Mediterranean and MIND diets reduced signs of Alzheimer’s in brain tissue, study finds
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People who consumed foods from the Mediterranean and MIND brain-focused diets had fewer of the hallmarks of Alzheimer’s — sticky beta-amyloid plaques and tau tangles in the brain — when autopsied, a new study found.
The MIND diet stands for Mediterranean Diet Intervention-DASH for Neurodegenerative Delay.
In fact, people who followed either diet most closely had “nearly 40% lower odds” of having enough plaques and tangles in brain tissue to be diagnosed with Alzheimer’s, according to the study.
“People who scored the highest for adherence to the Mediterranean diet had average amounts of plaque and plaque in their brains similar to being 18 years younger than people who scored the lowest,” according to a statement in the study. “The researchers also found that people who scored the highest on adherence to the MIND diet had average amounts of plaque and plaque similar to being 12 years younger than those who scored the lowest.”
That’s not all. Adding just one food category from each diet — such as eating the recommended amounts of vegetables or fruit — reduced the build-up of amyloid in the brain to a level similar to being about four years younger, the study said.
“Making a simple dietary modification, such as adding more greens, berries, whole grains, olive oil and fish, can delay the onset of Alzheimer’s disease or reduce the risk of dementia as you age,” said the author of Puja Agarwal study. , an assistant professor of internal medicine at Rush University Medical Center in Chicago.
The biggest benefit is from leafy greens, she said. However, adding more berries, whole grains and other healthy foods recommended by the diets was also helpful, she said.
“While this study does not conclusively prove that it is possible to slow brain aging through dietary choices, the data is compelling enough for me to add green leafy vegetables to most of my meals and suggest the Mediterranean-style diet for patients with my in. risk,” said Alzheimer’s disease researcher Dr. Richard Isaacson, a preventive neurologist at the Florida Institute for Neurodegenerative Diseases. He was not involved in the new study.
“Of course, the Mediterranean diet is also heart-healthy … reducing the risk for stroke and neurovascular injuries that may also increase the risk for Alzheimer’s disease pathology,” said Rudy Tanzi, a professor of neurology at Harvard Medical School, in who was not involved in the study.
“What’s good for the heart is good for the brain,” said Tanzi, who is also director of the genetics and aging research unit at Massachusetts General Hospital in Boston.
The Mediterranean diet focuses on plant-based cooking. The majority of each meal should be fruits and vegetables, whole grains, beans and seeds, along with some nuts. There is a strong emphasis on extra virgin olive oil. Butter and other fats are rarely, if ever, consumed. Sweets and products made from refined sugar or flour are rare.
Meat can have a rare appearance, but usually only to flavor a dish. Instead, meals may include eggs, dairy and poultry, but in much smaller portions than in the traditional Western diet. However, fish, which are full of brain-boosting omega-3s, are a staple.
The Mediterranean diet, which has won top honors as the best diet for years, has an impressive list of science behind it. Studies have found that this way of eating can prevent cognitive decline, but also help the heart, reduce diabetes, prevent bone loss, encourage weight loss, and more.
The MIND diet was developed in 2015 by Rush researchers interested in taking the Mediterranean diet to the next level by focusing it on brain health. Rather than making a blanket statement — eat more vegetables and fruits — like the Mediterranean diet does, the MIND diet recommends specific amounts of known brain-healthy foods, Agarwal said.
For example, leafy greens, the darker the better, should be eaten every day of the week on the MIND diet. They include arugula, collard greens, dandelion greens, endives, grape leaves, kale, mustard greens, romaine lettuce, spinach, Swiss chard and turnip greens.
Berries are also stressed over other fruits in the MIND diet. Blackberries, blueberries, raspberries or strawberries should be eaten at least five days a week.
A 2017 study of nearly 6,000 healthy older Americans with an average age of 68 found that those who followed the Mediterranean diet, or MIND, cut their risk of dementia by a third.
The study, published Wednesday in the journal Neurology, examined the brains of 581 people who each donated their bodies as part of the Memory and Aging Project at Rush University. The project, which began in 1997, has collected annual information on participants’ diets since 2004, Agarwal said.
The current study analyzed dietary data from 2014, for an average of six to seven years, and then compared that information with the number of plaques and tangles in each person’s brain at autopsy.
Looking at brain tissue to determine the specific level of dementia markers was a unique part of the study, Agarwal said: “Previous dementia risk studies were more on clinical outcome – cognitive performance over time – but our study in it’s really looking at the specifics. The hallmarks of disease in the brain after death.”
People who ate higher amounts of pastries, sweets and fried and fast foods had significantly higher levels of plaques and smudging in their brain tissue, the study found.
Which food was most helpful in reducing hoarding? Green leafy vegetables, which are packed with bioactives, chemicals in foods that reduce inflammation and promote health. Examples of bioactive compounds include vitamins, minerals, flavonoids (antioxidants) and carotenoids (pigments in vegetable skin).
The brain tissue of people who ate the most greens appeared nearly 19 years younger in plaque accumulation than those who ate one or fewer servings per week, the study said in a statement.
“The combination of different nutrients and bioactives in green leafy vegetables makes them unique,” said Agarwal. “They are very rich in many bioactives, flavonoids and lutein, which is important for brain health.”
There are various hypotheses as to why lutein may help with overall brain integrity,” she added, “such as reducing oxidative stress and inflammation.”
The most striking effect of the diets was on beta-amyloid accumulation, not tangles, and “the inverse association with beta-amyloid burden was stronger for the Mediterranean diet than for the MIND diet,” the study said.
There was a reduction in tau tangles, the other major marker of Alzheimer’s, but it was not as strong as that for amyloid, Agarwal said. However, Agarwai and her team conducted another study that found that eating berries, a key part of the MIND diet, was beneficial in reducing tangles in the brain.
“We still have to really tease out what exactly is going on,” she said. “But in general, these diets are rich in essential nutrients and bioactives, which reduce overall inflammation and oxidative stress in the brain and possibly lead to less accumulation of amyloid plaques and plaques.”