Impact of folic acid fortification on women's nutritional status and on the prevalence of neural tube defects

Abstract

In 2003 iron and folic acid fortification of wheat flour became mandatory in Argentina. Folate nutritional status was assessed in a national probabilistic sample of women 10-49 years old and pregnant women. Changes in the prevalence of neural tube defects (NTDs) were evaluated before and after fortification. Data from the National Nutritional and Health Survey done in 2005 were used for folate intakes (24 hs dietary recall) and serum levels. Fetal and infant mortality rates for NTDs were assessed in the period 2000-2006 from Vital Statistics Series, based on birth and death certificates. Prevalence of NTDs in hospital discharge statistics were analyzed in the pre and post fortification period. Median folate intakes were 532 and 821 microg/ day in women 10-49 years-old and pregnant women, respectively. In both groups, folic acid from wheat flour represented 245 and 331 microg/day. Serum folate was assessed in 5.322 women 10-49 years old and in 1.321 pregnant women. Prevalence of serum folate concentration <3 ng/mL was 0.8% in women of child-bearing age and 2.7% in pregnant women. Mortality rate due to anencephaly in 2000-2003 was 53.1 per 100.000 births and decreased to 23.3 per 100.000 births in 2005-2006. Spina bifida mortality rate decreased 67% in the same period. In a similar way, hospital discharge statistics showed a decrease of 54% for anencephaly, 33% for encephalocele, and 45% for spina bifida between 2000 and 2005. Food fortification with folic acid was associated with adequate intakes and serum folate levels in women. Concurrently, NTDs prevalence and mortality showed a significant reduction.