Reference Daily Intake
The Reference Daily Intake or Recommended Daily Intake (RDI) is the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97–98% of healthy individuals in every demographic in the United States (where it was developed, but has since been used in other places).
The RDI is used to determine the Daily Value (DV) of foods, which is printed on nutrition facts labels in the United States and Canada, which is regulated by the Food and Drug Administration (FDA), and Health Canada.
The RDI is based on the older Recommended Dietary Allowance (RDA) from 1968; newer RDAs have since been introduced in the Dietary Reference Intake system, but the RDI is still used for nutrition labeling.
Food labeling reference tables 
The following table lists the DVs based on a calorific intake of 2,000 cal, for adults and children four or more years of age.
|Total Fat||65 g|
|Saturated Fatty Acids||20 g|
|Total Carbohydrate||300 g|
|Dietary Fiber||25 g|
|Nutrient||RDI||highest RDA of DRI|
|Vitamin A||900 μg||900 μg|
|Vitamin C||60 mg||90 mg|
|Calcium||1000 mg||1300 mg|
|Iron||18 mg||18 mg|
|Vitamin D||400 IU (10 μg)||600 IU|
|Vitamin E||30 IU||15 mg (33 IU of synthetic)|
|Vitamin K||80 μg||120 μg|
|Thiamin||1.5 mg||1.2 mg|
|Riboflavin||1.7 mg||1.3 mg|
|Niacin||20 mg||16 mg|
|Vitamin B6||2 mg||1.7 mg|
|Folate||400 μg||400 μg|
|Vitamin B12||6 μg||2.4 μg|
|Biotin||300 μg||30 μg|
|Pantothenic acid||10 mg||5 mg|
|Phosphorus||1000 mg||1250 mg|
|Iodine||150 μg||150 μg|
|Magnesium||400 mg||420 mg|
|Zinc||15 mg||11 mg|
|Selenium||70 μg||55 μg|
|Copper||700 μg||900 μg|
|Manganese||2 mg||2.3 mg|
|Chromium||120 μg||35 μg|
|Molybdenum||75 μg||45 μg|
|Chloride||3400 mg||2300 mg|
The RDA was developed during World War II by Lydia J. Roberts, Hazel Stiebeling and Helen S. Mitchell, all part of a committee established by the U.S. National Academy of Sciences to investigate issues of nutrition that might "affect national defense" (Nestle, 35). The committee was renamed the Food and Nutrition Board in 1941, after which they began to deliberate on a set of recommendations of a standard daily allowance for each type of nutrient. The standards would be used for nutrition recommendations for the armed forces, for civilians, and for overseas population who might need food relief. Roberts, Stiebeling, and Mitchell surveyed all available data, created a tentative set of allowances for "energy and eight nutrients", and submitted them to experts for review (Nestle, 35). The final set of guidelines, called RDAs for Recommended Dietary Allowances, were accepted in 1941. The allowances were meant to provide superior nutrition for civilians and military personnel, so they included a "margin of safety". Because of food rationing during the war, the food guides created by government agencies to direct citizens' nutritional intake also took food availability into account.
The Food and Nutrition Board subsequently revised the RDAs every five to ten years. In the early 1950s, USDA nutritionists made a new set of guidelines that also included the number of servings of each food group to make it easier for people to receive their RDAs of each nutrient.
In 1997, at the suggestion of the Institute of Medicine of the National Academy, RDA became one part of a broader set of dietary guidelines called the Dietary Reference Intake used by both the United States and Canada.
Disputed value 
The value of RDA/RDIs is disputed among nutritionists. Indeed, even the "definition of RDAs and their relevance to health" is disputed.
For example, the daily maximum for some nutrients, like sodium are higher in the U.S. than in other parts of the developed world, and are far above established safe minimums. For instance, the National Research Council has found that 500 mg of sodium per day (approximately the amount in a quarter-teaspoon of table salt) is a safe minimum level. In Great Britain, the daily allowance for salt is 6g (approximately 1 tablespoon, about the upper limit in the U.S.), but are still considered "too high".
See also 
- Dietary Reference Values (United Kingdom)
- Canada's Food Guide
- Dietary mineral
- Essential amino acid
- Essential fatty acid
- Essential nutrient
- Food guide pyramid
- Healthy diet
- "Council for Responsible Nutrition". Crnusa.org. Retrieved 2011-03-30.
- "Information for Consumers (Drugs)". Fda.gov. 2008-10-29. Retrieved 2011-03-30.
- "Electronic Code of Federal Regulations:". Ecfr.gpoaccess.gov. Retrieved 2011-03-30.
- Peter L. Pellett, "Commentary: The R.D.A. Controversy Revisited" Ecology of Food and Nutrition 21:315, 1988
- "IOM Salt Reduction Strategies Report". .nationalacademies.org. 2010-04-20. Retrieved 2011-03-30.
- "Statement from the National High Blood Pressure Education Program". Nhlbi.nih.gov. 1999-10-14. Retrieved 2011-03-30.
- "Recommended Dietary Allowances: 10th Edition". Nap.edu. Retrieved 2011-03-30.
- "Daily salt intake allowances 'were set too high'". BBC News. 2009-11-25. Retrieved 2011-03-30.
- "Health | Britons told to cut salt intake". BBC News. 2004-09-13. Retrieved 2011-03-30.
Nestle, Marion. Food Politics. Berkeley: University of California Press, 2002. ISBN 979-0520224659.
- Food and Nutrition Information Center
- USDA Reference Daily Intakes
- Differences in RDA set by medical authorities-->link does not work in the UK, the European Union and the USA.