They should minimize the risk of developing a condition that is associated with the nutrient in question and that has a negative functional outcome. The DRIs apply to the apparently healthy general population. Meeting the recommended intakes for vitamin C, vitamin E, selenium, and carotenoids would not necessarily provide enough for individuals who are already malnourished, nor would they be adequate for certain disease states marked by increased requirements. Qualified medical and nutrition personnel must tailor recommendations for individuals who are known to have diseases that greatly increase requirements or who are at risk for developing adverse effects associated with higher intakes.
Although the RDA or AI may serve as the basis for such guidance, qualified personnel should make necessary adaptations for specific situations. In most cases, the amount taken from day to day may vary substantially without ill effect. The Recommended Dietary Allowance RDA is the average daily dietary intake level that is sufficient to meet the nutrient requirement of nearly all 97 to 98 percent apparently healthy individuals in a particular life stage and gender group see Figure The RDA is intended to be used as a goal for daily intake by individuals.
The Estimated Average Requirement EAR is the daily intake value that is estimated to meet the requirement, as defined by the specified indicator of adequacy, in half of the apparently healthy individuals in a life stage or gender group see Figure A normal or symmetrical distribution median and mean similar is usually assumed for nutrient requirements.
At this level of intake, the other half of a specified group would not have its nutritional needs met. The general method used to set the EAR is the same for all of the nutrients in this report. The specific approaches, provided in Chapters 5 through 8 , differ because of the different types of data available. The definition of EAR implies a median as opposed to a mean, or average.
The median and average would be the same if the distribution of requirements followed a symmetrical distribution and would diverge as a distribution became skewed. Three considerations prompted the choice of the term EAR: data are rarely adequate to determine the distribution of requirements, precedent has been set by other countries that have used EAR for reference values similarly derived COMA, , and the type of data evaluated makes the determination of a median impossible or inappropriate.
At intakes above the UL, the risk of adverse effects may increase. If data about variability in requirements are insufficient to calculate an SD, a coefficient of variation CV EAR of 10 percent will ordinarily be assumed and used in place of the SD. If the nutrient requirement is known to be skewed for a population, other approaches will be used to find the ninety-seventh to ninety-eighth percentile to set the RDA. If there is evidence of greater variation, a larger CV will be assumed.
For vitamins C and E, and selenium, there are very few direct data on the requirements of children. The method is described in Chapter 3. Together with an estimate of the variance of intake, the EAR may also be used in the assessment of the intake of groups or in planning for the intake of groups Beaton, see Chapter 9. The AI is a value based on experimentally derived intake levels or approximations of observed mean nutrient intakes by a group or groups of apparently healthy people.
In the judgment of the DRI Committee, the AI for children and adults is expected to meet or exceed the amount needed to maintain a defined nutritional state or criterion of adequacy in essentially all members of a specific, apparently healthy population, because it is set using presumably healthy populations.
Examples of defined nutritional states include normal growth, maintenance of normal circulating nutrient values, or other aspects of nutritional well-being or general health. For example, for young infants for whom human milk is the recommended sole food source for most nutrients in the first 4 to 6 months, the AI is based on the daily mean nutrient intake supplied by human milk for apparently healthy, full-term infants who are fed exclusively human milk.
In general, the values are intended to cover the needs of nearly all persons in a life stage group. For infants, the AI is the. Larger infants may have higher needs, which they meet by consuming more milk.
As with RDAs, AIs for children and adolescents may be extrapolated from adult values if no other usable data are available. The Tolerable Upper Intake Level UL is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects in almost all individuals in the specified life stage group see Figure As intake increases above the UL, the risk of adverse effects increases.
The term tolerable intake was chosen to avoid implying a possible beneficial effect. Instead, the term is intended to connote a level of intake that can, with high probability, be tolerated biologically.
The UL is not intended to be a recommended level of intake, and there is no established benefit for healthy individuals if they consume a nutrient in amounts exceeding the recommended intake the RDA or AI. The UL is based on an evaluation conducted using the methodology for risk assessment of nutrients see Chapter 4.
The need for setting ULs grew out of the increased fortification of foods and the use of dietary supplements by more people and in larger doses.
The UL applies to chronic daily use. As in the case of applying AIs, professionals should avoid very rigid application of ULs and first assess the characteristics of the individual or group of concern such as source of nutrient, physiological state of the individual, length of sustained high intakes, and so forth. For vitamin C and selenium, the UL refers to total intakes—from food, fortified food, and nutrient supplements. In other instances. This indicates the need for caution in consuming amounts greater than the recommended intakes; it does not mean that high intakes pose no risk of adverse effects.
