New insights into the role of vitamin D in the development of certain pathological processes

Recent studies have demonstrated that vitamin D influences not only phosphorus-calcium metabolism but also a range of other metabolic pathways, disturbances of which contribute to the development of various pathological processes. Vitamin D deficiency has become a global health issue, affecting approximately 1 billion people worldwide. Nearly 50 % of the population experiences vitamin D insufficiency, which is assessed by serum 25(OH)D levels. A severe deficiency is defined when 25(OH)D levels drop to 25–30 nmol/L or lower. Evidence suggests a strong correlation between calcitriol levels and metabolic alterations in obesity and diabetes mellitus. Specifically, vitamin D deficiency has been associated with low-grade inflammation in adipose tissue and the pancreas. Additionally, vitamin D plays a role in cardiovascular health, exerting both indirect effects – through risk factors such as obesity, diabetes, and hypertension and direct effects at the cellular level. Contemporary research also confirms a significant association between vitamin D deficiency and neurological and psychiatric disorders, indicating an increased risk for the development and progression of Alzheimer’s disease, schizophrenia, Parkinson’s disease, and others. This literature review highlights the critical role of vitamin D as a key regulatory molecule in normal physiological processes and underscores its promising potential as a prognostic and therapeutic tool.