WASHINGTON (AFP) - Eating less may keep the mind young, according to Italian scientists who reported Monday they have discovered the molecular process by which a strict diet may save the brain from the ravages of age.

The research, published in the US journal the Proceedings of the National Academy of Sciences, is based on a study of mice that were fed a diet of about 70 percent of the food they normally consumed.

Scientists found the calorie-restricted diet triggered a protein molecule, CREB1, that activates a host of genes linked to longevity and good brain function.

"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 author Giovambattista Pani, researcher at the Institute of General Pathology, Faculty of Medicine at the Catholic University of Sacred Heart in Rome.

Researchers have previously discovered that mice on diets showed better cognitive abilities and memory, less aggression, and tended to avoid or delay Alzheimer's disease. But they have not known exactly why.

"CREB1 is known to regulate important brain functions as memory, learning and anxiety control, and its activity is reduced or physiologically compromised by aging," said the study.

Mice that were genetically altered to lack CREB1 showed none of the same memory benefits if they were on a low-calorie diet as mice that had the molecule, and showed the same brain disabilities as mice that were overfed.

"Thus, our findings identify for the first time an important mediator of the effects of diet on the brain," Pani said.

"This discovery has important implications to develop future therapies to keep our brain young and prevent brain degeneration and the aging process."

According to Marc Gordon, chief of neurology at Zucker Hillside Hospital in Glen Oaks, New York, the findings could shed new light on why some people who are obese in middle age encounter cognitive problems later in life.

"Mid-life obesity has been associated with late-life dementia. However, the physiological basis for this association remains unclear," said Gordon, who was not part of the study.

"These investigators have studied the effects of limiting caloric intake in mice, and have identified a biochemical pathway that may mediate at least some of the brain's responses to dietary restriction."