Dietary Reference Intake

The Dietary Reference Intake (DRI) is a system of nutrition recommendations from the Institute of Medicine (IOM) of the National Academies (United States).[1] It was introduced in 1997 in order to broaden the existing guidelines known as Recommended Dietary Allowances (RDAs, see below). The DRI values differ from those used in nutrition labeling on food and dietary supplement products in the U.S. and Canada, which uses Reference Daily Intakes (RDIs) and Daily Values (%DV) which were based on outdated RDAs from 1968 but were updated as of 2016.[2]


DRI provides several different types of reference values:[1]

  • 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 of the Institute of Medicine to meet the requirements of 97.5% of healthy individuals in each life-stage and sex group. The definition implies that the intake level would cause a harmful nutrient deficiency in just 2.5%. 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 nutrient consumption that is considered to be safe for, and cause no side effects in, 97.5% of healthy individuals in each life-stage and sex group. The definition implies that the intake level would cause a harmful nutrient excess in just 2.5%. The European Food Safety Authority (EFSA) has also established ULs which do not always agree with U.S. ULs. For example, adult zinc UL is 40 mg in U.S. and 25 mg in EFSA.[3]
  • Acceptable Macronutrient Distribution Ranges (AMDR), a range of intake specified as a percentage of total energy intake. Used for sources of energy, such as fats and carbohydrates.

The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States, but values may differ.[4][3]

DRIs are used by both the United States and Canada, and are intended for the general public and health professionals. Applications include:

  • Composition of diets for schools, prisons, hospitals or nursing homes
  • Industries developing new foods and dietary supplements
  • Healthcare policy makers and public health officials


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".[5]

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.

The DRI was introduced in 1997 in order to broaden the existing system of RDAs. DRIs were published over the period 1998 to 2001. In 2011, revised DRIs were published for calcium and vitamin D.[6] None of the other DRIs have been revised since first published 1998 to 2001.

Current recommendations for United States and Canada

Vitamins and minerals

EARs, RDA/AIs and ULs for an average healthy 44-year-old male are shown below. Amounts and "ND" status for other age and gender groups, pregnant women, lactating women, and breastfeeding infants may be much different.[7]

NutrientEARHighest RDA/AIUL[7]UnitTop common sources, 100 grams, U.S. Department of Agriculture (USDA)[8]
Vitamin A6259003000µgcod liver oil, liver, dehydrated red sweet peppers, veal, dehydrated carrots
Thiamin (B1)1.01.2NDmgfortified breakfast cereals, energy bars, vegetarian, and baby food products
Riboflavin (B2)1.11.3NDmgfortified food products, lamb liver, spirulina
Niacin (B3)121635mgfortified food products, baker's yeast, rice bran, instant coffee, fortified beverages
Pantothenic acid (B5)NE5NDmgfortified food and beverage products, dried shiitake mushrooms, beef liver, rice bran
Vitamin B61.11.3100mgfortified food and beverage products, rice bran, fortified margarines, ground sage
Biotin (B7)NE30NDµgorgan meats, eggs, fish, meat, seeds, nuts[9]
Folate (B9)3204001000µgbaker's yeast, fortified food and beverage products, poultry liver
Cobalamin (B12)2.02.4NDµgshellfish, beef, animal liver, fortified food and beverage products
Vitamin C75902000mgfortified beverages, dried sweet peppers, raw acerola, dried chives and coriander, rose hips, fortified food products
Vitamin D1015100µgcod liver oil, mushrooms (if exposed to ultraviolet light), halibut, mackerel, canned sockeye salmon
α-tocopherol (Vitamin E)12151000mgwheat germ oil, fortified food and beverage products, hazelnut oil, fortified peanut butter, chili powder
Vitamin KNE120NDµgdried spices, fresh parsley, cooked and raw kale, chard, other leaf vegetables
CholineNE5503500mgegg yolk, organ meats from beef and pork, soybean oil, fish roe
Calcium80010002500mgfortified cereals, beverages, tofu, energy bars, and baby foods, dried basil and other spices, dried whey, cheese, milk powder
ChlorideNE23003600mgtable salt
ChromiumNE35NDµgbroccoli, turkey ham, dried apricots, tuna, pineapple, grape juice[10]
Copper70090010000µganimal liver, seaweed products, dried shiitake mushrooms, oysters, sesame seeds, cocoa powder, cashews, sunflower seeds
FluorideNE410mgpublic drinking water, where fluoridation is performed or natural fluorides are present, tea, raisins
Iodine951501100µgiodized salt, kelp, cod
Iron6845mgdried thyme and other spices, fortified foods, including baby foods, animal organ meats
Magnesium350420350mgcrude rice bran, cottonseed flour, hemp seeds, dried spices, cocoa powder, fortified beverages
ManganeseNE2.311mgfortified beverages and infant formulas, ground cloves and other dried spices, chickpeas, fortified breakfast cereals
Molybdenum34452000µglegumes, grain products, nuts and seeds[11]
Phosphorus5807004000mgbaking powder, instant pudding, cottonseed meal, hemp seeds, fortified beverages, dried whey
PotassiumNE3400NDmgbaking powder, dried parsley and other spices, instant tea and instant coffee, dried tomatoes, dried sweet peppers, soy sauce
Selenium4555400µgBrazil nuts and mixed nuts, animal kidneys, dried eggs, oysters, dried cod
SodiumNE15002300mgtable salt, baking soda, soup bouillon cube, seasoning mixes, onion soup mix, fish sauce
Zinc9.41140mgoysters, fortified breakfast cereals, baby foods, beverages, peanut butter, and energy bars, wheat germ

NE: EARs have not yet been established or not yet evaluated; ND: ULs could not be determined, and it is recommended that intake from these nutrients be from food only, to prevent adverse effects.

