Fundamentals of Human Nutrition/Dietary Reference Intakes

Dietary Reference Intakes

The National Center for Biotechnology Information defines dietary reference intakes (DRIs) as reference values that are quantitative estimates of nutrients (such as vitamins, proteins, fats, and other food components, such as fiber) intakes to be used for planning and assessing diets for healthy people. Dietary reference intake values vary by age, gender, and stage of life. It includes: estimated average requirements, recommended dietary allowance, adequate intakes, and tolerable upper limits.

"Estimated average requirements (EAR)" are the intake levels for nutrients estimated to meet the needs of half of the healthy individuals in a particular group (National Agricultural Library). EAR’s are used to gauge the adequacy of the populations food supply. An additional purpose of the EAR is that they are used as the basis for calculating the recommended dietary allowances for individuals

"Recommended dietary allowance (RDA)" are the intake levels for nutrients that meet the needs of nearly all healthy individuals in a particular group (National Institutes of Health). In this particular case, nearly means 97% of the individuals in a distinct group. By meeting a RDA value an individual lowers their chance of a deficiency. Hospitals and schools use RDA values to create healthy meals by making sure an ample amount of vitamins and minerals are in each dish. RDA’s are extremely useful and they apply to most nutrients. However, there are some cases where RDA’s cannot be established because there is not enough data. When this occurs an adequate intake is established.

"Adequate Intakes (AI)" are the approximations of the needed nutrient intakes when no RDAs exist (United States National Agricultural Library). An Adequate intake value is based on what healthy individuals typically eat, so an AI can be used as a target amount for a certain nutrient to help plan a healthy diet. People use AI’s in their everyday life when they look at different food components in a food item. For example, the fiber that is in cereal or bread.

The last set of dietary reference intakes is the "tolerable upper limit (UL)". This is the highest level of any nutrient or vitamin that nearly all the healthy people in a certain group can consume without having negative outcomes or side effects (National Institutes of Health). This limit is created to avoid toxicity. As intake increases above the UL, the potential risk of adverse effects may increase. Some nutrients may not have an established UL because there is a lack of data referring to adverse side effects in a particular group.

The Dietary Reference Intakes are developed and published by the Institute of Medicine (IOM). The DRIs represent the most current scientific knowledge on nutrient needs of healthy populations. Another often used term for the same nutrient content is Daily Value or %DV as the content in a given food amount. The DRI system is used by both the United States and Canada and is intended for the general public and health professionals

References

Dietary Reference Intakes. (n.d.). Retrieved November 26, 2015, from https://fnic.nal.usda.gov/dietary-guidance/dietary-reference-intakes Institute of Medicine (US) Food and Nutrition Board. (n.d.). Retrieved November 26, 2015, from http://www.ncbi.nlm.nih.gov/books/NBK45182/ Interactive DRI Glossary. (n.d.). Retrieved November 26, 2015, from https://fnic.nal.usda.gov/interactive-dri-glossary (n.d.). Retrieved November 26, 2015, from http://study.com/academy/lesson/dietary-reference-intakes-ear-rda-ai-ul.html

What is the dietary reference intake, otherwise known as the DRI? It is a collection of four reference values that include the Tolerable Upper Intake Level (UL), Recommended Dietary Allowance (RDA), Adequate Intake (AI), and Estimated Average Requirement (EAR). (“Dietary Reference”, 1998) All of these values together as the DRI represent the estimated nutrient intake that is appropriate for a healthy population. Created specifically for different gender groups and life stages, the values can vary depending on the category in which people identify with. (“Dietary Reference”, 1998) The values have been determined by utilizing an “expanded concept” that assesses indicators of proper health, adverse effects of overconsumption, and places an emphasis on chronic disease prevention. (“Dietary Reference”, 1998) Thousands of studies have been taken into consideration, resulting in a system that provides recommended intakes, but also upper intake levels to avoid harm that comes with digesting too much of a nutrient. Since these measurements are designed to meet the needs of people who are healthy and well, it is suggested that people with specific conditions are nutritional needs seek the advice or help from a health care professional. (Dobbins & Stencel, 2002) Several Medical Health and Nutrition boards in both the United States and Canada undertook this project. (“Dietary Reference”, 1998)

The Four Categories

The Recommended Dietary Allowance (RDA) is the daily average intake level appropriate to meet the nutrient needs of nearly 98% of all people in a given population determined by life stage and gender. This intake level should be utilized as a goal to meet nutritional needs. (“Dietary Reference”, 1998)

The Estimated Average Requirement is a daily nutrient intake amount that is predicted to meet health requirements in half of the people in a given population. This value proves to not be useful when used alone, but is used to help calculate the RDA. However, when combined with an estimated variance of intake, the EAR may be used to assess the consumption of a group of people, or used when planning appropriate intake levels for a group of people. (Beaton, 1994)

Next, the Adequate Intake (AI) should be utilized in circumstances for which there are no scientific facts to calculate the EAR. The AI looks at the level of consumption of an observed mean nutrient intake from a population of healthy people and is experimentally derived. It is believed that this value should either meet or exceed the appropriate nutrient amount required for every member in a healthy population. (“Dietary Reference”, 1998)

