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The 2011 Report on Dietary Reference Intakes for Calcium and Vitamin D from the Institute of Medicine: What Clinicians Need to Know - pdf attached
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Download the PDF here
The Journal of Clinical Endocrinology & Metabolism Jan 2011 Vol. 96, No. 1 53-58
A. Catharine Ross, JoAnn E. Manson, Steven A. Abrams, John F. Aloia, Patsy M. Brannon, Steven K. Clinton, Ramon A. Durazo-Arvizu, J. Christopher Gallagher, Richard L. Gallo, Glenville Jones, Christopher S. Kovacs, Susan T. Mayne, Clifford J. Rosen and Sue A. Shapses
Department of Nutritional Sciences (A.C.R.), Pennsylvania State University, University Park, Pennsylvania 16802; Department of Medicine (J.E.M.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02215; Department of Pediatrics (S.A.A.), Baylor College of Medicine, Houston, Texas 77030; Department of Medicine (J.F.A.), State University of New York at Stony Brook, Stony Brook, New York 11794; Winthrop University Hospital (J.F.A.), Mineola, New York 11501; Division of Nutritional Sciences (P.M.B), Cornell University, Ithaca, New York 14853; Division of Hematology and Oncology (S.K.C.), The Ohio State University, Columbus, Ohio 43210; Department of Epidemiology and Preventive Medicine (R.A.D.-A.), Loyola University Stritch School of Medicine, Maywood, Illinois 60153; Bone Metabolism Unit (J.C.G.), Creighton University Medical Center, Omaha, Nebraska 68131; Department of Medicine (R.L.G.), University of California, San Diego, La Jolla, California 92093; Department of Biochemistry (G.J.), Queen's University, Kingston, Ontario, Canada K7L 3N6; Faculty of Medicine-Endocrinology (C.S.K.), Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1B 3V6; Department of Epidemiology and Public Health (S.T.M.), Yale School of Public Health, New Haven, Connecticut 06520; Center for Clinical and Translational Medicine (C.J.R.), Maine Medical Center Research Institute, Scarborough, Maine 04074; and Department of Nutritional Sciences (S.A.S.), Rutgers University, New Brunswick, New Jersey 08901
"Conclusions: The available scientific evidence supports a key role for calcium and vitamin D in skeletal health, providing a sound basis for DRIs. The evidence, however, is not yet compelling that either nutrient confers benefits for, or is causally related to, extraskeletal health outcomes. Moreover, existing evidence suggests that nearly all individuals meet their needs at intake levels (RDAs) provided in this report and, for vitamin D, at 25OHD levels of at least 20 ng/ml (50 nmol/liter) even under conditions of minimal sun exposure. Furthermore, higher levels have not been shown consistently to confer greater benefits, challenging the concept that "more is better." The Committee finds that the prevalence of vitamin D inadequacy in the North American population has been overestimated by some groups due to the use of inappropriate cut-points that greatly exceed the levels identified in this report. Serum concentrations of 25OHD above 30 ng/ml (75 nmol/liter) are not consistently associated with increased benefit, and risks have been identified for some outcomes at 25OHD levels above 50 ng/ml (125 nmol/liter). Additional research, including large-scale, randomized clinical trials, is needed. In the meantime, however, we believe that there is an urgent clinical and public health need for consensus cut-points for serum 25OHD inadequacy to avoid problems of both undertreatment and overtreatment."
ABSTRACT
This article summarizes the new 2011 report on dietary requirements for calcium and vitamin D from the Institute of Medicine (IOM). An IOM Committee charged with determining the population needs for these nutrients in North America conducted a comprehensive review of the evidence for both skeletal and extraskeletal outcomes. The Committee concluded that available scientific evidence supports a key role of calcium and vitamin D in skeletal health, consistent with a cause-and-effect relationship and providing a sound basis for determination of intake requirements. For extraskeletal outcomes, including cancer, cardiovascular disease, diabetes, and autoimmune disorders, the evidence was inconsistent, inconclusive as to causality, and insufficient to inform nutritional requirements. Randomized clinical trial evidence for extraskeletal outcomes was limited and generally uninformative. Based on bone health, Recommended Dietary Allowances (RDAs; covering requirements of ≥97.5% of the population) for calcium range from 700 to 1300 mg/d for life-stage groups at least 1 yr of age. For vitamin D, RDAs of 600 IU/d for ages 1-70 yr and 800 IU/d for ages 71 yr and older, corresponding to a serum 25-hydroxyvitamin D level of at least 20 ng/ml (50 nmol/liter), meet the requirements of at least 97.5% of the population. RDAs for vitamin D were derived based on conditions of minimal sun exposure due to wide variability in vitamin D synthesis from ultraviolet light and the risks of skin cancer. Higher values were not consistently associated with greater benefit, and for some outcomes U-shaped associations were observed, with risks at both low and high levels. The Committee concluded that the prevalence of vitamin D inadequacy in North America has been overestimated. Urgent research and clinical priorities were identified, including reassessment of laboratory ranges for 25-hydroxyvitamin D, to avoid problems of both undertreatment and overtreatment.
