Efficacy of flour fortification with folic acid in women of childbearing age in Iran.

BACKGROUND 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 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 18.1 nmol/l; folate deficiency decreased from 14.3 to 2.3% (p < 0.001). The incidence rate of NTDs declined by 31% (p < 0.01) in the post-fortification period (2.19 per 1,000 births; December 2007 to December 2008) compared to the pre-fortification period (3.16 per 1,000 births; September 2006 to July 2007). CONCLUSIONS Implementation of mandatory flour fortification with folic acid can lead to a significant increase in serum folate and a significant decrease in NTDs.