Foods That Can Help Prevent Dementia

One of the most important steps you can take to optimize brain health and lower the risk of cognitive decline is to follow a healthy diet. Here, learn the latest science on the best foods to eat to keep your brain healthy.

Elderly woman drinking a smoothie

Are you worried about memory problems as you age? Who isn’t? Fortunately, there’s a growing body of evidence that we may have more influence over the likelihood and timing of cognitive decline than we realize, and diet plays a key role.

Good nutrition can slow cognitive decline and lower the risk of dementia, according to research. “There’s a vast amount of evidence showing that nutrition is important not just for overall health, but for brain health as well,” says Yuko Hara, PhD, Director of Aging and Alzheimer’s Prevention at the nonprofit Alzheimer’s Drug Discovery Foundation (ADDF). For instance, one study found that people whose diets rated the healthiest measured 7.5 years younger in cognitive abilities than those who had the least healthy diets.

For people who are already experiencing memory loss, it’s not too late to reap the benefits of a brain-boosting diet. “Exciting research shows that we can delay the onset of cognitive decline and also slow it down in people who have mild cognitive impairment,” says Howard M. Fillit, MD, a geriatrician, neuroscientist, and leading expert on Alzheimer’s disease as well as the Co-Founder and Chief Science Officer of the ADDF and a member of TheKey’s Scientific Advisory Board.

The bottom line: When it comes to brain health, “nutrition and diet are important and we should take them seriously,” says Dr. Hara.

How a Healthy Diet Protects the Brain

First, let’s break down what makes up a “healthy diet.” Several eating styles have proven brain benefits; what they all have in common is that they’re built around whole, unprocessed foods. These include the Mediterranean diet, inspired by the cuisines of southern Italy, Spain, and Greece; the low-salt DASH (Dietary Approaches to Stop Hypertension) diet; and the MIND (Mediterranean and DASH Intervention for Neurodegenerative Delay) diet. These approaches incorporate plenty of plant-based foods, including fresh fruits and vegetables, whole grains, legumes, seeds, and nuts, and they limit processed foods, added sugars, and animal meats high in saturated fats.

One of the reasons a healthy diet is beneficial for the brain is because good nutrition helps prevent or manage chronic conditions like obesity, Type 2 diabetes, high blood pressure, and high cholesterol. These conditions increase the risk of cognitive decline by damaging the blood vessels that carry blood to the brain. They also lead to inflammation in the body and chemical imbalances, both of which can hurt brain cells.

Healthy foods also deliver antioxidants, vitamins, and minerals that can protect brain cells. People who eat a diet rich in whole, unprocessed foods and healthy fats have higher blood levels of brain-derived neurotrophic factor (BDNF), a protein that supports the growth and survival of the brain cells that facilitate learning and memory, according to a study. Eating a variety of healthy foods also improves the gut microbiome (the organisms that live in our gut), which ongoing research has linked to improved brain health.

If a person’s diet is unhealthy, however, not only do they miss out on all these nutritional benefits, but the foods they may be eating can negatively affect the brain. A poor diet—meaning one that contains a lot of saturated fat, processed meats, fried foods, and sugar, and is low in vitamins, minerals, and antioxidants—can trigger systemic inflammation, which can prevent brain cells from functioning properly. Over time, nutritional deficiencies in vitamins, minerals, and antioxidants can lead to brain atrophy, research has shown.

And these problems can’t be avoided by simply popping a multivitamin. Whole foods deliver multiple nutrients at once, which work together synergistically. That tends to make them a better option than supplements. In fact, the Global Council on Brain Health published a report on supplements in 2019, declaring that the best way to get nutrients is from a healthy diet.

However, deficiencies in certain nutrients can negatively impact brain health, so supplementation is sometimes necessary. For example, many older adults lose the ability to absorb vitamin B12 through their stomachs as they age. So even if they are eating a diet rich in B12, they may still be deficient. “When someone comes into the office and complains of memory problems, one of the first things we do is measure their B12 levels,” says Dr. Fillit. “Often, if they take B12 supplementation, their memories will improve.” Before taking supplements, talk to your doctor about doing bloodwork to check for nutritional deficiencies.