Finally, the Tolerable Upper Intake Limit (UL) is set as the highest intake level of nutrients that is likely to pose no risk health effects to almost every individual in the general population. The more people rise above the UL, the more likely they are to experience health effect. (“Dietary Reference”, 1998) This value is important to make sure people do not consume too much of any nutrient that could result in harm to them. (Dobbins & Stencel, 2002)

Vitamins When determining the DRI for vitamins, several things are taken into consideration. The goal is to determine a level in which the nutrients are able to perform their function, without side effects or excess excretion of the nutrients. Particularly close attention has been given to the intake of choline and B vitamins to avoid the risk of developing chronic disease or developmental disabilities. (“Dietary Reference”, 1998) The range between those two extremes is the DRI.  

References Beaton GH. (1994). Criteria of an adequate diet. In: Shils ME, Olson JA, Shike M, eds. Modern Nutrition in Health and Disease, 8th ed. Philadelphia: Lea & Febiger. Pp. 1491–1505. [Online book] Dobbins, Chris, & Stencel, Christine. (2002). Reports Offer New Eating and Physical Activity Targets to Reduce Chronic Disease Risk. The National Academies of Science, Engineering, and Medicine. Retrieved from http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=10490 Institute of Medicine. (1998). Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: The National Academies Press, doi:10.17226/6015 [Online book]

Edited my HC

The Dietary Reference Intakes (DRI) is a set of nutrient intake values for healthy people in the United States and Canada. Through completed research studies nutrition experts have standardized these numbers to define the amounts of energy, nutrients, other dietary components, and physical activity that best support health. The DRI is broken down into four categories: Estimated Average Requirements (EAR), Recommended Dietary Allowances (RDA), Adequate Intakes (AI), and Tolerable Upper Intake Levels (UL).

Estimated Average Requirements

Definition: the average daily amount of a nutrient that will maintain a specific biochemical or physiological function in half the healthy people of a given age and gender group

The EAR was determined to quantify how much of a nutrient is required in the diet. The value, although subjective for each individual, is based upon factors such as the specific nutrients role in supporting activities of the body and the amount needed to reduce risks of diseases. Therefore, when comparing one individual to another, one may need more of a nutrient to maintain healthy body activities while the other may need far less to obtain the same level of functionality. By reviewing and studying entire populations, researchers were able to obtain an average that signified the amount of a nutrient needed for at least half the population.

Recommended Dietary Allowances

Definition: the average daily amount of a nutrient considered adequate to meet the known nutrient needs of practically all healthy people

The RDA was established so that a majority of the population would meet the necessary intake for nutrients. Since the EAR has a set point for that accommodates for half of the people in a population, the RDA aims to make sure almost all the population is getting enough of each nutrient. Because nutrient values differ from person to person, if everyone only consumed the EAR amount, half the population would be consistently deficient. To counter this, RDA is set near the top range to ensure that a majority of the population is meeting their proper intake. Even though some people may be consuming more of a nutrient than needed the small amounts greater than what their recommended for will do them no harm.

Adequate Intake

Definition: a value based on observed or experimentally determined approximations of nutrient intake by a group (or groups) of healthy people-used when an RDA cannot be determined

The AI reflects the average amounts of a nutrient that a group of healthy people consume because there is not sufficient scientific evidence to determine an EAR for it. Therefore AI values for specific nutrients are considered tentative values while the RDA values are more concrete.

Tolerable Upper Intake Levels

Definition: the maximum daily amount of a nutrient that appears safe for most healthy people and beyond which there is an increased risk of adverse health effects

Overconsuming a particular nutrient heavily or frequently past the recommended RDA can be toxic to an individual. These high doses can lead a number of symptoms that will endanger a body’s structure and function. This is why dietary supplements and fortified foods can be dangerous to certain individuals because if taken regularly the nutrient will become toxic to body and unhealthy diseases could develop.

References:

• Whitney, E., & Rolfes, S. (2002). An Overview of Nutrition. In Understanding nutrition (14th ed.). Belmont, California: Wadsworth.

• NETx. (n.d.). Retrieved December 1, 2015, from http://netx.squaremeals.org/nut_needs_dring_life.html

• Institute of Medicine (US) Food and Nutrition Board. Dietary Reference Intakes: A Risk Assessment Model for Establishing Upper Intake Levels for Nutrients. Washington (DC): National Academies Press (US); 1998. What are Dietary Reference Intakes? Available from: http://www.ncbi.nlm.nih.gov/books/NBK45182/

Edited by BM

Nutrition experts, thanks to the collaborative efforts of numerous research studies, have compiled information that shows the recommended amount of dietary components and physical activity necessary to support a healthy lifestyle. These recommended dietary amounts are known as the DRI, or Dietary Reference Intakes. These values are not the same for each individual due to each person in a population being different because of a variety of factors. However, some values can account for a large portion of the population. The DRI can be divided into four subtopics that grant a more holistic understanding of what these numbers mean.

