Motherisk alert: Folic acid fortification of flour--three years later

Fortification of flour with folic acid aims to prevent neural tube defects. In Canada, flour fortification began in 1997. The objective of this study was to quantify the changes in women's erythrocyte folic acid levels. Comparing these levels among normocytic women revealed an almost twofold increase (from 517+/-215 nmol/L in 1995 to 901+/-318 nmol/L in 1998) (P<0.00001). While the mean value increased substantially, even now, women at the low range of measured values (367 nmol/L) confer a relative risk of 3.2 for neural tube defects. For these women, higher intake of nutritional folic acid and perinatal supplementation of folic acid tablets continue to be crucial.