Flour fortification with folic acid is one of the main strategies for improving folate status in women of childbearing age. No interventional trial on the efficacy of folic acid fortification has been conducted so far in Iran. Objectives: To study the effects of flour fortification with folic acid on any reduction in neural tube defects (NTDs) and folate status of women of childbearing age. Methods: In a longitudinal hospital-based study, 13,361 postpartum women were studied after admission for

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... childbirth before and after fortification. In addition, two cross-sectional surveys were conducted before (2006) and after flour fortification (2008). The cluster sampling method was used and 580 women, 15-49 years old, were studied as a representative sample of Golestan province in the north of Iran. Fasting blood samples were collected to measure serum vitamin B 12, folate and plasma homocysteine. Sociodemographic data, health characteristics and dietary intake were determined. Results: The mean daily intakes of folate from natural food before and after flour fortification were 198.3 and 200.8 μg/day, respectively. The total folate intake increased significantly from 198.3 to 413.7 μg/day after fortification (p < 0.001). Folate intake increased by an average of 226 μg/day from fortified bread. The mean serum folate level increased from 13.6 to 18.