Abstract

OVERVIEW OF VITAMIN D

K. Shailaja*, Sneha Mavis M., Sowndharya S., Tharani A. and Preethi P.

ABSTRACT

The field of nutrition in the nineteenth century was substantially dominated by German chemists, under the direction of Justus von Liebig. The view of a diet containing 12% proteins, 10 to 30% fats, 5% minerals, and the remainder as carbohydrates as a means to meet daily adequate nutrition was largely unchallenged until the late 19th and early 20th centuries. With the discovery of vitamins, Sir Edward Mellanby in Great Britain began to reason that rickets might also be a disease caused by dietary deficiency. Based on the experiments of McCollum and Mellanby, Vitamin D became known as an essential nutrient. Vitamin D3 is a prohormone generated in the skin by UV irradiation of 7-dehydrocholesterol. It is physiologically inactive and must be converted in the liver to 25-hydroxyvitamin D3 and subsequently in the kidney to 1,25-dihydroxyvitamin D3. The hormonal form of vitamin D3, or 1,25-dihydroxyvitamin D3, works through a nuclear vitamin D receptor (VDR) to carry out its several tasks, which include absorption of calcium, and intestinal phosphate absorption, calcium mobilization in bone, and reabsorption of calcium in the kidney. Additionally, vitamin D has a wide range of non-skeletal impacts, especially on the cardiovascular, endocrine, and immunological systems. As a result of vitamin D's extensive involvement in several organ systems throughout the body, it might be thought of as a treatment goal for a variety of disorders. This overview provides a brief description of the discovery, sources, daily dietary requirements, metabolism, molecular mechanism, functions of vitamin D, and its effect on different body organs. The effects of 1,25(OH)2D on bone and calcium homeostasis are addressed, along with its impact on the immunological, reproductive, and cardiovascular systems. Furthermore, given the high prevalence of vitamin D deficiency, the measurement of vitamin D status, vitamin D deficiency, and vitamin D deficiency management are discussed. Additionally, it offers details on recent clinical trials that are being conducted regarding vitamin D effects on different diseases.

Keywords: Vitamin D, 1, 25(OH)2D, Vitamin D Receptor, metabolism, clinical trials.