Dose and time responses of vitamin D biomarkers to monthly vitamin D3 supplementation in overweight-obese African Americans with suboptimal vitamin d status: a placebo controlled randomized clinical trialReport as inadecuate




Dose and time responses of vitamin D biomarkers to monthly vitamin D3 supplementation in overweight-obese African Americans with suboptimal vitamin d status: a placebo controlled randomized clinical trial - Download this document for free, or read online. Document in PDF available to download.

BMC Obesity

, 2:27

First Online: 04 July 2015Received: 25 April 2015Accepted: 29 May 2015DOI: 10.1186-s40608-015-0056-2

Cite this article as: Bhagatwala, J., Zhu, H., Parikh, S.J. et al. BMC Obes 2015 2: 27. doi:10.1186-s40608-015-0056-2

Abstract

BackgroundA critical need exists to better understand the physiological sequel of vitamin D supplementation in obese individuals and African Americans. The aim was to comprehensively evaluate dose- and time-responses of a panel of vitamin D biomarkers to vitamin D supplements in this population.

MethodsWe conducted a 16-week randomized, double-blinded, and placebo-controlled clinical trial. Seventy overweight-obese African Americans age 13–45 years, 84 % females with 25-hydroxyvitamin D 25OHD concentrations ≤20 ng-mL were randomly assigned to receive a supervised monthly oral vitamin D3 of 18,000 IU ~600 IU-day, n = 17, 60,000 IU ~2000 IU-day, n = 18, 120,000 IU ~4000 IU-day, n = 18, or placebo n = 17.

ResultsThere were significant dose- and time-responses of circulating 25OHD, 1,25-dihydroxyvitamin D 1,25OH2D, and intact parathyroid hormone iPTH, but not fibroblast growth factor-23 FGF-23, phosphorus and urine calcium to the vitamin D supplements. The mean 25OHD concentrations in the 2000 IU and 4000 IU groups reached ≥30 ng-mL as early as 8-weeks and remained at similar level at 16-weeks. The increase of 25OHD was significantly higher in the 4000 IU group than all the other groups at 8-weeks. The increase of 1,25OH2D was significantly higher in the 2000 IU and 4000 IU groups than the placebo at 8-weeks. Only the 4000 IU compared to the placebo significantly reduced iPTH at 8- and 16-weeks.

ConclusionsOur RCT, for the first time, comprehensively evaluated time- and dose- responses of vitamin D supplementation in overweight-obese African Americans with suboptimal vitamin D status. Circulating 25OHD, 1,25OH2D, and iPTH, but not FGF-23, phosphorus and urine calcium, respond to vitamin D supplementation in a time- and dose–response manner. By monthly dosing, 2000 IU appears to be sufficient in achieving a 25OHD level of 30 ng-mL in this population. However, importantly, 4000 IU, rather than 2000 IU, seems to suppress iPTH. If replicated, these data might be informative in optimizing vitamin D status and providing individualized dosing recommendation in overweight-obese African Americans.

Trial registrationClinicalTrials.gov number: NCT01583621, Registered on April 3, 2012.

KeywordsMonthly vitamin D Overweight-obese African Americans Dose–response vitamin D 4000 IU vitamin D Abbreviations25OHD25-hydroxyvitamin D

IOMInstitute of Medicine

RCTRandomized clinical trials

1,25OH2D1,25-dihydroxyvitamin D

PTHParathyroid hormone

FGF-23Fibroblast growth factor-23

RDARecommended dietary allowance

BMIBody mass index

IRBInstitutional review board

DEQASVitamin D external quality assessment scheme

iPTHIntact parathyroid hormone

ELISAEnzyme-linked immunosorbent assay

SDStandard deviation

SEMStandard error of mean

Ca-CrCalcium-creatinine ratio

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Author: Jigar Bhagatwala - Haidong Zhu - Samip J. Parikh - De-Huang Guo - Ishita Kotak - Ying Huang - Robyn Havens - Michael Pham

Source: https://link.springer.com/



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