PPT《社区营养Community Nutrition》

2000 RDA的制定依据Defining basis of RDA 营养生理需要量(Nutritional Requirement) 有时也称为 生理需要量 . 是制定RDA和RNI的基础;

是机体维持 适宜营养状况 ,和良好的健康状态,在一定时期内必须平均每天吸收该营养素的最低量.各国对维持 适宜营养状况 的理解不同 To allow for individual differences, the RDA usually is set with a generous margin of safety. Thus, they are thought to meet the needs of 95to 97percent of the people within each age-sex group. 安全率是包括人群中个体差、应激等特殊情况下需要量的波动、食物的消化率、烹调损失以及各种食物因素和营养素之间的相互影响等,还兼顾社会条件和经济条件等问题.能量一般不主张考虑安全率.An exception is the RDA for energy, or calories RDA的制定―安全率(safety coefficient) RDA是以每天为基础表达的,但实际上不一定需要每天的膳食都要求所有的营养素达到RDA的量.大多数营养素的摄入量可以三天平均,有的如维生素A、维生素B12则可以几个月平均.RDA do not take account of special needs certain individuals may have due to genetic make up , metabolic disorders, chronic infections, and other abnormalities 关于 RDA……..

二、膳食营养素参考摄入量(DRIs) DRIs consist of the following four values:估计平均需求量 (estimated average requirement, EAR)推荐摄入量 (recommended nutrient intakes, RNI)适宜摄入量 (adequate intake, AI)可耐受的高限摄入水平 (tolerable upper intake level, UL) 世界各国的DRIs 1941年第一个RDA(军队).1989年颁布了第10版RDA.DRIs包括RDA、AT、UL. 膳食参考值(Dietary Reference Values, DRVs)包括:估计平均需要量(EAR)营养素参考摄入量(RNI)低营养素参考摄入量(LRNI) 平均需要量(Average Requirement,AR) 人群参考摄入量(Population Reference Intake,PRI)最低限摄入量(Lowest Threshold Intake,LTI) 美国 英国 欧共体 中国膳食营养素参考摄入量(Chinese dietary recommended intakes, Chinese DRIs) 1998年,中国营养学会(Chinese Society of Nutrition)成立专家委员会下设5个工作组:①energy and macronutrients workshop;

②macro elements workshop;

③microelement workshop;

④vitamins workshop;

⑤other dietary components workshop.2000年10月出版了《中国居民膳食营养素参考摄入量― Chinese DRIs》. 该书共分十章. 理化性质(physico-chemical property) 代谢(metabolism) 功能(functions) 营养状况评价(assessments of nutritional status) 食物来源(food resources) 《中国居民膳食营养素参考摄入量 ― Chinese DRIs》 Estimated Average Requirement, EAR: The average daily nutrient intake level estimated to meet the requirement of half of the healthy individuals in a particular life stage or gender group. 估计平均需求量 (EAR) 系指某一特定性别、年龄及生理状况群体对某营养素需要量的平均值,是制定RNI的基础. DRIs 的组成--EAR EAR的制定意义 评估群体中摄入不足的发生率.可以检查个体摄入不足的可能性是计划和计算RNI的基础 RNI=EAR+2SD RNI=1.2 *EAR recommended nutrient intake,RNI is the daily nutrient intake level that meets the nutrient requirements of

97 to 98% of healthy individuals in a particular life stage and gender group. 推荐摄入量(RNI) 是指可以满足某一特定性别、年龄及生理状况群体中绝大多数个体(97%~98%)需要量的摄入水平. DRIs 的组成--RNI The RDA exceeds the requirements of most individuals to ensure that the needs of nearly all are met. For this reason, a person who consumes a diet that provides less than the RDA for one or more essential nutrients is not necessarily getting a diet that is nutritionally inadequate长期摄入RNI水平,可以维持组织中有适当的营养素储备和保持健康.当某个体的营养素摄入量低于RNI时,并不一定表明该个体未达到适宜营养状态. RNI 的制定意义Importance of RNI RNI是健康个体膳食摄入该营养素的目标值,不是评价个体或群体膳食质量的标准. RNI是根据某一特定人群中体重在正常范围内的个体的需要量设定的.对个别身高、体重超过此参考范围较多的个体,可能需要按每千克体重的需要量调整其RNI. In fact, if an EAR cannot be determined for a nutrient, then this nutrient cannot have an RNI(RDA). How to solve this problem? An adequate intakes (AI) will be determined for a nutrient. Adequate Intake,AI is a recommended daily nutrient intake level based on observed or experimentally determined estimates of nutrient intake by a group of healthy people. 适宜摄入量 (AI) 系指通过观察或实验获得的健康人群某种营养素的摄入量. DRIs 的组成--AI AI 与RNI的关系 AI和RNI的相似之处是两者都能满足目标人群中几乎所有个体(97%-98%)的需要.AI和RNI的区别在于AI的准确性远不如RNI,可能高于RNI ,是个临时值.长期摄入超过AI值时,则可能产生毒副作用. 在研究资料不足而不能计算EAR,因而不能求得RNI时,可设定AI来代替RNI. There are numerous nutrients that have an AI value, including calcium, vitamin D, and vitamin K.Certain nutrients (such as vitamin A \ D and minerals ) can be highly toxic if high doses are used over a period of time. tolerable upper intake level , UL: The highest average daily nutrient intake level likely to pose no risk of adverse health effects to almost all individuals in a particular life stage and gender group. 可耐受的高限摄入水平(UL) 是指平均每日可以摄入某营养素的最高量,即这个量几乎对所有个体健康都无任何副作用和危险. DRIs 的组成--UL 摄入不足概率 过量毒副作用概率 摄入水平 营养素摄入不足和过多的危险性 RNI 安全摄入范围 安全摄入量 DRIs和传统的RDA区别 ①DRIs不仅考虑到防止营养不足的需要,同时考虑到降低慢性退行性疾病风险的需要②营养素摄入不足或过多的概率是制定DRIs基础③DRIs 建立了该营养素的 最高可耐受摄入量 ④有些膳食成分可能不符合营养素的传统概念,已经具备充分的资料也应建立DRIs . DRIs的应用Applications of DRIs Dietary assessment(膳食评价):To judge whether the dietary intake is suitable according to the DRIs. (根据参考标准确定被观察的膳食是大体上适宜的还是不适宜)Dietary planning(膳食计划): To propose rational suggestions of diets according to the DRIs (要根据参考标准提出合理摄取食物的建议) DRIs 应用举例 某小学7-9岁儿童458人,膳食锌平均摄入量10.2mg/d, 范围4.3-19.2mg/d.其中139人摄入量低于9.7mg/d(EAR), 占30%;