Is the MIND diet really best for preventing dementia?

A new study recently put this popular eating plan to the test —  and the results were surprising. Here’s what you need to know.

Older adult couple eating the MIND diet to prevent dementia

You are what you eat. Remember that phrase? Basically, it refers to the deep relationship between our physical health and what we put on our plates.

Well, that goes for your brain too. Everything you eat impacts your cognitive health, for better or worse. This connection was the inspiration for the MIND diet, which combines parts of the Mediterranean diet with parts of the DASH diet.

Quick decoder: DASH stands for Dietary Approaches to Stop Hypertension, while MIND is an acronym for Mediterranean-DASH Intervention for Neurodegenerative Delay. These acronyms may be giving you brain freeze, but the purpose of this eating plan is just the opposite: It aims to keep your brain sharp and clear and even protect against dementia.

Below, learn more about the MIND diet, and what research has shown about its effectiveness in fighting brain-related issues such as dementia.

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What were the initial results of studies on the MIND diet?

Let’s start first with its precursor, the DASH Diet. It has been around for a while, and was originally developed to improve high blood pressure and heart health. The MIND diet, on the other hand, has been around a lot less long — it was only first introduced in 2015. It’s based on the DASH diet — because what’s good for the heart is good for the brain — with a few twists to optimize it for brain health.

What’s been the evidence from the MIND diet so far? Two key studies from Rush University Medical Center and the Harvard T.H. Chan School of Public Health showed that people who follow the MIND diet are less likely to experience cognitive decline and develop dementia. As a result, many experts consider it a key way to decrease the risk of dementia.

Then in 2023, a study published in The New England Journal of Medicine suggested that even a low level of the dietary pattern, coupled with weight loss, may be healthy for the brain.

But the studies so far have been observational. That means that scientists have taken a large group of people and asked them what they ate over a number of years. Scientists have then compared the cognitive scores of people who tended to eat the foods in the brain-healthy MIND diet to people who didn’t tend to do that.

That’s a great leap forward for science — but it’s not the final step. That’s because it’s impossible to know if eating healthy causes improved brain function (or the opposite). And it stands to reason that people who already have better brain function may choose to eat healthier anyway.

To shed some light on this — and advance the science — a research team has just published results from a randomized controlled trial of the MIND diet, in which following the MIND diet is compared head-to-head with a control diet. That means that any differences that the study finds are specifically due to the differences between the MIND diet and the control diet.

So, what’s the verdict when it comes to food and cognitive health? We spoke with two experts to help explain the new research. Plus, what they believe is the best way to eat to support your brain.

What the new MIND diet study looked at

The new study compared two eating styles to see how they would affect the brain. Over the course of three years, it included two groups of over 600 people. All were older adults without cognitive impairment — but with a family history of dementia. People also were at least somewhat overweight and had a suboptimal diet.

One of the eating styles, of course, was the MIND diet. This plan emphasizes having a specific number of servings from core food groups. This includes:

Green leafy vegetables, 6+ servings a week
Other vegetables, 1+ serving a day
Berries, 2+ servings a week
Whole grains, 3+ servings a day
Fish, 1+ meals a week
Poultry, 2+ meals a week
Beans, 4+ meals a week
Nuts, 5+ servings a week

The MIND diet also calls for cutting down on red meat, fried food, cheese, butter, and sweets. Study participants were coached to lose weight as well.

The other study group was coached toward weight loss through portion control, but weren’t asked to follow any other specific nutritional guidelines.

What the results showed about diet and dementia

At the end of the trials, researchers compared the two groups across their cognitive scores and detailed pictures of the brain from magnetic resonance imaging (MRI).

Surprisingly, the researchers didn’t find significant differences between the two groups on either of those measures. In fact, both groups showed improved cognitive scores. And both groups showed equivalent normal declines in measures of brain health from the MRI scans. And importantly, both also lost weight — about 11 lbs.