• Estimated Average Requirement (EAR): This category refers the average amount of a nutrient that is required to help the body maintain a healthy physiology and ensure biochemical functions continue. Due to not every person needing the same amount of nutrients from any single source, numbers vary based on gender, age, physical activity, and many other variables, so the EAR accounts for only half the population.

• Recommended Dietary Allowances (RDA): This category refers to the recommended average amount of a nutrient that adequately fulfills the dietary needs of an individual. While the EAR accounts for half the population, the RDA accounts for 98% of the population and the amount it recommends is slightly higher than the EAR. This is because consuming slightly more than the daily recommendation for a nutrient does not do nearly as much harm as slightly below, so the RDA is positioned towards the top of the overall population's estimated needs at 98%.

• Adequate Intakes (AI): This category substitutes for the RDA when it cannot be determined due to a lack of information pertaining to specific nutrients. This value is usually used for determining how much of a nutrient should be consumed by healthy individuals. While the AI can be used, the RDA does a better job due to it covering the majority of the population, all the while having plenty of research backing its credibility.

• Tolerable Upper Intake Levels (UL): This category deals with the point that consumption of a nutrient is likely to develop a toxicity. This means that eating too much of a nutrient can prove detrimental to one's health. The UL consists of values that mark what amount of a nutrient can prove dangerous. However, the UL is not a specific number that means you will immediately fall ill upon reaching it. The UL means that once that value is reached, the individual is at a much higher risk of encountering health complications.

References:

• Whitney, E., & Rolfes, S. (n.d.). Chapter 1: Overview of Nutrition, Section 1.4a. In Understanding nutrition (Fourteenth ed.).

1.4.2.2 Vitamins

Vitamins are compounds that occur naturally in foods and are essential for several functions. They can be either fat-soluble or water-soluble. Fat-soluble vitamins are metabolized and stored by the fat in your body. Water-soluble vitamins are not stored and must be consumed every day. Your body excretes the water-soluble vitamins it doesn't use. Eating a balanced diet, incorporating foods from all food groups, ensures you get all of the important vitamins you need.

1.4.2.3 Minerals

Minerals are inorganic elements that are necessary for many processes in the body. There are two categories in which they are divided into, which are major minerals and minor minerals. Major minerals are the essential mineral nutrients that are required by the body in relatively large amounts, which is greater than 100 milligrams daily. Trace minerals are the essential mineral nutrients that are required by the body in relatively small amounts, which is less than 100 milligrams daily. It is important to be familiar with the Tolerable Upper Intake Level (UL) for each of the various minerals in order to avoid toxicity symptoms that could potentially arise if taken in excessive amounts. Tolerable Upper Intake Level (UL) is the highest average intake of a specific nutrient that can be taken without a risk of adverse health effects to almost all people in a general population. In addition, as an intake rises above the UL, the risk for adverse health effects rises as well.

The necessity for setting a UL arose from the increased fortifications of foods with nutrients over time and the increased use of dietary supplementation. It is important to remember that the UL is not a recommended level of intake, but the highest intake of a nutrient that can be tolerated by the body without any adverse health effects. Not all nutrients have a set upper limit due to insufficient data that points that specific nutrient to an adverse reaction. Therefore, it is advisable to practice caution when consuming these nutrients in large amounts because it doesn’t mean that they can’t pose health risks. Potassium is a mineral without a set upper limit. Chromium is also one the minerals that doesn’t have a UL due to data insufficiencies. There also isn’t any strong evidence that excess intake of chromium has led to an adverse health effect. Currently, the dietary intake of potassium is considerably lower than the AI in the United States and Canada. It is especially important for increased intake amongst African Americans due to high prevalence of high blood pressure and salt sensitivity. In a healthy population with normal kidney function, any excess potassium intake about the AI would be excreted in urine. Therefore an UL is not established. The UL for iron is 45 milligrams daily for adults due to the adverse effect of gastrointestinal distress. The UL for copper is 10 milligrams daily due to the adverse effect of liver damage. In the instance of fluoride, the UL stems from the risk of developing early signs of skeletal fluorosis. The UL for fluoride is 10 milligrams daily.

Citations

Otten, J. (2006). DRI, dietary reference intakes the essential guide to nutrient requirements (p. 8, 12, 299). Washington, D.C.: National Academies Press. http://www.nal.usda.gov/fnic/DRI/Essential_Guide/DRIEssentialGuideNutReq.pdf Otten, J. (2001). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. In DRI, dietary reference intakes the essential guide to nutrient requirements (p. 290). Washington, D.C.: National Academies Press. http://www.nal.usda.gov/fnic/DRI//DRI_Vitamin_A/290-393_150.pdf Otten, J. (2004). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. In DRI, dietary reference intakes the essential guide to nutrient requirements (pp. 187–188). Washington, D.C.: National Academies Press. http://www.nal.usda.gov/fnic/DRI//DRI_Water/186-268.pdf Whitney, E., & Rolfes, S. (2016). Understanding nutrition (14th ed.). Belmont, CA: Thomson/Wadsworth. http://ng.cengage.com/static/nb/ui/index.html?nbId=196342&nbNodeId=58604887&deploymentId=4842767387588213997397576#!&parentId=58605067