2008年10月 | ARCHIVE-SELECT | 2008年12月


Long Lives Well Lived #4/4 ( By TIME - jun. 14. 2003 )

Alas, the inhabitants of Asia's Shangri-Las aren't always immune to the temptations of modern eating habits. In 1978, engineers constructing the famed Karakoram highway that links Pakistan with China blasted a route through the mountains and exposed the Hunza Valley to the outside world. Since then, says local physician Khan, consumption of previously unheard-of items such as artery-clogging potato chips and white sugar has risen sharply. The consequences have been swift, too. In the past, "people would die from diarrhea or from falling off cliffs. That was about it," says Khan. "But now they are coming down with hypertension, heart attacks and cancer, just like everywhere else."

It's a similar story in Okinawa, where the island's youth are increasingly succumbing to the lure of fast food. "The young people are eating hamburgers and pork and don't do enough exercise," Suzuki says. "Okinawan male life expectancy used to be No. 1 in Japan. It started to decline 10 years ago, and hit 26th out of 47 prefectures in the 2000 census. I expect it to decline even further in the next census." The change is almost entirely due to a much higher mortality among younger people, according to Suzuki. "The elders are living longer but the young are dying younger." If any further evidence is needed of the dramatic effect a change in diet can produce, Suzuki points to the example of an Okinawan community in South America. Recruited to work on rubber plantations, several hundred thousand islanders moved to Brazil in the 1930s and switched to eating large amounts of beef because it was widely available and cheap. According to Suzuki, they now live an average 64 years―17 years lower than the Okinawa average.

Still, a healthy diet is hardly the only prerequisite for a long life. Scientists say another key factor is your mind-set―that's to say, the emotional resources that enable you to cope with the stresses of daily life from missing the bus to enduring the death of a loved one. Inner strength derives in part from vigorous activity, mental and physical. Bama centenarian Huang Maliang, for example, still prides herself on her ability to thread a tiny embroidery needle, although she no longer works in the fields since injuring her hip two years ago. Okinawan elder Setsuko Miyasato, 90, still spends three hours a day tending to her vegetable and fruit plots. "I used to have someone do the hoeing for me when I was younger," says the animated, silver-haired Miyasato, shielding her mouth as she giggles at the thought. "But I've done it myself since I was 48. The exercise is good for me. You've got to keep yourself busy."

That might be a mantra for elders across the region. Okinawan baker Asanori Takemura rises every morning at 5 o'clock to put in his shift at the bakery he started 50 years ago. At 93, he continues to create new confections for the bakery, which specializes in rakugan, cookies given as gifts on ceremonial occasions such as weddings. "He's still the boss here," says Takemura's son Isao. "He's the one who started the business and he still knows best."

Isao, 68, is smiling as he says this, but he isn't just humoring an old man. His tone is respectful, and his father simply nods his head at being given his due. Such reverence for the elderly is another constant in Asia's longevity oases―and it's apparently healthy. In the Hunza Valley, elders' opinions on critical issues such as when to plant the barley and the buckwheat are listened to with reverence. Haji Sikander, an 84-year-old former schoolteacher, sits with his friends under an ancient chinar tree in the village of Ganish, watching boys dive into a tank of silty brown, glacier-fed water. "The elders have always had a command here in the valley," he says with satisfaction. "What we say is respected."

As Setsuko Miyasato sees it, respect is important because it helps build the inner strength she believes is the key to achieving a long life. "In the end, it's your mental attitude that's most important," she says. "Every morning I wake up and I'm just grateful for being alive and healthy. You have to try not to worry about tomorrow too much. Don't get too serious. Don't think too much. Sing out loud and play your music."

Don't worry. Be happy. Live long. It might not be quite that simple, but it's time-honored wisdom from a woman who has lived by it for almost a century.

