The search for eternal life — preferably with optimal health and well-being — is alive and well in the United States, and particularly so in Aspen, where forever-young senior citizens are as physically active as 30-somethings and midlife crises are as likely to result in buying a new road bike or signing up for an endurance race than any of the more standard types of indulgences.

With more Americans living longer — and more Aspenites pushing the boundaries of what old age means — the quest for the fountain of youth is not likely to diminish anytime soon.

What’s often overlooked is the importance of a healthy brain to power a healthy body into advanced age.

Dr. Neal Barnard and Tony Buettner are two of the country’s foremost experts on brain nutrition and longevity, respectively, and both are sharing their findings at the fourth annual AspenBrainLab from 8:30 to 5 p.m. Saturday at the Aspen Institute’s Doerr-Hosier Center.

Buettner, a National Geographic fellow and best-selling author, has spent the past 12 years studying the world’s longest-lived populations. Over multiple expeditions, Buettner and teams of scientists and researchers identified five places in the world — dubbed “blue zones” — where people regularly live the longest and, in so doing, figure out what habits and characteristics those populations have to reverse aging.

Although he was searching for some kind of magic herb or compound that was the key to long life, Buettner said that with all these populations, “nobody ever tried to live to be 100. They never got on a longevity diet or bought a treadmill or joined a gym or called a 1-800 number. Longevity came with their lifestyle.”

In other words, long, healthy lives in blue zones are the result of lifestyles and habits baked into the local culture. Little of it has to do with genetics (scientists have determined that about 20 percent of how long you live is dictated by your genes), and surprisingly, very little is due to deliberate exercise — particularly the very American habit of sitting in an office chair all day and then driving to the gym or trailhead. Instead, physical activity — mostly walking everywhere and moving constantly — is simply part of their everyday lives.

The more Buettner dug into these long-lived populations, the more he found that their commonalities had more to do with mental health (ways to deal with the everyday stress of life), spirituality and strong social connections.

Though blue zones nonagenarians and centenarians live lives particular to their cultures, it doesn’t mean that blue zones concepts for healthy living can’t be exported. In 2009, Buettner launched the Blue Zones Project, a community well-being initiative that’s been adopted by several U.S. communities, cities and even states to help people live longer, healthier lives through permanent changes to environment, policy and social networks.

Barnard’s wake-up call to healthier living came when his father, a lifelong rancher, died after years of suffering from dementia. Barnard, who then switched to medicine and became a diabetes expert, found that things like dementia in older people and diabetes in a growing portion of the U.S. population were simply accepted as conditions to manage rather than cure or alleviate.

Barnard correlates the growth of diabetes with Americans’ increasingly meat- and fat-based diet, which began rising at the end of World War II and reached an all-time high in 2004. He began researching how various foods impacted the brain, and he came to some surprising conclusions about meat and dairy products that Americans — who are so in love with their barbecue and cheese-laden pizza — are none too thrilled to hear.

Yet Barnard, now a strong proponent of a vegan diet, also is optimistic that Americans can make healthier choices and learn to love the rich array of foods that are better for a healthy brain. And like Buettner, he recognizes that diet alone is not the only secret to a long, healthy life. Rather, an array of lifestyle choices including physical activity, mental stimulation and giving the brain a rest through adequate sleep will delay cognitive decline.

“The way to do this is to have fun with it,” he said. “And if we have fun and we make some noise, we can revolutionize the health of this country.”

Glenda Greenwald is the founding president of Aspen BrainLab and Aspen BrainForum. Learn more about Tony Buettner’s Blue Zones, Neal Barnard’s Power Foods for the Brain and more from 13 other brain experts at AspenBrainLab on July 23. A full agenda can be found at http://www.aspenbrainlab.com; tickets can be purchased at http://www.aspenshowtix.com.