Tolerable Upper Intake Level (UL)

The UL (Tolerable Upper Intake Level), according to EFSA, is the highest level of total chronic daily intake of a nutrient from all dietary sources at which no risk of adverse health effects is expected in humans. ^[1] The US and Canadian DRI system defines the same concept as “the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects for almost all individuals in the general population.” ^[2]

What does it describe?

The UL is a ceiling for habitual daily intake: it covers total intake from food, fortified foods and supplements. A single serving, a single day or a single product exceeding the UL does not match the situation the measure describes; what is meant is the amount taken habitually over a long time. The UL is not a recommendation or a target; it shows the safety limit, not the beneficial amount. For the value that shows requirement, see the term RDA.

Points to note

The UL is set separately by institution and by nutrient. In EFSA’s summary table, the UL for vitamin D in adults is given as 100 µg/day; for some nutrients such as biotin, it is stated that there are not enough data to derive a UL (“no adequate data to derive a UL”). ^[1] For some nutrients, EFSA gives a “safe level of intake” instead of a UL; for example, for iron, 40 mg/day total intake for adults. According to the document, the scope of use of safe levels is more limited than that of ULs: intake above the safe level does not necessarily mean a risk of adverse effects, and these values cannot be used to determine the proportion of the population at risk. ^[1] It is therefore stated which institution a value comes from and whether it is a UL or another reference value.

For the vitamin D example, see vitamin D excess for intake and blood level limits, and the guide How to read a label? for reading amounts on labels against the UL.