Excess Iodine Exposure Acutely Increases Salivary Iodide And Antimicrobial Hypoiodous Acid Concentrations In Humans

The lactoperoxidase (LPO)-hydrogen peroxide-halides reaction (LPO system) converts iodide and thiocyanate (SCN - ) into hypoiodous acid (HOI) and hypothiocyanite (OSCN - ), respectively. Since this system has been implicated in defense of the airways and oropharynx from microbial invasion, we measured the concentrations of these analytes in human saliva before and after iodine administration to test the hypothesis that an iodide load increases salivary iodide and HOI concentrations. Salivary iodide, SCN - , HOI and OSCN - were measured using standard methodology. Salivary iodide and HOI levels significantly increased after iodinated contrast injection compared with baseline levels, whereas there was no significant change in salivary SCN - and OSCN - levels. The contrast dye iodine load and changes of salivary iodide and HOI levels were positively correlated, suggesting that higher iodide in the circulation increases iodide output and salivary HOI production. Excess iodine exposure in humans increases the salivary output of iodide, increasing salivary HOI concentrations with no effect on SCN - /OSCN - levels. This first of its kind study suggests that a sufficient but safe iodide supplementation may augment the generation of antimicrobial HOI by the salivary LPO system against airborne viral pathogens, including coronaviruses and influenza viruses, a possible inexpensive means of effectively curbing viral pandemics.