BOOK OF THE WEEK
AGELESS: THE NEW SCIENCE OF GETTING OLDER WITHOUT GETTING OLD
by Andrew Steele (Bloomsbury £20, 400 pp)
A tortoise named Harriet died of a heart attack in an Australian zoo in 2006. She was 175 years old and had been collected from the Galapagos Islands by Charles Darwin during his round-the-world trip on HMS Beagle in 1835.
She had survived Darwin by well over a century. Not only that. She was in good health until her final year.
As Andrew Steele points out in his absorbing guide to the latest scientific thinking on growing old, Galapagos tortoises display what’s called ‘negligible senescence’. They don’t suffer the debilitating health consequences of old age. Harriet would have been as perky in the first years of the 21st century as she was when Queen Victoria was on the throne.
British author Andrew Steele, explores the latest scientific thinking on ageing in a new book (file image)
Human beings are not so lucky. Not only do the vast majority of us die before making it to 100, we also suffer the thousand natural shocks the flesh is heir to.
We grow increasingly frail and subject to disease. While the Galapagos tortoise’s risk of death remains more or less constant as it ages, our risk of death doubles every eight years. At 30, your chance of dying in the next year is one in 1,000; at 80, it’s one in 20.
Our life expectancy has, of course, improved dramatically over the past 200 years. As Steele tells us: ‘At 40, you’d be statistically dead in 1800.’
Today’s 20-year-old has better odds of having a living grandmother than 20-year-olds in the early 19th century did of having their mothers still alive.
Every year since 1840, maximum global life expectancy has increased by three months. And these improvements have not just been seen in rich countries. Today, 90 per cent of the world’s population lives in countries where life expectancy is over 60. By contrast, in India in 1950, it was 36.
This is the ‘age of ageing’ and, by 2050, it’s estimated that one in six of the global population will be over 60.
Paradoxically, we’ve become victims of our own success. Most of us now live long enough to ‘experience the frailty, loss of independence and diseases associated with growing old’. In Steele’s opinion, it’s high time for medical science to turn its attention to finding a ‘cure’ for ageing.
Every year since 1840, maximum global life expectancy has increased by three months (file image)
Humankind has long dreamt of finding ways of extending life.
Alchemists have yearned to find an elixir of immortality; travellers have gone in search of fountains of everlasting life; mythologies have spoken of lands like the Celtic Tir na nOg where no one grows old and sick. There’s also been a long history of ‘quacks peddling immortality with unevidenced treatments from potions and elixirs’.
In the 1920s, French-Russian surgeon Serge Voronoff even gained notoriety with his technique of grafting tissue from monkey testicles on to human testicles. The idea was to retard ageing. Unsurprisingly, it didn’t work.
There have been proven methods of increasing lifespan in the past but they have been even more extreme.
Male castration seems to have done the trick. Evidence from historical records kept of eunuchs in the Korean court shows three centenarians out of 81.
That compares to fewer than one in 10,000 men making it to 100 in modern Japan, the country with the largest number of centenarians. Despite this success rate, it seems unlikely there’d be a queue for the procedure now.
Andrew Steele argues today the new science of biogerontology offers a genuine and less alarming prospect of extending life (file image)
However, Steele argues, today the new science of biogerontology offers a genuine and less alarming prospect of extending life. For example, the common diabetes drug metformin is currently ‘a top contender to slow the ageing process’, although many more trials will be needed before it can be safely prescribed.
Another less familiar drug, rapamycin, was originally derived from bacteria found in the soil of the remote Easter Island. It’s licensed for use as an anti-cancer medication but its biggest contribution to human health in the future might be in helping to stave off old age. And then there are ‘senolytics’ — treatments which kill off the old and damaging cells slowly accumulating in our bodies as the decades pass.
Tests on mice show they can increase lifespans by up to 25 per cent and human trials are under way. ‘A senolytic,’ Steele predicts, ‘could well be the first true anti-ageing potion to pass your lips.’
AGELESS: THE NEW SCIENCE OF GETTING OLDER WITHOUT GETTING OLD by Andrew Steele (Bloomsbury £20, 400 pp)
In the longer term, new techniques of gene editing will ‘optimise the good stuff, reduce the bad and add new capabilities to our cells and organs’.
These are all prospects for the future — and that future may not be too distant. Every year you’re alive, your probable date of death recedes a few months.
That’s down to ever-increasing life expectancy and to the advances in biomedical science which Steele chronicles in his book. But it scarcely needs saying that you must stay alive to get the benefit. You still have to find an answer to the question — how can you live long enough to live even longer?
It’s not good news for smokers, of course. Best to give up immediately. Nor for members of the male sex — being born a woman improves life expectancy by about five years.
Nor for those of us who enjoy our food.
As long ago as the 1930s, a series of experiments with rats showed the power of dietary restriction. Rats allowed to eat what they wanted died younger. Those kept hungry but adequately nourished lived longer. And in better health. Eating less seemed to slow down the ageing process.
There’s now plenty of evidence the same is true for humans. Apart from cutting down on the calories, there’s plenty we can all do to prepare for longer lives, from getting more exercise to taking care of our teeth. (Dental health is proven to impact on lifespan.)
As Steele admits, ‘treating ageing sounds like science fiction’. This is certainly true of the more extravagant claims by scientists such as the visionary Aubrey de Grey who thinks humans will, in future, celebrate their thousandth birthdays.
But, after you’ve read Ageless, and heard about the latest developments in ageing biology, it begins to sound more like science fact.