We talk to experts about how things can be done differently to live a better life.
Since time immemorial, people have tried their best to cheat death. Today, as revolutionary developments transform science fiction materials into daily reality, are we closer to extending our lifespan or even immortality?
If so, do we really want eternal life? In his new book, “Why We Die: The New Science of Aging and the Quest for Immortality,” Nobel Prize-winning molecular biologist Venki Ramakrishnan delves into past and cutting-edge research to reveal the inspiring theories and practical limitations of longevity. Along the way, it raises critical questions about the social, political and ethical costs of efforts to live forever.
People are already living twice as long as they did 150 years ago, due to increased knowledge about diseases and their spread. Does this mean that interventions that will triple or quadruple our lifespan are just around the corner? Ramakrishnan shares his perspectives on the realities of aging, death, and immortality.
This conversation has been edited and condensed for clarity.
CNN: What is aging? How does it cause death?
Venki Ramakrishnan: Aging is the accumulation of chemical damage to molecules within our cells; This harms the cells themselves, thus the tissue, and ultimately us as organisms. Surprisingly, we begin to age while in the womb, but at that point, we are growing faster than we are accumulating damage. Aging occurs throughout our lives, from the very beginning.
The body has developed many mechanisms to correct age-related damage to our DNA and the poor quality proteins we produce. We would never live this long if there were no ways to fix such problems. Yet over time, the damage begins to exceed our ability to repair.
Think of the body as a city with many systems that need to work together. When an organ system critical to our survival fails, we die. For example, if our muscles weaken and our heart weakens to the point of stopping, we will no longer be able to pump the blood containing the oxygen and nutrients our organs need and we will die. When we say someone dies, we mean that he dies individually. In fact, when we die, most of us are alive, as are our organs. For this reason, organs of accident victims can be donated to transplant recipients.
CNN: Is there a fixed limit to human lifespan?
Ramakrishnan: Life spans of all organisms range from a few hours or days for insects to hundreds of years for some whales, sharks, and giant turtles. A layman might assume that all life forms are prearranged to die when they reach a certain age. But biologists do not believe that aging and death are programmed the way a fertilized egg is programmed to develop into a human.
Instead, evolution has optimized the lifespan equation of an optimized resource allocation for each species. Larger animals tend to live longer. If you are a small animal and therefore more likely to be eaten by predators, starve to death, or die in a flood, there is no point in evolution wasting resources repairing the damage needed to keep you alive longer. Instead, evolution chooses to grow fast and mature quickly so you can reproduce and pass on your genes.
If you are a larger animal, surviving longer will give you a better chance of finding a mate with whom you can have more children over your longer lifespan. Lifespan is about evolution maximizing your chances of passing on your genes. In humans, this finely tuned balance of resources gives us a maximum lifespan of approximately 120 years. But that doesn’t mean we can’t change biology, intervene in aging processes, and perhaps extend our lives. Like many aging scientists, I believe this is possible. But I do not share their optimism about how feasible such interventions might be.
CNN: Who has lived the longest so far?
Ramakrishnan: The oldest person for whom we have reliable records was a French woman named Jeanne Calment, who died in 1997 at the age of 122. She smoked for all but the last five years of her life and ate more than a pound of chocolate every week. But I wouldn’t recommend these particular strategies for longevity, except maybe chocolate.
CNN: Can the aging clock ever run backwards?
Ramakrishnan: The aging clock is ticking backwards with each generation. Although the child is born from the cells of adult parents, the child still starts at age zero. The child born to a 40-year-old woman is not 20 years older than the child born to a 20-year-old woman; They both start from scratch. So at some point the aging clock may reverse.
There is also cloning. While Dolly, perhaps the most famous of the cloned sheep, fell ill and died at about half her normal age, the other cloned sheep continued to live normal lives. This has convinced some that resetting the aging clock should be possible on a larger scale. While coaxing adult cells to become embryonic and begin growing again has been successful, practical difficulties make cloning highly inefficient. Many cells have accumulated too much damage to be removed; This requires numerous experiments to raise a single animal.