―With reporting by Mingi Hyun/Seoul, Susan Jakes/Pinghan, Hanna Kite and Yuki Oda/Okinawa and Tim McGirk/Hunza Valley

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| TIME | 07:16 | comments:0 | trackbacks:0 | TOP↑


Long Lives Well Lived #3/4 ( By TIME - jun. 14. 2003 )

Included in a "good lifestyle" is the avoidance of proven killers. Few of Asia's ancients smoke; if they once did, they kicked the vice long ago. Most will happily admit to taking a drink now and then, though, a habit whose benefits in moderation are well enough established that they are acknowledged even by such cautious institutions as the American Heart Association. The Hunza's are partial to "Hunza water"―potent wines made from the area's fruits such as grapes, mulberry and the ubiquitous apricot. Residents of Sunchang county in South Korea swear by their soju and makgoli, fiery rice spirits. Park Bok Dong, who is 101, attributes a major part of her continuing health (until a few years ago she was still working in her family's rice fields) to her practice of downing several daily shots of 50-proof soju. Okinawa, meanwhile, has awamori, a distilled rice spirit that has a whiff of kerosene in its bouquet but is much beloved on the island. "I used to like to drink a lot of awamori when I was young," smiles Asanori Takemura, a beaming Okinawan baker who recently turned 93. "I still like to, but these days I only take one glass a night―no more."

Indeed, dietary moderation is a consistent feature of the lives of the superwrinklies. Protein and animal fat typically play a minimal role in their menus. In Sunchang, for example, rice and boiled vegetables are a staple. "The white-rice-and-vegetables-dominated diet consists primarily of carbohydrate, while remaining low in fat," says Dr. Park Sang Chul, who heads the World Health Organization's aging-research center in Seoul and has spent three years studying the residents of Sunchang. "Low fat content is one of the more crucial keys toward longevity." The story is similar for the locals of Hunza Valley, says Khwaja Khan, a physician in the Hunza town of Karimabad who has treated many of the valley's eldest residents. The Hunza, Khan says, were cut off from the outside world for centuries by the 7,000-meter Himalayan peaks ringing the valley, and until recently were forced to subsist on a spartan menu of apricots, walnuts, buckwheat cakes and fresh vegetables. Many cross the century mark, and a few motor on for another 10 years or longer.

Living in relatively poor conditions in a village free of the industrialized world's dietary sludge―and miles from a fast-food restaurant―isn't required for long life. But eating habits influenced by scarcity appear to contribute to health. Says Chinese longevity expert Chen, the residents of Bama "are not starving, but for many years they weren't often full, either." In Okinawa, researchers found their subjects ate about 20% fewer calories than the Japanese average―which in turn is about 20% lower than the average in the U.S. According to Dr. Makoto Suzuki, leader of the study of Okinawan elders and one of Willcox's co-authors, a restricted-calorie diet might reduce the harmful effects of free radicals―molecules that occur naturally in the body during biochemical reactions but that can damage cells and are implicated in most of the deleterious effects associated with aging, including cancers and cardiovascular diseases.

Happily, living to an advanced age doesn't depend entirely on self-denial. Researchers are also trying to pinpoint particular foods consumed in each of the regions that can help avert the diseases and disabilities associated with aging. The people of Bama, for example, cook with oils derived from hemp and the fruit of tea bushes. These oils are rich in unsaturated fat, vitamin E and vitamin B1―antioxidant nutrients believed to contribute to a healthy cardiovascular system, says Chen, as well as helping prevent certain types of cancers. Suzuki says Okinawans do most of their stir-frying with canola oil, which has been widely shown to protect the body against free radicals.

The Okinawan elders who were part of Suzuki's study got most of their protein from fish, which provides another so-called good fat: omega-3. This oil is particularly prevalent in fish such as salmon, tuna and mackerel, whose established heart-protecting properties are considered by researchers to be an important reason that Japan's incidence of heart disease is one-third that of the U.S.'s. Okinawans have about one-fifth as many heart attacks as North Americans, Suzuki says, and when they do, they are twice as likely to survive.

