| |
The 2011 Report on Dietary Reference Intakes for Calcium and Vitamin D from the Institute of Medicine: What Clinicians Need to Know - publication pdf attached
|
| |
| |
Download the PDF here
This version published online on November 29, 2010
Journal of Clinical Endocrinology & Metabolism , doi:10.1210/jc.2010-2704
Submitted on November 16, 2010
Accepted on November 16, 2010
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; Departments of Medicine and Endocrinology (C.S.K.), Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1C 5S7; 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
* To whom correspondence should be addressed. E-mail: acr6@psu.edu.
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 ³97.5% 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.
excerpts
Dietary Intake Assessments
Major food sources of calcium include dairy products, selected low-oxalate vegetables, legumes, nuts, and forti- fied foods; for vitamin D, primary sources are fortified dairy products, fortified foods, and fatty fish. Based on national government surveys in the United States and Can- ada, it appears that most groups have adequate intake of calcium (as defined by intakes above the EAR), with the exception of girls aged 9 -18 who have high requirements. The data underscore the need to increase calcium intake among girls in mid-to-late childhood and adolescence; in contrast, among postmenopausal women, high calcium intake from supplements may be concerning. 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 above.
Uncertainties and Future Research Needs
The Committee identified a large number of uncertainties surrounding the DRI values, as well as extensive research needs. 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.
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. More- over, 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 re- search, 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 prob- lems of both undertreatment and overtreatment.
| |
| |
| |
|
|
|
