Food choices that can help you live longer

Since the dawn of time, humans have sought ways to live longer, healthier lives. Though genetics play a huge role in whether or not a person sees ripe old age, research has found that environment -- especially the foods we eat -- also make a big difference.

In his newly published book, "The Blue Zones Solution," longevity expert Dan Buettner examines the diets that have sustained some of the oldest living humans over the last century, and what we can learn from them. In his 10-year project with "National Geographic," Buettener identified pockets of the world where unusually high numbers of people were living into the triple digits.

"We call them 'Blue Zone' areas, where people have the highest life expectancy or the highest centenarian rate," Buettener told CBS News chief medical correspondent Dr. Jon LaPook.

In his travels, Buettner found five: Okinawa, Japan; Sardinia, Italy; Loma Linda, California; Icaria, Greece; and the Nicoya Peninsula of Costa Rica. He analyzed what elders in these communities were eating.

"[We] did a meta-analysis of some worldwide average of what 100-year-olds were eating for a century and averaged it out," he explained. "First of all they're eating mostly a plant-based diet -- about 90 percent. It's also a high-carb diet, about 65 percent of their caloric intake are things like whole grains, corn, sweet potatoes in Okinawa, and beans are the cornerstone of every longevity diet in the world. But the reality is food is just the runway to these bigger ideas, and the big epiphany in these Blue Zones is that longevity wasn't something individuals pursued. It was the outgrowth of having the right environment."

Each Blue Zone community had certain staples that play a role in health and longevity. In Sardinia, olive oil and wild greens are eaten abundance. In Okinawans rely on tofu and sweet potatoes for high nutrition. People on the Nicoya Peninsula eat plenty of squash and yams. And in Loma Linda, centenarians tend to avoid processed foods and eat lots of salmon and oatmeal.

In Icaria, Greece, age-related dementia is nearly nonexistent. Buettner attributes that phenomenon to eating a Mediterranean-style diet and drinking certain teas -- rosemary, sage and mint -- on a daily basis. These teas have diuretic and anti-inflammatory properties. Diuretics help lower blood pressure slowly over time.

Other healthy lifestyle habits also make a difference in longevity, he found. Daily physical activity, a sense of purpose, slower pace of life and strong family bonds all contribute. "Having a strong sense of purpose is worth eight extra years of life expectancy. Having a social group with at least five friends you can count on on a bad day is worth about seven years of life expectancy," he said.

Buettener has since brought this wisdom to the U.S. He's working with certain communities around the country to tweak their living environments in ways that will help people effortlessly lead healthier lives. For example, Iowa City now has a "complete streets policy" where every new street must be designed for both cars and humans, with wider sidewalks, trees and bike paths.

"Instead of trying to figure out scientifically what will make somebody live longer, he just went out around the world, figured out where people already live longest, figured out what they did in common and took that and applied it to real places," LaPook said.

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    Jessica Firger covers health and wellness for CBSNews.com