The longevity revolution

Today, two-thirds of those ever reaching the age of 65 are on the planet. Further, Washington University researchers may have the keys to help people live even longer, healthier and more productive lives — but is society ready?

Longevity revolution
(Illustrations by Maria Rendón)

When people dream about retirement, many imagine what Robert Levin, AB ’56 (economics), has. A student at Washington University’s Lifelong Learning Institute (LLI), Levin regularly takes noncredit classes at LLI on ­topics as varied as Chinese brush painting and Italian culture. Levin and his wife, Susan, AB ’61 (sociology), have been studying there for a few years.

“There’s a lot of pleasure in learning new things — in staying active, in keeping our minds active,” Levin says.

Levin also is active with the university’s Weidenbaum Center on the Economy, Government and Public Policy, and he plays golf regularly. He and his wife also love to read.

The Levins exemplify the vitality that needs to be captured in a new vision of “retirement years,” according to Nancy Morrow-Howell, PhD, the Ralph and Muriel Pumphrey Professor of Social Work and director of the Harvey A. Friedman Center for Aging. “We’re going to have to stay productively engaged in a variety of ways,” she says. “We can’t afford the vision of a retirement that’s solely leisure. We need a different balance.”

The reason? For one, the demographics are rapidly changing, with fewer children being born on one end, and people living longer on the other. These changes result in a rapidly growing older population. “One of the ­fastest growing age groups is those 85 and older,” Morrow-Howell says. “I mean, it’s crazy, but two-thirds of folks in human history who have made it to the age of 65 are on the planet right now.” By the year 2030, the number of people over age 65 in the United States will have doubled to 72 million. That’s one in five people.

Though the Social Security retirement age has been moved up to 67, many people live well into their eighth and ninth decades. When Social Security was first implemented, by way of perspective, the average life expectancy for an adult male was 65. Now, many people leaving the workforce at the normal retirement age can expect to spend two to three decades outside of the workforce. This situation presents challenges for entitlement programs and for older adults themselves, who might become disengaged from society or outlive their retirement savings.

Biomedical and public health research may lead to further increases in human life expectancy. All aspects of society need to change accordingly, Morrow-Howell says. “It’s a longevity revolution,” she says.

Reshaping society to accommodate productive aging

Right now, we think about three stages of life: youth, adulthood and old age. Gerontologists want to add a new stage, between midlife and old age.

“We basically think about people 65 and ­older as the old folks,” Morrow-Howell says. “In fact, 60-, 70-, 80- and 90-year-olds are very, very ­different, and we have to think about ways that we can enable people to educate ­longer, work longer, and be more civically ­engaged well into their 80s.”

In order to do that, we need new social ­policies and programs.

“There needs to be more flexible work to ­enable working longer,” Morrow-Howell says. Older adults might want to stay in the workforce part time, work from home, or do contract work. Employers or schools could also offer training that keeps older workers abreast of new ­technology and job skills.

Morrow-Howell would also like to see social policies that help keep older adults engaged, secure and healthy — the three cornerstones of healthy aging. Homes and businesses need to be accessible to people with reduced mobility. Public or alternative transportation needs to be readily available, since most Americans outlive their ability to drive by eight years. ­Communities and neighborhoods could be made more age-friendly, and long-term care needs to be more affordable.

Morrow-Howell would also like to see older adults get recognition for the work they already are doing. “Caregiving is vitally important, and older adults provide a lot of it to their parents, to their spouses, to their grandkids, to younger adults with some sort of disability,” she says. “We need to figure out ways to support vitally important caregiving activities.”

Morrow-Howell and her colleagues are ­studying all of these challenges at the ­Harvey A. Friedman Center for Aging at Washington ­University. There are some program innovations. For ­example, ­AmeriCorps now targets 10 percent of its money to engage older adults in service activities and ­allows educational stipends earned by seniors to be transferred to their children and grandchildren. Still, for Morrow-Howell, it’s not nearly enough.

“We should be investing as much in solving the challenges associated with living longer and changing society, as we do in figuring out how to help people live longer,” she says.

In an era of new scientific breakthroughs that may extend the average life span even further, her message has never been more urgent.

Shorter & longer: How obesity and longevity are shaping the future

Twelve years ago, Joe Cordell, LLM ’08, thought he was healthy. He lifted weights and ate a fairly nutritious diet that kept him at a muscular 170 pounds. Then he found The 120 Year Diet: How to Double Your Vital Years by Roy Walford, a UCLA doctor who also studied calorie restriction.

“Once I read it, perhaps it was the lawyer in me, but I found the arguments irresistible,” Cordell says.

Now, Cordell consumes only 1,850 to 1,900 calories per day. (The U.S. Department of ­Agriculture recommends that adult men take in 2,200 to 2,800 calories per day if they are moderately active.)

“It’s possible to practice calorie restriction without going hungry, as long as you’re prepared to eat the foods that are very filling and have lots of nutritional value, but are also low in calories,” he explains. “Those tend to be plant foods.”

For the last seven years, Cordell has been participating in a study run by ­researchers John Holloszy, MD, and Luigi Fontana, MD, PhD, in the Division of Geriatrics and ­Nutritional Science at the School of Medicine.

