The researchers explained that diets that are high in omega-3 fatty acids are linked to better memory and cognitive function in humans. The Mediterranean diet has plenty of fish, chicken and salad dressing - all of which are rich in omega-3 fatty acids.
The authors pointed out, though, that not such benefits were found among people with diabetes.
Georgios Tsivgoulis, M.D., a neurologist who works at both the UAB and the University of Athens, said:
"Since there are no definitive treatments for most dementing illnesses, modifiable activities, such as diet, that may delay the onset of symptoms of dementia, are very important."
Dr. Tsivgoulis and team collected data from the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study, which is housed at UAB. The study included data on 30,239 people aged 45+ years between January 2003 and October 2007. They were all followed up regularly for health changes.
In what Tsivgoulis claims is the largest study to date on the Mediterranean diet, dietary data from 14,478 Caucasians and African-Americans were examined to determine how closely they followed a Mediterranean diet. Their average age was 64. The participants also underwent tests to measure their memory and cognitive abilities over a period of four years. Seventeen percent of them had diabetes.
Mediterranean food is rich in omega-3 fatty acids
The researchers found that among those without diabetes who followed the Mediterranean diet more closely, the risk of developing problems with memory and thinking skills was 19% lower, compared to the rest of the population sample. The difference in declines between Caucasians and African-Americans was not statistically significant.
Unfortunately, as far as cognition and memory was concerned, no benefit was identified among those with diabetes who closely followed a Mediterranean diet.
"Diet is an important modifiable activity that could help in preserving cognitive functioning in late life," said Tsivgoulis. "However, it is only one of several important lifestyle activities that might play a role in late-life mental functioning. Exercise, avoiding obesity, not smoking cigarettes and taking medications for conditions like diabetes and hypertension are also important."
The study was sponsored by the Department of Health and Human Services and the National Institute of Neurological Disorders and Stroke (part of the National Institutes of Health).
Researchers from the University of Las Palmas de Gran Canaria and the University of Navarra, both in Spain, reported in the European Journal of Clinical Nutrition (June 2012 issue) that the Mediterranean diet is not only good for physical health, but mental health as well.
In February 2012, researchers from the University of Miami Miller School of Medicine reported in Archives of Neurology that a Mediterranean-style diet may be healthier for the brain. They found that a Mediterranean diet appears to reduce damage to small blood vessels in the brain.