The RDA for iron and all other nutrients is established by the Food and Nutrition Board of the National Academies. You may also see references to Dietary Reference Intakes (DRI), Estimated average requirement (EAR) Adequate intake (AI) level and Tolerable upper intake level (UL).
The RDA and the UL for iron: The RDA represents a daily nutrient intake goal for healthy individuals that should prevent deficiency disease in 97% of the healthy population.
Tolerable upper intake level (UL) The UL represents a ceiling -- the largest amount of a nutrient that healthy individuals can take each day without being placed at increased risk of adverse health effects or any kind of adverse reaction (negative side effect). The UL for iron is 45 milligrams per day, based on findings of adverse gastrointestinal effects, such as constipation and nausea that can occur when consuming iron supplements, especially when taken on an empty stomach.
A person can be iron deficient with or without anemia; a person can also have “false anemia”, which is a temporary defense measure the body uses to protect itself from nourishing harmful invaders such as bacteria. People with even mild infections can appear to be iron deficient, when in fact their body is withholding iron allowing just enough for body processes while assuring harmful germs cannot get the metal. This condition is called anemia of chronic disease or “false anemia”. It is different from iron deficiency anemia.
There are specific tests to help distinguish between these conditions. There are also supplement and diet tips for keeping iron in a healthy range.
For more information about disorders or tests go to the Resource Section
of The Reading Room.