In 1997, a The French woman named Jeanne Calment died at the age of 122. She was the oldest verified person in the world, according to the Gerontology Research Group. Her daily habits included drinking a glass of port wine and smoking a cigarette after meals (she also ate 2.5 pounds of chocolate each week). “No one else has lived more than 120 years since she died,” says Venki Ramakrishnan, a Nobel Prize-winning biologist and author of why we die. In fact, while the number of centenarians increases each year, the number of people living beyond 110 years does not increase. “This suggests that perhaps there is a natural limit to human lifespan.”
If such a limit exists, it is imposed by biological evolution. “Evolution wants to make sure that your genes have the maximum chance of being passed on,” Ramakrishnan says. “It doesn’t matter how long you live.” This explains, for example, why there seems to be a correlation between the size of animals and their life expectancy: in general, the larger the species, the longer it will live. Most mayflies live between one and two days. Monarch butterflies can live for months. Bowhead whales live more than 200 years. Greenland sharks can live more than 500 years. “If you are a smaller species, there is no point in spending a lot of resources on maintaining and repairing the body because the probability of you being eaten or starving is high,” Ramakrishnan says. “Larger species, on the other hand, will have the advantage of having more time to find a mate and produce offspring.”
However, some species appear to be exempt from this rule. The hydra, a small freshwater animal with 12 tentacles, does not seem to age at all. The immortal jellyfish can even age backwards. “This suggests that aging is not inevitable and that we could bypass our natural limits if we alter our biology,” says Ramakrishnan.
That’s why understanding the biological underpinnings of why we age and die is such a hot research topic today. Scientists are trying to figure out how to manipulate cellular aging processes; for example, how to destroy senescent cells (aged cells that cause inflammation) or how to reprogram cells to revert to an earlier developmental state. Over the past decade, more than 300,000 scientific papers have been published on aging, while billions of dollars have been funneled into more than 700 longevity startups, including Altos Labs, Human Longevity, Elysium Health and Calico.
One of the most promising avenues of research involves the discovery of chemical compounds that can mimic the effects of a low-calorie diet, recognized as one of the best-established ways to slow aging. One such compound is rapamycin, first discovered in the soil of Easter Island, due to its antifungal properties. “Later they discovered that it was also a potent antitumor and anti-inflammatory,” says Ramakrishnan. “It is also immunosuppressive, so it can also make people prone to infections and slow wound healing. “We need to find that sweet spot between not having the side effects and just having the (anti-aging) benefits.”
Longevity researchers are also familiar with a body of research showing that young blood can rejuvenate old bodies, at least in mice. This discovery came when researchers first surgically connected the circulatory systems of a young and old mouse (a technique called parabiosis) and observed that this procedure slowed the symptoms of aging, extending the older animal’s lifespan by 10 percent. Ramakrishnan notes that while scientists are still trying to identify the factors in young blood that cause this effect, “there are companies that have rushed in and started offering young plasma to billionaires.”
“While we’re waiting for all these things to happen, there are things we can do.” Ramakrishnan points out. “This is probably similar to the advice your grandparents gave you. Eat moderately, eat a healthy diet, get enough sleep, and exercise. It turns out that each of them affects the other two, so it’s really a virtuous circle. If you do them all at once, it works better than any medication on the market, has no side effects and is free.”
This article appears in the July/August 2024 issue of UK WIRED Magazine.
