Due to the Covid-19 pandemic, the intake of vitamin D (VD) has increased. Vitamin D has multiple regulatory effects in the human body, including immunological. Evidence accentuates the generation of a pro-tolerogenic T helper (Th) 2 cell state with VD, suppressing a Th1 inflammatory response. Th2 cell polarization is characteristic of atopy. However, VD promotes a balanced state through the action of regulatory T cells, controlling cytokines, both pro-inflammatory and anti-inflammatory, and by reducing B cell proliferation and differentiation, thus preventing the development of atopy.