A study published in the Archives of Latinoamerican Nutrition (2009; 59(3):278–286) examined the relationship between folic acid supplementation and depression in 459 Guatemalan women.
Participants were randomly assigned to one of four groups and followed for three months. Each group received a different weekly dose of folic acid—5 mg, 2.8 mg, 0.4 mg, or 0.2 mg—in combination with iron, zinc, and vitamin B12.
Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression 20-Item Scale (CES-D). At the beginning of the study, the prevalence of depression among participants was 49.3%. Women with the lowest folate levels, measured in red blood cells, had a higher risk of depression compared with women who had the highest folate levels.
