Vitamins estimated average requirement

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. 

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

Figures for infants under 12 months are Adequate Intakes, based on the observed mean intake of infants fed principally on breast milk for nutrients other than vitamin K, figures are RDA, based on estimated average requirement +2 SD figures for vitamin K are Adequate Intakes, based on observed ...

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. 

Hansen CM, Shultz TD, Kwak HK, Memon HS, and Leklem JE (2001) Assessment of vitamin B-6 status in young women consuming a controlled diet containing four levels ofvitamin B-6 provides an estimated average requirement and recommended dietary allowance./owma/ of Nutrition 131,1777-86. 

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... 

An Estimated Average Requirement (EAR) is the average daily nutrient intake level estimated to meet the requirements of half of the healthy individuals in a group. EARs have not been established for vitamin K, pantothenic acid, biotin, choline, chromium, fluoride, manganese, or other nutrients not yet evaluated via the DRI [cocess... 

Vitamin Bjj is not absorbed very well, so relatively large amounts need to be supplied through the diet The daily intake is estimated at 3-31 p,g and about 20 70% is absorbed. The amount of vitamin Bj2 actually needed by the body of an adult is very small, probably only about 2-3 p-g/day (the estimated average requirement is 2 p,g/day, recommended dietary allowance is 2.4 p,g/day), while pregnant and lactating women need 4 p,g/day. The need is met mainly by meat, meat products and offal (about 70% the richest dietary sources are the liver and kidney), followed by milk and dairy products (about 20%), eggs (about 9%) and cereal products (about 2%). Vegetables and fruits are very poor sources as they contain vitamin Bj2 only if contaminated by faecal bacteria. 

Als) rather than as recommended dietary allowances (RDAs) because insufficient data have been accumulated to determine estimated average requirements (EARs) across the life cycle. The Als listed in Table 1 are totally independent of skin production of vitamin D. Because of the uncertainty of knowing the amount of endogenous vitamin D, it is very difficult to determine, with accuracy, the amounts needed from the diet (see below). 

For some nutrients, such as the vitamins biotin (section 11.12) and pantothenic acid (section 11.13), and a number of trace minerals, deficiency is unknown except under experimental conditions. For these nutrients there are no estimates of average requirements, and therefore no reference intakes. As deficiency does not occur, it is obvious that average levels of intake are more than adequate to meet requirements. For these nutrients there is a range of intakes that is defined as safe and adequate, based on the observed range of intakes. 

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