The differences in rates of cancer deaths are similarly stunning. In Okinawa annually, there are an average of six breast-cancer deaths per 100,000 people; that rate is five times lower than in the U.S. The incidence of prostate cancer is seven times lower than in the U.S. Suzuki's team attributes the differences in part to Okinawans' very high intake of substances called flavonoids, relatively little-understood compounds that appear to help prevent cancer by neutralizing the destructive effect of free radicals. "Okinawa's national dish is a stir-fry called chample," says Suzuki. "The exact recipe varies from house to house but the basic ingredients are always there: tofu, soya beans and goya [a local variety of bitter gourd]. Those three are all very high in flavonoids as well as other compounds like isoflavones, saponins and vitamins B and C that provide protection against free radicals."

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| TIME | 07:37 | comments:0 | trackbacks:0 | TOP↑


Long Lives Well Lived #2/4 ( By TIME - jun. 14. 2003 )

At Asia's other extreme, the average life expectancy in Afghanistan is just 43.1 years. But in neighboring Pakistan there is the geriatric oasis of the Hunza Valley. High in the country's northern mountains, it's a place of such pristine beauty and with such a reputation for fostering longevity that author James Hilton was inspired by a visit there to write Lost Horizon, the 1933 novel about an isolated valley called Shangri-La whose residents lived for hundreds of years. Another death-defying region, currently being studied by gerontologists, is a cluster of villages in Sunchang county located in South Korea's mountainous southwest, where some local farmers continue to work the fields until they are well into their 90s.

Is it something in the water? Why do some communities, located in disparate places and harboring very different cultures, seem to be built atop a fountain of youth? Scientific efforts to uncover the secrets behind these mysterious, mini Shangri-Las have varied enormously in scope, ranging from a sporadic, amateur attempt by a busy general practitioner in the Hunza Valley to a quarter-century study in Okinawa during which researchers carefully amassed and analyzed data on everything from eating habits to the preferred hobbies of the oldest of the old (they enjoy playing the Okinawan three-string sanshin and singing traditional folk songs). There are tantalizing consistencies in research findings, offering priceless clues to aspiring centenarians on what it takes to live a long and healthy life.

You've heard some of the secrets of Asia's most senior citizens before (probably from your mother): eschew an excess of meat, eat your vegetables and get plenty of exercise. Other lessons from their lives are downright depressing, particularly for gastronomes who regard Asia as a place where one lives to eat rather than the reverse. For example, it's best to eat only until you are hara hachi bu, or "8 parts out of 10 full," as the Okinawan phrase puts it. An old wives' tale, perhaps, but scientific evidence has been steadily mounting for years that gives credence to this simple adage. A daily diet restricted to between half and three-quarters of the 2,100 calories recommended by the U.S. government appears to boost health in humans, and an equivalent reduction has extended the lives of lab rats.

But simply restricting your diet to watercress and celery won't get you to your personal centennial. There are no magic potions or simple regimens that automatically bestow longevity. It's the total package that counts: diet, exercise, mental attitude, family and societal support―and, of course, your genetic makeup. Some of the longest-lived Asians appear to have an extended shelf life hardwired into their anatomy by their progenitors. "My parents and grandparents lived until they were in their late 80s and early 90s," says Hide Nakamatsu, a 1.47-meter-tall, 91-year-old bundle of life force wrapped in a white cotton frock, cotton gloves and a bright blue-and-white bonnet. The headgear is necessary to shade her darting eyes during her daily game of gateball, a fiercely competitive Okinawan version of croquet that, in Nakamatsu's case, involves lots of running from one hoop to the next. Once she's dispatched her opponent's ball from the field with a sharp crack, Nakamatsu returns to the shade of palm trees sheltering the gateball court. None of her three children, 10 grandchildren or nine great-grandchildren has ever suffered a major disease, she says; they rarely go to the doctor. "I suppose it's something I gave them in my blood."

Nakamatsu is almost certainly right. Scientists are only just beginning to unravel how genetic makeup affects aging. But research published in recent months suggests that a single gene or group of genes appear to control the aging process. Scientists at Harvard University and the University of California say a gene related to insulin production seems to control the onset of aging in experiments on yeasts and worms. Although the research is in its early stages, the scientists say there is a high likelihood a similar system for control of the aging process exists in humans.

