FOLACIN ANALYSIS AND BIOAVAILABILITY

1968年，国家食品和营养委员会(FNB) 研究委员会(NRC)制定了一项推荐饮食 成人叶酸摄入量(RDA)为400微克/天 增加的额外津贴为400微克/天 怀孕和哺乳的需要。这一水平在 1980年修订的RDA。只有25%的普通叶酸 美国食品通常被认为是有营养的。 美国人的平均饮食提供了大约230 每天微克的叶酸，大约是 区域发展局。鉴于上述信息，叶酸广泛存在 美国人口不足是意料之中的事。这 然而，缺陷并没有通过详细的和 对《国民营养与健康》的反思 考试调查(NHANES II)数据显示，只有6% 或更少的人的血液叶酸水平是 被认为很低。 尽管区域发展目标是基于全面、深入的审查 在现有的科学证据中，现在很明显FNB是 由于以下方面的不足而阻碍了其区域发展区的发展 测量食物中的叶酸含量、叶酸摄入量和叶酸 生物利用度及其与叶酸含量的相关性 食物、叶酸摄入量和叶酸的生物利用度 将这些测量与临床和/或 叶酸状况的流行病学评估。这些不足之处 这在很大程度上是因为新开发的分析技术， 合成和结构化学还没有被应用于 获得基本成分、生物利用度和 这种维生素的营养状况数据。参考文献和 叶酸的标准测定仍是微生物测定| 这项建议旨在开发、验证和应用新的物理- 与高效液相联用的化学技术 质谱学和稳定同位素的上述任务。这个 来自这些研究的信息将提供可靠的成分 美国食品数据，并将评估营养生物利用度 这种重要的维生素在人体内的含量。各种各样的食物 将使用同位素稀释质量对物品进行叶酸分析 光谱分析(IDMS)准确测定个体叶酸 每种食物的同系物特征。曾经可靠的分析方法 是完美的，生物利用度将在动物模型中测量 -RAT-建立模型的有效性。经过验证的模型将 然后在随后的提案中应用于人类受试者。

In 1968 the Food and Nutrition Board (FNB) of the National Research Council (NRC) established a recommended dietary allowance (RDA) for folacin of 400 microgram/day for adults with an additional allowance of 400 microgram/day for the increased needs of pregnancy and lactation. This level was retained in the 1980 revision of the RDA. Only 25% of the folacin in common U.S. foods is generally throught to be nutritiionally available. The average American diet provides approximately 230 microgram of folacin per day which is approximately one half of the RDA. Given the above information widespread folacin deficiency in the American population would be expected. This deficiency, however, was not confirmed by a detailed and thoughtful review of the National Nutrition and Health Examination Survey (NHANES II) data which showed that only 6% or less of the population had blood folacin levels that were considered low. Although the RDAs are based on a comprehensive, in depth review of available scientific evidence, it is now clear that the FNB was handicapped in developing its RDAs because of inadequacies in measuring folacin content of foods, folacin intake, and folacin bioavailability and in correlating these measuring folacin content of foods, folacin intake, and folacin bioavailability and in correlating these measurements with clinical and/or epidemiologic evaluations of folacin status. These inadequacies persist largely because newly developed techniques of analytical, synthetic and structural chemistry have not been applied to the acquisition of fundamental compositional, bioavailability and nutritional status data for this vitamin. The reference and standard assay for folacin is still a microbiological assay| This proposal seeks to develop, validate and apply novel physico- chemical techniques of liquid chromatography in conjunction with mass spectrometry and stable isotopes to the above task. The information from these studies will provide reliable compositional data on America foods and will assess nutritional bioavailability of this important vitamin in human subjects. A variety of food items will be analyzed for folacin using isotope dilution mass spectrometry (IDMS) to accurately quantitfy individual folacin congener profiles for each food. Once reliable analytical methods are perfected, bioavailability will be measured in an animal model - rat - to establish the model's validity. The validated model will then be applied in human subjects in a subsequent proposal.