A Healthy Diet Works in Tandem with a Healthy Lifestyle

Diet is most beneficial when combined with other lifestyle behaviors, like those outlined in the World Health Organization’s first-ever position paper on optimizing brain health and in guidelines written by a team of leading experts convened by the nonprofit UsAgainstAlzheimer’s after reviewing the latest literature.

The research shows that 40 percent of dementias may be delayed or prevented. “It is never too early and never too late in the life course for dementia prevention,” state the study authors. Steps to protect your cognitive health include: exercise (at least 30 minutes of moderate-intensity exercise three to five days a week); sound sleep; alleviating stress; staying social; treating conditions like diabetes, high blood pressure, high cholesterol, and obesity; and continuing to challenge your brain through learning something new like how to play an instrument or speak a different language.

7 Top Foods for Cognitive Health

Below is a list of foods that help build and maintain brain health, based on science. Rather than choosing just a few of them to focus on, try eating a variety of these foods to get the most brain-boosting benefits.

1. Vegetables, Especially Leafy Greens

Vegetable intake is associated with a reduced risk of cognitive decline, and green leafy vegetables, such as spinach, kale, and lettuce, are particularly beneficial because they contain antioxidants, which protect against cellular damage, and fiber, which helps reduce inflammation. According to one study, the rate of cognitive decline among people who ate one to two servings of green leafy vegetables a day was the equivalent of being 11 years younger compared to those who rarely or never consumed these vegetables.

2. Fruits, Especially Berries

The reason: They are antioxidant powerhouses that help counter the effects of oxidation, which is a critical part of the brain aging process. “The sun’s rays cause tremendous amounts of oxidation, and over hundreds of millions of years, plants have developed some of the most effective antioxidants to be able to survive,” explains Dr. Fillit. “We, as scientists, have not been able to recreate what Mother Nature has done in these plants, and particularly the dark plants, the blackberries, blueberries, and strawberries, [which] have the highest amounts of antioxidants in them.” A study of older women found that greater intakes of blueberries and strawberries was associated with slower rates of cognitive decline.

3. Whole Grains

Incorporate whole grains such as oatmeal, quinoa, whole-grain breads, maize, millet, oats, wheat, and brown rice into your diet. Whole grains contain antioxidants not found in fruits and vegetables as well as fiber, which is anti-inflammatory, and other nutrients important to brain health like B vitamins, vitamin E, and magnesium. In studies, diets scored highest when they included three or more servings of whole grains a day.

4. Beans

Black beans, kidney beans, garbanzo beans (or chickpeas), soybeans, and lentils are a bountiful source of fiber, B vitamins, protein, and beneficial omega-3 fatty acids. Beans are also anti-inflammatory and may further help the brain by controlling blood sugar and cholesterol. The MIND diet calls for beans at least three times a week.

5. Olive Oil

A Spanish study of older adults at risk of cardiovascular disease compared cognition among people who ate a low-fat diet to those who consumed a Mediterranean diet supplemented with extra-virgin olive oil (EVOO). Those who ate the Mediterranean diet plus EVOO had improved cognitive function. The study authors note that EVOO is rich in healthy substances called phenolic compounds that may reduce damaging oxidation in the brain. In addition, EVOO may be beneficial because of its positive effect on cardiovascular health and improved blood flow to the brain.

6. Nuts

The study mentioned above also looked at people who ate a Mediterranean diet supplemented with nuts and found benefits similar to those of EVOO. Studies that looked specifically at walnuts showed that they improve cognitive function and reduce the risk of other diseases, such as cardiovascular disease, depression, and Type 2 diabetes, which are risk factors for the development of dementia. The MIND diet calls for five or more servings of nuts a week. Opt for plain nuts instead of salted or sugared.

