Does Folic Acid Supplementation Benefit Adults with Depression?

The association between nutrition and mental health has been known for over 50 years. Indeed, in 1967 a report published findings showing a correlation between mental illness and folate deficiency. Since that time several reports have found low folate levels in the patients with major depression. Folate deficiency has been found in approximately 30% of patients with depression, 24% of patients with organic psychosis, and 20% of patients with schizophrenia.

The effectiveness of antidepressant medications has also been shown to be influenced by initial folate levels. Treatment is less effective in individuals who start therapy with folate deficiency and supplementation with folate appears to increase antidepressant medication therapy.

Folate is a critical vitamin in numerous biological processes. In particular its function, along with vitamin B12, in the regulation of the conversion of homocysteine to methionine via the methionine synthase catalyzed reaction. This reaction is a component of what is referred to as the methionine cycle. Methionine is utilized in the synthesis of S-adenosylmethionine (SAM or AdoMet), the methyl donor in the synthesis of membrane lipids critical to nerve cell functions. In addition, SAM is required for the synthesis of several neurotransmitters including serotonin, dopamine, and norepinephrine. Details of the role of the folate and B12 in the methionine cycle and the many roles of SAM can be found in the Amino Acid Biosynthesis and Catabolism page of my website.

A recent study published in the journal, Nutrition and Food Science, utilized a meta-analysis of several studies, all of which were random controlled trials (RCT), to examine the efficacy of folic acid in treating depression:

The effects of folic acid supplementation on depression in adults: a systematic review and meta-analysis of randomized controlled trials

The studies examined in this meta analysis encompassed varying times of intervention from 6 to 24 weeks, and the dosages of folic acid supplementation were between 0.5 mg and 10 mg. The various studies included participants with major depression or with an eating disorder. All of the studies enrolled both sexes. Three studies used folic acid and fluoxetine, one study used folic acid and sertraline, one study used folic acid and citalopram, and one study used folic acid alone.

TAKE AWAY: The results of this meta analysis found that folic acid supplementation did indeed correlate to positive changes in depression test scores. In addition, it was found that folic acid supplementation was associated with a reduction in length of depressive episodes and length of hospital.