Boushey C J, Edmonds J W, Welshimer K J
Department of Foods and Nutrition, Purdue University, 1264 Stone Hall, West Lafayette, IN 47907-1264, USA.
Nutrition. 2001 Oct;17(10):873-9. doi: 10.1016/s0899-9007(01)00645-1.
With the recent implementation of the folic-acid-fortification program, our objective was to estimate its benefits in adult women and account for the higher bioavailability of synthetic folic acid in fortification programs and supplements.
The study used a cross-sectional design. Dietary assessment data were collected with a quantitative food-frequency questionnaire, the Nutrition DISCovery program. Fortification was simulated with the use of fortification standards (140 microg/100 g of flour) and new bioavailability standards for synthetic folic acid. Data were collected from 289 women 18 to 89 y old. Subjects were recruited from participants in two health-screening events in autumn of 1997. Chi-square tests were used to estimate the differences between categoric variables, and F tests were used in analysis of variance for continuous outcome measures. Results were considered significant at P < 0.05.
Estimated mean dietary intake of folate increased considerably with simulation of fortification (320 to 608 microg of dietary folate equivalents). Women in the lower quartiles for age (18 to 39 and 40 to 46 y) consumed 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 that most women met the new estimated average requirement. However, 61% of women of childbearing age had intakes of synthetic folic acid below the recommended level of 400 microg/d, and only those using supplements containing folic acid met the guideline.
Based on this sample of well-educated, adult women, the current level of folic-acid fortification should improve the intakes of a large proportion of women, especially when accompanied by supplements containing folic acid. These improvements in folate intake might not be seen in groups with limited resources, however. Further, under existing standards and practices, many women will not meet current recommendations for prevention of neural-tube defects.
随着近期叶酸强化计划的实施，我们的目的是评估其对成年女性的益处，并考虑强化计划和补充剂中合成叶酸更高的生物利用度。
本研究采用横断面设计。通过定量食物频率问卷“营养发现计划”收集膳食评估数据。使用强化标准（140微克/100克面粉）和合成叶酸的新生物利用度标准模拟强化情况。数据收集自289名18至89岁的女性。研究对象从1997年秋季两次健康筛查活动的参与者中招募。卡方检验用于估计分类变量之间的差异，F检验用于连续结局指标的方差分析。P<0.05时结果被认为具有显著性。
随着强化情况的模拟，叶酸的估计平均膳食摄入量显著增加（膳食叶酸当量从320微克增至608微克）。年龄处于较低四分位数（18至39岁和40至46岁）的女性比年龄处于较高四分位数（55至89岁）的女性食用面包组食物的份数更多。因此，强化后叶酸摄入量的改善在年轻女性中比老年女性显著更大（P<0.05）。尽管在估计叶酸摄入量方面存在局限性，但这些数据表明大多数女性达到了新的估计平均需求量。然而，61%的育龄女性合成叶酸摄入量低于推荐水平400微克/天，只有服用含叶酸补充剂的女性达到了该指南标准。
基于这个受过良好教育的成年女性样本，当前的叶酸强化水平应能提高很大一部分女性的摄入量，尤其是在同时服用含叶酸补充剂的情况下。然而，在资源有限的群体中可能看不到叶酸摄入量的这些改善。此外，按照现有标准和做法，许多女性将无法达到预防神经管缺陷的当前建议水平。