The most important genetic factor in longevity is no mystery. Women live longer than men all over the world, usually between five and seven years longer in industrialized nations. In Okinawa, as many as 86% of the centenarians are female, according to scientist Craig Willcox, one of three authors―including his brother Bradley―of the 2001 best-selling book The Okinawa Program. Researchers think women might have a not-yet-understood genetic advantage. But DNA isn't entirely destiny―men can improve their chances for a long life by avoiding destructive behaviors, such as heavy drinking, that most women tend to avoid. "From our studies, genetics accounts for about a third and lifestyle kicks in for the rest," says Willcox. "Of course, if you want to make it to 100, you need a very nice set of genes. But these days, making it to 90 isn't so hard, with a bit of luck and a good lifestyle."

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| TIME | 07:13 | comments(-) | trackbacks(-) | TOP↑


How To Live To Be 100 #7/7 ( By TIME - Aug. 30. 2004 )

They trigger our awe and our nostalgia as representatives of a flinty, hardscrabble culture that hardly exists today. They lived out a parable of man at one with nature. They used their bodies as they were designed and programmed over the millennia: for walking, for working, for being fed from the earth's natural bounty. It makes one wonder whether the next generation of oldsters will last quite as long. They will need not just the luck of the genetic draw but also the strength to renounce the lure of fast-food days and couch-potato nights that add yards of butt lard and shorten life-spans by years.

Will Americans in the supersize age resolve to go medieval on their own bodies? It would help, if they want to live to 100. As Poon says of his research pools, "I don't have any fat centenarians." And if research really does extend life by a vigorous couple of decades, the new millions of centenarians will need a support system that spreads beyond family and friends to include a hugely expensive Social Security and Medicare apparatus. The coming gerontocracy won't come cheap.

But that's for the future. Any child of today who hopes to live into the 22nd century without the aid of medical miracles should look to the past, and consider the lessons today's centenarians took from the 19th century. There's a poetry of common sense in their scheme for immortality. Eat sensibly. Keep walking. Keep knitting. If you can't keep friends, make new ones. Plan so much invigorating work that there's just no time to die. And no regret when you do.

--Reported by Alice Park/New York; Melissa August/Washington; Anne Berryman/Athens, Georgia; Hanna Kite/Okinawa; Chris Lambie/Halifax; Jeff Israely/Sardinia; and Francis X. Rocca/Rome

With reporting by Alice Park/New York; Melissa August/Washington; Anne Berryman/Athens, Georgia; Hanna Kite/Okinawa; Chris Lambie/Halifax; Jeff Israely/Sardinia; and Francis X. Rocca/Rome

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| TIME | 07:24 | comments:0 | trackbacks:0 | TOP↑


How To Live To Be 100 #6/7 ( By TIME - Aug. 30. 2004 )

Indeed, despite what the Swedish and Adventist studies suggest, there's evidence that in some families, at least, genes exert pretty powerful effects on life-span. The centenarians registered in the New England Centenarian Study, for example, showed no consistent patterns in diet, exercise or healthy habits that could explain their extended years. About 20% had smoked at some point in their lives, and some had eating habits that should have made them obese or unhealthy but somehow did not. At least 10% to 15% had a history of heart disease, stroke or diabetes for more than 20 years. Something in that group's genes was protecting them from succumbing to diseases that had felled the average American decades earlier. "These people still get to 100," says Perls. "They seem to have a functional reserve or adaptive capacity that allows them to get disease but not necessarily suffer from it. The key seems to be resilience."

Some of that resilience may be linked to human leukocyte antigen (HLA) genes, a group clustered on chromosome 6 that affects vulnerability to such autoimmune diseases as lupus, rheumatoid arthritis and multiple sclerosis. Centenarians living in Okinawa, for example, have variants of HLA that tend to protect against those diseases. Perls has found a region on chromosome 4 that centenarians and their siblings and children in the U.S. seem to have in common and that sets them apart from shorter-lived individuals. The finding has not yet been replicated by other groups, but Perls expects to publish a paper in the next month detailing his results.

