Gut Bacteria Help Prevent Diving Sickness by Breaking Down Hydrogen Gas
- Authors
- Andreas Fahlman
- Journal
- Rubicon Research Repository
- Year
- 2000
- Study Type
- Pig
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- Canada
- Health Condition
- Decompression Sickness
- Body System
- Digestive System
TL;DR
Scientists found that injecting a gas-eating microbe into pigs can lower their risk of getting decompression sickness after diving with hydrogen gas.
Key Finding
Hydrogen-metabolizing bacteria in the intestines, particularly when enhanced through bacterial injection, significantly reduced decompression sickness risk in pigs by accelerating the removal of hydrogen from body tissues during simulated deep dives.
Summary
Researchers tested whether hydrogen gas could be used safely for deep diving by studying how the body eliminates it. They exposed pigs to high-pressure hydrogen environments and found that natural bacteria in the intestines could break down hydrogen into water and methane, helping remove the gas from tissues faster. When they injected additional hydrogen-metabolizing bacteria into pigs, this process accelerated further, reducing the risk of decompression sickness (a dangerous condition caused by gas bubbles forming in the body during rapid pressure changes).
Practical Takeaway
This is early-stage research conducted only in pigs and focused on a specialized diving application, not on hydrogen water consumption. While the findings suggest that the body can metabolize hydrogen gas under extreme pressure conditions, this study does not provide evidence relevant to drinking hydrogen water for health purposes. Any application to human diving would require extensive additional research and safety testing.
Abstract
Biochemical decompression, a novel approach for decreasing decompression sickness (DCS) risk by increasing the tissue washout rate of the inert gas, was tested in pigs during simulated H2 dives. Since there is only limited physiological data on the use of H2 as a diving gas, direct calorimetry and respirometry were used to determine whether physiological responses to hyperbaric H2 and He are different in guinea pigs. The data suggested that responses in hyperbaric heliox and hydrox cannot be explained solely by the thermal properties of the two gas mixtures. To increase the washout rate of H2, a H2-metabolizing microbe (Methanobrevibacter smithii) was tested that converts H2 to H2O and CH4. Using pigs (Sus scrofa) comparisons were made between untreated controls, saline-injected controls, and animals injected with M. smithii into the large intestine. To simulate a H2 dive, pigs were placed in a dry hyperbaric chamber and compressed to different pressures (22.3-25.7 atm) for times of 30-1440 min. Subsequently, pigs were decompressed to 11 atm at varying rates (0.45-1.80 atm • min-1), and observed for severe symptoms of DCS for 1 h. Chamber gases (O2, N2, He, H2, CH4) were monitored using gas chromatography throughout the dive. Release of CH4 in untreated pigs indicated that H2 was being metabolized by native intestinal microbes and results indicated that native H2-metabolizing microbes may provide some protection against DCS following hyperbaric H2 exposure. M. smithii injection further enhanced CH4 output and lowered DCS incidence. A probabilistic model estimated the effect of H2-metabolism on the probability of DCS, P(DCS), after hyperbaric H2 exposure. The data set included varying compression and decompression sequences for controls and animals with intestinal injections of H2 metabolizing microbes. The model showed that increasing total activity of M. smithii injected into the animals reduced P(DCS). Reducing the tissue concentration of the inert gas significantly reduced the risk of DCS in pigs, further supporting the hypothesis that DCS is primarily caused by elevated tissue inert gas tension. The data provide promising evidence for the development of biochemical decompression as an aid to human diving.