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:
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.
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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).[1] 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 current Dietary Reference Intake recommendation is composed of:
The RDA is used to determine the Recommended Daily Value (RDV) which is printed on food labels in the U.S. and Canada.
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.[2]
| Nutrient | EAR | RDA/AI | UL | Unit | Top Sources in Common Measures, USDA[3] |
|---|---|---|---|---|---|
| Vitamin A | 625 | 900 | 3000 | µg | turkey, carrot juice, pumpkin |
| Vitamin C | 75 | 90 | 2000 | mg | orange juice, grapefruit juice, peaches |
| Vitamin D[4][5] | 10 | 15 | 100 | µg | 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 | beef liver, egg, salmon[6] |
| Calcium[4][5] | 800 | 1000 | 2500 | mg | fortified cereals, condensed cow's milk, cheese |
| Chloride | NE | 2300 | 3600 | mg | table salt |
| Chromium | NE | 35 | ND | µg | broccoli, turkey ham, grape juice[7] |
| Choline | NE | 550 | 3500 | mg | beef liver, condensed milk, chicken |
| Copper | 700 | 900 | 10000 | µg | beef liver, oysters, lobster |
| Cyanocobalamin (B12) | 2.0 | 2.4 | ND | µg | beef liver, turkey, clams |
| Fluoride | NE | 4 | 10 | mg | public drinking water |
| Folate (B9) | 320 | 400 | 1000 | µg | egg yolks, enriched white rice, fortified cereals, enriched cornmeal |
| Iodine | 95 | 150 | 1100 | µg | iodized salt |
| Iron | 6 | 8 | 45 | mg | fortified cereals, turkey, chicken |
| Magnesium | 330 | 400 | 350 | mg | buckwheat flour, trail mix, bulgur |
| Manganese | NE | 2.3 | 11 | mg | oat bran, whole grain wheat flour, bulgur |
| Molybdenum | 34 | 45 | 2000 | µg | legumes, grain products, nuts and seeds[8] |
| 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 | tomato paste, orange juice, beet greens |
| Riboflavin (B2) | 1.1 | 1.3 | ND | mg | spaghetti with meat sauce, 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 | 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 |
|---|---|---|---|
| Arsenic | - | ND | - |
| Silicon | - | ND | - |
| Vanadium | - | 1.8 | mg |
RDA/AI is shown below for males and females aged 40–50 years.[2]
| Substance | Amount (males) | Amount (females) | Top Sources in Common Measures[3] |
|---|---|---|---|
| Waterb | 3.7 L/day | 2.7 L/day | iceberg lettuce, beer |
| Carbohydrates | 130 g/day | 130 g/day | condensed milk, pie crust, barley |
| Proteinc | 56 g/day | 46 g/day | duck, chicken, turkey, beef |
| 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 | As low as possible | chicken giblets, turkey giblets, beef liver | |
| Trans fatty acids | As low as possible | ||
| Saturated fatty acids | As low as possible | white chocolate, coconut meat, ricotta cheese | |
| Added sugar | No more than 25% of calories | condensed milk, deglet noor dates, white chocolate | |
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:
RDA = EAR + 2 SD(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
RDA = 1.2 × EAR.
This level of intake statistically represents 97.5 percent of the requirements of the population."[1]
In September 2007, the Institute of Medicine held a workshop entitled “The Development of DRIs 1994–2004: Lessons Learned and New Challenges.”[9] 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.