Chapter 7 Public Nutrition

Chapter7PublicNutrition

Overview of public nutrition Definition Public nutrition is a broad-based, problem-solving approach to addressing malnutrition in complex emergencies that combines analysis of nutritional risk and vulnerability with action-oriented strategies. • 公共卫生营养 Public Health Nutrition • 社区营养 public Nutrition • 社会营养 Social Nutrition • 国际营养 International Nutrition

Overview of public nutrition Characteristics • Practicality: conducting research and nutritional interventions at the population level • Macroscopic: public nutrition studies target specific social groups • Sociality: social, economic, legal, cultural, behavioral habits and religious beliefs

Overview of public nutrition Solution • To establish a nutrition and health care system • Establish a nutrition and health care system • Promote nutrition legislation and nutrition improvement • Establish the professional team of nutrition education and consultation

Dietary structure Dietary Reference Intakes，DRIs Dietary Reference Intakes: DRIs is A set of nutritional reference values basically developed from RDA. DRIs provide dietary standards for healthy people only.

Dietary structure Dietary Reference Intakes，DRIs • Once a nutrient is identified, one of the principal research efforts of nutrition scientists is to determine how much of it is needed by people at various ages and stages of life. • In the united states, the most widely used nutrient guidelines were the recommended dietary allowance (RDA). • The RDA serve as dietary or nutritional standards for a wide range of age-weight-sex groups such as infants, children and old adults.

Dietary structure Recommended dietary allowances, RDA RDA development from 1988 in China and Revised during 1988-1998 DRIs finally published in 2000

Dietary structure Defining basis of RDA 营养生理需要量(Nutritional Requirement) It is the basis for the formulation of RDA and RNI；It is airframe maintains "appropriate nutrition condition", with good healthy state, must absorb this nutrient on average everyday in certain period of time lowest amount.

Defining basis of RDA Safety coefficient • 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. • An exception is the RDA for energy, or calories

Dietary structure Defining basis of RDA RDA do not take account of special needs certain individuals may have due to genetic make up , metabolic disorders, chronic infections, and other abnormalities

Dietary structure 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)

Dietary structure DRIs in countries around the world • 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) Average Requirement, AR Population Reference Intake，PRI Lowest Threshold Intake, LTI British America European public

Dietary structure 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： • energy and macronutrients workshop • macro elements workshop • microelement workshop • vitamins workshop • other 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》。

Dietary structure 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)

Dietary structure The composition of DRIs --EAR 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.

Dietary structure The significance of EAR formulation • To assess the incidence of inadequacy in the population. • The possibility of an individual not getting enough can be checked • It is the basis for planning and calculating RNI RNI=EAR+2SD RNI=1.2 ×EAR

Dietary structure The composition of DRIs --RNI • 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. • 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.

Dietary structure Importance of RNI RNI is the target value of dietary intake of this nutrient by healthy individuals, not the standard to evaluate the dietary quality of individuals or groups.RNI is based on the needs of individuals in a particular population who weigh in the normal range. For individuals whose height and weight exceed this reference range, RNI may need to be adjusted according to the requirement of weight per kilogram.

Dietary structure The composition of DRIs --AI 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.

Dietary structure The relationship between AI and 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.

Dietary structure The composition of DRIs --UL 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.

Dietary structure The risk of inadequate and excessive nutrient intake Safe intake amount 过量毒副作用概率摄入不足概率 RNI 安全摄入范围 Intake levels

Dietary structure Applications of DRIs • Dietary assessment(膳食评价)：To judge whether the dietary intake is suitable according to the DRIs. • Dietary planning(膳食计划)： To propose rational suggestions of diets according to the DRIs

Dietary guidelines Chinese dietary guidelines

Dietary guidelines Chinese dietary guidelines • 食物多样，谷类为主 • 吃动平衡，健康体重 • 多吃蔬果、奶类、大豆 • 适量吃鱼、禽、蛋、瘦肉 • 少盐少油，控糖限酒 • 杜绝浪费，兴新食尚

Dietary guidelines Chinese dietary guidelines 中国居民平衡膳食宝塔

Dietary guidelines Dietary balance pagoda

Methods determining nutrients requirement • Initial studies usually are conducted with laboratory animals, but the information developed in these studies cannot be applied directly to humans since people’s needs often are quite different from animals’ needs. • Human nutrition studies, on the other hand, are time-consuming, costly, and difficult to conduct, especially because of the problems of controlling variables and possibly causing harm to the individuals involved. • Because of the obstacles to collecting accurate data, our present knowledge of nutrient needs is incomplete, and the requirements of humans for many nutrients have not been established.

