Eat less, live longer
[ 2006-06-20 10:30 ]
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Scientists have
known for some time that laboratory mice on a low calorie diet
live longer than mice that eat as much as they want. Now a
researcher from Washington University in St Louis, Missouri, says a low calorie diet
might be key to slowing aging in people, too.
In a new study, Dr John Holloszy compared three groups of people: those
who ate fewer calories than in the typical western diet; regular eaters
who also did strenuous exercise; and another group of regular eaters who
didn't exercise.
He found those who were on a calorie-restricted diet had less of the
particular hormone that regulates their metabolism. "This is not an
abnormal decrease," he says, "and it's just a decline into the lower end
of normal."
In effect, metabolic hormones regulate the rate at which cells
function. Scientists think this might be related to how fast we age. "So
if you have high thyroid hormone levels,"
Holloszy explains, "you use a lot of oxygen, you have a fast heart rate
and you need large amounts of food in order to maintain weight. If you
have low thyroid hormone levels, your metabolic rate is slowed." He says
studies on rodents have shown that skinny, long-lived laboratory mice had
low thyroid hormone levels.
Another group in his study ate what they wanted but exercised
intensively. The exercise didn't seem to affect their thyroid hormone
levels, which remained high. Holloszy says they are continuing research to
see if eating less can slow aging in people as well as mice.
"Determining whether humans on caloric restriction live longer is not
something we're going to find out, at least not in my lifetime," he says
with a laugh. "You know, that's a 50 year study."
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Vocabulary:
thyroid hormone :甲狀腺激素
（來源：VOA
英語點(diǎn)津姍姍編輯）
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