The Mediterranean diet is a diet inspired by the eating habits of people who live near the Mediterranean Sea.
When initially formulated in the 1960s, it drew on the cuisines of Greece, Italy, France, and Spain.
This diet focuses on a high intake of olive oil, legumes, unrefined cereals, fruits, and vegetables, moderate to high intake of fish, moderate intake of dairy products (mostly cheese and yogurt), moderate wine drinking, and moderate intake of non-fish meat products.
Olive oil has been found important for reducing death risk and the risk of chronic diseases.
Recent studies have shown that the Mediterranean diet could benefit our health in multiple ways.
Brain Health
One study 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, researchers 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 team examined 512 people. Of those, 169 were cognitively normal, while 343 were identified as being at higher risk of developing Alzheimer’s disease.
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.
The researchers found that in the area of the brain most closely associated with 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.
These findings suggest 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.
Heart health
In another study, scientists from Uppsala University found a healthy quality Mediterranean diet could change the link between obesity and heart disease-related death.
Higher body mass (BMI) accounted for 4.0 million deaths globally in 2015 and more than two-thirds of those deaths were due to heart disease
Other factors, including healthy dietary patterns, might modify the higher risk of heart disease associated with higher BMI.
In the study, researchers examined BMI, diet, and mortality among 79,003 Swedish adults.
Adherence to a Mediterranean-like diet was assessed on a scale of 0 to 8, integrating information on intake of fruits and vegetables, legumes, nuts, unrefined or high-fiber grains, fish, red and processed meat, and olive oil.
Over 21 years of follow-up, the team found that 30,389 (38% of participants) died. Among overweight people, the group with the lowest death risk was those with high adherence to the Mediterranean diet.
Obese people who also had high adherence to the Mediterranean diet did not have a much higher death risk compared with those with normal weight and high adherence to the Mediterranean diet.
On the other hand, people with a normal BMI but low adherence to the Mediterranean diet had a higher death risk than those with normal weight and high adherence to the diet.
For heart disease death risk, which represented 12,064 of the deaths, the findings were broadly similar.
However, while heart death linked to high BMI was reduced by adherence to the Mediterranean diet, it was not fully countered.
These results suggest that adherence to healthy diets such as the Mediterranean diet may be a more appropriate focus on the avoidance of obesity for the prevention of overall mortality.
The study was published in PLOS Medicine and conducted by Karl Michaëlsson et al.
Frailty
In another study, scientists from Hebrew SeniorLife and Harvard found that eating the Mediterranean diet may prevent frailty.
Defined as a recognizable state of increased vulnerability resulting from a decline in function across multiple physiological systems, frailty affects 10–15% of older people and leads to other health issues.
Although the general benefits of the Mediterranean diet are well known, its role in the reduction of frailty in older Americans who do not normally consume such a diet was unclear.
In the study, researchers tested 2,384 older people with no frailty with Mediterranean-style dietary pattern scores and antioxidant intakes [vitamin C, E, and total carotenoids].
They found that eating a Mediterranean-style diet may prevent the development of frailty with aging.
Each unit’s higher score on the Mediterranean Style Dietary Pattern Score (i.e., higher adherence to a Mediterranean-style diet) reduced the odds of frailty by 3%.
The team also found whether specific antioxidants (carotenoids, vitamins E, and C) found in a Mediterranean-style diet are related to frailty.
Higher intake of carotenoids (an antioxidant commonly found in brightly colored fruits and vegetables) had the strongest link to reduced likelihood of frailty development in middle-aged and older men and women.
Each 10-mg higher total carotenoid intake reduced the odds of frailty by 16%. Vitamin E and C were not meaningfully linked to frailty prevention.
The team concluded that people may be able to prevent frailty by following the principles of the Mediterranean-style diet.
The research was published in The American Journal of Clinical Nutrition and conducted by Courtney L Millar et al.
Type 2 Diabetes
Another recent study from the Chalmers University of Technology found that eating a Mediterranean diet with a low glycemic index (GI) could lead to health benefits that can help prevent type 2 diabetes.
They examined how meal-related insulin sensitivity, so-called postprandial glycemia, was affected by a diet with a high and low glycemic index, GI.
The team tested 160 people with a high risk of type 2 diabetes. These people completed a 12-week dietary intervention assessing the effect of MED-HEP with a low versus high GI.
The people ate half of their daily carbohydrates as low GI foods such as pasta, brown rice, and flat bread, or high GI foods such as jasmine rice, potato, mashed potatoes, and couscous along with fruits, vegetables, and other carbohydrate-rich foods that all consumed.
The team found blood sugar levels were lower after the meals with a low GI diet, compared to the high GI diet − and the difference between the groups increased with time.
However, the difference between the groups was mostly due to the high GI participants increasing their blood glucose after a meal, while the participants that ate a low GI showed the same level as the baseline.
This suggests that glucose levels are increasing after eating foods with a high GI for 12 weeks.
The study showed that GI affects glucose levels in the blood among non-diabetic people despite eating a healthy Mediterranean diet.
The team says as foods with low GI like pasta are part of a traditional Mediterranean diet, the low GI may be an important component in the Mediterranean diet’s health benefits.
The research was published in Nutrients and conducted by Thérése Hjorth et al.
Depression
In a recent study from the University of Technology Sydney, researchers found people with a poor diet saw a big improvement in their symptoms of depression when they switched to a healthy Mediterranean diet.
Depression is a common mental health condition that affects approximately 1 million Australians each year. It is a big risk factor for suicide, the leading cause of death in young adults.
In the study, the team examined the impact of a Mediterranean diet on the symptoms of depression in young men (aged 18-25).
The diet used in the study was rich in colorful vegetables, legumes, and whole grains, oily fish, olive oil, and raw, unsalted nuts.
The team found those assigned to the Mediterranean diet were able to strongly change their original diets, under the guidance of a nutritionist, over a short time frame.
The study contributes to the emerging field of nutritional psychiatry, which aims to explore the effect that specific nutrients, foods, and dietary patterns can have on mental health.
It suggests that medical doctors and psychologists should consider referring depressed young men to a nutritionist or dietitian as an important component of treating clinical depression.
There are lots of reasons why scientifically food affects mood. For example, around 90 percent of serotonin, a chemical that helps us feel happy, is made in our gut by our gut microbes.
There is emerging evidence that these microbes can communicate to the brain via the vagus nerve, in what is called the gut-brain axis.
The team says to have beneficial microbes, people need to eat fiber, which is found in legumes, fruits, and vegetables.
The research was published in The American Journal of Clinical Nutrition and conducted by Jessica Bayes et al.
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