The best diet for Alzheimer’s prevention

Nearly 6 million Americans are living with Alzheimer’s disease, the most common form of dementia. This condition affects areas of the brain responsible for thought, memory, and language, worsening over time. At first, Alzheimer’s may exhibit as minor memory loss, but as the disease advances having a simple conversation or engaging in normal day-to-day activities can be difficult. The good news is that eating the right foods can help to prevent or slow down progression of Alzheimer’s.

Is Alzheimer’s linked to diet?

According to research, Alzheimer’s disease is strongly linked to inflammation throughout the body. Consuming an inflammatory diet—one that’s full of fried foods, refined starches, sugars, saturated or trans fats, and red or processed meats—may increase your chances of developing the disease as well as many other serious health conditions. 

On the flip side, eating certain foods may decrease your risk of cognitive decline, according to the U.S. Department of Health and Human Services’ National Institute on Aging. One study found that eating a Mediterranean diet consisting of foods like salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, and dark and green leafy vegetables may decrease a person’s risk of developing Alzheimer’s disease. (As long as you also limit high-fat dairy, red meat, organ meat, and butter.) 

Although diet can be protective against Alzheimer’s, it cannot reverse the disease, says 

Kristian Morey, RD, LDN, a clinical dietitian with the Nutrition and Diabetes Education program at Mercy Medical Center in Baltimore, Maryland. 

However, a recent Temple University School of Medicine study of mice showed that switching to a healthier diet reversed the cognitive impairment that was associated with their previous diet. “While this cannot be considered a therapy or cure, it may demonstrate that dietary changes can improve some cognitive impairment,” Morey says. 

What is the best Alzheimer’s diet?

A growing body of evidence suggests that a  Mediterranean diet may protect against cognitive decline and dementia. “To date, several studies have shown that individual nutrient characteristics of the Mediterranean diet reduce oxidative stress biomarkers and positively affect cognition,” says Reyzan Shali, MD, a primary care physician board-certified in internal medicine practicing in San Diego, California.

A typical aging brain displays signs of cell atrophy, which are most likely related to three main mechanisms: a decrease in cerebral blood flow and oxygen supply, mitochondrial dysfunction (caused by oxidative stress), and increased inflammation, Dr. Shali explains. The Mediterranean diet works on all three of these mechanisms. To prevent cell atrophy in your brain, consider including Mediterranean diet foods into your routine,” she says.

The Mediterranean diet limits red meat, eggs, and sugar, and focuses on the following:

• Vegetables including lettuce, cucumber, broccoli, cabbage, carrots, celery, beets, eggplant, asparagus, Brussels sprouts, spinach, garlic, zucchini, onions, and garlic
• Fruits such as tomatoes, olives, oranges, apples, citrus fruits, berries, grapes, peaches, pomegranates, and figs
• Whole grains including oats, farro, bulgur, and quinoa
• Legumes like chickpeas, kidney beans, lentils, fava beans, and lima beans
• Nuts and seeds including walnuts, sunflower seeds, pecans, almonds, and pine nuts
• Dairy products like Greek yogurt, milk, and cheeses
• Unsaturated fats such as olive oil and avocado
• Fish such as tuna, salmon, and sardines
• Seafood including shrimp, scallops, octopus, and lobster

The MIND Diet, a combination of the Mediterranean and DASH diets, also seems to be beneficial, says Morey. Like the Mediterranean diet, the MIND diet focuses on plant-based foods linked to dementia prevention and incorporates elements of the DASH diet (Dietary Approaches to Stop Hypertension). The DASH diet helps to lower high blood pressure, which is a known risk factor for Alzheimer’s disease. The MIND diet encourages eating recommended servings of these 10 healthy food groups each week:

• Leafy green vegetables, at least 6 servings/week
• Other vegetables, at least 1 serving/day
• Berries, at least 2 servings/week
• Whole grains, at least 3 servings/day
• Fish, 1 serving/week
• Poultry, 2 servings/week
• Beans, 3 servings/week
• Nuts, 5 servings/week
• Wine, 1 glass/day
• Olive oil in moderation
• 7 foods that prevent Alzheimer’s

Morey advises eating small meals with a combination of lean proteins, fruits and vegetables, and healthy fats at regular intervals, every three to four hours. “Limit items with little nutritional value such as caffeine, alcohol, candy, potato chips, and fried foods,” she says. The following seven foods and drinks may decrease Alzheimer’s risk or reduce progression:

1. Eggs

Eggs may have a positive effect on neurocognitive performance. In one study, egg intake was associated with improved performance on cognitive testing that assessed frontal lobe and executive functioning. 

