Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride (1997) / Chapter Skim
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2 Calcium and Related Nutrients: Overview and Methods
2 Calcium and Related Nutrients: Overview and Methods
Pages 38-50
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From page 38... ...
Although the development and preservation of bone mass are key elements in the estimation of the needs for these five nutrients for the population of the United States and Canada, the evidence consiclereci includes other biological roles for these nutrients and their possible relevance to human health and to decreasing risk of clisease. For the most part, however, it is the functioning of these nutrients in bone and teeth that provicleci the most convincing criteria on which to base the new Dietary Reference Intakes (DRIs)
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From page 39... ...
In some cases they were used to estimate intakes. If applicable, original scientific studies were used for the critical determinants of endpoints for deriving the Estimated Average Requirement (EAR)
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From page 40... ...
In developing estimates of average requirements for minerals such as calcium, phosphorus, and magnesium, the available literature until the late 1980s consisted primarily of balance studies in which
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From page 41... ...
In aciclition, balance studies tend to err toward a positive balance since intake is usually overestimated and excretion is unclerestimateci. With the advent of readily available noninvasive and fairly inexpensive methocis to detect changes in bone mineral content and bone mineral density, aciclitional information relative to small changes became available to augment information from balance studies.
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From page 42... ...
However, this method does not adjust for the underreporting of intake, which may be as much as 20 percent (Mertz et al., 1991~. Finally, food composition databases that are used to calculate nutrient intake from self-reported and observed intake data introduce errors due to random variability, genetic variation in content, and use of poor analytical methods.
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From page 43... ...
The 1994 to 1996 CSFII collected two nonconsecutive 24-hour recalls from approximately 16,000 subjects of all ages. Both surveys used a food composition database clevelopeci by USDA to calculate nutrient intakes (Perloff et al., 1990)
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From page 45... ...
No estimates of the extent to which exposure to sunlight met part of the incliviclual's requirements for vitamin D are available in these stuciies. Intakes of fluoride from foocis are difficult to estimate clue to wicle variations in the fluoride content of local water supplies and inadvertent consumption of fluoride through dental products.
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From page 46... ...
The lack of accurate estimates of a population's intake from supplements plus food prevents accurate examination of the upper end of the nutrient intake distribution. This, in turn, limits the ability to identify intakes that approach or exceed the UL.
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From page 47... ...
Population variations in the consumption of other cliet components such as protein and sodium may significantly affect population calcium and magnesium neecis and ULs. With regard to the neeci for calcium and related nutrients for bone health, cross-cultural comparisons must also consider variability among populations in activity, weight-bearing practices, and sun exposure.
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From page 48... ...
Since infants self-regulate milk intake from the breast, it is presumed that larger infants, who may require more milk than the average population intake, will achieve this by increasing milk intake volume. Calcium In this report, three major approaches were consiclereci in cleriving the AIs for calcium calcium balance studies of subjects consuming variable amounts of calcium, a factorial model using calcium accretion baseci on bone mineral accretion ciata, and clinical trials which investigated the response of change in bone mineral content/ density or fracture rate to varying calcium intakes.
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From page 49... ...
Comparison of the intakes neecleci to achieve desirable calcium retention or maintain minimal calcium loss using each of these three methods gave reasonable confidence and concordance to the levels of intake recommencleci as AIs. Thus the recommencleci AI for each life stage group is an approximation of the calcium intake that would appear to be sufficient to maintain calcium nutriture for almost all the inclivicluals in the specific group.
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From page 50... ...
the lack of concordance between observational and experimental ciata (mean calcium intakes in the United States and Canada are much lower than are the experimentally cleriveci values required to achieve average desirable calcium retention)
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