Since 1941 the Recommended Dietary Allowances for the intake of vitamins and minerals as well as fat, protein, and carbohydrate has been published by the National Academy of Sciences.

New standards called Dietary Reference Intakes have been created in the past five years to guide the use of vitamins and minerals for the populations in the United States and Canada. These standards are formulated by a blue ribbon panel within the National Academy of Science called the Food and Nutrition Board of the Institute of Medicine.

The Institute of Medicine is made up primarily of medical school and university faculty. They have a broad depth of experience and try to take all aspects into consideration before making their recommendations.

Each person taking a vitamin or mineral (micronutrient) supplement should have an understanding of what the recommendations are and why a particular amount is selected. Below is a definition of the common terms used at this web site and on the labels of foods and supplements.

Dietary Reference Intakes (DRIs) is a term referring to four types of values:

• Recommended Dietary Allowances (RDAs) are the dietary intakes sufficient to meet the nutrient requirements of nearly all healthy individuals (97 to 98%) in a group.
• Adequate Intakes (AIs) are used for daily intake guidelines when there is inadequate scientific evidence to be certain of the RDAs. Adequate Intakes are arrived at by experiments or observations demonstrating a diet which seems to prevent an unwanted result. For example insufficient intake of calcium causes calcium loss from bone.
• Estimated Average Requirements (EARs) are the intakes estimated to meet the nutrient requirements in at least 50% of a specific group. EARs are used in experimental studies to assess the adequacy of intakes for population groups and not as a recommended intake level.
• Tolerable Upper Intake Levels (ULs) are the maximum levels of daily intake that are unlikely to harm healthy people. The Tolerable Upper Intake Level is not intended to be a recommended level of intake. The need for defining ULs grew out of the increasing nutrient fortification of foods, and the growing use of dietary supplements, in larger doses, by more and more of the population.

The reference intake values are designed to meet the needs of individuals in the United States and in Canada who are healthy and free from specific diseases or conditions that may alter their daily nutritional requirements.

• View Table of DRIs for Vitamin C, Vitamin E, Selenium and Cartenoids
• View Table of DRIs for Thiamine, Ribloflavin, Niacin, Vitamin B6, Folate,
  Vitamin B12, Pantothnic Acid and Choline
• View Table of DRIs for Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride
• View Table of DRIs for Vitamin A, Vitamin K, Slenium, Manganese, Chromium, Copper, Iodine, Iron, Zinc, Boron, Molybdenum, Arsenic, Silicon and Vanadium