Fish is often referred to as brain food, and now there is evidence that this is true.

A study published recently in Neurology, the journal of the American Academy of Neurology, reported that those who consumed fish as a part of a Mediterranean-style diet had greater volumes of brain tissue than those who did not adhere to a diet rich in fish. The study found that brain differences were similar to adding five years of aging to those who did not have the diet similar to the Mediterranean style.

"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," said Yian Gu, Ph.D. of Columbia University of New York, who was involved in the study.

The study's objective was to determine if a Mediterranean-style diet had any impact on brain volumes or cortical thickness as measured by magnetic resonance imaging (MRI). The cross-sectional study collected information on 674 elderly subjects with an average age of 80 who did not have evidence of dementia. The diet information was collected by a food frequency questionnaire.

The Mediterranean-style diet used in the research included high intake of vegetables, legumes, fruits, cereals, fish and monounsaturated fatty acids such as olive oil. The diet had a lower intake of fatty acids, dairy products, meat and poultry. Eating more fish and less meat was found to be associated with less brain shrinkage and higher brain tissue volumes.

A diet low in saturated fatty acids, meat and dairy products has long been associated with a reduced risk of cardiovascular disease. As reported in November by Denes Stefler, M.D. of the Department of Epidemiology and Public Health at University College London, a Mediterranean-style diet has been found to be associated with significantly reduced deaths related to cardiovascular disease in a study looking at populations in Eastern European countries.

While the adherence to a Mediterranean-style diet was found in only one quarter of the 19,333 participants under study, it was associated with a lower risk of death from cardiovascular disease. The countries represented in the study were the Czech Republic, Poland and the Russian Federation. The impact of the diet was the same for each country.

Fish is good for the heart and certainly can be considered healthy brain food.

"Eating at least three to five ounces of fish weekly or eating no more than 3.5 ounces of meat daily may provide considerable protection against loss of brain cells equal to about three to four years of aging," Gu said.