Role of Vitamin D in Health and Disease: Important Therapeutic Options

Vitamin D (calciferol) is a fat-soluble compound that exists in two main forms: vitamin D2 and vitamin D3. This review aimed to provide an overview of the role of vitamin D in health and disease. Published literature was retrieved from PubMed, Scopus, and Google Scholar to gather evidence-based data on vitamin D and its clinical importance. Vitamin D2 (ergocalciferol) is obtained mainly from fungal sources, particularly in mushrooms and yeasts, while vitamin D3 (cholecalciferol) is synthesized in the human skin from 7-dehydrocholesterol upon exposure to sunlight and also obtained from animal-based food sources. Both D2 and D3 are used in supplements and the fortification of food. Vitamin D plays a central role in phospho- calcium metabolism, maintaining normal serum calcium levels, supporting bone development, and regulating the absorption of calcium, magnesium, and phosphate, thereby contributing to overall calcium homeostasis. In addition to its skeletal functions, vitamin D has important effects on the gastrointestinal, immune, and cardiovascular systems. The review also discusses the management of vitamin D deficiency and hypervitaminosis. Overall, vitamin D functions as an important hormonal regulator, and its deficiency is largely modifiable. Maintaining adequate levels or using vitamin D appropriately for therapeutic purposes may provide clinical benefits, and emerging data-mining techniques and artificial intelligence approaches may further support research and clinical decision-making in this field.