Chapter II Reference Intake of Dietary Nutrients
Dietary Nutrients Reference Intake (DRIs) is not only a measure to measure the suitability of ingested nutrients, It is also a tool to help individuals and people make dietary plans.
Overview in the first section
1. Reference intake of dietary nutrients in foreign countries
(1) Development of reference intake of dietary nutrients in the United States
The National Research Institute (NRC) of the United States issued the first recommended dietary recommended dietary allowance (RDAs) in 1943. Under the leadership of the Nutrition Committee, RDAs was revised several times. Until the 111th edition was published in 1989, RDAs has become an authoritative guiding document in the field of nutrient supply for Americans in different periods, which has had an important impact on the formulation of RDAs in many countries. < P > (2) The development of reference intake of dietary nutrients in European countries
1. Average requirement (EAR) indicates the average requirement of a population;
2. Nutrient reference intake (RNI), which means that the intake is almost certainly appropriate above this level.
3. Low nutrient reference intake (LRNI).
(3) Development of dietary nutrient reference intake in Asian countries
2. Recommended daily dietary recommended dietary allowance and dietary nutrient reference intake in China
(1 In 1941, Zheng Ji published My Humble Opinion on the Minimum Nutritional Needs of China People. In 1952, the Nutrition Requirement Table (standard of nutrient supply in daily diet) in the Food Composition Table compiled and published by the Department of Nutrition, Central Institute of Health included the requirements of calcium, iron and five vitamins (vitamin A, vitamin B1, vitamin B2\ nicotinic acid and vitamin C).
In p>1962, the symposium on biochemistry and nutrition of China Physiological Sciences Society further revised the RDA formulated in 1955, until the latest revision of RDAs was made by China Nutrition Society in October, 1988, and it was named "Recommended Daily Dietary recommended dietary allowance".
(II) Formulation of Dietary Nutrient Reference Intake DRIs》
In order to facilitate readers' understanding and avoid confusion with the original RDA, it was decided to use "recommended daily dietary recommended dietary allowance (RDAs)" instead of "recommended nutrient intake RNIs" to express the recommended daily nutrient intake.
the basic basis for formulating DRIs is the results of scientific research on the physiology, nutrition and toxicity of nutrients. The use of domestic data is emphasized in the formulation of DRIs for China residents. If our country has relevant research data, it will focus on domestic data and make necessary adjustments with reference to international data. When there is no domestic data, we choose to refer to international data, and most nutrients focus on the relevant publications in the United States in recent years.
The Reference Intake of Dietary Nutrients in China was published in October, 2111.
Requirements and Intake in Section II
1. Danger of insufficient or excessive intake of nutrients
If the human body ingests a certain nutrient for a long time, there is a risk of nutrient deficiency; When a certain nutrient is ingested in large quantities through diet, supplements or drugs for a long time, it may have certain toxic and side effects.
II. Definition and concept of nutrient requirement
Nutrient requirement is the minimum amount of the nutrient that the body "obtains" every day on average for a period of time in order to maintain "suitable nutritional status". "Appropriate nutritional status" means that the body is in good health and can maintain this state. The amount of "obtained" nutrients may refer to the amount of nutrients ingested or the amount of nutrients absorbed by the body. The group demand is obtained through the study of individual demand, and the individual demand is in a distribution state in any population.
The recommended energy intake of a population is equal to the average energy requirement of the population, not equal to the average energy requirement plus twice the standard deviation like other nutrients.
The recommended energy intake is equal to the average energy requirement of this population; The recommended intake of protein and other nutrients is the level that can meet the needs of the 95th percentile, or 97%-98% of individual needs.
Section III Dietary Nutrient Reference Intake (DRIs)
I. Definition and concept of Dietary Nutrient Reference Intake
Dietary Nutrient Reference Intake (DRIs) is a set of reference values of daily average dietary nutrient intake, which is developed on the basis of "Recommended Daily Dietary recommended dietary allowance (RDAs)" and includes four contents:
1. Average requirement (ear). EAR can meet the needs of 51% members of the group, but it can't meet the needs of the other 51% members. EAR is the basis of formulating RNI.
