A New Study Finds This One Food Habit Has a Huge Impact on Cognitive Decline

Yet another new study has found a link between diet and brain health.

Nature Mental Health reports that a study of 181,990 participants in the U.K. (with an average age of about 70) showed a link between a balanced, healthy diet and a balanced, healthy mind.

The study, done largely via questionnaire, divided food up into 10 different groups—including fruits, vegetables, meat and alcohol—and used data from sources including blood metabolic markers, brain imaging, cognitive function tests (which can help assess memory, attention span and reasoning) and genetic testing to check for links between different dietary choices and brain health.

The results were a doozy, but in a good way: Just like diversifying your bonds is great for your bank account, diversifying your food is great for your brain. According to the study, participants who had a varied diet scored higher on cognitive tests that measured reaction time, problem-solving skills and memory. The same participants also reported having fewer depression or anxiety symptoms than participants whose diets weren't as balanced. Study participants with a varied diet showed higher levels of grey matter, associated with intelligence and protection from neurodegenerative illnesses and conditions.

Related: 'I've Spent 40 Years Studying the Brain, and This Is the #1 Habit I Recommend for Memory Retention'

The news doesn't surprise Dr. Scott Kaiser, MD, family physician and geriatrician at Pacific Neuroscience Institute, and he recommends getting started right now on improving your diet for the sake of your brain.

"Lifestyle and nutritional choices play a key role in maintaining and improving brain health and are the cornerstone of any strategy to reduce the risk of cognitive decline and dementia," he tells Parade. "This is particularly important when it comes to broad risk reduction strategies aimed at reducing the overall burden of dementia. It is believed that something on the order of 40% of all dementia cases could theoretically be prevented, or significantly delayed, if a constellation of key risk factors were eliminated; many of them, including hypertension, diabetes, obesity and other metabolic conditions for which dietary and lifestyle factors play a key role."

The importance of food for brain health and the need to make changes sooner rather than later can't be overstated, according to Dr. Kaiser.

"Considering the predictions of rising numbers of people who will be impacted—worldwide dementia cases are projected to triple by 2050 to over 150 million people—we need to start thinking now, and on a massive scale, about the best possible strategies and approaches to prevent dementia. An ounce of prevention is well worth more than a pound of cure."

Find out the best way to do just that.

Related: A Change in This Daily Habit Could Be an Early Sign of Dementia, According to New Research

Does Diet Impact Brain Health, or Is This a Case of Correlation Over Causation?

The short answer: Diet probably impacts your brain, though science changes often, so most are loath to give a truly definitive answer. That said, Dr. Kaiser tells us it's safe to trust this overall.

"A growing body of evidence clearly supports a strong correlation between diet and brain health," Dr. Kaiser explained. "While this study, and other related cornerstone studies in this field, may not be designed to specifically establish causation, there are many clear causal pathways and plausible biological mechanisms that support the likelihood that various diets and nutritional factors may either be protective of our brain health or accelerate cognitive decline and otherwise impact our mental well-being."

What's more, Dr. Kaiser says, there's an entire field of study dedicated to food as brain fuel.

"The biological impacts of what we eat on our bodies, and especially our brains, are profound and an area of great interest," he notes. "In fact, the field of nutritional psychiatry is dedicated to understanding such connections—how what we eat might impact our mood, memory, thinking, and overall brain health—and how we can use this knowledge to improve our overall health and well-being."

Related: Maria Shriver on the Importance of a Brain-Healthy Lifestyle and Eating to Fight Dementia

What Makes Certain Foods Better for Brain Health Than Others?

Experts agree that foods that fight inflammation are some of the best for your brain. "Foods like berries, dark leafy greens, and olive oil are rich with anti-oxidant properties which help reduce inflammation," registered dietitian Shannon O’Meara, RD, MS, of Orlando Health, tells us. "The brain is very metabolically active and produces substances that cause inflammation, which is why you want to consume more antioxidant-rich foods."

Dr. Kaiser concurs that antioxidant-rich foods are great for the brain. He also notes that the connection between gut and brain health is impacted by diet, and that it's important to be mindful of what we eat—but not to deprive ourselves, either.

"As I guide patients interested in improving their brain health, we often begin by reviewing their diet, like the foods they typically eat or those they may avoid. This represents one of the most fundamental aspects of coming to understand how our lifestyles might influence our health and well-being and critical information needed to develop a personalized strategy to optimize brain health," he says. "The idea here is not about any fads or diets in what has come to be a traditional sense of the word 'restriction,' typically with the goal of weight loss—but in terms of the totality of what we consume and the influence this may have."

"While we might consider the amount of certain nutrients that might be included in one’s diet, for the most part, the focus is really on foods and food groups overall rather than any one isolated part," he adds. "With this, we can begin to find ways to add on certain brain-nourishing foods that can help maintain a healthy and balanced metabolism, deal with physiologic and 'oxidative' stress, support more resilient brains, and even help us grow new brain cells and connections between those cells 'synaptic connections' for a healthy and high-performing neural network."

Related: 'I'm a Neurologist—This Is the Vegetable I Eat Every Day for Brain Health'

What Foods Are Worst for Brain Health?

O'Meara and Dr. Kaiser agree: Sugary, ultra-processed foods are the worst for brain health.

