chasing eternal yoof

But over the past three decades science has focused on refining its quest for a truly effective elixir of youth. It first proposed oestrogen replacement and then testosterone injections. Then there was chromium. And beta-carotene. More recently, resveratrol, an extract of red wine, has been touted by pharmaceutical companies as increasing longevity by protecting cells from decay. There have been some promising signs in worms and mice. Sadly for boozers, no independent studies yet support its benefits in humans.

Then came the breakthrough with telomeres. In January 2010 a study in Nature showed that it was possible to reverse extreme ageing in mice by increasing their levels of telomerase, the enzyme that maintains telomeres. Trying this in humans is risky, though. Mice make telomerase throughout their lives, but the enzyme is switched off in adult humans, to stop cells growing out of control. Raising our telomerase might slow ageing, but send our cancer risk soaring.
And telomerase can’t be the whole story. The world’s longest-lived rodent is Africa’s naked mole rat. It can live up to 30 years, five times more than biologists would expect from its body size. But the rats have short telomeres. Suddenly the picture starts lto look very confusing. Worse still, scientists recently found more than 70 genetic variants in humans that may be linked to longevity. “This is a very complex puzzle,” says William Flew, the Boston University scientist who found the genes by studying hundreds of centenarians.

Up until now we have to thank two far more basic things for improving our true longevity: sanitation and basic medicine. During the Roman Empire, our life span averaged 25 years. By the Middle Ages it increased to 33 years. During the second half of the 20th century we gained almost 30 years, doubling all our previous gains. But now we want more. Not just more years, but more youth.