Vitamin B-6 level is associated with symptoms of depression

Background: A low level of vitamin B-6 might theoretically cause depression as vitamin B-6 is a cofactor in the tryptophan-serotonin pathway. In the present study, we examined the association between depression and the phosphate derivative of vitamin B-6 in plasma, pyridoxal phosphate (PLP). Methods: In 140 individuals, symptoms of depression were evaluated by the Major Depression Inventory, and biochemical markers of vitamin B deficiency were measured. Results: We found that 18 (13%) individuals were depressed. A low plasma level of PLP was significantly associated with the depression score (p = 0.002). No significant association was found between depression and plasma vitamin B-12 (p = 0.13), plasma methylmalonic acid (p = 0.67), erythrocyte folate (p = 0.77), and plasma total homocysteine (p = 0.16). Conclusion: Our study suggests that a low level of plasma PLP is associated with symptoms of depression. Randomized trials are now justified and needed in order to examine whether treatment with vitamin B-6 may improve symptoms of depression. Copyright (C) 2004 S. Karger AG, Basel.