How Genetics helps Healthy Ageing

Genetics is central to healthy ageing – however the genes you are born with are not a life sentence. How often have you heard someone worrying about their risk of a heart attack because it runs in the family, or the centenarian who claims the secret of a long life is choosing your parents carefully? In other words, that our risk of disease and how well we age is down to the genetic hand we were dealt at birth. The truth is quite the opposite.

Genetic nutritioneering

It’s now clear that our genes are remarkably porous; constantly responding to changes in our environment. Diet, micronutrients, toxins, love and affection, trauma and loss can all affect them. In fact, if you could see the genes in your body as points of light as they turned on and off, you would look like a firework display.

This has huge implications for anyone trying to improve their chances of a healthy old age by changing their lifestyle. No longer is genetic engineering something confined to research labs packed with millions of dollars of high-tech equipment, it is something that you can literally do on the kitchen table. The way to change the behaviour of your genes, even some of those inherited heart-attack ones, is with a good supply of omega-3 fats, healthy levels of vitamin D, eating a low-GL diet that keeps your blood sugar down and taking exercise.

The Methuselah worm

The gene–lifestyle link was first discovered when a top American geneticist became curious about exactly why calorie restriction (CR) had such a dramatic effect not just on lifespan but on ageing healthily. Professor Cynthia Kenyon of the University of California, San Francisco, wondered if the diet could be having a direct effect on gene activity, so she cut back on the calorie intake of a number of tiny roundworms just a millimetre long, which are the genetics researcher’s ‘lab rat’.

She found that one gene in particular was turned off by the CR diet. To her big surprise, it was one that normally made more insulin available. Even more of a surprise was the finding that turning the insulin gene off turned on another gene that controlled a cascade of extensive cell-repair processes. By tinkering with these genes she was able to breed some worms that lived for twice their normal 20-day lifespan.1 With more sophisticated techniques, she’s been able to genetically engineer a strain of roundworm that lives healthily and actively for an astonishing 144 days. The human equivalent of 450 years!

Discovering this genetic mechanism opens the way to making healthy lifestyle changes in a much more focused way. It has also revolutionised ageing research, according to 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 [Cynthia 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.’

Insulin – the secret ageing hormone

The key to slowing ageing could be in keeping the amount of insulin in your bloodstream down. So, all those refined sugars and carbs that you just can’t resist when you eat out could be speeding up the rate at which you are ageing. Dr Kenyon’s discoveries about what the genes in her long-lived worms were doing suggests that too much insulin is crucial in not just diabetes but in other chronic diseases as well. ‘We jokingly called the first gene the Grim Reaper,’ says Kenyon, ‘because when it’s on, which is the normal state of affairs, [the worms’] lifespan is fairly short.’

The second one had such a remarkable effect on the worms’ health that it was quickly nicknamed ‘Sweet Sixteen’, because it reduced the worms ‘age’ and turned them into teenagers. Kenyon had stumbled on a genetic Shangri la – the fictional valley where people barely aged.

Fortunately, humans have an equivalent to Sweet Sixteen (called Foxo) and turning that gene on has a number of...

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