Folate for depression
A B vitamin found in leafy green vegetables, citrus fruits, and beans may be useful in the treatment of depression and other psychiatric symptoms. Folate or folic acid, also known as vitamin B9, is already known to be important for health. Pregnant women need a certain amount to prevent miscarriage and birth defects, and although there is no proof, some think that it provides protection against heart disease, stroke, and certain cancers. Since 1998, the FDA has required the addition of folate to enriched flour and other grain products. The recommended dose is 400 mcg (0.4 mg) a day — 600 mcg for pregnant women. Older people may also need higher doses because they don't absorb folate well.
The evidence for a link between depression and folate levels comes from various sources.