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People who ate foods from the plant-based Mediterranean diet and the brain-focused MIND diets had fewer of the hallmark signs of Alzheimer’s — sticky beta-amyloid plaques and tau tangles in the brain — when they underwent autopsies, according to a new study. study.
The MIND diet is short for Mediterranean Diet-DASH Intervention for Neurodegenerative Delay.
In fact, people who most closely followed either diet 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 highest for adherence to the Mediterranean diet had average amounts of plaque and tangles in their brains similar to being 18 years younger than those who scored lowest,” according to a statement from the study. “The researchers also found that people who scored the highest for adherence to the MIND diet had an average amount of plaque and tangles similar to being 12 years younger than those who scored the lowest.”
It’s not just that. Adding just one food category from either diet — such as eating recommended amounts of vegetables or fruit — reduced amyloid buildup 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 actually delay the onset of Alzheimer’s disease or reduce the risk of dementia as you age,” said study author Puja Agarwal. . , assistant professor of internal medicine at Rush University Medical Center in Chicago.
The biggest benefit is from leafy greens, he said. However, adding more berries, whole grains and other healthy foods recommended by the diets was also beneficial, she said.
“Although this study does not definitively prove that it is possible to slow brain aging through dietary choices, the data is compelling enough that I add green leafy vegetables to most of my meals and recommend the Mediterranean diet for my risk patients,” said Alzheimer’s researcher Dr. Richard Isaacson, a preventive neurologist at the Florida Institute of Neurodegenerative Diseases. He was not involved in the new study.
“Of course, the Mediterranean diet is also heart-healthy … reducing the risk for brain and neurovascular injury that can also increase the risk for Alzheimer’s disease pathology,” said Rudy Tanzi, a professor of neurology at Harvard Medical School, who did not participate 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 a few nuts. Great emphasis is placed 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 may make 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 packed with 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 shown 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 providing 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. These include arugula, collards, dandelion greens, endive, grape leaves, kale, mustard greens, lettuce, spinach, chard and turnip greens.
Berries are also stressed over other fruits on the MIND diet. Blueberries, blackberries, 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 the MIND diet, reduced their risk of dementia by a third.
The study, published Wednesday in the journal Neurology, looked at 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 dietary information on participants 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.
Examining brain tissue to determine the specific level of dementia markers was a unique part of the study, Agarwal said: “Previous dementia risk studies have looked more at clinical outcome—cognitive performance over time—but our study looks at reality the specific signs of disease in the brain after death.”
People who ate higher amounts of baked goods, sweets and fried foods and fast food had much higher levels of plaques and tangles in their brain tissue, the study found.
Which food was most helpful in reducing the build-up? Green leafy vegetables, which are packed with bioactive, chemical compounds in foods that reduce inflammation and promote health. Examples of bioactive compounds include vitamins, minerals, flavonoids (antioxidants) and carotenoids (pigments in the skin of vegetables).
The brain tissue of people who ate the most leafy vegetables appeared nearly 19 years younger in plaque accumulation compared with those who ate one or fewer servings per week, according to a study statement.
“The combination of different nutrients and bioactive substances in green leafy vegetables makes them unique,” Agarwal said. “They are very rich in many bioactives, flavonoids and lutein, which is important for brain health.”
There are different hypotheses as to why lutein may help with overall brain integrity,” he added, “such as reducing oxidative stress and inflammation.”
The most striking impact of diet was on beta-amyloid accumulation, not confounds, and “the inverse association with beta-amyloid burden was stronger for the Mediterranean diet than for the MIND diet,” the study said.
There was some reduction in tau tangles, the other key marker of Alzheimer’s disease, 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 helpful in reducing clutter in the brain.
“We still have to sort out what exactly is going on,” he said. “But overall, these diets are rich in key nutrients and bioactives that reduce overall inflammation and oxidative stress in the brain and possibly lead to less accumulation of amyloid plaques and tangles.”