"The IOM Committee concluded that the evidence that vitamin D or calcium reduced risk of nonskeletal chronic disease outcomes was inconsistent, inconclusive, and did not meet criteria for establishing cause-and-effect relationships.......emerging evidence suggested a curvilinear or U-shaped curve for several outcomes related to vitamin D, including cardiovascular disease, vascular calcification, falls, frailty, pancreatic cancer, and all-cause mortality (7, 8, 9, 10, 11), with the lowest risk at moderate levels and increased risk at both low and high levels of 25OHD......The AI in infancy is estimated to be 400 IU/d. After age 1, the RDA is estimated to be 600 IU/d for all life-stage groups except men and women aged 71 and older (for whom the RDA is 800 IU/d). The Committee did not find compelling evidence that 25OHD levels or dietary intakes above these levels were associated with greater benefit for bone health or other outcomes. The assumption of minimal or no sun exposure for estimation of these intake levels provided further safety for individuals with lower endogenous synthesis of vitamin D. The specific studies contributing to these estimates are reviewed in detail in the full report (1)......The 1997 ULs for calcium were 2500 mg/d for all ages above 1 yr, whereas the ULs for calcium now range from 1000-3000 mg/d, depending on life-stage group (Table 1.......The 1997 ULs for vitamin D were 2000 IU/d for most age groups. The starting point for the current UL for vitamin D was 10,000 IU/d, because lower intakes have not been linked to hypercalcemia or acute toxicity.......the Committee also recognized that observational studies of correlations between 25OHD and clinical outcomes are subject to confounding and do not prove causation.......After a careful review of available literature, the Committee concluded that serum 25OHD levels of 16 ng/ml (40 nmol/liter) cover the requirements of approximately half the population, and levels of 20 ng/ml (50 nmol/liter) cover the requirements of at least 97.5% of the population. These levels will be useful to clinicians as they consider management of patients under their care. For upper levels of serum 25OHD, sparse data are available, particularly regarding long-term effects of chronically high concentrations, and a margin of safety for public health recommendations is prudent. Thus, serum 25OHD levels above 50 ng/ml (125 nmol/liter) should raise concerns among clinicians about potential adverse effects......Major food sources of calcium include dairy products, selected low-oxalate vegetables, legumes, nuts, and fortified foods; for vitamin D, primary sources are fortified dairy products, fortified foods, and fatty fish.......Regarding vitamin D, average intake from foods tends to be less than 400 IU/d, but mean 25OHD levels have been above 20 ng/ml (50 nmol/liter) in representative samples. Thus, based on these data and a level of 20 ng/ml (50 nmol/liter) identified as meeting the needs of at least 97.5% of the population across all life-stage groups, it appears that the majority of the North American population currently is meeting its needs for vitamin D. Nonetheless, subgroups of individuals, particularly those with poor nutrition, those living at northerly latitudes or in institutions, or those with dark skin pigmentation may be at increased risk of not meeting their needs, especially if their 25OHD levels are below 16 ng/ml (40 nmol/liter), the level identified as the average requirement as discussed....A particular priority is rigorous, large-scale, randomized clinical trials to test the effects of vitamin D on skeletal and nonskeletal outcomes, as well as to identify threshold effects and possible adverse effects where present. Elucidating the biology of the diverse effects of vitamin D, as well as effects of sun exposure, adiposity, body composition, race/ethnicity, and genetic factors on these associations, is also of great importance."
Bone Health: Dietary Reference Intakes and Updates since 1997
The DRIs shown in Table 1 are based on dietary requirements using bone health as an indicator. DRIs for each nutrient were predicated on intakes meeting requirements for the other nutrient. For both calcium and vitamin D, available evidence allowed for estimation of EARs and RDAs for all life-stage groups except infants (for whom AIs are provided). At the time of the 1997 report on calcium and vitamin D, evidence was insufficient for estimation of EARs and RDAs; thus, AIs were estimated for all life-stage groups. For calcium, the 2011 DRIs are based largely on the calcium content of human breast milk for infants, calcium balance studies for ages 1-50 yr, and observational and clinical trial evidence after age 50. For vitamin D, the 2011 DRIs are based primarily on the integration of bone health outcomes with evidence concerning 25OHD levels, which suggest that levels of 16 ng/ml (40 nmol/liter) meet the needs of approximately half the population (median population requirement, or EAR), and levels of at least 20 ng/ml (50 nmol/liter) meet the needs of at least 97.5% of the population (akin to the RDA). Intakes of vitamin D required to achieve these 25OHD concentrations are shown in Table 1, based on a simulation of available data across ages under conditions of minimal sun exposure. The AI in infancy is estimated to be 400 IU/d. After age 1, the RDA is estimated to be 600 IU/d for all life-stage groups except men and women aged 71 and older (for whom the RDA is 800 IU/d). The Committee did not find compelling evidence that 25OHD levels or dietary intakes above these levels were associated with greater benefit for bone health or other outcomes. The assumption of minimal or no sun exposure for estimation of these intake levels provided further safety for individuals with lower endogenous synthesis of vitamin D. The specific studies contributing to these estimates are reviewed in detail in the full report (1).
The 2011 DRIs are based on much more information and higher-quality studies than were available when the reference values for these nutrients were first set in 1997, allowing for the estimation of EARs and RDAs rather than AIs. Because the old and new DRIs reflect different calculations, the figures are not directly comparable. In 1997, the AIs for vitamin D were 200 IU/d through age 50, 400 IU/d for ages 51-70, and 600 IU/d for ages 71 and older. The 2011 DRIs for vitamin D specify RDAs, with levels of 400 IU/d for infants, 600 IU/d for children and adults through age 70, and 800 IU/d for ages 71 and older. However, the 2011 DRIs for vitamin D are nonetheless lower than those proposed by some in the current literature based on higher 25OHD levels that the Committee did not find justified by the evidence.
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