'Fitness our evolutionary advantage, not longevity'

Nobel laureate VENKI RAMAKRISHNAN's latest book, Why We Die, covers a journey that starts in the 1800s, when British biologists Charles Darwin and Alfred Wallace proposed natural selection, and continues to this day, as researchers investigate anti-ageing compounds. But how close are we really to cheating ageing and death? In an interview with ROHINI KRISHNAMURTHY, Ramakrishnan, who received the 2009 Nobel prize in chemistry, says the focus of research is on staying healthy for a bigger fraction of life. He also examines the causes of ageing, the drugs being explored to slow down this deterioration, the people involved in the research and a few controversial claims. Excerpts:

- ROHINI KRISHNAMURTHY

Can science help humans defy death?

Defying death is a tall order because it means that lots of systems need to be kept going. The breakdown of these systems is indeed the common cause of death. You could also die of an infectious disease or accident.

Some people feel that if you can address the underlying common causes, you could postpone death by preventing or slowing down ageing. But can we slow it down to an extent that we live well beyond our natural limit, which is about 110 years or so? Very few people live past 110, and only one person has lived past 120 [a record held by Jeanne Calment, a Frenchwoman who died in 1997 at the age of 122]. It would take some fundamental breakthroughs to go beyond that limit. I do not think it is as easy as some people claim it is.

Could improvement in health infrastructure or medicines push that limit beyond 110 years?

It would be very hard because there are other issues, like general frailty and tissue breakdown. For example, we have the drug semaglutide, which is being used to treat diseases that accelerate ageing, like obesity. But I do not know how much time that will buy us.

A lot of focus is on healthy ageing, which is not about extending life but staying healthy for a bigger fraction of your life, so that one does not spend two decades or so in really poor health at the end. The idea is to stay healthy so people can move around and be independent.

My father, until he was about 92, used to go on eight-mile (over 12 km) walks. He cooked and did laundry by himself. At 98, he still does these chores, but finds it hard to walk now. You can see a decline between 92 and 98, even in a relatively long-lived individual. So, the question is whether you can compress that period of decline so that you are healthy for a bigger fraction of your life.