Objective: The purpose of this study was to investigate folate status in healthy, nonpregnant women (18 to 45 years) following folic acid (FA) fortification of the food supply.
Design: This was a cross-sectional study design in which a fasting blood sample was obtained from socio-economically advantaged (n=85) and disadvantaged (n=50) women residing in Southern California who had not consumed supplemental FA within the past 12 months. Serum folate (SF), red cell folate (RCF) and plasma homocysteine (tHcy) concentrations were measured and methylene tetrahydrofolate reductase (MTHFR) genotype (C677T) was determined.
Results: SF and RCF concentrations (mean+/-SD) for socio-economically advantaged (54+/-18, 1387+/-329 nmol/L, respectively) and disadvantaged women (41+/-18, 1172+/-342 nmol/L, respectively) greatly exceeded the levels deemed acceptable for SF (> or = 13.6 nmol/L) and RCF (> or = 362 nmol/L). Moreover, 95% of socio-economically advantaged women and 78% of disadvantaged women achieved RCF concentrations > or = 906 nmol/L, which are associated with very low risk of neural tube defects (NTD). Plasma tHcy concentrations for both socio-economically advantaged (5.2+/-1.6 micromol/L) and disadvantaged women (6.1+/-1.6 micromol/L) were within the lower limit of normal range and indicative of adequate folate status. For the combined groups (n=135), the frequency of the C/C, C/T and T/T genotype was 56.0, 37.3 and 6.7%, respectively. MTHFR genotype was not associated with SF, RCF or tHcy.
Conclusions: These data suggest that women of childbearing age are achieving positive folate balance and RCF concentrations associated with reduced risk of NTD following FA fortification of the food supply.