Abbreviations: ND, not determinable; UL, upper intake level.

^a UL is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects to almost all individuals in the general population. Unless otherwise specified, the UL represents total intake from food, water, and supplements. Because of lack of suitable data, ULs could not be established for vitamin K, thiamin, riboflavin, vitamin B₁₂, pantothenic acid, biotin, or carotenoids. In the absence of a UL, extra caution may be warranted in consuming levels above recommended intakes. Members of the general population should be advised not to routinely exceed the UL. The UL is not meant to apply to individuals who are treated with the nutrient under medical supervision or to individuals with predisposing conditions that modify their sensitivity to the nutrient.

^b As preformed vitamin A only.

^c ND (not determinable) because of 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.

^d As α-tocopherol; applies to any form of supplemental α-tocopherol.

^e The ULs for vitamin E, niacin, and folate apply to synthetic forms obtained from supplements, fortified foods, or a combination of the two.

^f β-Carotene supplements are advised only to serve as a provitamin A source for individuals at risk of vitamin A deficiency.

^g Although the UL was not determined for arsenic, there is no justification for adding arsenic to food or supplements.

^h The ULs for magnesium represent intake from a pharmacological agent only and do not include intake from food and water.

ⁱ Although silicon has not been shown to cause adverse effects in humans, there is no justification for adding silicon to supplements.

^j Although vanadium in food has not been shown to cause adverse effects in humans, there is no justification for adding vanadium to food and vanadium supplements should be used with caution. The UL is based on adverse effects in laboratory animals, and this data could be used to set a UL for adults but not children and adolescents.

Adapted from: US Department of Health and Human Services. Nutrient Recommendations and Databases. National Institutes of Health Office of Dietary Supplements. Accessed May 30, 2017. https://ods.od.nih.gov/Health_Information/Dietary_Reference_Intakes.aspx.