Dietary reference intake average requirements

Committees of experts organized by the Food and Nutrition Board of the National Academy of Sciences have compiled Dietary Reference Intakes (DRIs)—estimates of the amounts of nutrients required to prevent deficiencies and maintain optimal health. DRIs replace and expand on Recommended Dietary Allowances (RDAs), which have been published wih periodic revisions since 1941. Unlike the RDAs, the DRIs establish Lpper limits on the consumption of some nutrients, and incorporate the role of nutrients in lifelong health, going beyond deficiency diseases. Boh the DRIs and the RDAs refer to long-term average daily nutrient itakes, because it is not necessary to consume the full RDA every day. 

Dietary Reference Intakes for vitamins and minerals in individuals one year and older. EAR = Estimated Average Requirement RDA = Recommended Dietary Allowance ... 

Optimal dietary intake is difficult to determine. Dietary Reference Intakes (DRIs) in the US are reference values that are quantitative estimates of nutrient intakes to be used for planning and assessing diets for apparently healthy people. DRIs are composed of reference values including Estimated Average Requirements (EARs), Recoimnended Dietary Allowances (RDAs), Adequate Intakes (AIs) and Tolerable Upper Intake Levels (ULs). Most nations have established the eqnivalent ofthe US DRIs. These are consensus and statistical valnes obtained from retrospective public health dietary studies, controlled experiments on metabolic wards, epidemiological surveys, isotopic tracer investigations, and extrapolation from animal models. 

The Average Requirement of ascorbic acid is 30 mg/day. The Population Reference Intake is 45 mg/day for adults. The Lowest Threshold Intake, for which considerable evidence exists, is 12 mg/day (1). These estimates have been supported by the relevant committee of the European Union. A communication from the US National Academy of Sciences, as part of the revision of US Dietary Reference Intakes, while estimating rather higher average requirements of ascorbic acid than the EU committee, does (100 mg/day) also proposed a tolerable upper intake... 

The. second organization that provides nutritional guidelines is the Nutrition Board of the National Academy of Sciences. Institute of Medicine. Their guidelines are publi.shed in the form of dietary reference intakes (DRIs), which include. several ways of evaluating the proper intake of vitamins and minerals, such as the e.stimated average requirement (EAR), recommended dietary allowance (RDA). ade-... 

The optimal dietary requirements of vitamin E for humans are not yet known, especially with the emergence of new paradigms regarding adequate levels of dietary micronutrients (Chalem, 1999). Recommendations in the United States and Canada have been reevaluated, and a new concept of Dietary Reference Intake (DRI, 2000) was issued for vitamin E and other antioxidants. The DRI recommendation should prevent specific deficiency disorders, support health in general ways and minimize the risk of toxicity, which carries more tasks than the previous recommendations (DRI, 2000). Accordingly, the recommendations for intakes were set to higher levels than previously. Estimated Average Requirements (EAR) for adults, both men and women, were set to 12 mg a-tocopherol/day, RDA to 15 mg/day and Tolerable Upper Intake Level (UL) to 1000 mg/day. Moreover, the EAR and RDA are based only on the 2R-stereoisomeric forms of a-tocopherol, because the other vitamers... 

Dietary Reference Intakes. There are too few studies to provide sufficient information to estimate Estimated Average Requirements (EAR) or Recommended Dietary Allowances (RDA). 

Dietary Reference Intakes (DRIs) are used quite a lot and refer to a set of four nutrient-based reference values that represent the approach to provide quantitative estimates of nutrient intakes. The DRIs replace and expand on the Recommended Dietary Allowances (RDAs) for the United States and the Recommended Nutrient Intakes (RNIs) for Canada. The DRIs consist of the RDAs, the Tolerable Upper Intake Level (UL), the Estimated Average Requirement (EAR), and the Adequate Intake (AI). Generally, each of these values represents average daily nutrient intake of individuals in the diet (Goldhaber, 2003 Murphy and Poos, 2002 Parr et ah, 2006 Trumbo et ah, 2001 Yates et ah, 1998). In addition, dietary intake data for minerals could be assessed within the context of the bioavailability and other factors affecting the utilization of elements by the human body, such as age, sex, and health aspects (Dokkum, 1995). 

The Food and Nutrition Board of the U.S. National Academy of Sciences has recently devised a new nomenclature for human nutrient needs [30]. Dietary Reference Intakes (DRI) refer to a set of four nutrient-based reference values, termed the estimated average requirement (EAR), the recommended dietary allowance (RDA), adequate intake (AI), and the tolerable upper intake level (UL). The EAR is defined in the same way as in the CEC and UK recommendations. The RDA is now somewhat more rigorously defined to be the EAR + 2 SD (standard deviations), i.e. equivalent to the RNI and PRI in the UK and CEC systems. 

DRIs, dietary reference intakes EAR, estimated average requirement RDA, recommended dietary allowance AI, adequate intake.-Data from Institute of Medicine of the National Academies (2002) Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, Amino Acids. Washington, DC The National Academies Press. 

The recommended dietary allowances (RDA) or dietary reference intakes (DRl) of protein for human male and female adults are in the range of 45-65 g per day. In accordance with this, an intake of 100 g of fish would contribute 15-25% of the total daily protein requirement of healthy adults and 70% of that of children. A look at the dietary importance of the Mediterranean diet is convenient one of its characteristics is the high consumption of all kinds of fish, chiefly fatty fish. In many Mediterranean countries, fish intake averages over 50 g per day (edible flesh) thus, fish protein contributes over 10% of the total daily protein requirements steadily over the whole year in those countries. 

