What Are the Tolerable Upper Limits of Vitamins?

Though necessary for good health, vitamins and minerals consumed in large amounts can cause harm. Safe intake levels prove valuable tools given the abundance of fortified foods and supplements on the market today.

History

• In 1995, the Food and Nutrition Board of the National Academy of Sciences established the Tolerable Upper Intake Level (UL) for nutrients as part of the Dietary Reference Intakes (DRIs).

Features

• ULs indicate the highest level of a nutrient that most likely poses no risk of toxicity for at least 98 percent of the population.

Function

• ULs serve as one of four reference values used in diet planning assessment. Other DRI values include: Recommended Dietary Allowance (RDA), Adequate Intake (AI) and Estimated Average Requirement (EAR). All DRI values vary according to gender and life stage.

Significance

• Though the original Recommended Dietary Allowances established in 1941 have been updated repeatedly, ULs are the first attempt to address nutrient toxicity.

Considerations

• As nutrient intake above the UL increases, risk of toxicity increases. Individuals should not strive to consume the UL for individual nutrients, but should consider UL when analyzing daily intake of a vitamin or any other nutrient over a long period of time.

  Individuals should always speak with their medical provider before consuming vitamin and mineral supplements; certain conditions or diseases may increase vulnerability to vitamin toxicity.

  ULs consider nutrient intake from food, water and dietary supplements.

  UL values have not been developed for every nutrient; only nutrients with adequate scientific data on adverse effects have ULs.