"Be Sure to Take Folic Acid," the Good Doctor Said

The neurologist said if you take nothing else, be sure to take folic acid. Why folic acid? Is it good for the brain, or just good for you in general? Folic acid helps cells with their chemical processes. It forms and grows red blood cells. Lack of folic acid can cause serious and lethal health problems. But the question remains: what does folic acid have to do with the brain?