Study Finds 52 Astronauts’ Gut Bacteria Shift to Protein Digestion in Space as Constipation Risk Rises
Updated
Updated · studyfinds.com · Aug 18
Study Finds 52 Astronauts’ Gut Bacteria Shift to Protein Digestion in Space as Constipation Risk Rises
3 articles · Updated · studyfinds.com · Aug 18
Summary
Blood samples from 52 ISS astronauts showed gut microbes switching from fiber to protein fermentation during missions, a pattern researchers say helps explain astronauts’ frequent constipation.
Microgravity appears to slow intestinal transit, leaving less fiber for bacteria to digest; about 40 blood compounds changed in flight, and several protein-fermentation byproducts returned to normal within days of landing.
488 plasma samples collected before, during and after flights lasting two to nine months showed the metabolic shift emerged soon after launch and stayed broadly stable in orbit.
Diet explained only 27.5% of the metabolic changes, with markers tied to caffeine and fish intake falling during missions, suggesting food choices were only part of the effect.
Researchers said adding more dietary fiber to space menus could reduce protein fermentation on future long-duration missions, though the observational study did not prove microgravity alone caused the shift.