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more news of calorie restriction and aging
Low-Cal Diet Blocks Aging Genes
26 August 1999
Source: Reuters Health News (with whom the copyright remains)
Experiments in mice suggest that low-calorie diets block the action of genes that trigger cell aging.
Previous studies have suggested that low-fat, low-calorie diets can extend life spans in animals. In fact, calorie restriction is the
only known method of slowing aging in mammals.
To help determine the mechanisms behind this effect, Weindruch and colleagues used sensitive tests to compare up to 10% of the
complete genome ('genetic blueprint') of 5-month-old (adult) mice and 30-month-old ('elderly') mice. In fact, study lead author Dr. Tomas
Prolla believes that "this study has analyzed more genes with regard to aging than all previous studies."
According to the researchers, the function of about 2% of the genes changed markedly with increasing age. Genes governing cellular
byproducts of metabolism) -- nearly doubled in activity.
These results were not surprising, since, according to Prolla, "at the molecular level, normal aging looks like a state of chronic injury."
On the other hand, the activity of genes concerned with energy metabolism, protein repair and biosynthesis fell by half in the 'elderly'
versus 'adult.' Each of these processes helps the body maintain normal healthy cellular function.
The investigators then compared age-related changes in gene activity in mice fed calorie-restricted (75% less food energy) diets to those
of mice on normal diets.
According to the researchers, the low-cal regimens completely or partially prevented 84% of the major gene changes described above.
longer, healthier lives -- at least in mice.
In an interview with Reuters Health, Weindruch said these latest findings may help lead to drug therapies that "retard the aging
process... on a tissue-specific basis."
He added that he and his colleagues are extending their studies to monkeys placed on a 30% calorie-restricted diet, and they plan similar
research in humans, as well.
Weindruch warned, however, that anyone attempting a dramatic reduction in calorie intake do so with caution. He suggests that those
toxins, thereby delaying the ageing process.
Some genes are likely to be responsible for mopping up the toxins before they do much damage. The latest research is a way of
identifying these genes, which could possibly lead to developing new drugs to augment their activity.
Calorie restriction appears to delay the onset of ageing in part by interfering with the way genes are switched on or off as people get
molecular level, normal ageing looks like a state of chronic injury.'' Half the mice in the study - published in the journal Science - were placed on
calorie-restricted diets from an early age and their genes showed just how the animals adapted to the reduced intake of energy.
``This is a big leap in understanding how a reduced-calorie diet works. There hasn't been much consensus on how calorie restriction
retards ageing,'' Professor Weindruch said. ``We now know which sets of genes that change with ageing are affected by caloric
restriction. We think this technology has led us to a panel of molecular markers of ageing which will enable use to screen panels of
potential anti-ageing drugs.''
showed larger, dark color spleens and some have tumors.
Low row: CR group, showed healthy,
small and normal size.
From UCLA, school of medicine
- Spleens from control and
calorie restriction mice
- Upper row: controls