How could that be? Turns out, even the control group — which didn’t follow the MIND diet — began eating healthier once the study began, notes study co-author Jennifer Ventrelle, M.S., R.D.N. She is co-author of The Official MIND Diet, an assistant professor in the departments of preventive medicine and clinical nutrition at Rush University Medical Center in Chicago, and lead dietitian for the medical center’s MIND Diet Trial to Prevent Alzheimer’s Disease.

These participants ended up eating more high-quality foods and fewer ultra-processed ones on their own. This might be because becoming part of a study about brain health and food made them more aware of their eating habits, suggests Ventrelle.

Additionally, both groups lost about the same amount of weight suggesting that both groups did eat a healthier diet. If both groups in a randomized controlled trial adopt healthier habits, then both groups will benefit — and this may have been what happened in this big study.

What’s the big takeaway from the new MIND diet study?

What experts have learned from the somewhat surprising results is that it may take some time to see the brain health benefits of a brain health diet. If the study had been longer, for example, it’s possible that the MIND diet group may have had stronger brain-health results than the control group.

“It typically takes at least five years to see significant movement in cognition, and it’s very difficult to design a clinical trial and keep people engaged for even two or three years,” Ventrelle says.

It’s also difficult to run a randomized controlled trial for a long period of time. Eventually, people in each group are likely to just eat what they want to eat, rather than follow the study’s requests.

That’s why it’s helpful to look at observational studies that can follow people for a longer period of time and collect real-world data about what those people eat. One investigation, published in JAMA Psychiatry, analyzed three different observational studies, one of which actually spanned 15 years, as tricky as that is for researchers to do.

In each of the three studies, participants filled out questionnaires about how closely they followed the MIND diet. They were given cognitive tests at the end. Over the course of the studies, some people developed dementia. But those who most strictly followed the MIND diet lowered their risk of dementia by 17%, suggesting it may take some time for the brain health benefits to kick in.

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The best foods for cognitive health, according to science

There may be another key conclusion to draw from the new study: the strong connection between eating nutrient-rich foods and improved cognitive health. Yes, the MIND diet does include lots of nutrients. But according to the new research, even loosely following the MIND diet may give you the cognitive benefits, says Ventrelle.

Registered dietitian Julie Andrews, M.S., R.D.N., Fellow of the Academy of Nutrition and Dietetics, and author of The MIND Diet Plan and Cookbook, reviewed the literature and notes that people who follow the MIND diet have slower cognitive decline, by up to 53%. The MIND diet focuses on increasing consumption of certain foods containing specific nutrients (such as B vitamins) that can directly benefit the brain.

Fiber can also positively impact brain health. For instance, fiber-rich diets can help lower blood pressure. This ensures that enough blood gets to the brain. “Increased blood flow is imperative for a functioning brain,” says Andrews. On the other hand, reduced blood flow to the brain is linked to dementia.

Another key nutrient for cognition: omega-3 fatty acids. They may protect against dementia because they help with brain function.

Foods that contain at least one of these key nutrients include:

Salmon
Walnuts
Berries
Leafy greens and all other vegetables
Beans and legumes
Lean poultry
Olive oil

All that said, many people prefer to follow a specific eating plan, with rules, rather than trying to figure things out themselves. In that sense, the MIND diet remains a great option for those who want to prioritize cognitive health. So do the Mediterranean and DASH eating plans.

The takeaway is this: Can following the MIND diet lower your risk of dementia? Yes, it can — even if you aren’t super strict about it. As long as your diet consists primarily of nutrient-rich foods and is low in ultra-processed ones, your brain will likely benefit. It may take a few years for the brain health benefits to show up — but the results will be worth it.

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Additional sources:
Creation of MIND diet: Harvard T.H. Chan School of Public Health
MIND diet study on cognition: The New England Journal of Medicine
Investigation of three MIND diet studies: JAMA Psychiatry
High fiber diet and dementia: Harvard Health Publishing: Harvard Medical School
Omega-3 fats: National Library of Medicine: MedlinePlus