Studies dating back more than 15 years suggest that people with depression are likely to have low blood levels of folic acid (or folate) and vitamin B12.

Of course, not all of the researchers have come to the same conclusion. But to start, here’s a summary of the most positive analysis of folic acid and B12.

  • Low folate and low vitamin B12 levels are reported in studies of depressed patients.
  • There’s an association between depression and low levels of the two vitamins in studies of the general population.
  • Low folate blood levels are found in patients with recurrent mood disorders treated with lithium.
  • A link between depression and low folate appears in patients with alcoholism.
  • Hong Kong and Taiwan populations follow diets rich in folate and have very low lifetime rates of major depression.
  • Low folate levels are linked to a poor response to antidepressant treatment.
  • Treatment with folic acid improves the response to antidepressants and possibly to better treatment outcomes.

On the basis of these findings, the authors of this article suggest that 800 mcg daily of folic acid and 1 mg daily of vitamin B12 should be tried to improve treatment outcomes in depression.

The Cochrane Collaboration reached a more reserved conclusion. “The limited available evidence suggests folate may have a potential role as a supplement to other treatment for depression. It is currently unclear if this is the case both for people with normal folate levels, and for those with folate deficiency.”

For more information, check out for a comprehensive listing of abstracts on depression, vitamin B12, and folic acid published since 1989.

Dietary sources of folic acid and vitamin B12 are listed here and here.


11/12/06 09:37 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.