STEVE INSKEEP, HOST:
Scientists are reporting an advance in the science of aging, and maybe even a clue how to reverse some of aging's effects. They have evidence that lifestyle changes already known to be good for you - like healthy diet, exercise, reducing stress - may prevent the chromosomes in our cells from unraveling. NPR's Richard Knox reports it's all about little caps on our chromosomes, called telomeres.
RICHARD KNOX, BYLINE: For a couple of decades now, scientists have been fascinated by telomeres. They're like the plastic tips of shoelaces. Telomeres protect the tips of chromosomes, the strings of genes in the heart of every cell that tell it what to do.
As people and other animals age, their telomeres get shorter and shorter. Dr. Dean Ornish, at the University of California-San Francisco, says some things accelerate the process.
DR. DEAN ORNISH: Smoking makes your telomeres shorter, and emotional stress is associated with shorter telomeres - and lack of exercise. And we know that shorter telomeres are associated with an increased risk of developing many chronic diseases and a shorter lifespan.
KNOX: Ornish and his colleagues, including a scientist who won the Nobel Prize for her work with telomeres, studied two groups of older men. One didn't do anything special. The other adopted healthier habits that will sound familiar.
ORNISH: These included a whole-foods, low-fat, plant-based diet that's also low in refined carbohydrates; walking for a half an hour a day; doing various stress-management techniques, including yoga and meditation for an hour a day; and spending more time with their loved ones and friends and family.
KNOX: Five years later, the telomeres of the men who did these things were different.
ORNISH: The more people changed their lifestyle, the more their telomeres got longer.
KNOX: The study is in the journal Lancet Oncology. Now, this is a small study - only 10 men in the better-lifestyle group, and 25 guys in the status quo group. But Ornish believes the findings are real and their implications, profound.
ORNISH: If your telomeres get longer then your life is probably going to get longer, and you're going to have a lower risk of developing a wide variety of conditions. And since it's the same lifestyle intervention that we've found could actually not only prevent, but even reverse the most common chronic diseases - like heart disease, early-stage prostate cancer, type 2 diabetes, etc. - it makes sense.
KNOX: Others in aging research are intrigued. But they're going to take some convincing. Nir Barzilai is at the Albert Einstein College of Medicine in New York.
NIR BARZILAI: Certainly, everybody in our field will agree that the telomere length is telling us something.
KNOX: But it's not clear what. And he says the new study doesn't answer that, either.
BARZILAI: At the end of the day, this hasn't stopped any argument. You know? Either you're healthy, so you have longer telomeres; or you have longer telomeres, and that's why you're healthy. You can pick and choose what you believe in, and make an argument.
KNOX: Apart from this fundamental disagreement, there's something that troubles scientists. It's not only healthy cells that have longer telomeres - so do cancer cells. That may be what keeps them dividing out of control. Aubrey de Grey is with the SENS Research Foundation, which funds aging studies.
AUBREY DE GREY: My sense is that the cancer problem is a really, really big problem. The implicit hope is that cancer either will not be stimulated in the manner that many people think it will; or else that even if it is, we'll find some other ways to get around cancer, somehow.
KNOX: Certainly, telomere research will go on. Some companies are hard at work on drugs and nutritional supplements that can lengthen your telomeres.
Richard Knox, NPR News.
(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.