We know that vitamin D controls from anywhere between 0. 5% of the human genome to up to 5%, depending on what review one reads. New genes are being discovered every day that vitamin D either upregulates or down regulates. That is, vitamin D either increases or decreases the protein that gene transcribes.
However, no one has ever done a gene microarray analysis (a way of looking at a large number of genes) of patients before and after vitamin D administration. That is, no one had ever done it until Professor Michael Holick’s lab reported such a study recently in the Plos Onejournal.