Nutrition

Can Certain Foods Really Stave Off Dementia?

Walnuts are a great choice. improve cognitive function. Blueberries can boost memory. Fish oil supplements can lower your risk of Alzheimer’s disease.

You may have noticed these buzzy “brain food” claims scattered across online health articles and social media feeds. Can certain foods and diets actually prevent or treat dementia?

Experts agree that nutrition studies can be difficult to conduct, but there is growing evidence that certain foods and diets may have real benefits for an aging brain. We interviewed two dozen researchers to learn more about the links between diet, dementia, and food choices.

Scientists don’t yet know for certain what causes Alzheimer’s diseaseThe most common form is dementia. And there is currently no medication that can reverse it, said Dr. Uma Naidoo, the director of nutritional and metabolic psychiatry at Massachusetts General Hospital and the author of “This Is Your Brain on Food.”

“But,” she said, “we can impact how we eat.”

Research shows that people who have certain conditions such as diabetes, heart disease, obesity, and high blood pressure are more likely to experience cognitive decline as they age. Dr. Naidoo stated that poor diet and exercise can increase the risk of developing these conditions. There are ways to reduce the chance of developing dementia.

There are two diets that stand out: the Mediterranean diet and The One-Eating-Per-Day Diet. MIND diet — both of which 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.

One study published in 2017The study examined the cognitive performance and diets for more than 5,900 older U.S. adults. Researchers found that those who closely followed either the Mediterranean diet, or the MIND diet had a 30-35 percent lower risk of cognitive impairment compared to those who did not.

“Pretty much anything that will help keep arteries healthy will reduce risk of dementia,” said Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health. And Dr. Ronald Petersen, a neurologist and the director of the Mayo Clinic Alzheimer’s Disease Research Center, agreed: “What’s good for the heart is good for the brain.”

One big change you can make to your diet, Dr. Naidoo said, is to “up your plant game.” Leafy greens are packed with nutrients and fiber, and some solid evidence has linked them with slower age-related cognitive decline.

In one randomized controlled trialResearchers in Israel conducted brain scans on more than 200 people and published their findings this year. They found that after 18 months, those who followed a “green” Mediterranean diet — one rich in Mankai (a nutrient-packed green plant), green tea and walnuts — had the slowest rate of age-related brain atrophy. Close behind were those who followed a traditional Mediterranean-style diet. Those who followed regular healthy diet guidelines — which was less plant-based and allowed for more processed and red meat than the other two diets — had greater declines in brain volume.

These neuroprotective effects were particularly evident in people over 50.

Experts say that the more colorful the produce on your plate the better it is for your brain.

In one 2021 observational studyResearchers followed more than 77,000 people over a period of 20 years. They found that those with diets high in flavonoids — natural substances found in colorful fruits and vegetables, chocolate and wine — were less likely than those who consumed fewer flavonoids to report signs of cognitive aging.

The MIND diet specifically mentions berries as good sources of fiber, antioxidants, and cognitive benefits. One studyPublished in 2012, the study examined more than 16,000 people who were 70 years old or older over a period of 12 years. It was found that older women who ate more blueberries or strawberries had a slower rate of cognitive decline, possibly by as much as 2.5 years.

“I don’t think there are miracle foods, but, of course, it’s really good to eat the fruits and vegetables,” said Dr. Allison Reiss, a member of the medical, scientific and memory screening advisory board at the Alzheimer’s Foundation of America.

“Fish is brain food,” said Dr. Mitchel Kling, the 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, the director of the Alzheimer’s Prevention Program at Weill Cornell Medicine.

Dr. Mosconi stated that DHA cannot be made by the body on its own. “We have to provide it from the diet, which is a strong argument toward eating fish.”

According to Dr. Willett, about two to three servings per week will provide “virtually all the benefit.”

Multiple studies have linked nuts and seeds to slower cognitive decline.

In one 2021 review of 22 studies on nut consumption involving nearly 44,000 people, researchers found that those at high risk of cognitive decline tended to have better outcomes if they ate more nuts — specifically walnuts. However, there were some inconsistencies in the studies and inconclusive data.

Another study published in 2014The study included approximately 16,000 women aged 70 and older between 1995 and 2001. Researchers found that women who reported eating at least five servings per week of nuts had higher cognitive scores than those who didn’t.

Whole grains and legumes like soybeans and lentils have been shown to be beneficial for cognitive function and heart health. In one 2017 studyResearchers analyzed data from more than 200 Italians aged 65 and over and found a link between three meals per week of legumes and better cognitive performance.

Olive oil, which is a major component of the Mediterranean and MIND diets has strong links to healthy cognitive aging. One 2022 study of more than 92,000 U.S. adults found that higher intakes of olive oil were associated with a 29 percent lower risk of dying from neurodegenerative disease — and 8 percent to 34 percent lower risk of mortality overall — when compared with those who never or rarely consumed olive oil.

According to the experts we spoke with, there is little to no evidence that dietary supplements — including fatty acids, vitamin B or vitamin E — will reduce cognitive decline or dementia.

“Supplements cannot replace a healthy diet,” Dr. Mosconi said.

One major study of about 3,500 older adultsFor example, a study concluded that omega-3 supplements, often promoted as supporting brain health, didn’t slow down cognitive decline.

When it comes to supplements like fish oil, Dr. Willett said, you don’t need to “load up like a seal.” Instead, Dr. Petersen, of the Mayo Clinic, said, remember this pithy adage: “If it comes from a plant, eat it. If it’s made in a plant, don’t eat it.”

Source: NY Times

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