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It’s an extraordinary claim. But scientists say you can extend your life AND stay fit throughout old age – just by a change of diet that switches on your youth gene…
Professor Kenyon has found out why drastically reducing calories has such a remarkable effect
For centuries man has dreamed of being immortal, fixated on tales of magic fountains that restore youth, the rejuvenating power of a vampire’s bite or asses’ milk.
More recently came claims that injections of monkey glands or hormone supplements would make us live longer.
But so far, what’s actually worked are medical advances such as vaccines and better living conditions. Over the past century these have boosted average life expectancy by far more than 50 per cent, from 50 to 88.
The problem is that this longevity does not mean a healthier life. Indeed, thanks to chronic diseases such as diabetes and arthritis, we’re becoming like the Struldbruggs — the miserable characters in Gulliver’s Travels who were immortal, but still suffered from all the diseases of old age.
Gradually they lost their teeth, their hair, their sense of smell and taste. All their diseases got worse and their memory faded, so they had no idea who their friends and relations were. At funerals they wept because they couldn’t die.
But now a U.S. geneticist is thought to have discovered the secret to a long life, full of health and energy. And the answer might be as simple as cutting down on carbohydrates.
Professor Cynthia Kenyon, whom many experts believe should win the Nobel Prize for her research into ageing, has discovered that the carbohydrates we eat — from bananas and potatoes to bread, pasta, biscuits and cakes — directly affect two key genes that govern youthfulness and longevity.
She made her remarkable breakthrough after studying roundworms, specifically the C.elegans, a worm just a millimetre in size that lives in soil in temperate climates all over the world.
By tweaking some of their genes she has been able to help these worms live up to six times longer than normal. ‘Not only that, but we also know how to make them stay healthy all that time as well,’ she told an audience at the Wellcome Collection in London earlier this month.
So, what do worms have to do with us?
A great deal, it seems. Professor Kenyon’s work has been successfully repeated in labs around the world — the genes she found controlling ageing in worms do the same thing in rats and mice, probably monkeys, and there are signs they are active in humans, too.
This work has revolutionised our understanding of ageing, explains Jeff Holly, professor of clinical sciences at Bristol University.
‘Ten years ago we thought ageing was probably the result of a slow decay, a sort of rusting,’ he says. ‘But Professor Kenyon has shown that it’s not about wear and tear, but instead it is controlled by genes. That opens the possibility of slowing it down with drugs.’
So how does a worm hold the key to human ageing?
At 18 days old the average roundworm is flabby, sluggish and wrinkled. Two days later it will probably be dead.
The carbohydrates we eat directly affect two key genes that govern youthfulness and longevity
However, Professor Kenyon, based at the University of California, San Francisco, found that damping down the activity of just one of their genes had a dramatic effect.
‘Instead of dying at about 20 days, our first set of mutant worms carried on living to more than 40 days,’ she says.
‘And they weren’t sluggish and worn out — they behaved like youngsters. It was a real shock. In human terms it was the equivalent of talking to someone you thought was about 30 and finding they were actually 60.’
With more sophisticated genetic manipulation, she now has some worms that have lived for an astonishing 144 days. An increase of that proportion would allow humans to live to 450.
Scientists already knew how to make laboratory animals live longer and healthier lives — you just cut back their calories to about three-quarters of their normal amount.
It’s not a practical solution for humans, because you feel cold and hungry all the time.
But what Professor Kenyon found out was why drastically reducing calories has such a remarkable effect.
She discovered that it changed the way two crucial genes behaved. It turned down the gene that controls insulin, which in turn switched on another gene, which acted like an elixir of life.
‘We jokingly called the first gene the Grim Reaper because when it’s switched on, the lifespan is fairly short,’ she explains.
The second ‘elixir’ gene seems to bring all the anti-ageing benefits — its proper name is DAF 16, but it was quickly nicknamed ‘Sweet Sixteen’ because it turned the worms into teenagers.
‘It sends out instructions to a whole range of repair and renovation genes,’ says Professor Kenyon.
‘Your supply of natural antioxidants goes up, damping down damaging free radicals.’
These are the compounds produced by our body and the environment, which are linked to a host of diseases from cancer to Alzheimer’s.
The Sweet Sixteen gene also ‘boosts compounds that make sure the skin and muscle-building proteins are working properly, the immune system becomes more active to fight infection and genes that are active in cancer get turned off,’ she adds.
Kenyon had stumbled on the genetic equivalent of Shangri-La, the fictional valley where people could live for years without really ageing.
Discovering the Grim Reaper gene has prompted the professor to dramatically alter her own diet, cutting right back on carbohydrates. That’s because carbs make your body produce more insulin (to mop up the extra blood sugar carbs produce); and more insulin means a more active Grim Reaper. …
This was interesting enough to bring me out of blog hibernation for a new post. Time to start exercising again. Less sitting every day too! I picked up a blood sugar meter and my fasting level is 114 on my last test. My dad says the safe range used to go up to 120 but they changed it to sell more drugs. That may be, but after reading the above article, I’d like to work on getting down to 90 or so.
A normal fasting blood glucose target range for an individual without diabetes is 70-100 mg/dL (3.9-5.6 mmol/L). The American Diabetes Association recommends a fasting plasma glucose level of 70–130 mg/dL (3.9-7.2 mmol/L) and after meals less than 180 mg/dL (10 mmol/L).
9//25/14 Update: It turns out I have an “incurable” autoimmune disease that will destroy my pancreas and lead to type 1 adult onset diabetes where I’ll have to inject insulin to stay alive for the rest of my life. Good thing I stopped blogging because I’ve needed all the spare time to research options. Even if I can’t win, I can put up a hell of a fight. My fasting blood sugar was 111 this morning. Not great, but not horrible. Over the past few months I’ve had some really bad days where I’m over 150. I’ve learned so much, and will be sharing it in book form if possible. Do what you can to get your blood sugar down if it is high, because high blood sugar causes a lot of damage, and some of this damage causes even higher blood sugar. In other words, high blood sugar causes high blood sugar.