Effect of vitamin D supplementation and ultraviolet B exposure on serum 25-hydroxyvitamin D concentrations in healthy volunteers: a randomized, crossover clinical trial.

What Was Tested

This randomized controlled trial looks at Vitamin D, K2, Magnesium and Zinc.

Solar ultraviolet (UV) radiation during the summer and vitamin D supplementation are two major sources of vitamin D for humans at northern latitudes.

However, little is known about the relative efficiency of these two vitamin D sources.

Who Took Part

By PubMed's age tags, the people studied were young adults, adults and middle-aged adults, both men and women.

Healthy volunteers were randomized into two groups: group 1 received vitamin D supplementation followed by 10 whole-body sunbed exposures; group 2 started with 10 sunbed exposures followed by vitamin D supplementation.

How the Study Was Run

The design is described as randomized and crossover.

The participants were allocated by chance, so the Vitamin D, K2, Magnesium and Zinc group and the comparison group should start out alike.

In the crossover set-up each of the participants took both Vitamin D, K2, Magnesium and Zinc and the comparison in turn, acting as their own control.

What Was Measured

The subject headings attached to it are Dietary Supplements, Healthy Volunteers, Seasons, Sunlight, Ultraviolet Rays, Vitamin D and Vitamins.

What This Means in Plain Language

The paper is a randomized and crossover study of Vitamin D, K2, Magnesium and Zinc.

Its findings take up roughly 5 sentences of the abstract and are left out here on purpose; the source paper is the place to read them.

The publication is from 2013 (The British journal of dermatology), a journal based in England.

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