Fountain of Health
“People are always sort-of looking for the fountain of youth. And what we’re looking for is the fountain of health,” Winifred Rossi, deputy director of NIA’s Division of Geriatrics and Clinical Gerontology, told GEN.
The major studies have found that while environment plays a larger role than genes in healthy aging—estimates range from 70%−30% (NECS) to 80%−20% (LGP)—the role of genetics seems to grow with age, especially past 100.
Centenarians are indeed rare—one of every 5,000 U.S. citizens, according to the 2010 U.S. Census, while one in 20,000 people are 105 or older.
The older the centenarians, the greater the progressive delay in the age of onset of physical and cognitive function impairment, age-related diseases, and overall morbidity, according to a study based on NECS data and published April in the Journal of Gerontology.
The findings were consistent with the 1980 hypothesis of James F. Fries, M.D., professor emeritus at Stanford University School of Medicine, who posited that, as the practical limit of human life span is approached as with “supercentenarians” aged 110 and older, morbidity is compressed toward the end of their lives, resulting in a shorter period of illness.
“I think all of that compression of morbidity and disability speaks to some genetic advantages that help these individuals age more slowly, and markedly delay and in some cases escape certain age-related diseases, like Alzheimer’s,” Dr. Perls told GEN.
Those advantages, he added, may be affected by environment: “There could be certain exposures to certain environmental factors, or lack of exposure certainly—something like smoking. So I would not rule out the possibility of diet in some individuals playing a role. What that specific diet might be, we don’t know yet.”
That’s an area warranting at least as much further study as the genetics of aging to 100, where the major studies have proven most helpful.
“To be a centenarian, we believe that you need special genes—that if you don’t have them, you can get maybe past 80, if you’re lucky maybe past 90, but not more than that,” Nir Barzilai, M.D., LGP’s lead investigator, explained.
He added, however, that genetics alone doesn’t fully explain why some people live past the century mark.
“It’s a total interaction. You cannot separate them. If you eat sugar, it will unfold the protein and increase its expression in the tissue, so that environment works directly on expression of genes. That’s an interaction. It’s not that they contribute equally,” said Dr. Barzilai, who is also the Ingeborg and Ira Leon Rennert Chair of Aging Research and director of the Institute for Aging Research at Einstein.
“If you look at exceptional longevity in families, it’s much more than 20% genetics. It’s 50% to 80%. One of the interesting things in our centenarians is that they mostly have a family history of longevity.”
That suggests the presence of genes not yet known that promote slower and healthier aging in some people.
“What that tells us is that there’s some small subset of the population that effectively won the genetic lottery. They’ve got the right genes,” Brian K. Kennedy, Ph.D., CEO and president of the Buck Institute for Research on Aging, told GEN. “Understanding what’s going on with these centenarians is critical. It’s a longer-term perspective. It’s not going to yield a treatment next year, but you’ve got to start.”