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the AI may indicate the need for further assessment of nutritional status by biochemical tests or clinical examination.

The inherent limitations of the AI must always be taken into account in its application. The AI depends on a greater degree of judgment than is applied in estimating the Estimated Average Requirement (EAR) and subsequently deriving an RDA. Therefore, the AI provides a more imprecise basis for the planning and assessment of nutrient intakes for individuals than would an RDA. For example, when an AI is used, it is less clear at what point it would be nearly certain that the individual’s requirement would not be met. The AI might deviate significantly from the RDA if it could be determined, and might be numerically higher than the RDA would be if it were known. For this reason, AIs must be applied with greater care than is the case for RDAs.

When applying an AI to the nutrition of individuals, professionals should first assess particular risk factors and other characteristics of apparently healthy individuals that are relevant to the specific nutrient or food component. In most circumstances AIs are useful only as surrogates for RDAs for individuals. In the absence of EARs and depending on how the AIs are derived, it may be possible for an AI to be taken into account when nutritionally adequate diets are planned for populations or the diets of population groups are assessed. The extent to which AIs can be used in population planning and assessment will be addressed further in subsequent reports.

USING TOLERABLE UPPER INTAKE LEVELS

The Tolerable Upper Intake Level (UL) may be used to examine the possibility of overconsumption of a nutrient. The evaluation of true status requires clinical, biochemical, and anthropometrie data. If an individual’s usual nutrient intake remains below the UL, it is unlikely that there would be an increased risk of adverse effects from excessive intake. The risk of adverse effects increases as intakes above the UL are continued over time. However, the intake at which a given individual will develop adverse effects as a result of taking large amounts of a nutrient cannot be known with certainty. There is no established benefit for healthy individuals from consuming amounts of nutrients that exceed the Recommended Dietary Allowance (RDA) or Adequate Intake (AI).

The UL may also be used to determine the prevalence of intakes that pose a risk of adverse effects. For the B vitamins the form of the vitamin may need to be considered when intake data are examined, and this may be impossible with current survey data (see “Specific



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