The Role of Folate-supplementation in Depression: A Narrative Review

Background: There is a relationship between the etiology and management of clinical depression and vitamin deficiencies. Aim: To review the effect of dietary folic acid supplementation on cause, severity and treatment of depression. Methods: A narrative review of empirical and theoretical literature on the effect of folic acid supplementation on the severity and treatment outcomes of depression. Results: Many enzymes and neurotransmitters depend on folic acid for optimal functions. The monoamine hypothesis of depression confirms the depletion of serotonin, dopamine, and norepinephrine. The systemic level of methyl folate is dependent upon the enzyme methylenetetrahydrofolate reductase [MTHFR], which is encoded by a polymorphic gene [C677T-MTHFR], as well as being dependent on dietary folic acid intake. However, folate has procarcinogenic properties because its coenzymes are involved in de novo purine and thymine nucleotide biosynthesis. Besides, folate deficiency in normal tissues may also predispose to neoplastic transformation, while folate supplementation may suppress the development of tumors in normal tissues. Epidemiological studies revealed that low folate status is associated with depression; especially in terms of severity and the outcome of antidepressant use. Conclusion: The role of folic acid in the etiology and the management of depression cannot be overemphasized. Folate supplementation has been yielding positive results in the management of depression.