X-Message-Number: 12335
Date: Thu, 26 Aug 1999 12:50:15 +0000
From: Kennita Watson <>
Subject: Calorie restriction study

From today's AP wire:

     Gene Study: Eat Less, Live Longer

     Thursday, 26 August 1999
     W A S H I N G T O N  (AP)

     GENES THAT play a key role in aging tend to stay vigorous in
     response to a low-calorie diet, says a study that may help
     explain why animals that eat less often live longer. 

     Tomas A. Prolla and Richard Weindruch, both of the
     University of Wisconsin, Madison, said their genetic analysis
     of mice showed that genes that normally deteriorate with age
     tended to continue functioning in a youthful way when the
     mice were underfed. 

     They said the study, to be published in the journal Science on
     Friday, may explain why a reduced-calorie diet can cause mice
     to live up to 50 percent longer. 

     Weindruch said it is not scientifically appropriate yet to
     recommend that people of normal weight go on
     calorie-restricted diets in order to prolong life, but he added:
     "This line of research bears watching." 

     He also said the research could lead to drugs that would help
     slow the aging process in humans, although there have been
     no definitive studies proving that a reduced-calorie diet in
     humans will extend life. 

     What is clear, Weindruch said, is that obesity damages health
     and that one reason for this might be changes in genes linked
     to aging. 

     There have been studies in monkeys that show a low calorie
     diet does lower blood pressure and raise levels of "good"
     cholesterol, both signs of improved health that suggest a
     longer life. Those studies, however, did not examine the
     fundamental genetic changes that occur as a part of the aging

     "This study is quite important because it breaks new ground
     in giving us an understanding of what happens to gene
     expression with age," said Dr. Raj Sohal, a professor of
     biological sciences at Southern Methodist University. Although
     the study was with mice, he said it suggests that "if you
     overeat, you are accelerating the aging process." 

     "This study has analyzed more genes with regard to aging
     than all previous studies combined," said Prolla. He said 5 to
     10 percent of the entire mouse genome was examined. 

     In the Wisconsin laboratory study, the researchers fed one
     group of mice a regular diet while restricting by 24 percent
     the calories in the food given to another group. The diets all
     contained healthful levels of vitamins, minerals and proteins.
     Only the calories were reduced. This creates a condition of
     undernutrition, but not malnutrition, Weindruch said. 

     After 30 months, muscles were taken from the animals and
     the activity of 6,347 genes was analyzed. 

     "We chose muscle for analysis because it is an important
     target for the effects of aging," said Weindruch. "Muscle is lost
     routinely with old age and contributes to physical frailty." 

     The researchers found that more than 100 genes either
     increased or decreased their activity with age. 

     "At the molecular level, normal aging looks like a state of
     chronic injury in muscle," said Prolla. 

     However, for mice fed the restricted diet, about 84 percent of
     the genetic alterations associated with aging were completely
     or partially suppressed. 

     "At the molecular level," the study found, "calorie-restricted
     mice appear to be biologically younger than animals receiving
     the control diet." 

     "This clearly suggests that the reduction of calorie intake not
     only increases lifespan in mice, but seems to affect a broad
     spectrum of age-associated changes at the gene expression
     level," said Weindruch. He said these genetic changes clearly
     play a role in extending life in those animals. 

     Many of the genes affected by aging are those that help the
     body rid itself of oxygen radicals, chemicals produced during
     the process of metabolizing calories in cells. Oxygen radicals
     are known to be damaging to DNA, the body's genetic

     Mice fed the full-calorie diet tended to lose the benefit of these
     oxygen radical control genes with age. The genes continued to
     work vigorously, however, in mice fed the calorie restricted

     Though the study evaluated muscles, Weindruch said that
     similar molecular effects may occur in the brain and in the
     heart, both of which tend to show the effects of the aging

Kennita Watson           |   Late to bed, early to rise,
       |      work like hell, and advertise."  
http://i.am/Kennita      |               -- Werner von Braun

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