Meanwhile, experiments in mice used cellular reprogramming so that cells can partially reverse development and have the capacity to regenerate tissue. By changing the cells to a slightly earlier state, scientists produced mice with better blood markers and improved fur, skin and muscle tone. Even with all the research in this area, I’m not sure how easy it would be to turn this into something useful for humans.
CNN: Your father just turned 98. What impact will his health and independence have on your life? How much are aging and longevity affected by genetics?
Ramakrishnan: There is a correlation between the ages of parents and their children, but it is not perfect. A study of 2,700 Danish twins showed that heritability (how much of our longevity is down to our genes) accounts for only 25% of lifespan. Yet researchers have found that a mutation in a single gene can double the lifespan of a particular species of worm. There is obviously a genetic component, but the effects and consequences are complex.
CNN: What does cancer science reveal about anti-aging research?
Ramakrishnan: The relationship between cancer and aging is complex. The same genes can have different effects over time; It helps us grow when we’re young, but increases the risk of dementia and cancer as we get older. Our risk of cancer increases with age because we accumulate defects in our DNA and genome that sometimes cause gene defects that lead to cancer. But many of our cellular repair systems that seem designed to prevent cancer early in life also cause aging later in life.
For example, cells can detect breaks in our DNA that could allow chromosomes to combine abnormally, leading to cancer. To prevent this fusion, the cell will either kill itself or enter a state called senescence in which it can no longer divide. This makes sense from the perspective of an organism like us, which has trillions of cells. Even if millions of cells are destroyed in this way, these actions protect the entire organism. But the accumulation of senescent cells is one of the ways we age.
CNN: Has your research into why we die affected how you live your life?
Ramakrishnan: It is interesting that evidence-based recommendations about what can help us live long, healthy lives reflect common sense advice passed down through the ages. We got this from our grandmothers: Don’t be a glutton. Exercise. Avoid stress, which changes our metabolism and creates hormonal effects that can accelerate aging. Getting enough sleep.
Aging research helps us understand the deep biological implications of this advice. Eating a variety of healthy foods in moderation can prevent the health risks of obesity. Exercise helps us regenerate new mitochondria, the energy-providing powerhouses of our cells. Sleep allows our body to repair at the molecular level. Learning the biology behind this age-old and sound advice can encourage us to take other actions that will help support a long, healthy life.
I often say that personally I am long past my expiration date, but as a human being I feel that I am still alive and have something to contribute.
CNN: What are the social costs of the quest to deceive aging and death, especially inequalities?
Ramakrishnan: In both the US and the UK, the top 10% of earners live more than a decade longer than the bottom 10%. This disparity is even greater when you look at healthspan (healthy lifespan). Poor people live shorter and less healthy lives.
Many wealthy people pour large amounts of money into research, hoping to develop advanced technologies that will prevent aging. If these efforts are successful, the very wealthy will initially benefit, followed by those with very good insurance, and so on. will benefit. Rich countries will likely have access before poor countries. Therefore, both domestically and globally, such advances have the potential to increase inequalities.
CNN: Has researching this topic changed your thoughts and feelings about aging and death?
Ramakrishnan: Most of us don’t want to grow old or leave this life. We don’t want to leave while the party is still going on. However, we continue to exist even as the cells in our body are constantly forming and dying. Similarly, life on Earth will continue as individuals come and go. On some level we have to accept that this is just part of the order.
I think this quest for immortality is a mirage. One hundred and fifty years ago, you could expect to live to about 40 years old. Life expectancy today is around 80, which, as author Steven Johnson says, is almost like adding an extra life. But we’re still obsessed with dying. I think if we lived to be 150, we’d be worrying about why we didn’t live to be 200 or 300. This never ends.
Jessica DuLong Based in Brooklyn, New York, he is a journalist, book collaborator, writing coach, and author of “Saved at the Seawall: Stories From the 9/11 Boat Lift” and “My River Chronicles: Rediscovering the Work That Building America.”
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