Hydrogen gas can be generated in small amount by hydrogenase of certain members of the human gastrointestinal tract microbiota from unabsorbed carbohydrates in the intestine through degradation and metabolism, which then is partially diffused into blood flow and released and detected in exhaled breath, indicating its potential to serve as a biomarker.
Many studies
have shown that H2 therapy can reduce oxidative stress. This, however, contradicts radiation therapy and chemotherapy, in which ROS are required to induce apoptosis and combat cancer. Yet many studies show
chemoprotective
and
radioprotective
and some even show
chemosentizing
Nevertheless there are some papers claiming
ROS ↑
for cancer cells