The MIT biologist rejects Aubrey de Gray’s claim that humans may soon be able to live forever, but thinks we might add 50 years to our lifespan.

Question: Are there trends in your field that concern you?

Leonard Guarente: Well, I think the problem -- yes -- I think the problem with this field, and what has bedeviled this field over the years, is false claims. And there are all kinds of things that have been claimed about ways you can slow down or stop aging. And what I would say they have in common is that, you know, until -- anything that was claimed that's not based on very recent science is not true; it's baloney. And so I wouldn't believe any claim of an anti-aging procedure, and would really look at claims that are grounded in current science, because I think the science of aging has really only taken off in the past decade and has reached a level of quality that you can trust it, and that it would lead to interventions that would actually work. That's only happened recently. So the thing to look at in any claim -- like this vitamin or that treatment or that bath, whatever it may be, or cream -- is, is it based on the recent science of aging or not? And if it's not, I would tend not to believe it. Even if it is, I would look at whether it's based on good science or not. But there is some good science now in the area of aging.

Question: Do you agree with Aubrey de Grey that people may soon be able to live forever?

Leonard Guarente: No. No, I think that what they're saying is -- it's a good example, I think, of something that's not based on recent science in the field of aging. And so, you know, I don't think that there's any reason to believe that it's true. I mean, it may turn out that it true. I mean, his basic idea is, we're going to make incremental discoveries in aging that will make us live a little bit longer and give us a little bit more time to make the next discovery, which will make us live still longer, and then we'll make more discoveries, and so on and so on and so on and so on. And you know, that would be great, but that's certainly not scientific thinking, and that's not based on current science. So I think that we're talking about -- if you look at all the genetic interventions that have been described -- and we should really get into discussing some of that in a few minutes -- and all the dietary interventions that have been described that promote longevity, what you're looking at is something like 50 percent as a maximum extension, I would think.

So it's nothing to sneeze at, and it's, we think, accompanied by an increase in the number of years we stay healthy. And if we can tap into that and even develop it so that we get some of the benefit -- let's say 10 years of healthier living. So instead of having to retire and stop functioning at a high level at age 70 or 75, you push that back now 10 years -- I think that's a major change in our society.

 Record on November 9, 2009