Dietary calcium does not interact with vitamin D3 in terms of determining the response and catabolism of serum 25-hydroxyvitamin D during winter in older adults
| Autor: | Kelly M. Seamans, J. Y. Zhang, Sinéad M O’Donovan, Aoife Hayes, Karen Galvin, Mairead Kiely, Michael Kinsella, Kevin D. Cashman |
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| Rok vydání: | 2014 |
| Předmět: |
Calcium metabolism
Vitamin medicine.medical_specialty Nutrition and Dietetics Catabolism Medicine (miscellaneous) chemistry.chemical_element Parathyroid hormone Context (language use) Calcium chemistry.chemical_compound Endocrinology chemistry Internal medicine medicine Vitamin D and neurology Cholecalciferol |
| Zdroj: | The American Journal of Clinical Nutrition. 99:1414-1423 |
| ISSN: | 0002-9165 |
| Popis: | Background: Interactions between calcium and vitamin D may have implications for the regulation of serum 25-hydroxyvitamin D [25(OH)D] and its catabolism and, consequently, the vitamin D dietary requirement.Objective: We investigated whether different calcium intakes influenced serum 25(OH)D and indexes of vitamin D activation and catabolism during winter and in the context of both adequate and inadequate vitamin D intakes.Design: A 15-wk winter-based, randomized, placebo-controlled, double-blind vitamin D3 intervention (20 μg/d) study was carried out in free-living men and women aged ≥50 y (n = 125) who were stratified according to calcium intakes [moderate-low ( 1000 mg/d) intake]. The serum 25(OH)D concentration was the primary outcome, and serum calcium, parathyroid hormone (PTH), 1,25-dihydroxyvitamin D [1,25(OH)2D], 24,25-dihydroxyvitamin D [24,25(OH)2D], the ratio of 24,25(OH)2D to 25(OH)D, vitamin D–binding protein, and free 25(OH)D were exploratory outcomes.Results: A repeated-measures ANOVA showed there was no significant (P = 0.2) time × vitamin D treatment × calcium intake grouping interaction effect on the mean serum 25(OH)D concentration over the 15-wk intervention period. Serum 25(OH)D concentrations increased (P ≤ 0.005) and decreased (P ≤ 0.002) in vitamin D3 and placebo groups, respectively, and were of similar magnitudes in subjects with calcium intakes 1000 mg/d. The response of serum PTH, 1,25(OH)2D, 24,25(OH)2D, the ratio of 24,25(OH)2D to 25(OH)D, and free 25(OH)D significantly differed in vitamin D3 and placebo groups but not by calcium intake grouping.Conclusions: We found no evidence of a vitamin D sparing effect of high calcium intake, which has been referred to by some authors as “vitamin D economy.” Thus, recent dietary vitamin D requirement estimates will cover the vitamin D needs of even those individuals who have inadequate calcium intakes. This trial was registered at clinicaltrials.gov as NCT01990872. |
| Databáze: | OpenAIRE |
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