Estimates of the effects of folic-acid fortification and folic-acid bioavailability for women

OBJECTIVE: With the recent implementation of the folic-acid-fortification p rogram, our objective was to estimate its benefits in adult women and accou nt for the higher bioavailability of synthetic folic acid in fortification programs and supplements. METHODS: The study used a cross-sectional design. Dietary assessment data w ere collected with a quantitative food-frequency questionnaire, the Nutriti on DISCovery program. Fortification was simulated with the use of fortifica tion standards (140 mug/100 g of flour) and new bioavailability standards f or synthetic folic acid. Data were collected from 289 women 18 to 89 y old. Subjects were recruited from participants in two health-screening events i n autumn of 1997. Chi-square tests were used to estimate the differences be tween categoric. variables, and F tests were used in analysis of variance f or continuous outcome measures. Results were considered significant at P < 0.05. RESULTS: Estimated mean dietary intake of folate increased considerably wit h simulation of fortification (320 to 608 <mu>g of dietary folate equivalen ts). Women in the lower quartiles for age (18 to 39 and 40 to 46 y) consume d more servings from the bread group than women did in the upper quartile ( 55 to 89 y). Thus, the improvement in folate intake with fortification was significantly greater for the younger than for the older women (P < 0.05). Despite the limitations of estimating folate intakes, these data suggest th at most women met the new estimated average requirement. However, 61% of wo men of childbearing age had intakes of synthetic folic acid below the recom mended level of 400 <mu>g/d, and only those using supplements containing fo lic, acid met the guideline. CONCLUSIONS: Based on this sample of well-educated, adult women, the curren t level of folic-acid fortification should improve the intakes of a large p roportion of women, especially when accompanied by supplements containing f olic acid. These improvements in folate intake might not be seen in groups with limited resources, however. Further, under existing standards and prac tices, many women will not meet current recommendations for prevention of n eural-tube defects. Nittrition 2001;17-873-879.(C) Elsevier Science Inc. 20 01.