There's not enough scientific evidence to prove that vitamins help treat brain fog, as of 2015; however, some doctors and patients claim B vitamins help with cognitive function, states About.com. Other supplements that people find helpful in treating brain fog include carnitine, choline, omega 3 and St. John's wort.
Doctors may also suggest that patients add brain-friendly foods to their diets, such as walnut or canola oil, fish, eggs, fruits and vegetables. Some research suggests that moderate exercise also helps support cognitive function, says About.com. For others, treating pain or sleep disorders remedies brain fog. Cognitive training is treatment that is under investigation for treating brain fog.