Nutritional survey and nutritional surveillance Nutrition survey • nutrition survey is conducted to investigate the average nutrients levels and to assess the nutritional status in a fixed people group at present. • Nutritional survey: 1958, 1982, 1992, 2002 • Hypertension survey: 1959, 1979, 1991 • Diabetes survey: 1984, 1996 • Nutrition & Health survey: 2002.8-12

Nutritional survey and nutritional surveillance Nutrition survey -- objective and content • Goals To understand the dietary intake of residents and the comparison with the nutritional supplyTo understand the constitution and health status of residents closely related to nutritionConduct comprehensive or thematic scientific research • Contents • Dietary survey; • Biochemical examination of human nutrition; • Clinical examination of malnutrition; • Analysis of anthropometric data;

Nutritional survey and nutritional surveillance Organization of nutrition survey • Population: all residents in the survey area shall be included in the stratified sampling survey in proportion. • Survey period: once each season, at least twice in summer, autumn, winter and spring. • Dietary survey time: 3-5 days, no holidays. • Quality assurance of investigation: scientific, strict and feasible design and cooperation and support from leaders at all levels and investigation objects.

Nutritional survey and nutritional surveillance Dietary survey • Goals: track the amount and quality of energy and nutrients a person consumes through their diet over a period of time • It is a basic component of nutrition investigation, and it is also a relatively independent content. • Methods: weighing method, accounting method, inquiry method, chemical analysis method, food frequency method

Nutritional survey and nutritional surveillance Weighing method Recording food name Steps Weighing Calculating the raw and cooked ratio Calculating food consumption per person per day Calculating daily nutrient intake per person

Nutritional survey and nutritional surveillance Simplify of weighting methods • The labor intensity that is investigated personnel, age difference is not big, Recording total dine number only. If the difference is large, the mixed coefficient method should be used. • The recommended energy level (2400kcal) of adult males with light manual labor is set as the standard person as 1.0, and the recommended energy level of other groups is converted into the coefficient compared with the standard person.

Nutritional survey and nutritional surveillance weighting method • Advantages: it can accurately reflect the food ingestion of the investigated subjects, and it can also get the distribution of three meals a day, which is applicable to the dietary survey of groups, individuals and families.。 • Disadvantages: It takes a lot of time and effort and is not suitable for large-scale nutrition surveys.

Nutritional survey and nutritional surveillance Record method • Record method: Looking up namely in the past the sort of the food consumption inside certain period refectory and gross amount, and according to the number of meals in the same period, a rough calculation of each person's daily intake of various foods. • Applicable object: the unit of the collective canteen with food accounts • Advantages: Simple, fast • Disadvantages: Not precise enough

Nutritional survey and nutritional surveillance Query method • Inquiry method is to retrospectively understand the dietary nutrition status of the investigated subjects by means of question and answer. • The results of this method are not accurate and are used only in cases where the weighing and audit methods are not available. • It is generally believed that 24-hour dietary recalls are the most accessible to reliable data from surveys.

Nutritional survey and nutritional surveillance • Dietary review method: 24 hours Not suitable for under 6 years old and over 75 years old • Dietary history method: Usually daily meal patterns Double-check meal patterns with food lists Recording your food intake for three days

Nutritional survey and nutritional surveillance Chemical analysis method • Collecting all the main and non-staple foods that should be consumed in the daily diet of the investigated subjects • The quantity and quality of its energy and nutrients are determined by laboratory chemical analysis. • Usually not.

Nutritional survey and nutritional surveillance Food frequency method • Qualitative food frequency method • Quantitative food frequency method

Nutritional survey and nutritional surveillance Individual-Level nutritional assessment • By means of biochemical and physiological technique to find individuals under- or over-nutritional status (or to investigate the effects of some factors on the nutritional status)。 • Sampling: easy to obtain, sensitive; Such as blood and urine.

Chapter 7 Public Nutrition