Improved brain function

Please tell me when you are on a diet, what foods should you include in your diet just to improve your brain function?

Many gastroenterologists say that foods rich in polyphenols, such as extra virgin olive oil, are healthy, and that polyphenols provide many health benefits, including supporting cardiovascular health, brain health, weight control, and reducing inflammation. I also came across a service where there is information about the Health Benefits of Olive Oil and Plant Polyphenols, I emphasized a lot for myself and will work on my nutrition even more.