Article

Estimation of the dietary requirement for vitamin D in free-living adults >=64 y of age.

Department of Food and Nutritional Sciences, University College, Cork, Ireland.
American Journal of Clinical Nutrition (Impact Factor: 6.5). 03/2009; 89(5):1366-74. DOI: 10.3945/ajcn.2008.27334
Source: PubMed

ABSTRACT Older adults may be more prone to developing vitamin D deficiency than younger adults. Dietary requirements for vitamin D in older adults are based on limited evidence.
The objective was to establish the dietary intake of vitamin D required to maintain serum 25-hydroxyvitamin D [25(OH)D] concentrations above various cutoffs between 25 and 80 nmol/L during wintertime, which accounted for the effect of summer sunshine exposure and diet.
A randomized, placebo-controlled, double-blind, 22-wk intervention was conducted in men and women aged >/=64 y (n = 225) at supplemental levels of 0, 5, 10, and 15 microg vitamin D(3)/d from October 2007 to March 2008.
Clear dose-related increments (P < 0.0001) in serum 25(OH)D were observed with increasing supplemental vitamin D(3) intakes. The slope of the relation between total vitamin D intake and serum 25(OH)D was 1.97 nmol . L(-1) . microg intake(-1). The vitamin D intake that maintained serum 25(OH)D concentrations >25 nmol/L in 97.5% of the sample was 8.6 microg/d. Intakes were 7.9 and 11.4 microg/d in those who reported a minimum of 15 min daily summer sunshine exposure or less, respectively. The intakes required to maintain serum 25(OH)D concentrations of >37.5, >50, and >80 nmol/L in 97.5% of the sample were 17.2, 24.7, and 38.7 microg/d, respectively.
To ensure that the vitamin D requirement is met by the vast majority (>97.5%) of adults aged >/=64 y during winter, between 7.9 and 42.8 microg vitamin D/d is required, depending on summer sun exposure and the threshold of adequacy of 25(OH)D. This trial was registered at http://www.controlled-trials.com/ISRCTN20236112 as ISRCTN registration no. ISRCTN20236112.

0 Bookmarks
 · 
89 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Serum samples from 74 obese women were assayed for 25-hydroxyvitamin D [25(OH)D] concentrations using an automated immunoassay [Architect (Abbott)] and ELISA (Alpco Diagnostics), and results were compared with the LC/MS/MS reference method (Quest Diagnostics). The Architect values were significantly lower (mean difference: –13 nmol/L; 95% limits: –54; 28 nmol/L) and the ELISA values were significantly higher (mean difference: 24 nmol/L; 95% limits: –36; 84 nmol/L) than the LC/MS/MS values. The slope of the Passing-Bablok regression line relative to LC/MS/MS was 0.5 [95% confidence interval (CI): 0.41; 0.60] and 1.17 (95% CI: 0.87; 1.56) for Architect and ELISA, respectively, with an intercept of approximately 16 for both assays. Using 50 nmol/L as the cut-point for deficiency, Architect and ELISA misclassified 20 and 27% of the subjects, respectively. In subjects with low circulating 25-hydroxylated ergocalciferol [25(OH)D2] (2 (≥10 nmol/L), Architect demonstrated poor agreement (Kappa = 0.40; 95% CI: 0.16–0.65). ELISA demonstrated a higher degree of overestimation in women with minimal 25(OH)D2 than those with high 25(OH)D2, suggesting that ELISA overestimates 25-hydroxylated cholecalciferol [25(OH)D3] but underestimates 25(OH)D2.
    Journal of AOAC International 08/2014; 97(4). · 1.39 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Institute of Medicine (IOM) issues dietary recommendations on the request of the U.S. and Canadian governments. [...].
    Nutrients 10/2014; 6(10):4472-5. · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The benefits of and thresholds for 25-hydroxyvitamin D administration in individuals with chronic kidney disease (CKD) remain uncertain. In this report, NKF-KDOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) endeavors to provide health care providers with the latest information on a controversial area in the management of CKD, the role for nutritional vitamin D. Although knowledge of the biological mechanisms of vitamin D for bone maintenance in individuals with all stages of CKD has expanded, no consensus currently exists within the medical community regarding methods for 25-hydroxyvitamin D supplementation or optimal 25-hydroxyvitamin D levels in individuals with CKD. Within this report, existing CKD guidelines are summarized and scrutinized and ongoing clinical trials are cited as sources for future guidance on the optimal management of vitamin D in CKD.
    American Journal of Kidney Diseases 07/2014; · 5.76 Impact Factor

Full-text

Download
4 Downloads
Available from
Jan 7, 2015