Space Gut: Astronauts' Intestines Slow in Orbit

Analysis of blood samples from 52 astronauts indicates that gut bacteria alter their activity during spaceflight, leading to increased protein fermentation. This phenomenon appears relatively quickly after departure and persists throughout missions. Researchers hypothesize that the lack of gravity slows intestinal transit, allowing gut bacteria to break down protein when fiber is depleted.

The consequences of this increased protein fermentation extend beyond digestion. Metabolites produced can enter the bloodstream, potentially affecting the gut-brain axis and influencing mood or concentration. While protein fermentation is normal, its elevated levels in astronauts suggest a distinct intestinal environment in space.

These findings are crucial for planning extended space missions to the Moon and Mars, potentially requiring interventions like increased dietary fiber or prebiotics. The research also holds relevance for individuals experiencing constipation due to prolonged bed rest on Earth, as similar digestive slowdowns may occur.

This study provides a potential explanation for a common challenge in space travel: the digestive system's reduced function in microgravity. The research utilized a non-targeted metabolomics approach, analyzing a broad range of blood metabolites to identify spaceflight-associated changes.