Human longevity is having a moment. There are at least three reasons why, the first being demography: the world is greying at the temples, with the International Monetary Fund describing population ageing, not rapid population growth, as the planet’s “most formidable demographic challenge”. The World Health Organisation estimates that by 2030 one in six people will be aged 60 or over; by 2050, their number will exceed two billion, with almost half a billion of them older than 80.
The second is science. There has been an explosion of scientific revelations about the biology of ageing in the last half-century. Essentially, we age because our cells accumulate damage over time and gradually lose the ability to repair and renew themselves. The unlovely consequences include frailty, dementia, diabetes, cancer, heart disease, stroke and eventually death.
Then there is money: biologists have found chemical ways of turning the clock back for human cells, and investors sense the beginning of a new industry that might finally change the game on age-related diseases. Delaying decrepitude would, by implication, extend youthfulness, theoretically offering the prospect of extra decades, even centuries, of lifespan.
Accordingly, the field of human longevity research now comprises a discordant mix of biomedical scientists wanting to cure disease and wealthy optimists hoping to live forever. Books with titles such as Outlive and The Case Against Death stoke the immortality dream. Longevity stocks are touted as a future trillion-dollar industry and the world’s richest people are taking early positions. Amazon’s Jeff Bezos is among the reported backers of the recent biotech start-up Altos Labs, based in the UK and California, which has recruited superstar scientists working on so-called cell rejuvenation. Google’s parent company, Alphabet, has its own life-extension company, Calico.
As the biologist Venki Ramakrishnan muses in Why We Die: “When [today’s tech billionaires] were young, they wanted to be rich, and now that they’re rich, they want to be young.” For the Silicon Valley elite, ageing “is just another engineering problem to be solved by hacking the code of life”. His book delves into that code – inscribed in untold complexity in the genes, molecules and proteins that lurk inside every human body – and chronicles the various quests to defy ageing and death, from calorie-restricted diets and cryonics (corpse freezing) to vampiric blood transfusions.
Given Ramakrishnan’s grandee credentials – the Indian-born 71-year-old has won the Nobel Prize for chemistry, was president of the Royal Society, and runs a research group at the Medical Research Council’s Laboratory for Molecular Biology in Cambridge – I feared his style might be ponderous and pompous. In fact, Why We Die is both an engaging, accessible overview of the science of ageing and a barbed takedown of the immortality crowd. It is also a love letter to our fleeting existence, “an eternal feast that we join when we are born” and which we fear leaving almost as soon as we realise that life is finite and precarious.
In truth, Ramakrishnan, whose book Gene Machine covered his prize-winning research, seems horrified by the “living forever” brigade. “Many truly distinguished scientists now have financial stakes in the [longevity] industry, either through their own companies or as employees or consultants,” he writes, which is fine, “… [but] when I see some of them constantly touting their findings or their companies’ prospects, I wonder whether they can all really believe what they are saying.”
Ageing is a complex and curious business. It is not preordained by evolution, because the only thing that matters for survival is that we live long enough to reproduce and pass on our genes. That means evolution has no need to weed out diseases that generally show up later in life, like Alzheimer’s. The animal kingdom, meanwhile, shows that ageing is not inevitable. When stressed or injured, Turritopsis dohrnii, or the “immortal jellyfish”, will regress to an earlier stage of development and live its life again. For this wobbly Methuselah, the risk of dying does not increase with age (even if predators and disease remain an ever-present headache).
Why do humans come statistically closer to death with each passing year? Each one of us is made up of trillions of cells; each cell contains our DNA. This DNA, unique to us, acts loosely as a blueprint as our cells divide throughout life, keeping us alive. But the copying and replication of new cells can introduce typos, or mutations; environmental factors, such as chemicals and radiation, also cause cumulative cellular damage.
These slings and arrows, which affect the proteins we can make and the way our body functions, build up over time. Rogue damaged cells, if not cleared out, can proliferate uncontrollably to produce tumours; proteins, which need to fold correctly to work, can pile up like anarchic origami in the brain, leading to Alzheimer’s. Death happens when our cells can no longer sustain the complex biochemical choreography to keep a whole organism alive (though individual organs might still be “alive” after death, in the sense that they are transplantable).
Could scientists reprogram cells by making them young again? Well, there must be a reset button somewhere because, when we have children, they are not born old like us. All babies start life with their biological clocks reset to zero.
Shinya Yamanaka, a scientist in Japan, has come closest to discovering the secret of such a reset: bathe an adult cell in four proteins now known as “Yamanaka factors”, and it will rewind to a more juvenile state known as pluripotency. Using that method to rejuvenate whole tissues, though, appears to render them susceptible to cancerous tumours. Yamanaka, who won a Nobel Prize in 2012 for this breakthrough, is now an adviser to Altos.
Ramakrishnan has a hunch that lifespan is biologically limited to perhaps around 120 years; nobody has yet broken the record of Jeanne Calment, who died aged 122 in 1997. Despite improved healthcare, he notes, it is still rare to find supercentenarians, people older than 110 years. They tend to show a “compression of morbidity”, living long lives in mostly good health with a short decline at the end, rather than lingering for decades in poor health. Anti-ageing research should follow that lead, Ramakrishnan writes, by attempting to extend “healthspan” rather than lifespan. And, currently, science cannot beat diet, exercise and sleep, which “currently work better than any anti-ageing medicine on the market, cost nothing and have no side-effects”.
But that hasn’t stopped the immortality “crackpots”, like those pushing cryonics, which freezes people after death with a view to thawing them out when science has advanced sufficiently (not a credible idea, he insists). Ramakrishnan has a flair for lucid explanation and these later chapters show him at his most compelling, fusing deep scientific insights with thoughtful reflections on society – and delivering a velvet-gloved pummelling to some of the most prominent figures in ageing research.
Of Aubrey de Grey, the much-interviewed eccentric who heads the Longevity Escape Velocity Foundation, Ramakrishnan observes dryly: “His longevity in longevity research is remarkable, as is his ability to continue to obtain funding from rich benefactors.” The Harvard professor David Sinclair, who believes humans could live to 200, makes claims that “cause some of his critics to cringe and even fellow scientists who respect his ability to be embarrassed for him”. Ouch.
Ramakrishnan explores, though not as deeply as I would have liked, the social implications of radical life extension: rising health inequality, intergenerational injustice, overpopulation, the economics of retirement and a possible decline in human creativity as an ageing world becomes more staid. Rightly, he acknowledges his own hypocrisy: continuing to run a lab in his seventies, despite thinking his intellectual powers are fading; and taking pills to lower blood pressure and cholesterol, which are, effectively, anti-ageing medications.
By the end, one realises that Why We Die is not an attempt to solve the enigma of mortality but an exhortation to dine well during our brief appearance at the feast of life: “When our time comes, we can go into the sunset with good grace, knowing that we were fortunate to have taken part in that eternal banquet.”
Why We Die: The New Science of Ageing and the Quest for Immortality
Venki Ramakrishnan
Hodder, 320pp, £25
Anjana Ahuja writes a weekly science column for the Financial Times
Venki Ramakrishnan appears at Cambridge Literary Festival on 21 March: cambridgeliteraryfestival.com
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[See also: How to live forever]
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This article appears in the 20 Mar 2024 issue of the New Statesman, Easter Special 2024