2. Coffee

Coffee consumption may decrease the risk of developing Alzheimer’s. Results from the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study found that drinking three to five cups of coffee every day at midlife was linked to a 65% decrease risk of dementia and Alzheimer’s in late-life.

RELATED: 10 health benefits of coffee

3. Oatmeal

A component in oatmeal, avenanthramide-C (Avn-C) may have the potential to reverse Alzheimer’s disease-related cognitive problems. According to research, Avn-C acts to improve Alzheimer’s-related memory and behavioral impairments.

4. Walnuts

Walnuts have high amounts of omega-3 fatty acids and antioxidants, which may help to reduce inflammation throughout the body. Research suggests that walnuts decrease oxidative stress, inflammation, and cell damage, all of which play pivotal roles in the development of Alzheimer’s disease.

5. Dark leafy greens

According to research, dark leafy greens may slow the progression of Alzheimer’s, Morey says. One study found that eating one serving of this type of vegetables every day (such as spinach, lettuce, collards or kale) was associated with slower age-related cognitive decline. Dark leafy greens are rich sources of the nutrients folate, phylloquinone, nitrate, α-tocopherol, kaempferol, and lutein, which are all individually linked to slower rates of cognitive decline.

6. Fish

A diet that includes regular fish consumption is associated with higher cognitive function and slower cognitive decline with age, Morey says. According to research, individuals who consumed at least one serving of fish per week scored better on memory and cognition tests than those who did not consume fish every week. 

7. Apples, oranges, and bananas

Fruit is a source of vital nutrients, dietary fiber, and antioxidants, but it also has important cognitive benefits. One study showed that apples, oranges, and bananas, the fruits most commonly consumed by Americans, provide protection against neurodegenerative diseases including Alzheimer’s. 

2 foods to avoid with Alzheimer’s

There are specific foods to avoid if you want to reduce your chances of Alzheimer’s and dementia. In addition to foods that trigger an inflammatory response, stay away from these two foods and drinks that may increase Alzheimer’s risk or progression:

1. Red meat

A cohort study of close to 500,000 patients found that processed meat consumption is a potential risk factor for dementia, and the higher the consumption, the greater the risk. Dr. Shali recommends avoiding red and processed meats altogether because of their negative impact on brain health.

2. Alcohol 

Excessive alcohol consumption and binge drinking have been associated with increased risk of developing dementia, says Morey. One study showed that heavy alcohol consumption, particularly of hard liquor, contributed to a faster rate of cognitive decline in Alzheimer’s patients. 

The typical Western diet (high glycemic and high fat- particularly saturated and trans fats) is linked to a higher risk of developing dementia, Morey says. And eating this way can cause existing dementia to worsen—that’s why it’s a good idea to follow the Mediterranean diet or the MIND diet.

Does fasting prevent Alzheimer’s?

Research indicates that intermittent fasting may have a positive impact on cognitive decline, but the exact mechanisms involved in these effects is unclear, and further investigation is warranted.

Other ways to reduce Alzheimer’s risk or progression

Alzheimer’s is not reversible, but there are many ways to reduce the development or progression of Alzheimer’s disease. In addition to a poor diet, many other things can cause Alzheimer’s to worsen, says Dr. Shali. These include lack of sleep, unhealthy eating habits, not staying active, missing medications, and not having social interactions. 

Lifestyle changes

They include lifestyle changes such as getting more sleep, being active, eating healthy, reducing stress levels, and socializing with others.

Eating habits can also be modified. Those with Alzheimer’s should take their time during meals, use mealtime as an opportunity to connect with others, and limit distractions such as electronics or television, says Dr. Shali.

Patients who are experiencing the following symptoms should visit their primary care provider: 

• Memory loss that disrupts daily life
• Difficulty completing familiar tasks
• Misplacing things and losing the ability to retrace steps
• Trouble following or joining a conversation

Sometimes, people with Alzheimer’s disease stop eating. The most common reason is that they forget to eat, says Dr. Shali. Or, the person may no longer recognize the foods on their plate, says Morey. Poor fitting dentures, new medications, or lack of physical activity may also contribute to decreased food and water intake, she says.

Medications

Currently, the following drugs are approved by the FDA to manage Alzheimer’s symptoms: 

• Aduhelm (aducanumab)
• Aricept (donepezil)
• Exelon (rivastigmine)
• Namenda (memantine)
• Namzaric (memantine/donepezil)
• Razadyne (galantamine)

RELATED: Alzheimer’s medications and treatments

It is important to talk with your healthcare provider about your specific possible food-drug interactions as well when modifying your diet for Alzheimer’s.

Supplements

According to the U.S. Department of Health and Human Services, no vitamins or supplements are currently recommended for the prevention or treatment of Alzheimer’s disease or other forms of cognitive decline.