The safety of routine, long-term intake above the UL is not well documented. Although members of the general population should be advised not to routinely exceed the UL, intake above the UL may be appropriate for investigation within well-controlled clinical trials.
Clinical trials of doses above the UL should not be discouraged as long as subjects participating in these trials have signed informed consent documents regarding possible toxicity and as long as these trials employ appropriate safety monitoring of trial subjects. In the derivation of the EAR or AI, close attention has been paid to the determination of the most appropriate indicators of adequacy. A key question is, Adequate for what?
In many cases, a continuum of benefits may be ascribed to various levels of intake of the same nutrient. One indicator may be deemed the most appropriate to determine the risk that an individual will become deficient in the nutrient, while another may relate to reducing the risk of chronic degenerative disease such as common neurodegenerative diseases, cardiovascular disease, cancer, diabetes mellitus, cataracts, or age-related macular degeneration.
With the acquisition of additional data relating intake to chronic disease or disability, the choice of the criterion for setting the EAR may change. These nutrients, their role in health, and the types of evidence considered are discussed in Chapter 2. The life stage categories described below were chosen by keeping in mind all the nutrients to be reviewed, not only those included in this report.
Additional subdivisions within these groups may be add-. If data are too sparse to distinguish differences in requirements by life stage or gender group, the analysis may be presented for a larger grouping.
Infancy covers the period from birth through 12 months of age and is divided into two 6-month intervals. The first 6-month interval was not subdivided further because intake is relatively constant during this time. That is, as infants grow, they ingest more food; however, on a body weight basis their intake remains the same.
During the second 6 months of life, growth velocity slows, and thus total daily nutrient needs on a body weight basis may be less than those during the first 6 months of life. For a particular nutrient, average intake by full-term infants who are born to presumably healthy, well-nourished mothers and exclusively fed human milk has been adopted as the primary basis for deriving the Adequate Intake AI for most nutrients during the first 6 months of life.
The value used is thus not an Estimated Average Requirement EAR ; the extent to which intake of human milk may result in exceeding the actual requirements of the infant is not known, and ethics of experimentation preclude testing the levels known to be potentially inadequate.
Therefore, the AI is not an EAR in which only half of the group would be expected to have their needs met. Using the infant fed human milk as a model is in keeping with the basis for estimating nutrient allowances for infants developed in the last Recommended Dietary Allowances NRC, and Recommended Nutrient Intake Health Canada, reports. It also supports the recommendation that exclusive human milk feeding is the preferred method of feeding for normal full-term infants for the first 4 to 6 months of life.
In general, for this report, special consideration was not given to possible variations in physiological need during the first month after birth or to the variations in intake of nutrients from human milk that result from differences in milk volume and nutrient concentration during early lactation.
The previously published RDAs and RNIs for infants have led to much misinterpretation of the adequacy of human milk because of a lack of understanding about the derivation of these. Although they were based on the composition of human milk and the volume of intake, the previous RDA and RNI values allowed for lower bioavailability of nutrients from nonhuman milk.
Ages 0 through 6 Months. To derive the AI value for infants ages 0 through 6 months, the mean intake of a nutrient was calculated based on the average concentration of the nutrient from 2 to 6 months of lactation, using consensus values from several reported studies Atkinson et al. Because there is variation in both of these measures, the computed value represents the mean. It is expected that infants will consume increased volumes of human milk as they grow.
Ages 7 through 12 Months. There is no evidence for markedly different nutrient needs during the period of infants' growth acceleration and gradual weaning to a mixed diet of human milk and solid foods from ages 7 through 12 months. Tolerable Upper Intake Level UL : The maximum intake that it unlikely to pose risks of adverse health effects in nearly all individuals in a specific group.
As intake increases above the UL, the risk of adverse effects increases. For some nutrients, there may be insufficient data to develop a UL. That doesn't mean that the nutrient isn't potentially harmful at high levels of intake.
My Account Sign In. Connect with us:. See list of nutrients. Elements Minerals : Includes arsenic, boron, calcium, chromium, copper, fluoride, iodine, iron, magnesium, manganese, molybdenum, nickel, phosphorus, selenium, silicon, vanadium and zinc.
Estimated Average Requirement EAR : The average daily nutrient intake level estimated to meet the requirement of half the healthy individuals in a particular life stage and gender group. Estimated Energy Requirement EER : The average dietary energy intake that is predicted to maintain energy balance in a healthy adult of a defined age, gender, weight, height, and level of physical activity consistent with good health.
ND: Not determinable due to lack of data of adverse effects in this age group and concern with regard to lack of ability to handle excess amounts. Source of intake should be from food only to prevent high levels of intake.
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