2. Recommended intake (RNI)
RNI is equivalent to the traditional RDA, which can meet the needs of most individuals in a certain group (97%-98%).
Long-term intake of RNI level can meet the body's needs for this nutrient, maintain health and maintain proper reserves in tissues.
The main purpose of p>RNI is to serve as the target value of daily intake of this nutrient by individuals.
RNI is based on EAR. Given the standard deviation of the EAR, RNI is defined as the EAR plus two standard deviations, that is, RNI=EAR+2SD. So RNI=1.2*EAR.
3. Appropriate intake (AI)
AI is not obtained by studying the individual requirements of nutrients, but by observing or experimenting the intake of healthy people.
when the data of individual requirement of a certain nutrient is insufficient, it is impossible to calculate the EAR, so RNI can not be obtained, and the appropriate intake can be set instead of RNI.
the mp>AIn purpose of ai is to target individual nutrient intake. AI and RNI are similar in that they are both used as targets of individual intake, which can meet the needs of almost all individuals in the target population. The difference between AI and RNI is that the accuracy of AI is far less than that of RNI, and sometimes it may be significantly higher than that of RNI.
4. The maximum tolerable intake (UL)
(UL) is the maximum daily intake of this nutrient. "Tolerable" means that this intake level is generally tolerable, and it will probably not harm the health of almost all individuals in the population. When the intake exceeds UL and further increases, the risk of damage to health increases. UL is the upper limit of daily intake, not a recommended intake level.
II. Basis for formulating nutrient reference intake
The basis for formulating nutrient reference intake may involve animal experimental research data, human metabolism research data, population observation research data and clinical research data. These different sources of information have their own advantages and disadvantages, and their respective characteristics should be considered when using them.
the fourth section uses the reference intake of dietary nutrients to evaluate the diet
1. Use DRIs to evaluate the individual intake
1. Use the average requirement (EAR) to evaluate the individual intake
Theoretically, the probability of a person's insufficient intake of a nutrient can be calculated by the daily intake, the average requirement and standard deviation of the nutrient.
In fact, we can only judge whether the observed intake is higher or lower than the average requirement of the corresponding population in a period of time.
In practical application, it can be considered that the observed intake is lower than the EAR, because the probability of insufficient intake is as high as 51%; Through many days of observation, when the intake reaches or exceeds RNI, or even if the result is much higher than RNI in a few days, it can be considered that the intake is sufficient.
it is quite difficult to determine whether the intake is appropriate for those whose intake is between EAR and RNI, and it should be improved for safety reasons.
2. Evaluate the individual's intake with the tolerable maximum intake (UL)
Compare the observed intake with UL in a short time, and infer whether the individual's daily intake is too high, which may endanger health.
The intake of some nutrients, such as vitamin B1 and folic acid, can only be calculated through supplementation, fortification and medication, while other nutrients, such as vitamins, should also include food sources.
UL is an upper limit of intake for the vast majority of individuals in a general population, which is probably not harmful to health. If the daily intake exceeds UL, it may cause harm to some individuals. The consequences of excessive intake of some nutrients are serious, and some consequences are even irreversible.
A person's real needs and daily needs can only be an estimated result, so the evaluation result of individual dietary suitability is inaccurate.
second, using RDAs to evaluate group intake
To evaluate group nutrient intake, we need to pay attention to two aspects: First, what percentage of individuals in the population consume a certain nutrient below their needs? Second, what percentage of people have a high daily intake and may face health risks?
In order to correctly evaluate people's nutrient intake, it is necessary to obtain accurate dietary data, select appropriate reference values, adjust the distribution of individual intake variation and its influencing factors, and reasonably explain the results.
