Follow the recommendations for whole foods nutrition here on this site, including the avoidance of sugar, gluten, and dairy. Be sure you are eating regularly throughout the day (with protein every few hours for focus/attention), and drinking plenty of water to rid your body of toxins as well. Additionally, making sure you are getting adequate sleep and you have relievers of stress in place to help keep the mind calm and focused on the present moment. – Coach Zoe

I started reading a book called Brain Fog  by Mike Dow, it might help you.