What exactly that stretch of DNA does remains to be discovered, but it may be a key not just to long life but also to the resilience found among U.S. centenarian-study participants, with their 20% smoking rate and imperfect eating habits. That group may be especially genetically blessed, and researchers are eager to tap its secrets.

We certainly need them. For as medical science adds years to our collective lives, we chip away at them by doing things--stewing at our desk jobs, eating fatty processed foods, blowing a gasket in a freeway traffic jam, exercising no more than our fingers at the computer--that centenarians can't imagine. Most of them were born into an America as remote from today's metaphorically as the craggy villages of Sardinia, Okinawa and Nova Scotia are geographically. In the early 1900s people walked miles to work not by choice but out of necessity; cars were still a luxury. People tilled the fields because their farmer parents needed cheap help. People ate what they grew because it was there. Most labor was manual then, and most nutrients were natural. Preserved food was what Aunt Maud sealed in a jar. Tobacco and alcohol were available, but most of today's centenarians didn't indulge to excess.

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| TIME | 07:05 | comments(-) | trackbacks(-) | TOP↑


How To Live To Be 100 #5/7 ( By TIME - Aug. 30. 2004 )

Oldsters in Sardinia, another wellspring of longevity, have many similarities to their Okinawan counterparts--except that the Sardinian ratio of centenarians is about equal for men and women (in most societies, 100-plus females outnumber males by 3 or 4 to 1). They maintain very active lives and powerful social networks; extended family and friends are available to share troubles and take some of the emotional burden out of life. Says researcher Gianni Pes, part of a team from Sardinia's University of Sassari, which is studying the group: "The 100-year-olds are less depressed than average 60-year-olds."

That makes perfect sense to Leonard Poon, director of the University of Georgia Gerontology Center. Since 1988 he has studied American centenarians--he calls them "expert survivors"--and compared them to people in their 80s ("master survivors") and to relative youngsters in their 60s. Poon found that out of 16 personality traits, the experts exhibited four coping mechanisms. First, he says, "centenarians are more dominant. They want to have their way," and they are not easily pushed around. Many are characterized by "suspiciousness. They do not take information on the superficial level" but will question an issue and think it through. They tend to be practical rather than idealistic. And in their approach to life, they are likely to be more relaxed. In other words, they are strong but not inflexible characters.

Poon also determined that people whose age reaches three figures tend to have a high level of cognition, demonstrating skill in everyday problem solving and learning. That's another reason exercise is important: to keep plenty of blood flowing to the brain as well as to stay in shape. Many of his subjects aren't rich; some of them have homes with mud floors. But they make good out of making do. "Many have their own gardens," he notes. "They can their own vegetables. They're living down to earth."

Like the Okinawans, Sardinians and Nova Scotians, the U.S. centenarians enjoy a strong social-support system. Few Americans live in a village anymore, but having outlived family and friends of the same age, the superold find new helpers and confidants among people younger by a generation or more. It might be someone to help with groceries or car trips or simply a sympathetic voice on the other end of the line. Maintaining a connection with the world, with younger people, keeps their outlook youthful.

With so much evidence that lifestyle is the key to healthy aging, it might be tempting to ignore the role of genes altogether. That would be a mistake. Brothers of centenarians are 17 times as likely to live to 100 as are people without 100-year-olds in the family, while sisters of centenarians are 8.5 times as likely to live into their second century. Given statistics like that, says Winifred Rossi, director of the National Institute on Aging's study on exceptional survival, "we are interested in looking for some kind of genetic component to longevity." Her approach is to look at family members, especially the children, of centenarians. Says Perls, who does similar research: "Kids of centenarians who are in their 70s and early 80s are very much following in the footsteps of their parents, with a 60% reduced risk of heart disease, stroke and diabetes. They are the model for successful aging and a great group to study."

