The following was adapted from Dr. Randolph’s 2020 book, “The Brain Health Book: Using the Power of Neuroscience to Improve Your Life.”
In terms of a dietary style with solid scientific evidence related to promoting brain health, nothing comes closer than the Mediterranean diet.
Essentially, the name of this diet references dietary tendencies among people who live in the Mediterranean region (think Italy, Greece, France, Spain, and the Middle East). The diet is mostly plant-based and consists of lots of fruits and vegetables, beans, nuts, and whole grains. Olive oil is emphasized, particularly for cooking. Moderate amounts of fish and poultry are included. A little red wine is generally considered part of the “package,” too.
Foods that are de-emphasized include red meat, high-fat dairy products, and processed items.
Also included in the broader diet are lifestyle choices such as moderate physical activity, social engagement, and adequate daily rest and nightly sleep.
The science connecting Mediterranean diet to brain function
Findings differ slightly across the science, but the majority of research shows a significantly reduced risk of mild cognitive impairment or Alzheimer’s disease—about a 20 to 40 percent reduced risk—in those who consistently eat lots of Mediterranean diet foods like fish, olive oil, fruits, and vegetables.
There also is less risk of converting from mild cognitive impairment to dementia in those who maintain this diet over time, and a lower risk of stroke and depression.
One study a few years ago evaluated the diets of more than 2,000 people to see whether increased adherence to the Mediterranean diet translated into a lower risk of cognitive problems. The subjects were rated on a 0 to 9 scale to determine how well they stuck to the diet. Over the 4-year period, people who were moderately committed to the diet (a score of 4 or 5) had a 20 percent reduced risk of dementia, while those who really adhered to the diet (a score of 6 to 9) had a 40 percent reduced risk.
Notably, the study also found that eating specific foods within the Mediterranean diet—such as fruits, fish, and legumes—was less powerful in reducing one’s risk of dementia than committing to the entire diet.
This suggested that broader dietary patterns seem to matter more than individual foods in ramping up brain health.
Why is the Mediterranean diet good for the brain?
It seems that the Mediterranean diet affects the brain on a number of levels.
On a microscopic, molecular level, the diet is rich in antioxidants and anti-inflammatory components that reduce the negative effects of what is called oxidative stress, or an abundance of toxic free-radical molecules on the brain.
At least one study suggests the diet also may have antithrombotic and antiatherogenic features, which is a fancy way of saying that it reduces the risk of strokes, clogged arteries, and depression.
More brain volume equates to a better working brain.
Studies (such as this and this) note people adhering to the Mediterranean diet have denser brain matter in multiple regions—including in the frontal and temporal lobes—and show reduced shrinkage or atrophy of the brain over time. Less dietary intake of red meat and dairy products and more fish consumption—along the lines of the Mediterranean diet—are associated with higher brain volume.
Finally, a 2015 study indicates people eating the Mediterranean diet also have brain regions showing better structural connectivity, which means the regions are more intimately linked. The saying, “you are what you eat,” really applies here, particularly in terms of the brain.