-- A diet that has been popular for thousands of years may have another benefit, by helping to alleviate brain atrophy.
It involves eating a well-balanced diet that focuses on eschewing a lot of meat and instead favoring vegetables, fish, legumes, nuts and monounsaturated fatty acids, such as found in olive oil.
In the study, researchers looked at 674 people over the age of 80 who did not have any signs of dementia. The subjects took a questionnaire on their diet and had their brain scanned to see what their brain volume looked like.
Those adhering to a Mediterranean diet had a brain volume of 13.11 milliliters larger than those not on the diet, with their gray matter volume being 5 milliliters larger and their white brain matter 6.41 milliliters larger, researchers found. The average human brain is about 1,400 milliliters, but people in their 80s would likely have smaller brains, since brains tend to shrink with age.
Lead study author Yian Gu, assistant professor of neuropsychology at Columbia University, said the results may help show a way for people to keep their brain healthy into old age.
"These results are exciting, as they raise the possibility that people may potentially prevent brain shrinking and the effects of aging on the brain simply by following a healthy diet,” Gu said in a statement today.
She told ABC News that the researchers were particularly struck that those who had a higher intake of fish and lower intake of meat seemed to clearly benefit.
Dr. Brian Appleby, a geriatric psychiatrist at University Hospitals Case Medical Center, said the study adds to a growing body of evidence showing that a healthy diet can have long impacts on brain health.
"The old adage, you are what you eat, is very well demonstrated here," Appleby, who was not involved with this new study, told ABC News. "It makes sense if you have a healthy diet that it’s going to be reflective at a cellular level at your brain."
The healthy fat in fish is made up of the same kinds of fatty acids that make up brain cells, Appleby noted. However, he said more research is needed to understand exactly how the Mediterranean diet interacts with the body and brain cells.
Those living in the Mediterranean area who eat the Mediterranean diet that may also take part in social activities that contribute to their mental and brain health, Appleby said.
"The Mediterranean diet is almost a lifestyle in the way," Appleby said. "They eat sitting down in large groups of people."
Some of those aspects can also "help decrease the risk of dementia," he said.