7. Fatty Fish, Like Salmon

People who had a high intake of fatty fish had a 36 percent lower risk of developing Alzheimer’s disease than those who had a low intake, according to a meta-analysis. Fatty fish is a source of DHA, an omega-3 polyunsaturated fatty acid that is essential for optimum brain functioning. “DHA plays a critical role in [maintaining] the axons, the long connections between nerve cells, which are the cables in the brain center that transmit information,” explains Dr. Fillit. DHA helps axons function properly. People who are deficient in DHA have more cognitive impairment, he says.

7 Worst Foods for Cognitive Health

The following foods have been shown by research to damage brain health. While the occasional meal containing one of them is okay, aim to limit their frequency in your diet.

1. Processed Meat, Like Bacon, Ham, Salami, Sausages, and Burgers

Processed meat contains preservatives that can increase oxidative stress and inflammation. It is also high in sodium, which can raise blood pressure, reducing blood flow to the brain and affecting brain health. A study found that each additional 25 grams a day of processed meat was associated with increased risk of dementia.

2. Foods High in Saturated Fat

Think: butter, full-fat cheese, red meat, and coconut oil. Studies have found that people with the most saturated fat in their diets had twice the risk of developing Alzheimer’s disease than those who generally avoided this fat.

3. Fried Foods

Loaded with saturated fat and sodium, fried foods may accelerate brain aging due to inflammation and plaque buildup in the arteries. A cross-sectional study assessing diet consumption found that people who ate a diet high in inflammatory foods, like fried foods, had smaller brains and less gray matter, both of which are early markers for dementia.

4. Foods Containing a Lot of Salt

A diet high in salt can raise blood pressure and reduce blood flow to the brain. A 2019 study in mice also found that salt contributed to structural changes in the brain that were a hallmark of Alzheimer’s.The American Heart Association recommends lowering your intake to 1,500 milligrams or less per day. Limit your consumption of processed foods, which can be packed with sodium.

5. Sodas and Diet Sodas

People who drank one to seven servings of sugar-sweetened beverages a week were more than three times as likely to develop Alzheimer’s disease than those who consumed none, according to research. But don’t switch to diet soda: Another study found that people who drank artificially sweetened beverages, like diet sodas, were almost three times more likely to develop Alzheimer’s disease than those who did not drink them. Skip the soda and instead sip on water or beverages linked to brain-health such as coffee and green tea.

6. Sweets

Sugar has no essential nutrients and it can also lead to inflammation, which has been shown to affect the size of the brain and the amount of gray matter. Minimize added sugars to less than 10 percent of your calories. To satisfy your sweet tooth, trade in a pastry or ice cream for a piece of dark chocolate. The cocoa bean is high in brain-healthy plant chemicals called flavanols. In addition, dark chocolate has antioxidant effects that can reduce damage to the brain from oxidative stress. Look for chocolate without the words “Dutch processing” or “alkalization” on the label since this reduces the amount of flavanols. And check the ingredients list for minimal added sugar or fat.

7. Alcohol

While traditionally part of the Mediterranean diet, experts advise limiting alcohol to two drinks a day for men and one drink a day for women—or to cut it out completely. In a study of over 31 million people in France, extremely heavy alcohol consumption was associated with a greater than three-fold increased risk of dementia. “As we age, we metabolize alcohol less efficiently and our brains are less tolerant of the alcohol,” says Dr. Fillit. “What might be a reasonable recommendation for a 30-year-old might not be the right recommendation for a 70- or 80-year-old. I recommend to my patients who have memory problems not to drink at all.”

For more information about the benefits of specific foods and supplements for brain health, check out Cognitive Vitality, a ratings program from the ADDF. And see how nutrition plays a role in TheKey’s approach to wellness and personalized care through the Balanced Care Method.

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Dana Hudepohl
A freelance journalist for 25 years, Dana Hudepohl has published more than 500 articles in more than 40 national magazines, newspapers, and websites.