Consequences of aging, why we die explained by Nobel biologist

Nobel Prize-winning molecular biologist Venki Ramakrishnan sat down with ABC News Live to discuss the science and ethics of extending the human lifespan.

In his new book, "Why We Die: The New Science of Aging and the Quest for Immortality," Ramakrishnan explains why we may not want to lengthen our lives much longer.

Ramakrishnan's thought-provoking argument is that a society where people lived for hundreds of years could potentially become stagnant, as it would consist of the same group of people living longer, raising important questions about societal dynamics and progress.

He discussed the cycle of life and why we die.

ABC NEWS LIVE: If you think it might be wonderful to live forever, you may want to hear what a Nobel Prize-winning molecular biologist has to say that could change your mind. Venki Ramakrishnan has examined the latest science, weighed the possibilities and researched the ethical cause of lengthening our lifespans in his new book, 'Why We Die The New Science of Aging and the Quest for Immortality.' Doctor, thank you so much for joining us.

RAMAKRISHNAN: Thank you.

ABC NEWS LIVE: So humans now live twice as long as we did 150 years ago. But you raise some, some caveats to why we may not want to lengthen our lives that much longer. Why is that?

RAMAKRISHNAN: Well, I think a society where everybody lived indefinitely or very long time, say, hundreds of years would be a very different society. It would be quite stagnant. It'd be the same group of people just living longer and longer.

You wouldn't have that turnover between generations. You know, maybe new ideas, things like that. But I think that's still in the realm of science fiction. I think biology is looking at the causes of aging, and that's allowing us to tackle some of these causes. But most of the focus is how to live healthily for longer, because all developed societies are living longer lives.

So we're having more and more older people well past retirement. And we want to see how can we keep older people healthy and productive, you know, and energetic and and actually lively. So I think a lot of biology is trying to understand those causes so we don't suffer some of the debilitating consequences of aging.

ABC NEWS LIVE: Explain why it is that sometimes our biological age doesn't match our chronological age.

RAMAKRISHNAN: That's because aging you can think of as an accumulation of damage as over time. And we have very sophisticated repair mechanisms, and we have ways to deal with the problems of old age, of the accumulation of damage, accumulation of garbage in the cells. We have recycling mechanisms and all those things break down. And the rate at which they break down is different for different people.

ABC NEWS LIVE: Explain the new research, though, that talks about how there are certain blood markers that indicate why people age faster than others, and we could say this is separate from drinking and smoking or lack of sleep.

RAMAKRISHNAN: Yeah. So blood -- there are different markers for aging. So some markers are on our DNA. Our DNA acquires marks called epigenetic marks as we age. And that changes the pattern with which we express different genes.

So it changes how our biology works. There are also markers in our blood. And this was found because when they connected an old animal with a young animal and allowed them to exchange their blood supply, the old animal benefited from the young blood. And that suggested these things in younger blood that deteriorate or don't exist or have changed in older blood. And people are trying to find what those markers are.

ABC NEWS LIVE: Let's say in the next few decades, we're able to come up with cure for, for cancer, high blood pressure, diabetes. What's the best-case scenario, do you think, for the longevity of human life?

RAMAKRISHNAN: So someone did a calculation. And if we eliminated some of the major causes of fatality today, like the things you mentioned, you would only gain about 15 years. But what biologists think is if you tackle the underlying causes of aging, then you could really, expect to, live a longer and healthier life.

ABC NEWS LIVE: Really fascinating. Doctor, we thank you so much for joining us. Want to let our viewers know "Why We die? The New Science of Aging and the Quest for Immortality" is now available wherever books are sold.