Abstract
This chapter examines the latest research findings on the association between vitamin D levels and insulin resistance (IR) in various populations, including pregnant and postpartum women, children and adolescents, and individuals with certain health conditions such as diabetes, obesity, multiple sclerosis (MS), polycystic ovary syndrome (PCOS), non-alcoholic fatty liver disease (NAFLD), diabetic kidney disease (DKD), and diabetic peripheral neuropathy (DPN). Existing evidence suggests that Vitamin D plays a crucial role as an immunomodulator, affecting important human disorders like insulin resistance, glucose homeostasis, and mineral and bone metabolism. Extensive evidence suggests that vitamin D has a substantial impact on the development of insulin resistance (IR), through its influence on different gene variants related to vitamin D and the metabolic and immunological pathways associated with it. Supplementing with vitamin D can be beneficial in properly managing and enhancing insulin resistance. Diverse research approaches have yielded both favorable and unfavorable results on the correlation between vitamin D and insulin resistance (IR). Further research is recommended to clarify the correlation between vitamin D and insulin function, as well as to determine any variations in this association among different age groups, genders, and illnesses.