Bioassays to Assess the Safety of Potassium and Sodium Nitrates and Nitrites

(1) Background: Advances in food processing practices and health care are some of the most significant advances in modern daily life. The goal of this study is to evaluate the safety of potassium and sodium nitrates and nitrites when they are used as fertilizers in agriculture and food additives, as well as the known conversion of nitrate to nitrite in humans. (2) Methods: Various bioassays were conducted to investigate the effects of nitrates and nitrites in the Drosophila melanogaster genetic tester system. These assays focused on the modulation of degenerative processes at the molecular, cellular, individual, and population levels. Additionally, we assessed the chemopreventive potential and the ability to induce DNA strand breaks in HL-60 tumour cells. (3) Results: All nitrate and nitrite concentrations tested were shown to not be toxic or genotoxic in Drosophila since none of the compounds reached the LD50 and significant genetic mutation. A positive or null protective capacity against a toxic agent was found for nitrates, not for nitrites, showing that sodium nitrite has a synergistic effect when combined with the oxidant toxin hydrogen peroxide; and a nutraceutical potential in the lifespan only for sodium nitrate to improve the quality of life in 5 days at ADI concentration. The in vitro results in human leukemia cells showed a chemopreventive potential only for potassium nitrate and sodium nitrite due to reducing the viability of HL-60 cells growth to 18% and 29%, respectively, compared to the controls at ADI (acceptable daily intake) concentrations. However, neither of these showed DNA damage or methylation modifications. (4) Conclusions: The tested compounds were shown to be safe to use during in vivo and in vitro tests when used at the extrapolated ADI concentrations.