Dietary Reference Intake
The Dietary Reference Intake (DRI) is a system of nutrition recommendations from the Institute of Medicine (IOM) of the U.S. National Academy of Sciences. The DRI system is used by both the United States and Canada and is intended for the general public and health professionals. Applications include:
- Composition of diets for schools, prisons, hospitals or nursing homes
- Industries developing new food stuffs
- Healthcare policy makers and public health officials
The DRI was introduced in 1997 in order to broaden the existing guidelines known as Recommended Dietary Allowances (RDAs). The DRI values are not currently used in nutrition labeling, where the older Reference Daily Intakes are still used.
The Recommended Dietary Allowance (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 United States National Academy of Sciences in order 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, United States Department of Agriculture nutritionists made a new set of guidelines that also included the number of servings of each food group in order to make it easier for people to receive their RDAs of each nutrient.
Current recommendations 
The current Dietary Reference Intake recommendation is composed of:
- Estimated Average Requirements (EAR), expected to satisfy the needs of 50% of the people in that age group based on a review of the scientific literature.
- Recommended Dietary Allowances (RDA), the daily dietary intake level of a nutrient considered sufficient by the Food and Nutrition Board to meet the requirements of 97.5% of healthy individuals in each life-stage and gender group. It is calculated based on the EAR and is usually approximately 20% higher than the EAR (See Calculating the RDA).
- Adequate Intake (AI), where no RDA has been established, but the amount established is somewhat less firmly believed to be adequate for everyone in the demographic group.
- Tolerable upper intake levels (UL), to caution against excessive intake of nutrients (like vitamin A) that can be harmful in large amounts. This is the highest level of daily consumption that current data have shown to cause no side effects in humans when used indefinitely without medical supervision.
The RDA is used to determine the Recommended Daily Value (RDV) which is printed on food labels in the U.S. and Canada.
Vitamins and minerals 
EARs, RDA/AIs and ULs for an average healthy 25-year old male are shown below. EARs shown as "NE" have not yet been established or not yet evaluated. ULs shown as "ND" could not be determined, and it is recommended that intake from these nutrients be from food only, to prevent adverse effects. Amounts and "ND" status for other age and gender groups, pregnant women, lactating women, and breastfeeding infants may be much different.
|Nutrient||EAR||RDA/AI||UL||Unit||Top Sources in Common Measures, USDA|
|Vitamin A||625||900||3000||µg||carrots, carrot juice, turkey, pumpkin|
|Vitamin C||75||90||2000||mg||orange juice, grapefruit juice, peaches, kiwifruit, bell peppers|
|Vitamin D||10||15||100||µg||fortified cereals, mushrooms, yeast, sockeye salmon, swordfish, rainbow trout (also fortified foods and beverages)|
|Vitamin K||NE||120||ND||µg||kale, collards, spinach|
|Vitamin B6||1.1||1.3||100||mg||fortified cereals, chickpeas, sockeye salmon|
|α-tocopherol (Vitamin E)||12||15||1000||mg||fortified cereals, tomato paste, sunflower seeds|
|Biotin (B7)||NE||30||ND||µg||whole grains, almonds, peanuts, beef liver, egg, salmon|
|Calcium||800||1000||2500||mg||fortified cereals, collards, almonds, condensed cow's milk, cheese, figs, orange juice|
|Chromium||NE||35||ND||µg||broccoli, turkey ham, grape juice|
|Choline||NE||550||3500||mg||broccoli, beef liver, condensed milk, peanuts|
|Copper||700||900||10000||µg||sunflower seeds, oysters, lobster|
|Cyanocobalamin (B12)||2.0||2.4||ND||µg||fortified cereals, turkey, clams|
|Fluoride||NE||4||10||mg||public drinking water, where fluoridation is performed or natural fluorides are present|
|Folate (B9)||320||400||1000||µg||leafy greens, enriched white rice, fortified cereals, enriched cornmeal|
|Iron||6||8||45||mg||fortified cereals, turkey, walnuts, seeds|
|Magnesium||330||400?||350?||mg||buckwheat flour, trail mix, bulgur, bananas|
|Manganese||NE||2.3||11||mg||oat bran, whole grain wheat flour, bulgur|
|Molybdenum||34||45||2000||µg||legumes, grain products, nuts and seeds|
|Niacin (B3)||12||16||35||mg||fortified cereals, yellowfin tuna, sockeye salmon|
|Pantothenic acid (B5)||NE||5||ND||mg||fortified cereals, beef liver, shiitake mushrooms|
|Phosphorus||580||700||4000||mg||cornmeal, condensed milk, wheat flour|
|Potassium||NE||4700||ND||mg||potatoes, bananas, tomato paste, orange juice, beet greens|
|Riboflavin (B2)||1.1||1.3||ND||mg||almonds, sesame seeds, spaghetti, beef liver, turkey|
|Selenium||45||55||400||µg||Brazil nuts, rockfish, yellowfin tuna|
|Sodium||NE||1500||2300||mg||onion soup mix, miso, table salt|
|Thiamin (B1)||1.0||1.2||ND||mg||fortified cereals, enriched wheat flour, breadcrumbs|
|Zinc||9.4||11||40||mg||nuts, oysters, fortified cereals, baked beans|
EAR: Estimated Average Requirements; RDA: Recommended Dietary Allowances; AI: Adequate Intake; UL: Tolerable upper intake levels.
