Monday, July 30, 2001

Okinawans chew
way to the top
of longevity charts

A plant-based diet is the basis
for their long lives, a study finds

By Leila Fujimori

Results of a 25-year study focusing on Okinawans and published in the United States confirm what some health professionals in Hawaii have suspected.

"Japanese as a whole are the longest-lived people," said Bradley Willcox, co-author of the book "The Okinawa Program."

"Okinawans happen to be the longest-lived of the longest-lived," he said.

The study, begun in 1976 by cardiologist and geriatrician Makoto Suzuki, found that Okinawa had the highest prevalence of documented centenarians, 34 per 100,000 last year, compared with 10 per 100,000 in the United States. An estimated 45,000 to 50,000 ethnic Okinawans live in Hawaii, according to the Hawaii United Okinawan Association's executive director, Gary Honda.

Willcox, an internist and a geriatrics fellow in the Division on Aging at Harvard Medical School, co-authored the book with Suzuki and twin brother D. Craig Willcox of the Okinawa Prefectural University-College of Nursing.

One of the key factors of Okinawans' longevity was diet -- primarily vegetarian fare that helps fend off or significantly delay heart disease, cancer and stroke until the final stages of life, Willcox said.

On average, their diet consisted of seven servings of fruits and vegetables daily, 80 grams of soy products a day, plenty of grains and legumes (herbs, beans, peas, etc.) and limited amounts of fish, lean meats and dairy products -- the opposite of the average American diet, Willcox said.

Willcox said his centenarian study is being expanded to other parts of the world. "We'd like to get some genetic controls, like the Hawaiian Okinawans," he said.

One study that has examined specific ethnic groups is the Honolulu Heart Program. Begun in 1965, the ongoing study has compared 8,000 first- and second-generation Okinawans and other ethnic Japanese from other parts of Japan in Hawaii.

Katsuhiko Yano, cardiologist and epidemiologist with the Honolulu Heart Program, said that study has found no difference in the incidence of heart attack and stroke during a 20-year period between people from Okinawa and people from other parts of Japan.

"This is not consistent with the well-known fact that the Okinawan people in Japan live longest among Japanese and have the lowest mortality rates," Yano said.

He said both groups had equally good health and long life expectancy, adding that Japanese Americans in Hawaii live longer than those in Japan and about equally to those in Okinawa, not due to genetic background, but because of diet and physical activity.

One aspect of Willcox's study being disputed is his finding that dementia rates are 30 percent lower than in the United States at older ages. He said high homocysteine levels from meat consumption and lack of folate-rich foods from green leafy vegetables have been implicated in dementia and stroke.

Lon White, principal investigator in research in Alzheimer's disease with the Honolulu Heart Study, questioned the study's methods of measuring cognitive impairment.

"You can't use anecdotes or look at the people who come to your office or who elect to volunteer," White said.

He said a study of 8,006 Japanese-American men concluded that eating soy products may increase dementia. Autopsies of those who ate tofu showed their brains had shrunk more, an advanced sign of aging, he said.

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