Dietary Reference Intakes for Calcium and Vitamin D

The Tolerable Upper Intake Level (UL) is not a recommended intake. Rather, it is intended to specify the level above which the risk for harm begins to increase, and is defined as the highest average daily intake of a nutrient that is likely to pose no risk of adverse health effects for nearly all persons in the general population. As intake increases above the UL, the potential risk for adverse effects increases. In short, the UL is a reference value intended to guide policy-makers and scientists charged with ensuring a safe food supply and protecting the health of the U.S. and Canadian populations. It applies to intakes on a chronic basis among free-living persons. Those responsible for determining the appropriate dosages of nutrients to be studied in carefully controlled experimental trials conducted in clinical or community settings have the opportunity to bring other considerations into play when deciding on the acceptable levels of nutrients that are appropriate for subjects taking part in such studies. ULs are not designed to address experimental protocols in which safety monitoring occurs. This chapter is organized to include hazard identification (indicator review and selection) and hazard characterization (intake–response assessment and reference value specification), the first two steps of the general risk assessment approach for Dietary Reference Intake (DRI) development. Therefore, compared with the discussions presented in the two chapters on reference values for adequacy (Chapters 4 and 5), the discussions for ULs are contained in a single chapter. This chapter addresses adverse effects of excess intakes of calcium and vitamin D. Although adverse effects are also associated with deficiencies of calcium and vitamin D, those concerns are