Blood tests reveal why astronauts get constipated in space

Spaceflight may dramatically change the gut within weeks, causing bacteria to break down more protein as food moves more slowly through the intestines. The shift could help explain astronaut constipation and may have wider effects on health, making it an important concern for future missions to Mars. Blood tests reveal why astronauts get constipated in space.

Blood tests reveal why astronauts get constipated in space Science News from research organizations Blood tests reveal why astronauts get constipated in space Astronauts’ gut bacteria shift within weeks of entering space, potentially revealing why constipation is so common in microgravity. New research from the University of Copenhagen, conducted in collaboration with NASA, offers a possible explanation. Scientists analyzed blood samples from 52 astronauts who spent months aboard the International Space Station and found signs that the digestive system begins changing relatively soon after astronauts leave Earth.

"We see changes in astronauts’ blood samples that indicate that the gut bacteria begin to ferment protein to a greater extent than usual within weeks after the astronauts arrive in space, and this change continues until they are back on Earth," says joint first author and associate professor at the Department of Nutrition, Exercise and Sports, Giorgia La Barbera. Gut Bacteria Shift Toward Protein Protein fermentation occurs when bacteria in the intestines begin breaking down protein rather than fiber because available dietary fiber has already been used. The process is not unique to astronauts and can also occur in people on Earth.

The researchers suspect that microgravity may slow the movement of food through the digestive tract.