Genetics of vitamin D increase after supplementation

Introduction The 25-Hydroxyvitamin D (25[OH]D) level depends on vitamin D intake, endogenous vitamin D production and genetic factors. The latter have been demonstrated in large genome-wide association studies indicating that single nucleotide polymorphisms (SNPs) in genes related to the vitamin D metabolism are as important for serum 25(OH)D levels as the influence of season. The aim of the present study was to investigate genetic effects of ten selected SNPs related to vitamin D metabolism on vitamin D increase 25(OH)D after vitamin D supplementation in three randomized controlled trials.

Methods Genotypes of SNPs related to vitamin D metabolism were determined in 411 participants with 25(OH)D levels < 75 nmol/l receiving 20,000 IU cholecalciferol per week for 8 and 12 weeks respectively after inclusion in the study. The main outcome measure was delta 25(OH)D.

Results For the VDR rs10783219 polymorphism, the minor A-allele was associated with lower delta 25(OH)D values in the entire study population (p = 0.022) which was not consistent in all three cohorts when analysed separately.

Discussion VDR rs10783219 might therefore be a genetic modulator of vitamin D levels. Considering the wide-spread use of vitamin D supplementation, future large and well-designed RCTS should investigate the clinical impact of this polymorphism.

Keywords Vitamin D, RCT, Genetics

Korrespondenzadresse Barbara Haidenberger, Ernährungsberatung - Knochengesund essen, Plettstr. 15, 81735 München, Deutschland,

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