It is also recommended that the following substances not be added to food or dietary supplements. Research has been conducted into adverse effects, but was not conclusive in many cases:
|Substance||RDA/AI||UL||units per day|
RDA/AI is shown below for males and females aged 40–50 years.
|Substance||Amount (males)||Amount (females)||Top Sources in Common Measures|
|Waterb||3.7 L/day||2.7 L/day||water, iceberg lettuce|
|Carbohydrates||130 g/day||130 g/day||condensed milk, pie crust, barley|
|Proteinc||56 g/day||46 g/day||duck, chicken, turkey, beef, legumes (pulses and lentils), nuts, seeds, fruits, milk|
|Fiber||38 g/day||25 g/day||barley, bulgur, legumes|
|Fat||20–35% of calories||pie crust, white chocolate, trail mix|
|Linoleic acid, an omega-6 fatty acid (polyunsaturated)||17 g/day||12 g/day|
|alpha-Linolenic acid, an omega-3 fatty acid (polyunsaturated)||1.6 g/day||1.1 g/day|
|Cholesterol||300 milligrams(mg)||chicken giblets, turkey giblets, beef liver|
|Trans fatty acids||As low as possible|
|Saturated fatty acids||20 g||white chocolate, coconut meat, ricotta cheese|
|Added sugar||No more than 25% of calories||condensed milk, deglet noor dates, white chocolate|
- b Includes water from food, beverages, and drinking water.
- c Based on 0.8 g/kg of body weight
Calculating the RDA 
The equations used to calculate the RDA are as follows:
If data about variability in requirements are insufficient to calculate an SD, a coefficient of variation (CV) for the EAR of 10 percent is assumed, unless available data indicate a greater variation in requirements. If 10 percent is assumed to be the CV, then twice that amount when added to the EAR is defined as equal to the RDA. The resulting equation for the RDA is then
This level of intake statistically represents 97.5 percent of the requirements of the population."
Recent developments 
In September 2007, the Institute of Medicine held a workshop entitled “The Development of DRIs 1994–2004: Lessons Learned and New Challenges.” At that meeting, several speakers stated that the current Dietary Recommended Intakes (DRI’s) were largely based upon the very lowest rank in the quality of evidence pyramid, that is, opinion, rather than the highest level – randomized controlled clinical trials. Speakers called for a higher standard of evidence to be utilized when making dietary recommendations.
See also 
- Healthy diet
- Acceptable daily intake — upper limit on intake (United Kingdom)
- Dietary Reference Values — recommended dietary requirements (United Kingdom)
- Harper AE (November 2003). "Contributions of women scientists in the U.S. to the development of Recommended Dietary Allowances". J. Nutr. 133 (11): 3698–702. PMID 14608098.
- "A Consumer's Guide to the DRIs (Dietary Reference Intakes)". Health Canada. 2010-11-29. Retrieved 2012-08-17.
- Dietary Reference Intakes (DRIs): Recommended Intakes for Individuals, Food and Nutrition Board, Institute of Medicine, National Academies, 2004, retrieved 2009-06-09
- Dietary Reference Intakes (DRIs): Tolerable Upper Intake Levels, Vitamins., Food and Nutrition Board, Institute of Medicine, National Academies, 1997
- USDA National Nutrient Database for Standard Reference, SR23, 2010
- Dietary Reference Intakes for Calcium and Vitamin D. Washington DC: National Academy Press. 2011. ISBN 0-309-16394-3. [..., The IOM finds that the evidence supports a role for vitamin D and calcium in bone health but not in other health conditions. Further, emerging evidence indicates that too much of these nutrients may be harmful, challenging the concept that “more is better Lay summary].
- "Biotin". Micronutrient Information Center, Linus Pauling Institute, Oregon State University.
- "Chromium". Micronutrient Information Center, Linus Pauling Institute, Oregon State University.
- "Molybdenum". Micronutrient Information Center, Linus Pauling Institute, Oregon State University.
- "14. Appendix F: Calculate the Percent Daily Value for the Appropriate Nutrients". Guidance for Industry: A Food Labeling Guide. Office of Nutrition, Labeling, and Dietary Supplements, Center for Food Safety and Applied Nutrition, Food and Drug Administration, U.S. Department of Health and Human Services. October 2009.
- Panel on Micronutrients 2001
- The Development of DRIs 1994–2004: Lessons Learned and New Challenges. Workshop Summary, November 30, 2007
Further reading 
- Nestle, Marion (2002). Food Politics. Berkeley: University of California Press. ISBN 0-520-22465-5.
- Panel on Micronutrients, Subcommittees on Upper Reference Levels of Nutrients and of Interpretation and Use of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes (2001). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington DC: National Academy Press. ISBN 0-309-07279-4.
- US Government Food and Nutrition Information Center list of Dietary Reference Intakes (DRI) and Recommended Dietary Allowances (RDA, the deprecated nutritional recommendations)
- USDA RDA chart (PDF file)
- USDA Dietary Reference Intakes (DRI)
- Article comparing recommended amounts of vitamins and minerals in different countries from the European Union (PDF file)
- Differences in RDA set by medical authorities in the UK, the European Union and the USA.