Yates A A
Food and Nutrition Board, Institute of Medicine, The National Academies, Washington, DC 20418, USA.
J Nutr. 2001 Apr;131(4 Suppl):1331S-4S. doi: 10.1093/jn/131.4.1331S.
Dietary reference intakes (DRI), like its predecessor, the recommended dietary allowances (RDA) and the Recommended Nutrient Intakes (RNIs), are reference values, based on the best scientific evidence available. They serve as reference amounts of specific nutrients and food components for use in assessing the adequacy of and in planning for nutritious diets. They have been used for over 50 y as the basis for national nutrition monitoring and intervention programs in the United States, Canada, and other countries and as the basis for dietary guidance developed for both individuals and for targeted groups of people. Thus, although not developed for specific policy applications, they have represented the best scientific perspectives regarding what should be the basis for nutrition and public health policy related to foods and supplements. In determining DRIs, as was the case with the RDA, significant attention must be paid to the form of the nutrient or food component that is evaluated. Research conducted to determine how much of a nutrient is needed must evaluate the chemical form provided, the matrix in which it is given and the effect of other food components on absorption and/or utilization. Because the DRI recommendations will be used in population-wide policy development, assumptions must be made explicitly about what is expected for all of these factors in a typical diet. At the same time, where data exist relative to nontypical but potentially very significant effects on bioavailability, these must also be delineated to be of use in a variety of settings. Finally, one of the most important aspects of determining bioavailability in developing reference intakes is that as new information emerges, new complexities enter into the process. As more chemical complexes of nutrients and food components become available in the marketplace, new bioavailability factors may need to be established. Examples of such changes exist in the DRI reports already published for vitamin B-12 and folate and in previous RDA for iron and protein. It is often the different assumptions related to bioavailability that alter the reference intakes used as the basis for public health policy in different countries, rather than the basic science from which the recommendation is derived.
膳食参考摄入量（DRI）与其前身推荐膳食摄入量（RDA）和推荐营养素摄入量（RNI）一样，都是基于现有最佳科学证据的参考值。它们作为特定营养素和食物成分的参考量，用于评估营养饮食的充足性以及规划营养饮食。在美国、加拿大和其他国家，它们已被用作国家营养监测和干预计划的基础达50多年之久，也是为个人和特定人群制定膳食指南的基础。因此，尽管它们并非为特定政策应用而制定，但它们代表了关于食品和补充剂营养及公共卫生政策应以何为基础的最佳科学观点。在确定DRI时，与RDA情况一样，必须高度关注所评估的营养素或食物成分的形式。为确定所需营养素量而进行的研究必须评估所提供的化学形式、给予该营养素的基质以及其他食物成分对吸收和/或利用的影响。由于DRI建议将用于全人群的政策制定，因此必须明确就典型饮食中所有这些因素的预期情况做出假设。同时，对于生物利用度存在非典型但可能非常显著影响的数据，也必须加以描述，以便在各种情况下使用。最后，在制定参考摄入量时确定生物利用度的最重要方面之一是，随着新信息的出现，新的复杂情况会进入这一过程。随着市场上出现更多营养素和食物成分的化学复合物，可能需要建立新的生物利用度因子。此类变化的例子已见于已发布的维生素B-12和叶酸的DRI报告以及先前铁和蛋白质的RDA中。往往是与生物利用度相关的不同假设改变了不同国家用作公共卫生政策基础的参考摄入量，而非推导该建议的基础科学。
