Longitudinal metabolomics profiles reveal increased gut microbial protein fermentation during Spaceflight

Area of Science:

• Human physiology
• Space medicine
• Metabolomics

Background:

• Spaceflight, particularly microgravity, can impact gastrointestinal function and metabolism.
• Dietary habits and meal timing may be altered during space missions on the International Space Station (ISS).

Purpose of the Study:

• To characterize the plasma metabolome of astronauts before, during, and after spaceflight.
• To understand the impact of spaceflight on human metabolism and gut microbiota activity.

Main Methods:

• Longitudinal assessment of 52 astronauts' plasma metabolome.
• Utilized liquid chromatography coupled with mass spectrometry (LC-MS).

Main Results:

• Spaceflight altered approximately 40 circulating metabolites, with changes observed shortly after launch and subsiding post-landing.
• Metabolic changes indicated increased protein fermentation by gut microbiota, potentially due to prolonged intestinal transit time in microgravity.
• Minor diet-related metabolic changes were observed but were less impactful than spaceflight effects.

Conclusions:

• Microgravity significantly affects astronaut metabolism, primarily through increased gut protein fermentation.
• Dietary interventions, such as increasing slow-fermented carbohydrates, could mitigate negative gastrointestinal effects for future long-term spaceflights.