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). 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in nutrition labeling in the U.S. and Canada, which uses Reference Daily Intakes (RDIs) and Daily Values (%DV) based on outdated RDAs from 1968.

The DRI provides several different types of reference value:

• 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, zinc UL is 40 mg in U.S. and 25 mg in EFSA.
• 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 DRI 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

History

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".

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 2010, revised DRIs were published for calcium and vitamin D.

Current recommendations

The current DRI values may differ from those used in nutrition labeling in the U.S. and Canada, which uses Reference Daily Intakes (RDIs) and Daily Values (%DV) based on RDAs from 1968. Example of DRIs not matching DVs: the U.S. RDA for vitamin B12 is 2.4 µg/day whereas 100% DV is 6.0 µg/day.

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.

• "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.

Nutrient	EAR	RDA/AI	UL	Unit	Top Sources in Common Measures, USDA
Vitamin A	625	900	3000	µg	turkey and chicken giblets, liver, red capsicum, carrots, pumpkin, sweet potato
Vitamin C	75	90	2000	mg	guavas, oranges, grapefruits, frozen peaches, bell peppers
Vitamin D	10	15	100	µg	fortified cereals, mushrooms, yeast, sockeye salmon, swordfish, rainbow trout, sardines, cod liver oil (also fortified foods and beverages)
Vitamin K	NE	120	ND	µg	kale, collards, spinach, broccoli, brussel sprouts, asparagus, prunes, green peas
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 yolk, salmon
Calcium	800	1000	2500	mg	fortified cereals, collards, almonds, condensed cow's milk, cheese, figs, yogurt, milk
Chloride	NE	2300	3600	mg	table salt
Chromium	NE	35	ND	µg	broccoli, turkey ham, dried peaches, tuna, grape juice
Choline	NE	550	3500	mg	egg yolk, meats, lecithin, beef liver, condensed milk, quinoa, salmon, cod
Copper	700	900	10000	µg	sesame seeds, sunflower seeds, oysters, lobster, cashews, dark chocolate, pearled barley, Brazil nuts, walnuts, peanuts, yellow peas, chickpeas
Cyanocobalamin (B12)	2.0	2.4	ND	µg	fortified cereals, turkey, clams, beef, egg yolk, sardines, tuna fish, mackerel
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
Iodine	95	150	1100	µg	iodized salt, kelp, cod
Iron	6	8	45	mg	cocoa powder, cashew nuts, white beans, turkey, dark chocolate
Magnesium	330	400	350	mg	buckwheat flour, rolled oats, spinach, almonds, dark chocolate, bulgur, quinoa
Manganese	NE	2.3	11	mg	oat bran, whole grain wheat flour, bulgur, rolled oats, brown rice, parboiled rice, dark chocolate
Molybdenum	34	45	2000	µg	legumes, grain products, nuts and seeds
Niacin (B3)	12	16	35	mg	fortified cereals, yellowfin tuna, sockeye salmon, chicken meat
Pantothenic acid (B5)	NE	5	ND	mg	fortified cereals, beef liver, shiitake mushrooms
Phosphorus	580	700	4000	mg	cornmeal, condensed milk, wheat flour, rolled oats, brown rice, bulgur, milk, meats
Potassium	NE	4700	ND	mg	potatoes, bananas, tomato paste, tomatoes, bell peppers, orange juice, beet greens, quinoa, rolled oats, bulgur, beans, peas, cashews, pistachio nuts
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, beef, sardines, salmon, egg yolk, pearled barley, mackerel
Sodium	NE	1500	2300	mg	onion soup mix, miso, table salt, egg whites
Thiamin (B1)	1.0	1.2	ND	mg	fortified cereals, enriched wheat flour, breadcrumbs
Zinc	9.4	11	40	mg	nuts, oysters, fortified cereals, beef, baked beans, oatmeal

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

Macronutrients

RDA/AI is shown below for males and females aged 40–50 years.

Substance	Amount (males)	Amount (females)	Top Sources in Common Measures
Water	3.7 L/day	2.7 L/day	water, watermelon, iceberg lettuce
Carbohydrates	130 g/day	130 g/day	milk, grains, fruits, vegetables
Protein	56 g/day	46 g/day	meats, fish, legumes (pulses and lentils), nuts, milk, cheeses, eggs
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, sunflower oil, safflower oil,
alpha-Linolenic acid, an omega-3 fatty acid (polyunsaturated)	1.6 g/day	1.1 g/day	Linseed oil (Flax seed), salmon, sardines
Cholesterol	300 milligrams(mg)		chicken giblets, turkey giblets, beef liver, egg yolk
Trans fatty acids	As low as possible
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		foods that taste sweet but are not found in nature, such as sweets, cookies, cakes, jams, energy drinks, soda drinks, many processed foods

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:

$RDA = EAR + 2SD(EAR)$

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

$RDA = 1.2EAR$

This level of intake statistically represents 97.5 percent of the requirements of the population."

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.” 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.

Adherence

Nutrient	Percent of U.S. population ages 2+ meeting EAR in 2004
Protein	88.9%
Vitamin A	46.0%
Vitamin C	51.0%
Vitamin E	13.6%
Thiamin	81.6%
Riboflavin	89.1%
Niacin	87.2%
Vitamin B6	73.9%
Folate	59.7%
Vitamin B12	79.7%
Phosphorus	87.2%
Magnesium	43.0%
Iron	89.5%
Selenium	91.5%
Zinc	70.8%
Copper	84.2%
Calcium	30.9%
Fiber	8.0%
Potassium	7.6%
% calories from total fat <= 35%	59.4%
% calories from saturated fat < 10%	40.8%
Cholesterol intake < 300 mg	68.4%
Sodium intake <= 2,300 mg	29.9%

See also

• Acceptable daily intake – upper limit on intake (United Kingdom)
• Canada's Food Guide
• Dietary Reference Values – recommended dietary requirements (United Kingdom)
• Dietary mineral
• Essential amino acid
• Essential fatty acid
• Essential nutrient
• Food composition
• Food guide pyramid
• Healthy diet
• Reference Daily Intake
• Reference Intakes – a system of nutrient labeling used in Europe
• Vitamin poisoning

External links

• Dietary Reference Intakes Tables and Application, Institute of Medicine of the National Academies