BLOG

The relationship between diet and brain health is complex, with many different factors at play. While it is known that dietary choices have a major impact on the brain, scientists are still trying to figure out which combinations of foods specifically play a role in optimizing brain functioning and overall health. Some research supports the notion that certain dietary patterns can positively impact mental health while other diets may have the opposite effect. For example, diets with high levels of fruits, vegetables and fish may help to decrease the risk of depression and may also reduce anxiety risk. Conversely, eating a diet high in fat and refined carbohydrates may increase the risk of both disorders. Not only can dietary choices have an impact on mental health disorders, but they can also have an effect on how well the brain functions.

“The study analyzed 182,000 participants and found that those who followed a balanced diet were more likely to have improved cognitive functioning and better mental health.”

A recent study published in Nature Mental Health in April of this year looked more closely at how different dietary patterns affect specific areas of brain health such as mental health, cognitive function, metabolic biomarkers, and brain structure as measured by a brain imaging technique call magnetic resonance imaging or MRI. The investigators analyzed 182,000 participants and found that those who followed a balanced diet were more likely to have improved cognitive functioning and better mental health. It is important to note that they did find specific genetic differences which had an impact among different dietary groups. The researchers focused on four main dietary patterns by looking at participants’ food preferences:

1. Starch-free or reduced starch — this group preferred fruits, vegetables, and protein but showed a lower preference for starchy foods like bread or pasta
2. Vegetarian — this group preferred fruits and vegetables but showed a lower protein preference
3. High-protein and low-fiber — this group preferred snacks and protein foods and had a lower preference for fruits and vegetables
4. Balanced diet — this group showed similar preferences in all food groups.

The researchers then looked at the association between these dietary preferences and different brain-related outcomes such as mental health which encompasses anxiety, depressive symptoms, mania symptoms, psychotic experience, trauma, self-harm and well-being. They also further evaluated cognitive function through several tests, looked at blood biochemistry and metabolic biomarkers, and examined brain structure via MRI.

“…the balanced diet benefited the most out of all four diet subtypes and the participants received lower scores for mental health measurements and higher scores for well-being.”

Lastly, the researchers looked at polygenic risk scores for mental disorders which measure how genetics factor into risk for mental illness and did a gene enrichment analysis. The study found that the balanced diet benefited the most out of all four diet subtypes and the participants received lower scores for compromised mental health measurements and higher scores for well-being. This group also had the best-measured reaction time, while the high-protein, low-fiber diet group scored the best on a cognition test involving symbol substitution. Participants following the balanced diet and vegetarian diet had higher levels of gray matter in certain areas of the brain compared to the high-protein, low-fiber group. Conversely, the vegetarian group had a higher genetic risk for Alzheimer’s disease, bipolar disorder, schizophrenia, and several other mental disorders. The high-protein and low-fiber group had a higher genetic risk for ischemic stroke.

As with any study, this one has a few limitations that are worth noting in order to conduct improved research in the future. The cohort was comprised of older individuals between the ages of 53-87 with an average age of 71 years old. These individuals were recruited over 20 years ago which at the time represented an accurate pool of the ethnic makeup in the UK, but may not be quite as representative of today’s population. While this still allows for valuable findings, future research could focus on younger participants who accurately match the current demographic.

“Not only can incorporating more of these healthy foods into your diet improve brain health, but it is also a great way to boost overall health and well-being.”

Overall, eating a balanced diet with an emphasis on fresh and nutritious foods continues to be the common theme amongst brain health research. Some foods to focus on when trying to optimize brain health include dark leafy greens that provide healthy nutrients such as vitamin K, lutein, folate and beta carotene which may slow cognitive decline. Fatty fish are also rich in omega-3 fatty acids, healthy unsaturated fats that have been linked to lower blood levels of beta-amyloid—the protein that forms damaging clumps in the brains of people with Alzheimer’s disease. Berries contain high levels of flavonoids, the natural plant pigments that give berries their brilliant hues, also help improve memory, high quality research shows. A study done by researchers at Harvard’s Brigham and Women’s Hospital found that women who consumed two or more servings of strawberries and blueberries each week delayed memory decline by up to two-and-a-half years. Adding nuts to your diet is a great source of protein and healthy fats. Walnuts in particular are high in a type of omega-3 fatty acid called alpha-linolenic acid (ALA) which has been linked to lower blood pressure and cleaner arteries which is good for both the heart and the brain. A study from UCLA actually linked higher walnut consumption to improved cognitive test scores. Not only can incorporating more of these healthy foods into your diet improve brain health, but it is also a great way to boost overall health and well-being. Considering all the body’s systems are closely interconnected, doing good for one part will likely benefit the whole body.