December 20, 2011
Eating Less Improves Brain Function
Calorie restriction activates genes linked to longevity and brain function, according to a new Italian study with mice.
The researchers found that overeating may cause brain aging, while eating less turns on a molecule that helps the brain stay young.
The discovery could lead to new treatments to keep the brain in a healthy, youthful state without the need for a restrictive diet, the researchers said.
Previous studies using animals have found that low calorie diets extend life, improve memory and reduce the risk of dementia and disease, although scientists were not sure why this was so.
In the current study, researchers found that consuming fewer calories triggers a protein known as CREB1, which activates genes linked to longevity and proper brain functioning.
"Our hope is to find a way to activate CREB1, for example through new drugs, so to keep the brain young without the need of a strict diet," said lead researcher Dr. Giovambattista Pani at the Institute of General Pathology, Faculty of Medicine at the Catholic University of Sacred Heart in Rome.
Animals given just 70 percent of the calories they would normally eat typically live a one-third longer than average, and demonstrate better memory and mental function, according to many experimental models.
Studies have also shown that caloric-restricted mice do not become obese, develop diabetes or Alzheimer's disease, and show greater cognitive performance and memory.
By comparison, many studies suggest that obesity is bad for our brain, slows it down, causes early brain aging, making it susceptible to diseases typical of older people, such as the Alzheimer's and Parkinson's.
But the precise molecular mechanism behind the positive effects of a calorie-restricted diet on the brain remained unknown until now.
The Italian team discovered that CREB1 is activated by caloric restriction, and that it mediates the beneficial effects of the diet on the brain by turning on another group of molecules linked to longevity, the "sirtuins".
This finding is consistent with the fact that CREB1 is known to regulate important brain functions such as memory, learning and anxiety control, and its activity is reduced or physiologically compromised by aging.
The Italian researchers discovered that the action of CREB1 can be dramatically increased by simply reducing caloric intake, and have shown that CREB is absolutely essential to make caloric restriction work on the brain.
In fact, if mice lack CREB1, the benefits of caloric restriction on the brain disappear, such that animals without CREB1 show the same brain disabilities typical of overfed or older animals.
"Our findings identify for the first time an important mediator of the effects of diet on the brain," Dr. Pani said.
"This discovery has important implications to develop future therapies to keep our brain young and prevent brain degeneration and the aging process. In addition, our study shed light on the correlation among metabolic diseases as diabetes and obesity and the decline in cognitive activities."
The study appears this week in the Proceedings of the National Academy of Sciences USA (PNAS).
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