Since January 2000 the Chilean Ministry of Health has required the fortification of wheat flour with folic acid (FA) at a concentration of 2.2 mg FA/kg in order to reduce the risk of neural tube defects (NTD) in newborns. This policy was expected to result in a mean additional intake of approximately 400 microg FA/d. We assessed the effectiveness of the FA flour fortification program on bread folate content and on blood folate concentration in women of childbearing age in Santiago, Chile. The prefortification folate status of 751 healthy women of reproductive age was assessed. The folate content of 100 bread samples bought at retail bakeries was measured, average wheat flour consumption was estimated and postfortification FA dietary intake was calculated. The effect of flour fortification on blood folate concentration in this group of women (n = 605) was evaluated in a follow-up study. Blood folate concentrations of the 605 women in the follow-up group increased (P < 0.0001) following fortification. Before fortification the mean serum and red blood cell folate concentrations were 9.7 +/- 4.3 and 290 +/- 102 nmol/L, respectively, compared with 37.2 +/- 9.5 and 707 +/- 179 nmol/L postfortification, respectively. The mean FA content of bread was 2020 +/- 940 micro g/kg. The median FA intake of the group evaluated postfortification was 427 microg/d (95% CI 409-445) based on an estimated intake of 219 g/d (95% CI 201-229) of wheat flour, mainly as bread. Fortification of wheat flour substantially improved folate status in a population of women of reproductive age in Chile. The effect of the FA fortification program on the occurrence of NTD is currently being assessed.
