Drastic diet may extend human life, study finds

March 2, 2008

Nov. 15, 2007

Special to World Science

Eating little may help people live longer, a study has found, offer

ing support for an idea that has tantalized scientists for decades.

Researchers have long known that cutting animals' food supply to near-

starvation levels gives them—for reasons still unclear—longer lives

and healthier old age. Studies have found that in humans, too,

sharply reduced eating is associated with healthier aging, as long as

nutritional balance is maintained.

Less food on the plate could mean a longer life, researchers say.

(Courtesy pdphoto.org)

----

----------

But whether this practice could actually lengthen our lives has re

mained uncertain.

Some scientists have argued that it's doubtful, because humans al

ready live unusually long. Only one small past study in humans of

fered weak evidence that people eating less lived longer, according

to its authors, who were also involved in the new research.

The new study is the first to probe the claim by comparing human

populations, wrote the American and Japanese scientists in a report

on their findings.

Moreover, they added, it's " the first study that has shown extended

average and maximum life span in a human population that is poten

tially due to " reduced eating. The practice is known as caloric re

striction.

The researchers studied residents of the Japanese island of Okinawa,

known through much of the last century both for exceptionally long-

lived inhabitants and for very spare, though balanced diets. The in

vestigators said they found evidence that the two things are at least

partially related.

Although that conclusion might seem obvious to some—given the past re

search—the scientists wrote that to reach it, they had to account for

some factors that had hampered systematic analysis. For one, Okinawan

diets have changed, becoming richer since about the end of the 1960s.

Also, it wasn't clear how to best assess historical dietary intake

and compare it to that of other populations.

The findings, by Bradley Willcox of the Pacific Health Research Insti

tute and John A. Burns School of Medicine in Honolulu and colleagues,

appear in the November issue of the research journal Annals of the

New York Academy of Sciences.

Animal tests have found that the extreme dieting of caloric restric

tion entails cutting some 40 percent of calories to get the strongest

life-extending effects. Animals placed on such regimens live up to 40

percent longer than normal, as long as the diet remains nutritionally

balanced. (Some scientists propose—again based mostly on animal tests—

that taking a substance called resveratrol may replicate caloric re

striction's benefits, without the unpleasantness.)

Willcox and colleagues found that at least from the mid-20th century

through the 1960s, the Okinawan diet was about 11 percent short of

what would normally be recommended to maintain body weight. As of

1995, the average Okinawan lived about five years longer than the av

erage American, and about 18 months more than the average Japanese.

The islanders' spartan diets may have been a legacy of " periodic crop

failures that occurred in Okinawa in the early 20th century and a

long history of marginal food supply, " the researchers wrote.

The study had some weaknesses, they added; for instance, it couldn't

rule out that Okinawans lived longer because of the types of nutri

ents they ate, rather than the amount. Nonetheless, the " tentative "

findings fit with a broad array of animal studies, and point to a

need for still more research, Willcox and colleagues wrote.

Article Link:

http://www.world-science.net/exclusives/071115_caloric.htm

www.world-science.net

Sign In

Drastic diet may extend human life, study finds

Recommended Posts

Guest guest

Link to comment

Share on other sites

Join the conversation

Support the Ashram

Join Groups

Top Downloads