When rodents are put on a high-nutrient, low-calorie diet, it extends their life spans. Holloszy, professor of medicine, and Fontana, research professor of medicine, think the same is true in humans, but evidence is not yet ­conclusive.

“We have several studies, and one of the most exciting is the study of people who are members of the calorie-restriction society [like Cordell],” Fontana says. “Ten of them are in their late 70s to early 80s. We are going to see if in 15 years from now these people outlive their brothers and sisters and parents without developing diseases.”

The health benefits don’t come from simply being lean. Mice that are lean from exercise don’t age more slowly.

According to Holloszy, calorie restriction protects against disease. People like Cordell have low blood pressure and low cholesterol, and aren’t at risk for diabetes or heart disease. But those are only secondary characteristics of aging. The real question is if the diet slows aging.

Fontana says signs point to yes. “These people have a cardio-metabolic risk profile that is like a teenager,” he says. On other tests, too, calorie restrictors look “15 or 20 years younger” than those consuming a regular American diet with very little exercise or even compared with those who consume a typical diet coupled with ­rigorous exercise.

The doctors think it best to eat fruits and vegetables with moderate protein intake, but the study will take more time to tell exactly.

“What people can do is eat enough to stay lean,” Holloszy says. “Eat a lot of fresh fruit and vegetables and keep your saturated fat intake low.”

Unfortunately, Holloszy is describing the exact opposite of the typical American diet.

The shortening life span

In 2012, 34.9 percent of adults were obese, which means at least 35 pounds overweight.

According to William Powderly, MD, the J. ­William Campbell Professor of Medicine, director of WUSTL’s Institute for Public Health and co-director of the Division of ­Infectious Diseases, obesity reduces the likelihood that an adult will see old age. Further, if they do reach their senior years, the likelihood they’ll be disabled is higher.

“When we talk about aging well or having healthy aging, we are really talking about not only living longer, but being able to do things,” ­Powderly says. “If you can’t get around because of mobility problems, then the quality of your life will be significantly impaired.”

But what worries him more is the high ­number of obese children and adolescents. “We have no idea what that is going to mean in terms of their life expectancy,” he says.

An obese 50-year-old’s life will be eight to 10 years shorter. “But if you are obese when you’re 15, how long are you going to live?” he asks. He points out that these teens are getting heart disease and diabetes and other age-related diseases.

“Instead of dying from a heart attack, you [could] live five years longer than you would have,” Powderly says. “But if you get that heart attack when you’re 35 instead of 65, the fact that we’ve lengthened the survival after the heart ­attack isn’t going to do much good.”

If we don’t fix the obesity epidemic, Powderly guesses either medical science’s breakthroughs will be moot and life spans will start shortening, or medical science will be able to keep people alive longer but those senior years will be ­unhealthy and, probably, unhappy.

A signal that extends lives

In a lab at the School of Medicine, ­Shin-ichiro Imai, MD, PhD, a professor in biology and ­internal medicine, and his postdoctoral ­research associate, Akiko Satoh, PhD, have found a way to maybe make people age more healthfully no matter their diet.

It began when Satoh noticed that mice on a low-calorie diet had more of a certain type of ­protein in their brains. The protein, called SIRT1, has been linked to aging and ­longevity ­regulation in other non-mammalian ­species such as flies and worms. Imai’s lab ­genetically engineered mice to always produce higher amounts of SIRT1 ­regardless of diet, and the results were dramatic.

“The female mice showed about a 16 percent increase in the medium life span,” Satoh says. “And the males showed about a 9 percent increase.”

“If I dare translate this number to humans, that basically means that women could get an extra 13 to 14 years, which makes an average of almost 100 years,” Imai says. Men could get an extra seven.

The genetically engineered mice, known as BRASTO (brain-specific SIRT1-­overexpressing) mice, also became healthier. Normally, as ­animals age they become less active. The ­BRASTO mice stayed active into their human-equivalent 70s. They also absorbed more ­oxygen in their blood, maintained a higher body ­temperature, got better and deeper sleep, and had stronger ­musculoskeletal systems.

According to Satoh, the mice weren’t ­aging more slowly — the extra SIRT1 was actually ­delaying the onset of aging.

“SIRT1 regulates a very specific pathway in the hypothalamus,” Imai says. This signal goes to the sympathetic nervous system and stimulates skeletal muscles. “This connection between the hypothalamus and skeletal muscle is the key for maintenance of healthier physiology and also longevity,” he explains.

If SIRT1 operates in a similar way in humans, regulating it would help older people sleep more deeply or stay mobile. Imai’s lab is currently working on ways to feed mice more of a chemical called NAD (nicotinamide adenine dinucleotide), which encourages the production of SIRT1.

“The really important point is that the brain, or, more specifically, the hypothalamus, is the control center of aging and longevity,” Imai says. This region of the brain also regulates metabolism, sleep cycle, emotion and hormone production. “It’s really the critical center for our basic biological functions.”

Imai thinks this might mean that the secret to longevity is actually very simple. “The take-home message is to keep your brain happy.”