"Foods I recommend to limit are foods high in saturated fat, sodium and added sugar," O'Meara advises. "Try to limit how much you consume of animal fat, poultry skin, full fat dairy products, and foods with high amounts of added sugar and salt. These foods cause more inflammation in the body and can lead to chronic inflammatory diseases like heart disease and diabetes along with impacting your brain health."

"Mounting evidence points to the harmful effects of ultra-processed foods on cognition and overall brain health," Dr. Kaiser warns. "Within our practice, the Pacific Brain Health Center, we’ve long been encouraging patients to avoid highly processed foods and supporting them in adopting and maintaining healthier diets as a critical component of preventing, or slowing, cognitive decline; with this, recognizing such nutritional changes as a cornerstone of a brain-healthy lifestyle strategy. The evidence supporting the negative impacts of out-processed foods on cognition and brain health builds upon the well-established links between ultra-processed food consumption and increased risk of cardiovascular disease, metabolic syndrome and obesity."

Highly processed and refined foods are often low in fiber, digested quickly and can cause large swings in our blood sugar levels," he adds. "These blood sugar fluctuations, and the broad constellation of physiologic consequences with our body’s response, can increase inflammation and oxidative stress and have many other deleterious effects upon our brain health."

Dr. Kaiser tells us that sugars and sweeteners in highly processed foods are some of the worst ingredients for your brain. "Sugars are Enemy No. 1," Dr. Kaiser says. "Processed 'junk foods' including snacks, cookies, cakes, donuts, candy, pastries and other sweets, can include many ingredients—not the least of which are large quantities of highly refined sugars—that can have immediate and long-term negative impacts on brain health."

Enemy No. 2 per Dr. Kaiser would be trans fats, especially from fast food or other fried foods.

"Studies have demonstrated clear links between trans fats and many diseases, including heart disease and Alzheimer’s disease," he says. "The research on saturated fats is a little more murky but there are clear indications that eating too much saturated fat—especially certain kinds—is associated with poor brain health."

Related: 'I'm a Cleveland Clinic Neuropsychologist—Here's What I Wish Every Woman Knew About Their Risk for Alzheimer's and Dementia'

What Diets Are Best for Brain Health?

When it comes to eating for your brain, O'Meara and Dr. Kaiser are both big fans of the "MIND Diet," and not just for the ultra-clever name. It combines elements of the Mediterranean Diet and the DASH (Dietary Approaches to Stop Hypertension) Diet and stands for "Mediterranean-DASH Intervention for Neurodegenerative Delay." According to Dr. Kaiser, the MIND Diet has been demonstrated to slow brain aging by about 7.5 years and may also reduce one's Alzheimer's risk.

"The MIND Diet recommends eating whole grains, vegetables, green leafy vegetables, nuts, berries, beans, poultry, fish and olive oil and limiting pastries and sweets, red meat, cheese, fried foods, butter and margarine," O'Meara says. "The Mediterranean Diet is also a good diet to follow which include a lot of the foods the MIND Diet recommends."

In terms of how it works: "The MIND Diet appears to benefit the brain by reducing beta-amyloid proteins (a build-up of which is found in the brains of people with Alzheimer’s disease), reduction in oxidative stress and improved sugar regulation and overall metabolic profiles that are supportive of immediate and long-term optimal brain health," Dr. Kaiser says.

One aspect of the MIND Diet that sets it apart from some other common diets is that it doesn't call for a complete nixing of red meat—with Dr. Kaiser pointing out that eliminating red meat can make some miss out on important nutrients like zinc or compensate too much for its lack with refined carbs. Instead, the MIND Diet recommends limiting your red meat (beef, lamb and pork) intake to three weekly servings.

Related: The Best Foods for Memory, According to Brain Health Experts

What Are the Best Foods for Brain Health?

O'Meara and Dr. Kaiser agree that the best foods for brain health are rich in antioxidants and flavonoids, which have been associated with lower Alzheimer's risk.

"These 'phytonutrients'—chemicals that plants produce to keep themselves healthy—can actually reduce inflammation in our brains, protect brain cells from injury, support learning and memory and deliver other obvious benefits for brain health," Dr. Kaiser says. "As far as flavanols, a specific type of flavonoid that are highly protective, apples are on the list; so 'an apple a day' really may keep the doctor away (just add some kale and a handful of blueberries and call me in the morning)."

That said, just some of the best foods for brain health (including from the Mediterranean Diet) include:

  • Almonds

  • Apples

  • Arugula

  • Avocados

  • Black beans

  • Beets

  • Blackberries

  • Blueberries

  • Broccoli

  • Brown rice

  • Canned light tuna

  • Chard

  • Chia seeds

  • Cod

  • Coffee

  • Collard greens

  • Cottage cheese

  • Dark chocolate

  • Eggplant

  • Flax seeds

  • Gouda

  • Grapes

  • Green tea

  • Kale

  • Kefir

  • Kimchi

  • Kombucha

  • Lentils

  • Miso

  • Mussels

  • Oysters

  • Pollack

  • Pumpkin seeds

  • Raspberries

  • Red cabbage

  • Red peppers

  • Salmon

  • Sardines

  • Sauerkraut

  • Seaweed

  • Spinach

  • Strawberries

  • Tomatoes

  • Turmeric

  • Walnuts

  • Whole grain bread

Phew—you have plenty of options! Now get to the grocery store and start meal-prepping for that mind of yours.

Next, Research Says You Can Lower Your Dementia Risk 33% By Doing This One Thing