Mediterranean diet is one that is rich in vegetables, fruits, beans, whole grains, olive oil and oily fish.
The study, published in the journal of the American Geriatrics Society, discouraged processed foods, fried and fast foods, snack foods, red meat, poultry and whole-fat dairy foods.
The healthy foods encouraged include green leafy vegetables, such as spinach and kale; other vegetables, such as red peppers, squash and broccoli; nuts, berries, particularly blueberries and strawberries; beans, lentils and soybeans; whole grains, seafood, poultry, olive oil, and wine (in moderation).
The study examined data from 5,907 older people with an average age of almost 68 who had enrolled in a study on health in retirement.
All the participants had filled out questionnaires about their eating habits, while the researchers measured their thinking skills, particularly their memory and ability to concentrate.
They found that those who ate Mediterranean diet scored significantly better than those who ate a less healthy diet.
Participants who followed a Mediterranean-style diet had a 35% lower risk of scoring poorly on tests for thinking ability.
The findings also revealed that those who ate a moderate Mediterranean-style diet had 15% lower risk of doing poorly on cognitive tests.
The researchers noted that Mediterranean diet is rich in antioxidants, monounsaturated and omega-3 fatty acids, and is also low in saturated fat.
“This research builds on growing evidence suggesting that following a Mediterranean-style diet may hold valuable health benefits as we enter our later years,” David Reynolds, chief scientific officer at Alzheimer’s Research UK, said in a statement.
“Observational studies like these can be useful for highlighting factors linked to healthy ageing, but this type of research can’t definitively answer whether specific diets can prevent dementia.
“Current dementia risk reduction efforts are exploring ways to support people in mid-life to adopt healthier diets, as this may help build resilience to conditions such as dementia.
“While we know there are positive lifestyle changes that can impact dementia risk, it’s important to remember that dementia is caused by complex brain diseases influenced by age and genetics as well as lifestyle.”