How serious is the risk of adverse effects for individuals chronically consuming nutrients at levels greater than the Tolerable Upper Intake Level (UL)?

The critical adverse effects used to set the UL are listed in Table 6-1. The dose, the seriousness of the adverse effects, and the extent to which the effects are reversible upon intake reduction should be considered in evaluating the risk of adverse effects.

If the mean intake of a population equals the UL, is there no risk?

A population mean intake at the UL suggests that a large proportion (as much as half) of the population is consuming levels above the UL. This would represent a very serious population risk of adverse effects.

How different are the ULs from doses that would confer acute toxicity?

The ULs are the maximum levels that can be consumed daily on a chronic basis without adverse effects. The ULs will generally be much lower than the levels that are necessary to produce adverse effects after a single exposure. Few evaluations of the acute toxic intake of nutrients have been made.