Frontiers Jul 18 2025 Vitamin D is not only an essential nutrient, but also the precursor of the hormone calcitriol, indispensable for health: it regulates the uptake of phosphate and calcium necessary for bones by the intestines, as well as cell growth and the proper function of muscles, nerve cells, and the immune system. Now, researchers have shown for the first time in Frontiers in Endocrinology that a particular gene, called SDR42E1 , is crucial for taking up vitamin D from the gut and