(1) Evaluating the nutrient intake of population with EAR
In practical work, there are two methods to evaluate the suitability of population intake, namely "probability method" and "average requirement tangent point method".
1. probability method actually has the distribution data of population demand, and can calculate a risk degree of insufficient intake for each intake level, and obtain the probability of insufficient intake of the population by weighted average.
2. Tangent point method The conditions for using this method are: there is no correlation between nutrient intake and requirement; The distribution of group demand can be considered as normal distribution; The variation of intake is greater than that of requirement. EAR tangent method does not require calculating the risk of insufficient intake at each intake level, but simply counts how many individuals in the observation population have a daily intake lower than EAR. The proportion of these individuals in the population is equal to the proportion of individuals with insufficient intake in the population.
3. Adjustment of the distribution data of intake It is essential to evaluate the probability of insufficient intake of nutrients in the population by any method. In order to obtain this data, the observed intake must be adjusted to exclude the diurnal differences (intra-individual differences) of individual intake. The adjusted distribution of daily intake should better reflect the differences among individuals. To adjust the distribution of intake, at least one representative sub-population should be observed, in which each individual has at least three consecutive days' dietary data or at least two independent daily dietary data.
(2) Evaluating the population intake with the appropriate intake (AI)
When the average intake or median intake of the population is equal to or greater than the nutrient AI of the population, it can be considered that the probability of insufficient intake in the population is very low. When the average or median intake of the population is below AI, it is impossible to judge the degree of insufficient intake of the population. There is no definite relationship between AI and EAR of nutrients, so don't try to infer EAR from AI.
(3) Assessing the population intake with UL
UL is used to assess the risk of health hazards caused by excessive intake of nutrients. According to the proportion of people whose daily intake exceeds UL, this part of people whose daily intake exceeds UL may face health risks.
It is very difficult to quantitatively assess the health risk based on the data that the daily intake is greater than UL, because the uncertainty coefficient is used in the derivation of UL. At present, UL can only be used as the cut-off point of safe intake.
It is necessary to obtain more and more accurate human research data before it is possible to predict the degree of harm caused by intake exceeding UL with confidence.
Third, reduce the potential errors in dietary assessment with DRIs
1. It is not appropriate to use the average intake to assess the level of population intake
2. It is not appropriate to use RNI to assess the prevalence of population under-intake
3. It is not appropriate to use the food frequency questionnaire to assess population intake
4. Pay special attention to the difference between energy and protein and other nutrients
Section 5 plans meals with reference intake of dietary nutrients
. Meal planning can be carried out at different levels, and it can be simple to plan things for individuals and prepare meals.
you can arrange recipes and plan food purchases for groups.
it can be a larger-scale plan, such as a regional nutrition improvement plan or food aid project formulated by a department.
1. Steps of planning meals for individuals with reference intake of dietary nutrients
(1) Setting nutrient intake targets
Setting appropriate nutrient intake targets should consider all nutrients for which DRIs has been established. The intake of various nutrients should be within the safe intake range, that is, they can reach their respective RNI or AI without exceeding their UL.
(2) Making a meal plan
Planners can use the Dietary Guide for China Residents and the Balanced Diet Pagoda to make a food consumption plan in practical work, and then check whether the planned meal meets RNI and AI without exceeding their UL level according to the nutritional data of the food.
if there is a local food composition list, it is best to verify whether the planned diet can provide sufficient nutrients according to the local food nutritional composition. Under certain circumstances, it may be necessary to use fortified foods or even some nutritional supplements to ensure the supply of specific nutrients.
2. Steps of planning meals for homogeneous groups with reference intake of dietary nutrients
Planning group meals needs to be carried out step by step, that is, determining nutritional goals, planning how to achieve these goals and evaluating whether these goals have been achieved.
Plan meals for homogeneous groups
1. Determine the planning objectives
2. Set the target daily nutrient intake distribution
3. Compile the target daily nutrient intake distribution recipe
4. Evaluate the results of the planned meals
Give you a website.