- New research links two popular diets to a lowered risk of Alzheimer’s disease.
- People who most closely followed the diets had less tangles and plaques in their brains.
- Experts say the findings are promising, but more research is needed.
Alzheimer’s disease is a complicated condition, and experts are still trying to figure out why some people develop it while others don’t. Now, a new study suggests that what you eat can play a role in your risk of developing Alzheimer’s—and two diets in particular may help lower your chances of developing the devastating disease.
The study, which was published in the journal Neurology, examined the brains of more than 580 people who donated their body to Rush University’s Memory and Aging Project, which has been collecting annual dietary information and doing annual check-ups on study participants since 2004. The study analyzed data on the dietary habits of participants from 2014 through 2020 or 2021, and compared that with the number of plaques and tangles that were in each person’s brain during an autopsy.
Plaques and tangles, in case you’re not familiar with them, are key markers of Alzheimer’s disease. In a person who has Alzheimer’s disease, beta-amyloid proteins clump together to form plaques that collect between neurons and interfere with cell function, according to the National Institute on Aging (NIA). Tangles are an accumulation of a protein called tau that collect inside neurons and interfere with communication between neurons, the NIA says.
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The researchers discovered that people who had eating patterns that closely followed the MIND or Mediterranean diets had almost 40% lower chances of developing Alzheimer’s disease than others.
The researchers specifically found that green leafy vegetables were the most beneficial, with brain tissue from people who ate the most leafy greens looking nearly 19 years younger in terms of plaque buildup than those who only had one or less servings of leafy greens a week.
The study raises a lot of questions about diet’s role in Alzheimer’s disease, as well as why these eating plans in particular may be helpful in lowering your risk. Here’s the deal.
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How can diet impact a person’s Alzheimer’s risk?
There are a lot of potential factors that can influence your risk of developing Alzheimer’s disease, including genetics and aging, the NIA says. As for diet, the National Institutes of Health (NIH) says that it’s possible that what you eat may influence your risk of developing Alzheimer’s disease. The NIH also points to the MIND and Mediterranean diets as being especially helpful in the prevention of Alzheimer’s disease.
“We and others previously found that healthy diets are associated with reduced dementia risk and better cognitive function in an aging population,” says lead study author Puja Agarwal, Ph.D., an assistant professor of internal medicine at the Rush University Medical Center in Chicago. What the latest study shows is that diet may be directly related to the formation of plaques and tangles in the brain, Agarwal says.
“The exact mechanism of how diet and plaques and tangles relate needs further investigation and we speculated that there might be other mechanisms through which diet may impact the risk for Alzheimer’s disease,” she says.
And, at a basic level, you are what you eat, says Amit Sachdev, M.D., M.S., medical director in the Department of Neurology at Michigan State University. “Diet is a metric for overall wellness,” he says. “In general, healthy body means healthy brain.”
Why might the MIND and Mediterranean diets lower your risk of developing Alzheimer’s?
Again, this is still being explored. However, there are some theories.
“One of the proposed mechanisms is that both the MIND and the Mediterranean are plant-based diets rich in various essential nutrients and bioactive compounds that are required to maintain brain health,” Agarwal says. “They also have antioxidant and anti-inflammatory properties which may help prevent amyloid burden and neuronal loss.”
Dr. Sachdev agrees that the diets’ anti-inflammatory properties may play a role. “Some diets are better at controlling body-wide inflammation,” he says. “Unfortunately, the typical starch-heavy American diet is not a great choice.” However, he says, the Mediterranean and MIND diets “balance styles of food and portion size in a way that reduces overall burden of body inflammation.”
Dr. Sachdev also notes that the Mediterranean diet in particular is linked to blood vessel health. “When we think of Mediterranean diet, we think of the health of blood vessels in the brain and reducing strokes. There is strong evidence for this,” he says. Research has also found that blood vessel issues are linked to an increased risk of Alzheimer’s.
Mediterranean diet basics
The Mediterranean diet is based on the lifestyles of people who live in the Mediterranean region, which includes Greece, Italy, and Spain, explains Jessica Cording, R.D., author of The Little Book of Game-Changers. It focuses on high intakes of vegetables, legumes, fruits, nuts, grains, fish, seafood, extra virgin olive oil, and some red wine. The diet also encourages followers to limit red meat, Cording says.
“The Mediterranean diet is designed to be a lifestyle,” Cording says, noting that people on the diet are also encouraged to be active. Research has linked the Mediterranean diet with good heart health, optimal blood sugar levels, and a lowered risk of dementia.
MIND diet basics
The MIND diet (which stands for Mediterranean–DASH Intervention for Neurodegenerative Delay) is a form of the Mediterranean diet that focuses on plant-based foods linked to dementia prevention, according to the NIA. It specifically encourages people to eat from these food groups:
- Leafy green vegetables, at least six servings/week
- Other vegetables, at least one serving/day
- Berries, at least two servings/week
- Whole grains, at least three servings/day
- Fish, one serving/week
- Poultry, two servings/week
- Beans, three servings/week
- Nuts, five servings/week
- Wine, one glass/day
- Olive oil
The diet also recommends that you limit servings of red meat, sweets, cheese, butter and margarine, and fast and fried foods, the NIA says.
What does this mean for your diet?
If you’re concerned about your Alzheimer’s disease risk, experts say it’s definitely worth taking a look at your diet. However, it’s important to stress that diet isn’t the only factor in the development of Alzheimer’s disease.
“Alzheimer’s disease risk is greatly influenced by genetics and age. Diet is a part of the conversation,” Dr. Sachdev says.
If you want to change up your diet but are uncertain where to start, Agarwal recommends keeping in mind basic principles of both the MIND and Mediterranean diets. Both diets “emphasize consuming more vegetables, especially green leafy, fruits including berries, whole grains, legumes, nuts, poultry, fish, and olive oil,” Agarwal says. “These diets also encourage avoiding or limiting high-fat, high-sugar foods, including red meat, fried foods, butter, full-fat cheese, and pastries and sweets.”
Not sure where to start? Try “incorporating more whole plant foods into your diet,” says Molly Rapozo, R.D.N., senior nutrition and health educator at Pacific Neuroscience Institute in Santa Monica, Calif. “If leafy greens aren’t a staple already, this could be a great place to start,” she says.
And, if you want to improve your diet but aren’t sure how to make changes work for you, Cording suggests that you consider meeting with a registered dietitian. They can help guide you on foods and meals to try to get you on the right track.