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| TIME | 07:42 | comments(-) | trackbacks(-) | TOP↑


How To Live To Be 100 #4/7 ( By TIME - Aug. 30. 2004 )

Scientists working for the U.S. National Institutes of Health and Japan's Ministry of Health have been following oldsters like Toguchi since 1976 in the Okinawa Centenarian Study (OCS) and they've learned that he's typical. Elderly Okinawans tend to get plenty of physical and mental exercise. Their diets, moreover, are exemplary: low in fat and salt, and high in fruits and vegetables packed with fiber and antioxidant substances that protect against cancer, heart disease and stroke. They consume more soy than any other population on earth: 60-120 g a day, compared to 30-50 g for the average Japanese, 10 for Chinese and virtually 0 g for the average American. Soy is rich in flavonoids--antioxidants strongly linked to low rates of cancer. This may be one of many reasons why the annual death rate from cancer in Okinawa is far below the U.S. rate.

But it's not just what Okinawans eat; it's how much. They practice a dietary philosophy known as hara hachi bu--literally, eight parts out of 10 full. Translation: they eat only to the point at which they are about 80% sated. That makes for a daily intake of no more than 1,800 calories, compared to the more than 2,500 that the average American man scarfs down. And as scientists have learned from lab animals, the simple act of calorie restriction can have significant effects on longevity (see box).

Aging Okinawans also have a much lower incidence of dementia--Alzheimer's or other forms of senility--than their U.S. and European counterparts do. Part of that may also owe to diet; it's high in vitamin E, which seems to protect the brain. But perhaps just as important is a sense of belonging and purpose that provides a strong foundation for staying mentally alert well into old age. Okinawans maintain a sense of community, ensuring that every member, from youngest to oldest, is paid proper respect and feels equally valued. Elderly women, for example, are considered the sacred keepers of a family's bond with the ancestors, maintaining the family altars and responsible for organizing festivals to honor them. OCS data show that elderly Okinawans express a high level of satisfaction with life, something that is not as true in Western societies, where rates of suicide and depression are high among the elderly.

Need convincing evidence that our modern lifestyle can shorten lives? Look what happens when Okinawans move permanently off the island. They pick up the diet and cultural behaviors of their adopted country--and within a generation, their life-spans decrease and their rates of cancer and heart attack zoom. Even on the island, young males are following the seductive, virulent American style and renouncing imo for hamburgers. "Okinawan male life expectancy used to be No. 1 in Japan," says Dr. Makoto Suzuki, leader of the study of Okinawan elders. "It started to decline 10 years ago and hit 26th out of 47 prefectures in the 2000 census. I expect it to decline even further in the next census."

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| TIME | 07:28 | comments:0 | trackbacks:0 | TOP↑


How To Live To Be 100 #3/7 ( By TIME - Aug. 30. 2004 )

Studies of Seventh-Day Adventists in Utah support this finding. Those unusually clean-living Americans are genetically diverse, but they avoid alcohol, caffeine and tobacco--and they tend to live an average of eight years longer than their countrymen. All of this is good news, with a Surgeon General's warning attached: you can't change your genes, but you can change what you eat and how much you exercise. "The lesson is pretty clear from my point of view in terms of what the average person should be doing," says Perls. "I strongly believe that with some changes in health-related behavior, each of us can earn the right to have at least 25 years beyond the age of 60--years of healthy life at good function. The disappointing news is that it requires work and willpower."

At least that's true for many Americans, whose fat-and calorie-packed diets and largely exercise-free lives are a prescription for heart disease and plenty of other ills. For Okinawans, by contrast, the traditional way of life seems tailor-made for living forever--one day at a time.

Each day, Seiryu Toguchi, 103, of Motobu, Okinawa, wakes at 6 a.m., in the house in which he was born, and opens the shutters. "It's a sign to my neighbors," he says, "that I am still alive." He does stretching exercises along with a radio broadcast, then eats breakfast: whole-grain rice and miso soup with vegetables. He puts in two hours of picking weeds in his 1,000-sq.-ft. field, whose crops are goya--a variety of bitter gourd--a reddish-purple sweet potato called imo, and okra. A fellow has to make a living, so Toguchi buys rice and meat with the profits from his produce.

