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DRI DIETARY REFERENCE INTAKES: Applications in Dietary Assessment G Glossary and Abbreviations Acute exposure An exposure to a toxin or excess amount of a nutrient that is short term, perhaps as short as one day or one dose. In this report it generally refers to total exposure (diet plus supplements) on a single day. Adequacy of nutrient intake Intake of a nutrient that meets the individual's requirement for that nutrient. Adverse effects In the toxicological sense, defined symptoms of poor or undesirable health resulting from administration of a toxin or excess amounts of a nutrient. AI Adequate Intake; a recommended intake value based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate—used when an RDA cannot be determined. Bias Used in a statistical sense, referring to a tendency of an estimate to deviate from a true value (as by reason of nonrandom sampling). To be unbiased, a statistic would have an
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DRI DIETARY REFERENCE INTAKES: Applications in Dietary Assessment expected value equal to a population parameter being estimated. Chronic exposure Exposure to a chemical compound such as a nutrient for a long period of time, perhaps as long as every day for the lifetime of an individual. Cluster analysis A general approach to multivariate problems, the aim of which is to determine whether individuals fall into groups or clusters. Cut-point The exact point when something stops or changes. The EAR is used as a cut-point in the EAR cut-point method of assessing the prevalence of inadequacy for a group. Deficiency An abnormal physiological condition resulting from inadequate intake of a nutrient or multiple nutrients. Dietary reference standards Nutrient intake values established as goals for individuals or groups for good nutrition and health. Dietary status The condition of an individual or group as a result of food and nutrient intake. Dietary status also refers to the sum of dietary intake measurements for an individual or a group. Disappearance data Data that refer to food and nutrients that disappear from the marketplace. The term refers to food and nutrient availability for a population that is calculated from national or regional statistics by the inventory-style method. Usually taken into account are the sum of food remaining from the previous year, food imports, and agricultural production; from this sum is subtracted the sum of food remaining at the end of the year, food exports, food waste, and food used for non-food purposes. Disappearance data do not always take account of food that does not
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DRI DIETARY REFERENCE INTAKES: Applications in Dietary Assessment enter commerce, such as home food production, wild food harvests, etc. Distribution of observed intakes The observed dietary or nutrient intake distribution representing the variability of observed intakes in the population of interest. For example, the distribution of observed intakes may be obtained from dietary survey data such as 24-hour recalls. Distribution of requirements The distribution reflecting the individual-to-individual variability in requirements. Variability exists because not all individuals in a (sub) population have the same requirements for a nutrient (even if individuals are grouped into homogenous classes, such as Hispanic men aged 19 to 50 years). Distribution of usual intakes The distribution of long-run average dietary or nutrient intakes of individuals in the population. The distribution should reflect only the individual-to-individual variability in intakes. Statistical procedures may be used to adjust the distribution of observed intakes by partially removing the day-to-day variability in individual intakes, so the adjusted distribution more closely reflects a usual intake distribution. Dose-response assessment Determines the relationship between nutrient intake (dose) and either some criterion of adequacy or adverse effect. DRI Dietary Reference Intake; a reference value that is a quantitative estimate of a nutrient intake. It is used for planning and assessing diets for healthy people. EAR Estimated Average Requirement; a nutrient intake estimated to meet the requirement of half the healthy individuals in a particular life stage and gender group.
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DRI DIETARY REFERENCE INTAKES: Applications in Dietary Assessment EAR cut-point method A method of assessing the nutrient adequacy of groups. It consists of assessing the proportion of individuals in the group whose usual nutrient intakes are below the EAR. Error in measurement Mistake made in the observation or recording of data. Food balance sheet See disappearance data. Former RDA and RNI Recommended daily dietary intake level of a nutrient sufficient to meet the nutrient requirement of nearly all healthy persons in a particular life stage and gender group. These standards were last issued in the United States in 1989 (RDA, Recommended Dietary Allowance) and in Canada in 1990 (RNI, Recommended Nutrient Intake). Household Individuals sharing in the purchase, preparation, and consumption of foods. Usually this will represent individuals living as a family in one home, including adults and children. A household may be the unit of observation rather than the independent individuals within it. Inadequacy of nutrient intake Intake of a nutrient that fails to meet the individual's requirement for that nutrient. Interindividual variability Variability from person-to-person. Intraindividual variability Variability within one person. The term is generally used to refer to day-to-day variation in reported intakes, also called the within-person variation or standard deviation within (SDwithin). Joint distribution Simultaneous distribution of both requirements (y-axis) and usual intakes (x-axis) for a single nutrient by individuals within a population or group.
