Common variants in CYP2R1 and GC genes are both determinants of serum 25-hydroxyvitamin D concentrations after UVB irradiation and after consumption of vitamin D₃-fortified bread and milk during winter in Denmark.

What Was Tested

Researchers studied Vitamin D, K2, Magnesium and Zinc in this randomized controlled trial publication.

Second, the researchers aimed to determine whether the genetic variations in CYP2R1 and GC have similar effects on 25(OH)D concentrations after artificial UVB irradiation and supplementation by vitamin D₃-fortified bread and milk.

Why It Was Studied

Little is known about how the genetic variation in vitamin D modulating genes influences ultraviolet (UV)B-induced 25-hydroxyvitamin D [25(OH)D] concentrations.

Who Took Part

PubMed indexes the participants as children, teenagers, young adults, adults and middle-aged adults, men only.

The VitmaD study included 201 healthy Danish families who were given vitamin D₃-fortified bread and milk or placebo for 6 mo during the winter.

How the Study Was Run

In design terms this was a randomized, double-blind and placebo-controlled study.

Because people in this Vitamin D, K2, Magnesium and Zinc study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

As a double-blind Vitamin D, K2, Magnesium and Zinc study, the assignments were hidden from both participants and investigators until the end.

The comparison arm used a placebo, so changes seen with Vitamin D, K2, Magnesium and Zinc could be set against what happens without it.

What Was Measured

PubMed files the paper under topics including 25-Hydroxyvitamin D 2, Bread, Calcifediol, Cholecalciferol, Cholestanetriol 26-Monooxygenase, Cytochrome P450 Family 2 and Denmark.

The authors tagged it with the keywords SNPs, UVB radiation, genetic polymorphism, vitamin D status and vitamin D supplements.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Vitamin D, K2, Magnesium and Zinc.

The abstract goes on to report its results in about 3 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 2015 (The American journal of clinical nutrition), a journal based in United States.

More context: the Vitamin D, K2, Magnesium and Zinc compound page, all human trials.