2021 Volume 70 Issue 3 Pages 109-118
Background：Recently, it has been shown that hydrogen gas has a strong antioxidant effect. Therefore, molecular hydrogen is drawing attention as a new therapeutic strategy against tissue damage caused by peroxides in post-ischemic reperfusion injury.
Methods：In the present study, we investigated the effect of consuming 1000 ml/day of either carbonated water（CO2-water）or hydrogen-molecule-added carbonated water（H2/CO2-water）for 26 days on physiological and laboratory parameters. Thirty-nine healthy volunteers were recruited and put on either of the water regimens using a cross-over design with 31-day washout period.
Results：Among physiological parameters, SPO2 significantly increased by 0.43% after drinking CO2-water, whereas after drinking H2/CO2-water, systolic and diastolic blood pressure decreased significantly by 5.2 and 2.8 mmHg, respectively, and H2 concentrations in end-expiratory air increased by 38% although statistically not significant. As for the biochemical and blood cell parameters, by the CO2-water regimen, total bilirubin, γ-GTP, cholinesterase, CK-MB, Ca, erythrocyte and platelet counts significantly decreased（P<0.01）．However, the differences were all found small when compared to the allowable limit of within-individual variation of each parameter, called reference change value（RCV）．Whereas by the H2/CO2-water regimen, γ-GTP and CK-MB significantly decreased（P<0.01），but the differences were again within the RCV, and thus regarded as not clinically significant. Comparison of differences between the two regimens showed that only heart rate and total bilirubin were significantly higher by the H2/CO2 regimen, but of minor degree.
Conclusion：Reduction of blood pressures observed in the H2/CO2-water regimen may represent an antioxidant effect of hydrogen molecule in water, although an additional trial by increasing H2 concentration and/or longer drinking period is required to fortify the finding. As for the influences on other physiological and laboratory parameters, statistical differences were observed in several parameters by either of the regimens. However, in comparison to the RCV, the changes were within physiological ranges, and thus there was no safety concern in drinking either of the water preparations.
