Overview of the Vital Role of Vitamin D: Functions, Deficiency Syndromes, and Impact Throughout Life

Abstract

The recent study provides a comprehensive overview of vitamin D, emphasizing its biological roles, sources, and health implications. Vitamin D, a fat-soluble prohormone, is essential for bone health, immune function, mental well-being, reproductive health, and the prevention of chronic diseases. Discovered in the early 20th century due to the anti-rachitic effects of cod liver oil, vitamin D includes two main inactive precursors: vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol). Vitamin D3 is endogenously synthesized in the skin through ultraviolet B (UVB) radiation (290–320 nm), while vitamin D2 originates from plants and is obtained through dietary intake. The synthesis and activation of vitamin D are influenced by factors such as UVB exposure, with excessive exposure leading to the formation of inactive metabolites like tachysterol and lumisterol. This overview underscores the critical importance of maintaining adequate vitamin D levels for optimal health outcomes.