The Mediterranean diet is one of the most widely described and evaluated dietary patterns in scientific literature.
It is characterized by high intakes of vegetables, legumes, fruits, nuts, grains, fish, seafood, extra virgin olive oil, and a moderate intake of red wine.
A growing body of scientific evidence shows that the Mediterranean Diet has a beneficial effect on obesity, metabolic syndrome, heart disease, and type 2 diabetes.
Recent studies have found that eating the Mediterranean diet could help protect brain health.
Cognitive Functions
In a study from the University of Illinois, researchers linked higher levels of several key nutrients with more efficient brain connectivity and performance on cognitive tests in older people.
They looked at 32 key nutrients in the Mediterranean diet and examined 116 healthy adults 65-75 years of age.
The analysis linked specific patterns of a handful of nutrient biomarkers in the blood to better brain health and cognition.
The researchers also directly examined the brain using high-resolution brain imaging. Functional MRIs can indicate the efficiency of individual brain networks.
They looked at ‘local efficiency’ – how well information is shared within a spatially confined set of brain regions—and also ‘global efficiency,’ which reflects how many steps are required to transfer information from any one region to any other region in the network.
The team found a robust link between higher levels of several nutrient biomarkers in the blood and enhanced performance on specific cognitive tests.
These nutrients, which appeared to work synergistically, included omega-3 and omega-6 fatty acids, carotenoids, lycopene, riboflavin, folate, vitamin B12, and vitamin D.
The team also found that a pattern of omega-3s, omega-6s, and carotene was linked to better functional brain network efficiency.
Different nutrient patterns appeared to moderate the efficiency in different brain networks.
For example, higher levels of omega-3 fatty acids paralleled the positive relationship between a healthy frontoparietal network and general intelligence.
The frontoparietal network supports the ability to focus attention and engage in goal-directed behavior.
This study suggests that diet and nutrition moderate the association between network efficiency and cognitive performance.
The study was reported in the journal NeuroImage.
In another study, scientists from the Swinburne University of Technology found that a Mediterranean diet may improve daily memory performance.
They reviewed many studies that tested how a Mediterranean diet may impact cognitive functions in adults over time.
Researchers included studies that used either a food questionnaire or a food diary. These tools recorded people’s daily eating behavior.
A total of 18 studies were included in the review. These studies also measured people’s cognitive performance.
The team found that eating a Mediterranean diet was associated with slower rates of cognitive decline, reduced risk of Alzheimer’s disease, and improvements in cognitive functions.
Importantly, the specific cognitive functions that were found to benefit from an improved Mediterranean diet were memory, executive functions, and visual functions.
Executive functions include attention control, reasoning, problem-solving, planning, inhibitory control, and cognitive flexibility.
The researchers suggest that a healthy diet, such as the Mediterranean diet, may be essential to maintain quality of life and reduce the potential social and economic burden of dementia.
To start a Mediterranean diet, people can replace butter with healthy oils as often as possible, increase protein intake, eat vegetables and fruits every day, eat whole-grain bread, snack on nuts, seeds, or low-fat cheese, drink less alcohol, and eat slowly.
The paper was published in Frontiers in Nutrition.
Alzheimer’s Disease
In another study, scientists from the German Center for Neurodegenerative Diseases found that eating a Mediterranean diet that is rich in fish, vegetables and olive oil may protect the brain from protein build-up and shrinkage that can lead to Alzheimer’s disease.
In the study, the team looked at abnormal proteins called amyloid and tau. Amyloid is a protein that forms into plaques, while tau is a protein that forms into tangles.
Both are found in the brains of people with Alzheimer’s disease but may also be found in the brains of older people with normal cognition.
The Mediterranean diet includes a high intake of vegetables, legumes, fruits, cereals, fish, and monounsaturated fatty acids such as olive oil, and a low intake of saturated fatty acids, dairy products, and meat.
The team examined 512 people. Of those, 169 were cognitively normal, while 343 were identified as being at higher risk of developing Alzheimer’s disease.
The researchers looked at how closely people followed the Mediterranean diet based on their answers to a questionnaire asking how much they ate of 148 items over the previous month.
People who often ate healthy foods typical of the Mediterranean diet, like fish, vegetables, and fruit, and only occasionally ate foods non-typical of the Mediterranean diet, like red meat, received the highest scores, for a maximum score of nine.
The researchers found that in the brain area most closely linked to Alzheimer’s disease, every point lower people scored on the Mediterranean diet scale was equal to almost one year of brain aging.
When looking at amyloid and tau in people’s spinal fluid, those who did not follow the diet closely had higher levels of biomarkers of amyloid and tau pathology than those who did.
When it came to a test of memory, people who did not follow the diet closely scored worse than those who did.
The study suggests that eating a diet that’s high in unsaturated fats, fish, fruits, and vegetables, and low in dairy and red meat may protect the brain from the protein build-up that can lead to memory loss and dementia.
The research was published in Neurology and conducted by Tommaso Ballarini et al.
Stroke
Another recent study from the University of East Anglia showed that eating a Mediterranean diet may reduce the risk of stroke by more than one-fifth in women aged 40 or older, but it appears to have no big impact on men’s risk of stroke.
In that study, the team looked at the food diaries of 23,232 people, aged 40 to 77, in Norfolk, UK, to find out if following a Mediterranean diet could prevent stroke of any type.
They measured the Mediterranean diet by calculating a score based on how close it was to a traditional Mediterranean diet.
They also measured blood cholesterol and blood pressure and collected other important factors that affect stroke risks such as diabetes and smoking.
Researchers also found that in both men and women at high risk of heart disease, those who followed a Mediterranean diet had a 13% reduced risk of stroke, although this reduction was largely driven by women.
The team found the Mediterranean diet as a whole appears to be more strongly protective against the risk of stroke than the individual foods within it.
When they analyzed individual foods, the benefits appear to come from the additive effects of combining a diet high in fish, fruits, vegetables, nuts and beans, cereals, and potatoes.
A Mediterranean diet also has a lower intake of meat and dairy and a lower ratio of unsaturated to saturated fat.
The study was published in Stroke and conducted by Ailsa Welch et al.
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