 Eat yourself a longer life
Age-defying isotopes
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 Scientists have for the first time significantly increased the life span of an animal using diet. Previous successes extending life involved withdrawing food to near starvation levels (called caloric restriction). The latest discovery, which researchers hope to publish soon, leads to the intriguing possibility that diet could be used to extend human lifespan and drastically reduce the incidence of cancer and other diseases of ageing.
A group led by researcher Mikhail Shchepinov, formerly of Oxford University, fed nematode worms, Caenorhabditis elegans, nutrients reinforced with natural isotopes. A 10% extension in life span was observed, which according to Shchepinov is due to the fact that the bodily constituents and DNA produced from isotopically-reinforced nutrients are more resistant to detrimental processes, such as free radical attack, responsible for ageing.
Free radical attack (oxidation) is by far the most widely accepted theory of ageing. Free radicals, highly reactive molecules produced by the mitochondria as a byproduct of metabolism, are thought to damage all bio-molecules, including proteins, sugars, fatty acids and nucleic acids. It is the accumulation of this damage that causes the body to age.
According to Shchepinov, replacing atoms in bonds susceptible to attack with their natural isotopes changes the quantum mechanical dynamics such that the bond is harder to break (KIE-kinetic isotope effect). ‘Because these bonds are so much more stable, it should be possible to slow down the process of oxidation and ageing,’ he said.
He suggests that isotopes could be used in animal feed so that humans could get the ‘age-defying’ isotopes indirectly in animal products, like steaks or chicken fillets, rather than eating chemically enhanced products themselves. Isotopes could also be used in pet food or as a means to protect workers or soldiers from radiation.
In recently published work (Rejuventation Research 2007; doi: 10.1089/rej.2006.0506), Shchepinov demonstrated that proteins, fatty acids and nucleic acid components can all be reinforced against oxidation using isotopes and incorporated into the body via the diet. The bodily components most damaged by free radical attack are essential and must be obtained through diet.
Sets of compounds reinforced with isotopes, such as deuterium, 13C, 15N and 18O, could be synthesised. Price may initially be an issue, but economies of scale and changes in manufacturing processes could bring cost down.
Other scientists in the field are very impressed with the isotopic approach. Aubrey de Grey, the Cambridge-based gerontologist and editor of Rejuventation Research, said it could be very relevant to the rates of a large range of chemical and enzymatic processes relevant to ageing ‘It is a highly novel idea,’ he said. ‘It remains to be seen whether it can be the source of practicable therapies, but it is a prospect that certainly cannot be ruled out.’
Charles Cantor, a professor of biomechanical engineering at Boston University, said: ‘The idea of selectively using heavy natural isotopes to suppress oxidative damage is fundamental and extremely clever. Preliminary data indicate that this approach can potentially increase lifespan without adverse side effects.
‘If this is borne out by further experiments the implications are profound,’ he said.
Shchepinov has founded the company Retrotope to commercialise his ideas.
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