Despite being effective in animal models of T2DM, as it is summarized in Table 2, all acute [67], mid-term [68,69], and long-term [70,71,72] oral dosing of inorganic NO3− and NO2−, either as pharmacological forms (i.e., KNO3, NaNO3, and NaNO2) or food-based supplementation (i.e., NO3−-rich beetroot juice or powder) have failed to show beneficial effects on glucose and insulin parameters, including fasting and post-prandial serum glucose and insulin concentrations, insulin resistance indices, and HbA1c levels in patients with T2DM. This evidence concerns the gene INS and type 2 diabetes mellitus.