Since his wife Kame's death seven years ago, at 93, he has done all the housework himself. He rejected his children's suggestion to come live with them because, he explains, "I enjoy my freedom." Although his doctors insist Toguchi is in excellent health, the farmer takes no chances. "If he feels that something is wrong," says his daughter Sumiko Sakihara, 74, "even in the middle of the night, he calls a taxi and goes to the hospital." But he doesn't want the other villagers to worry, so, she says, "he writes a note explaining where he is and tapes it to the shutters."

At 12:30 Toguchi eats lunch: goya stir-fry with egg and tofu. He naps for an hour or so, then spends two more hours in his field. After dinner he plays traditional songs--a favorite is Spring When I Was 19--on the three-stringed sanshin and makes an entry in his diary, as he has every night for the past decade. "This way," he says, "I won't forget my Chinese characters. It's fun. It keeps my mind sharp." For a nightcap he may have a sip of the wine he makes from aloe, garlic and tumeric. And as he drifts off, he says, "my head is filled with all the things I want to do tomorrow."

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| TIME | 07:29 | comments:1 | trackbacks:0 | TOP↑


How To Live To Be 100 #2/7 ( By TIME - Aug. 30. 2004 )

Scientists are as obsessed with the question of why the superold survive and thrive as Ponce de Leon was to find the Fountain of Youth. They want to understand why the Japanese islands of Okinawa are home to the world's largest population of centenarians, with almost 600 of its 1.3 million inhabitants living into their second century--many of them active and looking decades younger than their actual years. Like weekend visitors on the summer ferry to Martha's Vineyard, scientists and sociologists clog the boats to Sardinia and Nova Scotia, Canada, to see why those craggy locales harbor outsize clusters of the superold. (Gerontologists are not so beguiled by the Russian Caucasus, where exaggerated longevity claims sparked a series of Dannon yogurt commercials 30 years ago.)

As well as studying these populations intensively to unlock their secrets, scientists have also taken a hard look at the very old in the U.S., most notably in the New England Centenarian Study, led by Dr. Thomas Perls, a geriatrician at Boston University, and in a major study under way at the National Institute on Aging. While the very old are happy to offer homespun explanations for their longevity--"I never took a drink"; "I drank a shot of whiskey every day"--experts are trying to unravel and understand the biological factors that allow some people to reach 100 while others drop off in their 70s or 80s. Researchers are particularly interested in determining which factors allow up to 30% of those who reach 100 to do so in sufficient mental and physical health: a whopping 90% of centenarians, according to Perls, remain functionally independent up to age 92. "It's not 'the older you get, the sicker you get,' but 'the older you get, the healthier you've been,'" he says. "The advantage of living to 100 is not so much how you are at 100 but how you got there."

It's pretty obvious even to nonscientists that how you get there depends partly on the genes you are born with and partly on lifestyle--what and how much you eat, where you live and what types of stress and trauma you experience. How much depends on each factor, though, was unknown until Swedish scientists tackled the problem in 1998. They did it by looking at the only set of people who share genes but not lifestyle: identical twins who were separated at birth and reared apart. If genes were most important, you would expect the twins to die at about the same age. In fact, they don't, and the average difference convinced the scientists that only about 20% to 30% of how long we live is genetically determined. The dominant factor is lifestyle.

"You could have Mercedes-Benz genes," says Dr. Bradley Willcox, of the Pacific Health Research Institute in Honolulu, "but if you never change the oil, you are not going to last as long as a Ford Escort that you take good care of. Those who have healthier genes and live healthier lives--those guys really survive for a long time."

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| TIME | 07:33 | comments(-) | trackbacks(-) | TOP↑

2008年10月 | ARCHIVE-SELECT | 2008年12月