Really interesting article (to me at least) in Science Daily ….
For decades, scientists have been searching for the fundamental biological secrets of how eating less extends lifespan.
It has been well documented in species ranging from spiders to monkeys that a diet with consistently fewer calories can dramatically slow the process of aging and improve health in old age. But how a reduced diet acts at the most basic level to influence metabolism and physiology to blunt the age-related decline of tissues and cells has remained, for the most part, a mystery.
Now, writing in the Nov. 18 online issue of the journal Cell, a team of scientists from the University of Wisconsin-Madison and their colleagues describe a molecular pathway that is a key determinant of the aging process. The finding not only helps explain the cascade of events that contributes to aging, but also provides a rational basis for devising interventions, drugs that may retard aging and contribute to better health in old age.
“We’re getting closer and closer to a good understanding of how caloric restriction works,” says Tomas A. Prolla, a UW-Madison professor of genetics and a senior author of the new Cell study. “This study is the first direct proof for a mechanism underlying the anti-aging effects we observe under caloric restriction.”
The Wisconsin study focuses on an enzyme known as Sirt3, one of a family of enzymes known as sirtuins, which have been implicated in previous studies in the aging process, gene transcription, programmed cell death and stress resistance under reduced calorie conditions. In mammals, including humans, there are seven sirtuins that seem to have wide-ranging influence on cell fate and physiology.
Sirt3 has been less studied than other members of the sirtuin family, but the new study provides “the first clear evidence that sirtuins have anti-aging effects in mammals,” according to John M. Denu of UW-Madison’s Wisconsin Institute for Discovery and a senior author of the report.
The Sirt3 enzyme, Denu explains, acts on mitochondria, structures inside cells that produce energy and that are the sources of highly reactive forms of oxygen known as free radicals, which damage cells and promote the effects of aging. Under reduced-calorie conditions, levels of Sirt3 amp up, altering metabolism and resulting in fewer free radicals produced by mitochondria.
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