The effect of a single, large bolus of vitamin D in healthy adults over the winter and following year: a randomized, double-blind, placebo-controlled trial.

What Was Tested

The paper reports a study of Vitamin D, K2, Magnesium and Zinc, published as a randomized controlled trial.

Who Took Part

The study group was 28 adults.

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

In this double-blind, placebo-controlled trial, the researchers assessed plasma 25(OH)D and PTH concentrations at baseline, 5, 90 and 365 days after drug administration in 28 healthy adults.

How the Study Was Run

The researchers set it up as a randomized, double-blind and placebo-controlled study.

Random assignment meant chance, not the researchers, decided who got Vitamin D, K2, Magnesium and Zinc and who got the comparison, which limits bias.

Neither the adults nor the staff measuring them knew who was on Vitamin D, K2, Magnesium and Zinc, so expectations could not easily colour the readings.

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

Topics PubMed links to this paper include Calcium, Cholecalciferol, Dietary Supplements, Healthy Volunteers, Parathyroid Hormone, Seasons and Vitamin D.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Vitamin D, K2, Magnesium and Zinc in 28 adults.

With fewer than 40 people, it is a small study, so it is better read as an early signal for further research than as a settled answer.

The abstract goes on to report its results in about 7 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 2015 (European journal of clinical nutrition), a journal based in England.

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