    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:

    SubstanceRDA/AIULunits per day


    RDA/AI is shown below for males and females aged 19-70 years.[7]

    Substance Amount (males) Amount (females) Top Sources in Common Measures[8]
    Water[lower-roman 1] 3.7 L/day 2.7 L/day water, watermelon, iceberg lettuce
    Carbohydrates 45-65% of calories[lower-roman 2] milk, grains, fruits, vegetables
    130 g/day 130 g/day
    Protein[lower-roman 3] 10-35% of calories[lower-roman 4] meats, fish, legumes (pulses and lentils), nuts, milk, cheeses, eggs
    56 g/day 46 g/day
    Fiber 38 g/day 25 g/day barley, bulgur, rolled oats, legumes, nuts, beans, apples
    Fat 20–35% of calories oils, butter, lard, nuts, seeds, fatty meat cuts, egg yolk, cheeses
    Linoleic acid, an omega-6 fatty acid (polyunsaturated) 17 g/day 12 g/day sunflower seeds and oil, safflower oil
    alpha-Linolenic acid, an omega-3 fatty acid (polyunsaturated) 1.6 g/day 1.1 g/day Linseed oil (flax seed), chia seed, hemp seed, walnut, soybeans
    Cholesterol 300 milligrams(mg)[12] chicken giblets, turkey giblets, beef liver, egg yolk
    Trans fatty acids As low as possible partially hydrogenated oils, margarine
    Saturated fatty acids As low as possible while consuming a nutritionally adequate diet coconut meat, coconut oil, lard, cheeses, butter, chocolate, egg yolk
    Added sugar No more than 25% of calories non-natural sweet foods: sweets, cookies, cakes, jams, energy and soda drinks, many processed foods
    1. Includes water from food, beverages, and drinking water.
    2. Acceptable Macronutrient Distribution Range (AMDR).
    3. Based on 0.8 g/kg of body weight.
    4. Acceptable Macronutrient Distribution Range (AMDR).

    Calculating the RDA

    The equations used to calculate the RDA are as follows:

    "If the standard deviation (SD) of the EAR is available and the requirement for the nutrient is symmetrically distributed, the RDA is set at two SDs above the EAR:

    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."[13]

    Standard of evidence

    In September 2007, the Institute of Medicine held a workshop entitled “The Development of DRIs 1994–2004: Lessons Learned and New Challenges.”[14] 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. The only DRIs to have been revised since that meeting are vitamin D and calcium.[6]


    Vitamin A46.0%
    Vitamin C51.0%
    Vitamin E13.6%
    Vitamin B673.9%
    Vitamin B1279.7%
    % calories from total fat <= 35%59.4%
    % calories from saturated fat < 10%55.8%
    Cholesterol intake < 300 mg10.4%
    Sodium intake <= 2,300 mg29.8%

    See also


    1. "A Consumer's Guide to the DRIs (Dietary Reference Intakes)". Health Canada. 2010-11-29. Retrieved 2017-08-29.
    2. "Federal Register, Food Labeling: Revision of the Nutrition and Supplement Facts Labels. FR page 33982" (PDF). US Food and Drug Administration. 27 May 2016.
    3. Tolerable Upper Intake Levels For Vitamins And Minerals (PDF), European Food Safety Authority, 2006
    4. "Overview on Dietary Reference Values for the EU population as derived by the EFSA Panel on Dietetic Products, Nutrition and Allergies" (PDF). 2017.
    5. 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. doi:10.1093/jn/133.11.3698. PMID 14608098.
    6. Dietary Reference Intakes for Calcium and Vitamin D. Washington DC: National Academy Press. 2011. ISBN 0-309-16394-3. Lay summary Institute of Medicine. ..., 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".
    7. Dietary Reference Intakes (DRIs): Recommended Intakes for Individuals, Food and Nutrition Board, Institute of Medicine, National Academies, 2004, retrieved 2009-06-09
    8. "Search ordered by selected nutrient per 100 gram amounts: sort by nutrient among all foods, USDA National Nutrient Database for Standard Reference, SR28". 2016. Retrieved 28 October 2017.
    9. "Biotin, Fact Sheet for Health Professionals". Office of Dietary Supplements, US National Institutes of Health. 3 October 2017. Retrieved 28 October 2017.
    10. "Chromium". Micronutrient Information Center, Linus Pauling Institute, Oregon State University.
    11. "Molybdenum". Micronutrient Information Center, Linus Pauling Institute, Oregon State University.
    12. "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.
    13. Panel on Micronutrients 2001
    14. The Development of DRIs 1994–2004: Lessons Learned and New Challenges. Workshop Summary, November 30, 2007
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