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DRI DIETARY REFERENCE INTAKES: Applications in Dietary Assessment Likelihood Probability. LOAEL Lowest-observed-adverse-effect level; lowest intake (or experimental dose) of a nutrient at which an adverse effect has been identified. Mean intake Average intake of a particular nutrient or food for a group or population of individuals. Also average intake of a nutrient or food over two or more days for an individual. Mean requirement Average requirement of a particular nutrient for a group or population of individuals. NOAEL No-observed-adverse-effect level; the highest intake (or experimental dose) of a nutrient at which no adverse effects have been observed in the individuals studied. Normal distribution In the statistical sense, refers to a specific type of distribution of the values for a parameter within a group or population. The distribution is symmetrical and the mean ± 2 standard deviations will encompass the parameter for 95 percent of the individuals in the group. Nutrient requirement The lowest continuing intake level of a nutrient that will maintain a defined level of nutriture in a healthy individual; also called individual requirement. Nutritional status Condition of an individual or group resulting from nutrient intake and utilization of a nutrient at the tissue level. Population A large group; in this report, a large group of people. Prevalence The percentage of a defined population that is affected by a specific condition at the same time.
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DRI DIETARY REFERENCE INTAKES: Applications in Dietary Assessment Prevalence of inadequate intakes The percentage of a population that has intakes below requirements. Probability approach A method of assessing the nutrient adequacy of groups. It uses the distribution of usual intakes and the distribution of requirements to estimate the prevalence of inadequate intakes in a group. Also known as the NRC approach. Probability of inadequacy Outcome of a calculation that compares an individual's usual intake to the distribution of requirements for persons of the same life stage and gender to determine the probability that the individual's intake does not meet his or her requirement. RDA Recommended Dietary Allowance; the average daily intake level sufficient to meet the nutrient requirement of nearly all (97 to 98 percent) healthy individuals in a particular life stage and gender group. Requirement The lowest continuing intake level of a nutrient that will maintain a defined level of nutriture in a healthy individual. Risk The probability or likelihood that some unwanted effect will occur; in this report, refers to an unwanted effect from too small or too large an intake of a nutrient. Risk assessment A scientific undertaking to characterize the nature and likelihood of harm resulting from human exposure to agents in the environment (in this case, a dietary nutrient). It includes both qualitative and quantitative information and a discussion of the scientific uncertainties in that information. The process of risk assessment can be divided into four major steps: hazard identification, dose-response assessment, exposure assessment, and risk characterization.
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DRI DIETARY REFERENCE INTAKES: Applications in Dietary Assessment Risk curve Used to demonstrate inadequacy or excess of a particular nutrient. As defined in the usual statistical sense, a risk curve is in contrast to the concept of probability curve. Risk of excess In relation to the DRIs, the likelihood that an individual will exceed the UL for a particular nutrient. Risk of exposure In the toxicological sense, the likelihood that individuals will experience contact with a toxin (or consume levels of a nutrient above the UL). Risk of inadequacy The likelihood that an individual will have usual intake of a particular nutrient that is less than the individual's requirement. Sensitivity analysis Technique of varying the implicit assumptions or presumed conditions of an analysis approach to see how much this affects the overall outcome. Skewed distribution A distribution that is not symmetrical around its mean. For example, a skewed distribution can have a long tail to the right (right-skewed distribution) or to the left (left-skewed distribution). Symmetrical distribution A distribution that has the same number of values (observations) above and below the mean and has equal proportions of these values around the mean. Threshold The point in a dose-response curve that is accepted as the point beyond which a risk of adverse effects occurs. Toxicity An adverse condition relating to or caused by a toxin.
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DRI DIETARY REFERENCE INTAKES: Applications in Dietary Assessment True prevalence The actual prevalence of a condition assuming no error in measurement of either requirements or intakes that would result in false negative or false positive classifications. UF Uncertainty factor; a value assigned to a specific nutrient reflecting the level of uncertainty about data used to establish a Tolerable Upper Intake Level. UL Tolerable Upper Intake Level; the highest average daily nutrient intake level likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects increases. Unit of observation The level of aggregation at which data are collected. For example, the unit of observation for dietary assessment may be the individual, the household, or the population. Univariate distribution The distribution of a single variable. Usual intake The long-run average intake of food, nutrients, or a specific nutrient for an individual. Variance of usual intakes or requirements In the statistical sense, reflects the spread of the distribution of usual intakes or requirements on both sides of the mean intake or requirement. When the variance of a distribution is low, the likelihood of seeing values that are far away from the mean is low; in contrast, when the variance is large, the likelihood of seeing values that are far away from the mean is high. For usual intakes and requirements, variance reflects the person-to-person variability in the group.
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