Exhaled Breath Vapor of Humans Reflects the Changes in Deuterium Concentration in the Body Water

Abstract

The concentration of the heavy isotope of hydrogen, deuterium (D), is not routinely measured in (human) medical laboratory tests, even though an increasing number of papers prove the pivotal role of D in tumor growth, cell cycle regulation, cell metabolism, and aging. Data from a prospective phase 2 clinical study and numerous retrospective clinical studies proved the anticancer effect of deuterium depletion achieved by replacing the regular water intake with deuterium-depleted water (DDW). In previous studies, the changes in serum D concentration of DDW-consuming patients were followed using blood samples and mass spectrometry, which was invasive, costly, and time-consuming. As future clinical trials will also require a follow-up of internal D level and the patient’s compliance, a new sampling device and procedure was developed based on condensing the exhaled breath water vapor and measuring its D content using a liquid water isotope laser analyzer. Test results showed that the device provided accurate, reliable, and reproducible data. According to the data, the internal D level in a person consuming normal water was stable. In contrast, exclusive consumption of DDW for several days resulted in a gradual decrease of D concentration in exhaled breath condensate (EBC), which was proportional to the D concentration of DDW. These data confirm that orally applied DDW equilibrates with the person’s water pool quickly, leading to a reduced internal D level reflected in the D content of EBC.