FOLACIN ANALYSIS AND BIOAVAILABILITY

1968年，国家食品和营养委员会（FNB） 研究理事会（NRC）制定了一个推荐的膳食 叶酸的允许量（RDA）为400微克/天， 增加400微克/天的额外津贴， 怀孕和哺乳的需要。 这一水平保留在 1980年修订RDA。 只有25%的叶酸 美国 食物通常是有营养的。 美国人的平均饮食提供大约230 微克叶酸，大约是 RDA。 鉴于上述信息广泛的叶酸 美国人口的不足是可以预料的。 这 然而，缺陷没有得到详细的证实， 对国家营养与健康的深思熟虑的审查 考试调查（NHANES II）数据显示，只有6%的人 或更少的人血液叶酸水平 认为低。 虽然RDA是基于全面、深入的审查， 根据现有的科学证据，现在很清楚，FNB是 由于缺乏足够的资源， 测定食物中叶酸含量、叶酸摄入量和叶酸 生物利用度和相关的这些测量叶酸含量 食物，叶酸摄入量和叶酸生物利用度， 将这些测量结果与临床和/或 叶酸状况的流行病学评估。 这些不足 主要是因为新开发的分析技术， 合成和结构化学尚未应用于 获得基本成分、生物利用度和 这种维生素的营养状况数据。 参考和 叶酸标准测定仍然是微生物测定| 该提案旨在开发，验证和应用新的物理- 液相色谱化学技术 质谱和稳定同位素的上述任务。 的 这些研究的信息将提供可靠的组成 美国食品的数据，并将评估营养生物利用度 这种重要的维生素在人体中的作用。 各种食品 将使用同位素稀释质量分析项目中的叶酸 准确定量单个叶酸的IDMS 每种食物的同源物概况。 曾经可靠的分析方法 生物利用度将在动物模型中进行测量 - 老鼠-建立模型的有效性。 经验证的模型将 然后在随后的提案中应用于人体。

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.