The Recommended Dietary Allowance (RDA) is the average daily dietary intake that is sufficient to meet the nutrient requirement of 97.5% of individuals and is set at 20% above the EAR -1-2 CVs where the CV is 10%. During recent years, dietary reference intakes have been revised by the US Institute of Medicine. The recommended intakes of Mg are given in Table 3. It is not known whether decreased urinary Mg and increased maternal bone resorption provide sufficient amounts of Mg to meet increased needs during lactation. Thus, the French Society for Nutrition suggests adding 30 mg/day to intake for lactation. 

Reference Intakes (DRIs). In the past, the recommended dietary allowances (RDAs), which are the levels of intake of essential nutrients that are considered to be adequate to meet the known nutritional needs of practically all healthy persons, were the primary reference value for vitamins and other nutrients. The DRIs also include other reference values, such as the estimated average requirement (EAR) and the adequate intake (AI). The RDA, EAR, and AI reference standards define nutritional intake adequacy. Since these recommendations are given for healthy populations in general and not for individuals, special problems, such as premature birth, inherited metabolic disorders, infections, chronic disease, and use of medications, are not covered by the requirements. Separate RDAs have been developed for pregnant and lactating women. Vitamin supplementation may be required by patients with special conditions and for those who do not consume an appropriate diet. 

Adequate Intake For some vitamins, notably biotin (Section 11.5) and pantothenic acid (Section 12.6), dietary deficiency is more-or-less unknown, and there are no data from which to estimate average requirements or derive reference intakes. In such cases, the observed range of intakes is obviously more than adequate to meet requirements, and the average intake is used to calculate an adequate intake figure. 

Dietary vitamin D makes little contribution to status, and the major factor is exposure to sunlight, a conclusion that is supported by the two-fold seasonal variation in plasma calcidiol in temperate regions (see Table 3.2). There are no reference intakes for young adults in the United Kingdom and Europe for house-bound elderly people, the reference intake is 10 /rg per day, based on the intake required to maintain a plasma concentration of calcidiol of 20 nmol per L (see Table 3.5). This will almost certainly require supplements of the vitamin, because average intakes are less than half this amount. The U.S./Canadian adequate intake is 5 /xg per day up to age 50, increasing to 10 /xg between 51 to 70, and 15 /xg over 70 years of age (Institute of Medicine, 1997). 

Based on the plasma concentration of a-tocopherol to prevent significant hemolysis in vitro (14 to 16 /xmol per L), the U.S./Canadian estimated average requirement is 12 mg per day, giving a Recommended Dietary Amount (RDA) of 15 mg per day (Institute of Medicine, 2000) - a 50% increase on the previous RDA (National Research Council, 1989). This increase arose partly as a result of considering only the 2R isomers in dietary intake (Section 4.1). Average intakes are of the order of 8 to 12 mg of a -tocopherol equivalent per day it would be difficult meet this reference intake without significant changes in diet or use of supplements. 

The depletion/repletion studies of Horwitt et al. (1956) and others have suggested, on the basis of restoration of urinary excretion of -methyl nicotinamide, that the average niacin requirement is 5.5 mg per 1,000 kcal (1.3 mg per MJ). Allowing for individual variation, reference intakes (see Table 8.2) are set at 6.6 mg niacin equivalents (preformed niacin - -1 /60 of the dietary tryptophan) per 1,000 kcal (1.6 mgper MJ). Even when energy intakes are very low, it must be assumed that energy expenditure will not fall below 2,000 kcal, and this is the basis for the calculation of reference intakes for subjects with low energy intakes. 

More recent depletion/repletion studies, using more sensitive indices of status in which subjects were repleted with either a constant intake of vitamin Be and varying amounts of protein, or a constant amount of protein and varying amounts of vitamin Bg, have shown average requirements of 15 to 16 /xg per g of dietary protein, suggesting a reference intake of 18... 

Vitamin B12 is a mixture of cobalamins. Dietary vitamin B12 is converted to the active forms, methyl-cobalamin (mecobalamin) and adenosylcobalamin. The Average Requirement of total cobalamins in adults is 1.0 microgram/day and the Population Reference Intake is 1.4 micrograms/day. The Lowest Threshold Intake is 0.6 micrograms/day. Hydroxocobalamin (rINN vitamin Bi2a) and cyanocobalamin (rINN) have been used therapeutically. 

If sufficient scientific evidence is not available to calculate an Estimated Average Requirement, a reference intake called an Adequate Intake (Al) is used instead of a Recommended Dietary Allowance. The Al is a value based on experimentally derived intake levels or approximations of observed mean nutrient intakes by a group (or groups) of healthy people. The Al for children and adults is expected to meet or exceed the amount needed to maintain a defined nutritional state or criterion of adequacy in essentially all members of a specific healthy population LA = linoleic acid LNA = n-linolenic acid DHA = docosahexaenoic acid EPA = eicosapentaenoic acid TRANS-EA = trans fatty acids SAT = saturated fatty acids MONOs = monounsaturated fatty acids. 

It is difficult to determine requirements for dietary vitamin D, as the major source is synthesis in the skin. The main criterion of adequacy is the plasma concentration of calcidiol. In elderly subjects with little sunlight exposure, a dietary intake of 10 fg of vitamin D per day results in a plasma calcidiol concentration of 20 nmol/L, the lower end of the reference range for younger adults at the end of winter. Therefore, the reference intake for the elderly is 10 Jg/day. Average intakes of vitamin D are less than 4 Jg/day, so to achieve an intake of 10 Xg/day will almost certainly require either fortification of foods or the use of vitamin D supplements. 

EAR. estimated average requirement RNI, reference nutrient intake DRV, dietary reference value BMR, basal metabolic rate... 

---