Intake estimates recommendations

It was recommended that the first step is to use a conservative, theoretical/hypothetical approach (such as the budget method) if no problems are encountered, then there is no need for further estimation. The next step would be a refinement of the intake estimate by undertaking a 3-day dietary study supplemented with a food frequency questionnaire to estimate percentage of consumers a minimum study population size would be 200 persons. If the intake estimate is stiU above the ADI, it would be necessary to carry out a risk assessment. 

The risk to health from chemicals in food can be assessed by comparing estimates of dietary exposure with recommended safe levels of exposure. For most metals and other elements, these are the Provisional Tolerable Weekly Intakes (PTWIs) and the Provisional Tolerable Daily Intakes (PTDIs) recommended by the Joint Expert Committee on Food Additives of the Food and Agricultural Organisation of the United Nations and the World Health Organisation International Programme on Chemical Safety (JECFA). The European Commission s Scientific Committee on Food has established other relevant safe levels. These are Acceptable Daily Intakes (ADIs) for chemicals added to food, and Tolerable Daily Intakes (TDIs) for chemical contaminants. The use of the term tolerable implies permissibility rather than acceptability. All the above recommendations are estimates of the amount of substance that can be ingested over a lifetime without appreciable risk, expressed on a daily or weekly basis as appropriate. 

Adequate Intake (AI). Estimated recommendation of a nutrient, based on survey of scientific data on healthy subjects, when the RDA cannot be... 

Estimated recommended human daily intake required as a function of age (source Institute of Medicine). 

Ca requirements in the United States are currently set as AIs. The recommended AI for Ca is an approximated value estimated to cover the needs of all healthy individuals in the age group based on experimental or observational data that show a mean intake which appears to sustain a desired indicator of health (e.g., desirable Ca retention) however, lack of sufficient evidence precludes specifying with confidence the percentage of individuals covered by this intake (Standing Committee of the Scientific Evaluation of Dietary Reference Intakes, Food and Nutrition Board, and Institute of Medicine, 1997). 

Recommended dietary allowances for vitamins have proved to be useful guidelines however it has to be appreciated that these guidelines are not more than estimates made from experiments on only a limited number of subjects. These recommended dietary allowances also need periodic reevaluation. While vitamin deficiencies due to inadequate intakes are encountered in developing countries, few cases are seen in the Western world apart from patients with an increased risk for deficiencies such as diabetics or alcoholics. On the contrary, the widely held belief that vitamins promote better health is deceptive and may lead to overdose disorders. 

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. 

The total body content of chromium is estimated to be 6 to 10 mg. The recommended safe limit for daily chromium intake by adult is 0.05 to 0.2 mg. 

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 ... 

Adequate Intake (Al) The Al is set instead of an RDA if sufficient scientific evidence is not available to calculate an EAR or RDA The Al is based on estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate. For example, the Al for young infants, for whom human milk is the recommended sole source of food for the first four to six months, is based on the estimated daily mean nutrient intake supplied by human milk for healthy, full-term infants who are exclusively breast-fed. 

Research Council defined 1 mg of a-tocopherol as 1 unit of a-TE (mg x 1). The activities as a-TE of other vitamers were (3-tocopherol, mg x 0.5 y-tocopherol, mg xO. 1 8-tocopherol, mg x 0.03 a-tocotrienol, mg x 0.3 and (3-to-cotrienol, mg x 0.05. The activities of y- and 8-tocotrienol were undetectable. The Recommended Dietary Allowances (RDAs) are only based on intake of the 2R-stereoisomeric forms of a-tocopherol (RRR-, RSR-, RRS-, and RSS-tocopherol) from food, fortified food, and vitamin supplements (Food and Nutrition Board, 2000). The 2S-stereoisomeric forms of a-tocopherol and the other tocopherols ((3-, y-, and 5-tocopherol) and tocotrienols are not used to estimate the RDAs. 

Many vegetables and fruits, other than citrus, contain ascorbic acid. It was estimated that citrus fruits and tomatoes provided only 18% of the total vitamin C intake in the American diet during the decade of 1910. These two fruits supplied 41% of vitamin C in 1956-58 (6j. Today orange juice alone provides nearly 60% of the U.S. Recommended Daily Allowance (U.S. RDA) of vitamin C in the American diet (7). 

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