The Tolerable Upper Intake Level (UL) is the appropriate DRI to use to assess the risk of adverse health effects from excessive nutrient intake. As intake increases above the UL, the potential for risk of adverse health effects increases.
Depending on the nutrient, the UL assessment requires accurate information on usual daily intake from all sources, or from supplements, fortificants, and medications only. Usual intake distributions will allow determination of the fraction of the population exceeding the UL. This fraction may be at risk of adverse health effects.
Difficulties arise in attempts to quantify the risk (likelihood) of adverse health effects in the general population from daily nutrient intakes exceeding the UL. The use of uncertainty factors to arrive at the UL reflects inaccuracies in reported nutrient intake data, uncertainties in the dose-response data on adverse health effects, extrapolation of data from animal experiments, severity of the adverse effect, and variation in individual susceptibility. As more accurate data from human studies become available, predicting the magnitude of the risk associated with intakes exceeding the UL may become possible. For now it is advisable to use the UL as a cutoff for safe intake.
The evaluation of dietary survey data merits special attention. This includes three major components: describing the dietary survey data, estimating the prevalence of inadequate or excessive intake, and evaluating differences among subgroups in intake. These applications are discussed in Chapter 7 and summarized in Table S-2.
Dietary assessment at the group level typically involves comparing usual nutrient intakes with nutrient requirements to assess the prevalence of nutrient inadequacy. The preferred outcome measure used to assess the prevalence of inadequate nutrient intake is the percentage of a group with usual intake less than the EAR. For nutrients with an AI, the best that can be done is to look at mean and median intake relative to the AI. However, when mean intakes of groups are less than the AI, nothing can be inferred about the prevalence of inadequacy. To estimate the proportion of the population at risk of excessive intake, the outcome measure is the percentage