People who follow a Mediterranean diet may think a little more clearly into old age, hints a new study.
The findings add to a handful of evidence that a Mediterranean-style diet may be as good for the brain as it is for the rest of the body.
Traditionally associated with the consumption of a lot of wine, fruits, vegetables, legumes, olive oil and fish, and with very little red meat, the Mediterranean way of eating has been credited with helping to prevent various ailments, including heart disease, cancer and diabetes, lead researcher Dr Christine Tangney of Rush University Medical Centre in Chicago said.
To determine if slower brain aging might join the diet's list of potential health benefits, Dr Tangney and her colleagues looked at the dietary habits and cognitive function of nearly 4,000 Midwesterners aged 65 and older.
The researchers gave participants two different diet scores, one reflecting adherence to the traditional Mediterranean diet and another based on how well participants met the 2005 US Dietary Guidelines.
The participants' cognitive status was assessed every three years, based on measures such as word memory and basic math skills.
Out of a maximum score of 55 on the MedDiet scale reflecting a quintessential Mediterranean diet, the average study participant received a 28. And those with higher MedDiet scores appeared to have slower cognitive decline over time, even after accounting for other factors such as education, according to a report published online in the Journal of Clinical Nutrition.
The differences had practical significance. If there were two older adults of the same age with Mediterranean diet scores 10 points apart, for example, the individual with a 10-point higher score would perform mentally as if she or he were three years younger than the other adult, Dr Tangney said.
Meanwhile, "better" scores based on the US Dietary Guidelines, which gave less weight to fish, legumes and moderate alcohol intake compared to the Mediterranean diet score, did not appear to influence rates of cognitive decline.
Explanations for the effects
The researchers point to some explanations for the effects, such as wine's potential role in protecting the brain from damage. Traditional Mediterranean foods may also reduce oxidative stress and the inflammation that is thought to play a role in Alzheimer's disease.
Dr Tangney also noted that the findings are consistent with other studies in New York and France that found a reduced risk of cognitive impairment and Alzheimer's disease among those with higher Mediterranean diet scores, despite using different methods of measuring adherence to the diet.
Further research is still needed to confirm their findings, the authors note. But one advantage of following a more Mediterranean diet is the ability to focus on specific foods rather than just single nutrients.
"Incorporating more vegetables, more olive oil, fish and moderate wine consumption coupled with greater physical activity is good for our aging brains," said Dr Tangney.
(Reuters Health, Lynne Peeples, December 2010)