How Gut Bacteria Use Hydrogen Gas to Process Bile Acids and Affect Health

Authors
Journal
FEBS Letters
Year
DOI
10.1002/1873-3468.13064
Study Type
clinical
Peer Reviewed
Yes
Country
United States
Health Condition
Metabolic Disorders
Body System
Digestive

TL;DR

Your gut bacteria use hydrogen gas and bile acids (a substance made by your liver) to survive and help keep your body healthy, and scientists found that one specific bacteria called Eggerthella lenta is really good at using these two things together to create helpful stuff like acetate. This discovery matters because it could help doctors develop new ways to treat diseases related to a unhealthy gut microbiome by controlling hydrogen levels in your intestines.

Key Finding

Gut bacteria, particularly Eggerthella lenta, couple the breakdown of bile acids to the production of acetate in ways that depend on hydrogen gas levels, suggesting hydrogen metabolism plays a role in regulating both the gut microbiome structure and host metabolism.

Summary

This review examines how bacteria in the human gut use hydrogen gas and bile acids (digestive compounds made from cholesterol) as part of their metabolism. Researchers focused on a bacterium called Eggerthella lenta, which appears to convert bile acids into acetate (a short-chain fatty acid) using hydrogen gas under certain conditions. These microbial processes help maintain a healthy gut ecosystem and may influence how the body processes nutrients and manages cholesterol.

Practical Takeaway

This is a review article summarizing existing research rather than a new experimental study, and it does not include human trials or direct evidence about hydrogen water consumption. While it suggests hydrogen gas metabolism in the gut may influence metabolic health, much more research—especially in humans—would be needed before drawing conclusions about whether consuming hydrogen water could affect these processes.

Abstract

The human gut microbiome refers to a highly diverse microbial ecosystem, which has a symbiotic relationship with the host. Molecular hydrogen (H2) and carbon dioxide (CO2) are generated by fermentative metabolism in anaerobic ecosystems. H2 generation and oxidation coupled to CO2 reduction to methane or acetate help maintain the structure of the gut microbiome. Bile acids are synthesized by hepatocytes from cholesterol in the liver and are important regulators of host metabolism. In this Review, we discuss how gut bacteria metabolize hydrogen gases and bile acids in the intestinal tract and the consequences on host physiology. Finally, we focus on bile acid metabolism by the Actinobacterium Eggerthella lenta. Eggerthella lenta appears to couple hydroxyl group oxidations to reductive acetogenesis under a CO2 or N2 atmosphere, but not under H2. Hence, at low H2 levels, E. lenta is proposed to use NADH from bile acid hydroxyl group oxidations to reduce CO2 to acetate.