Hydrogen-rich water as a modulator of gut microbiota?

Abstract

Abstract Hydrogen-rich water (HRW) is an innovative functional drink with many professed benefits for human health, including good intestinal viability and gut microbiota upregulation. A source of molecular hydrogen, HRW might be a convenient medium to deliver this bioactive gas to the gastrointestinal tract, and perhaps modulate the activity of both hydrogen-producing and hydrogen-consuming bacteria, abundant members of the intestinal microbiota community. This paper summarizes the findings from previous studies evaluating a response of gut microbiota to HRW intake and discusses possible mechanisms and medical consequences of this interaction. It appears that only a handful of rodent studies and one human randomized-controlled trial investigated how drinking HRW affects gut microbiota, with all studies published from 2018 onwards. HRW-induced protection of the gut barrier integrity and upregulation of butyrate-producing bacteria were seen in most studies, with HRW ameliorated clinical features of gut microbiota disturbances, including diarrhea rate, weight, and fluid loss. However, no well-powered multicentric trial evaluated the effectiveness of HRW consumption so far in common gastrointestinal diseases with gut flora scenario, including inflammatory bowel disease, irritable bowel syndrome, gastroenteritis and colitis of infectious origin. HRW might be an up-and-coming compound that might tune endogenous H2 homeostasis and modulate gut microbiota but it should still be perceived as an experimental drink and not widely recommended to the general public.