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 remarkable effects. ‘Your supply of natural antioxidants goes up, damping down damaging oxidants,’ says Kenyon, ‘There’s a boost to compounds that make sure the skin and muscle building proteins are working properly, the immune system becomes more active in fighting infection and genes that are active in cancer get turned off.’
What surprised many is that the research clearly implicated insulin as being a key player in ageing and very possibly in diabetes, heart disease and cancer as well. One clear message was that keeping your insulin levels to a minimum with a low-GL diet could be a recipe for healthy ageing. High blood sugar, which triggers insulin, means the Grim Reaper stays on, and so Sweet Sixteen never gets activated.
Other ways to lower insulin release and help switch on skinny genes is to supplement chromium. The basic daily requirement for chromium, which is found in whole foods, is 50mcg, ten times this amount, 500mcg, improves insulin sensitivity, which means your body makes less, again switching on the skinny genes.2 Some supplements also provide a cinnamon extract called Cinnulin, which also helps improve your metabolism.3 Specific kinds of exercises help. You need the combination of resistance training and aerobic exercise. Interval training, which involves short bursts of 30 to 60 second intense activity, such as a sprint, helps reverse insulin resistance.
The pleasures of CR without the pain
So, a low-GL diet looks like a powerful way of keeping insulin at a healthy level but, there is another way to get the benefits of CR without being condemned to a permanent state of semi-starvation. It is ridiculously simple. Eat every other day. That’s it. You fast for one day and eat as much as you like the next. Fast for another day, then eat normally and so on. Of course there are variations and guidelines. Most people eat something on the ‘down’ day, as it is called: usually between 20 and 50 per cent of the calories you’d normally have, depending on how ......
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