can of nuts improve cognitive function. blueberries can increase memory. Fish oil supplements can reduce the risk of Alzheimer’s disease.
You may have noticed these “brain food” claims scattered throughout health articles online and on social media. But can certain foods or diets really ward off or prevent dementia?
Experts say that while nutrition studies are notoriously difficult to conduct, there is a compelling and ever-growing body of research that suggests that some foods and diets may offer real benefits for an aging brain. So we talked to two dozen researchers and took a hard look at the research to better understand the links between diet and dementia.
Four Pillars of a ‘Brain Boosting’ Diet
Scientists still don’t know for sure what causes Alzheimer’s disease, the most common form of dementia. And there is currently no drug that can reverse it, said Dr. Uma Naidoo, director of nutritional and metabolic psychiatry at Massachusetts General Hospital and author of “This Is Your Brain on Food.”
“But,” he said, “we can affect the way we eat.”
Research shows that people with certain conditions, such as heart disease, high blood pressure, obesity, and diabetes, are more likely than those without such conditions to experience age-related cognitive decline. And the risks of developing those conditions can be increased by poor diet and exercise, suggesting there are things you can do to lower your chances of developing dementia, Dr. Naidoo said.
Two diets in particular, Mediterranean diet and the mind diet — both encourage fresh produce, legumes and nuts, fish, whole grains, and olive oil — have been shown in scientific studies to offer strong protection against cognitive decline.
A study, published in 2017looked at the diets and cognitive performance of more than 5,900 older U.S. adults. The researchers found that those who adhered most closely to the Mediterranean diet or the MIND diet had a 30 to 35 percent risk of cognitive decline percent lower than those who adhered less to these diets.
“Virtually anything that helps keep arteries healthy will reduce the risk of dementia,” said Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard TH Chan School of Public Health. And Dr. Ronald Petersen, a neurologist and director of the Mayo Clinic Alzheimer’s Disease Research Center, agreed: “What’s good for the heart is good for the brain.”
green leafy vegetables
One big change you can make to your diet, Dr. Naidoo said, is to “up your plant game.” Leafy green vegetables are packed with nutrients and fiber, and some strong evidence has linked them to slower age-related cognitive decline.
In a randomized controlled trial conducted in Israel and published this year, for example, researchers took brain scans of more than 200 people who had been divided into three diet groups. They found that after 18 months, those who followed a “green” Mediterranean diet, rich in Mankai (a nutrient-packed green plant), green tea, and walnuts, had the slowest rate of age-related brain atrophy. He was closely followed by those following a traditional Mediterranean diet. Those who followed the regular guidelines of a healthy diet, which was less plant-based and allowed more red and processed meat than the other two diets, had larger decreases in brain volume.
These neuroprotective effects were especially pronounced in people aged 50 years and older.
colorful fruits and vegetables
The more colorful the items on your plate, the better the food is for your brain, several experts said.
In one Observational study 2021, the researchers followed more than 77,000 people for about 20 years. They found that those with diets rich in flavonoids (natural substances found in colorful fruits and vegetables, chocolate, and wine) were less likely to report signs of cognitive aging than those who consumed fewer flavonoids.
The MIND diet specifically targets berries, good sources of fiber and antioxidants, which have cognitive benefits. A study published in 2012 looked at more than 16,000 people aged 70 and over over a dozen years. He concluded that older women who ate more blueberries and strawberries had later rates of cognitive decline — perhaps as long as 2.5 years.
“I don’t think there are any miracle foods, but of course it’s very good to eat fruits and vegetables,” said Dr. Allison Reiss, a member of the Alzheimer’s Foundation of America’s medical, scientific and memory evaluation advisory board.
“Fish is food for the brain,” said Dr. Mitchel Kling, director of the memory assessment program at the New Jersey Institute for Successful Aging at the Rowan University School of Osteopathic Medicine.
One specific omega-3 fatty acid, docosahexaenoic acid, or DHA, found in cold-water fatty fish like salmon, is “the most prevalent brain fat,” said Lisa Mosconi, director of the Alzheimer’s Prevention Program at Well Cornell Medicine. .
Our bodies can’t make enough DHA on their own, Dr. Mosconi said. “We have to provide it through diet, which is a strong argument for eating fish.”
According to Dr. Willett, about two to three servings per week will provide “pretty much all the benefit.”
Nuts, whole grains, legumes and olive oil
Nuts and seeds have been repeatedly linked to slower cognitive decline.
In a 2021 review From 22 studies of nut consumption involving nearly 44,000 people, researchers found that people at high risk of cognitive decline tended to do better if they ate more nuts, specifically walnuts. However, the authors acknowledged some inconsistency between studies and inconclusive evidence.
another study, published in 2014looked at about 16,000 women aged 70 and older between 1995 and 2001. The researchers found that women who said they ate at least five servings of nuts per week had better cognitive scores than those who didn’t eat nuts.
Whole grains, as well as legumes such as lentils and soybeans, also appear to have benefits for heart health and cognitive function. In a 2017 study Of more than 200 people in Italy over the age of 65, researchers found an association between consuming three servings of legumes per week and higher cognitive performance.
And olive oil, a main component of the Mediterranean and MIND diets, has strong links to healthy cognitive aging. One studio 2022 of more than 92,000 U.S. adults found that a higher intake of olive oil was associated with a 29% lower risk of dying from neurodegenerative disease, and an 8% to 34% lower risk of mortality overall, compared to those who never or rarely consumed olive oil.
Dietary supplements may have little effect
According to the experts we spoke with, there is little or no evidence that dietary supplements, including fatty acids, vitamin B, or vitamin E, reduce cognitive decline or dementia.
“Supplements cannot replace a healthy diet,” said Dr. Mosconi.
A major study of approx. 3,500 older adultsfor example, it concluded that taking omega-3 supplements, which are often marketed as supporting brain health, did not slow cognitive decline.
When it comes to supplements like fish oil, Dr. Willett said, you don’t need to “load like a seal.” Instead, Dr. Petersen of the Mayo Clinic said, remember this pithy saying: “If it comes from a plant, eat it. If it’s made in a plant, don’t eat it.”
