Folate, vitamin B12 and homocysteine status in women of childbearing age: baseline data of folic acid wheat flour fortification in Iran.

BACKGROUND: Folic acid fortification implemented mandatorily in many countries has been associated with significant increase in blood folate concentrations and reduction in the prevalence of neural tube defects. However, there are controversial findings on the probability of vitamin B(12) deficiency being masked in the population after folic acid fortification. Baseline data on folate and vitamin B(12) status are necessary before mandatory flour fortification is implemented.

OBJECTIVES: To assess dietary intake of folate and vitamin B(12) and to determine blood concentrations of folate, vitamin B(12) and homocysteine in women of childbearing age as baseline data regarding folic acid fortification in Iran.

METHODS: A descriptive cross-sectional survey was performed with 579 healthy women as a representative sample of the Golestan province. Fasting blood samples were taken and dietary (24-hour recall), health and sociodemographic data were collected with an interview. Serum concentrations of folate and vitamin B(12) were measured with radioimmunoassay, and plasma homocysteine concentrations were assessed by high-performance liquid chromatography with fluorescence detection.

RESULTS: Mean serum concentrations of folate and vitamin B(12) were 13.6 nmol/l (95% CI 12.8-14.4) and 194.4 pmol/l (95% CI 183.8-205.0), respectively. Inadequate serum folate levels were present in 14.3% of the women and 22.7% had serum vitamin B(12) levels below normal. Mean plasma homocysteine concentration was 12.6 micromol/l (95% CI 12.1-13.2) and hyperhomocysteinemia was observed in 38.3% of the women. Mean daily intake of folate and vitamin B(12) was 198.3 microg (95% CI 185.4-211.3) and 2.6 microg (95% CI 1.9-3.2), respectively. Folate intake from food was positively correlated with serum folate concentrations (r = 0.084, p < 0.05) and inversely correlated with plasma homocysteine concentrations (r = -0.115, p < 0.01).

CONCLUSIONS: An insufficient vitamin B(12) as well as folate status is present in Iranian women of childbearing age. The final evaluation will be carried out 18 months after flour fortification and the results will be compared with baseline data obtained from the present study in order to show the efficacy and safety of folic acid fortification in Iran.