Astronauts’ faeces reveal ‘missing link’ in preparation for crewed Mars mission

All six participants showing major changes in body mass, muscle strength, and gut microbiota

(Nasa/HeroX)

Astronauts’ faecal matter has revealed startling changes to how the human body is affected in isolation, such as during a crewed mission to Mars.

The Mars500 experiment put crew members from Russia, Europe, and China in a completely sealed habitat between June 2010 and November 2011. Researchers have looked again at the data from that work – and discovered new information that could help future trips.

The aim of this was to test the physiological and psychological effects on human health, with all six participants showing major changes in body mass, muscle strength, and gut microbiota.

One of these symptoms was major disruption to glucose metabolism, which is often seen after space flight. Glucose is a subcategory of carbohydrates, found in bread, fruits, vegetables, and dairy products, and is one of the body’s preferred source of fuel.

Researchers discovered that there was a loss of beneficial gut bacteria that would usually break down starch, prevent intestine inflammation, and absorb nutrients. They also discovered it increased gut bacteria that has only recently been discovered in humans – the effects of which are not yet fully understood.

“We have to be careful not to assume a causal relationship between the gut microbiome changes and the disruption of crew metabolism,” said Nicholas Brereton, a research fellow at McGill University and the Université de Montreal’s Institut de recherche en biologie végétale and lead author of this study.

“The significant reduction in these particular gut bacteria do make sense with the symptoms and identification of significant microbiome changes is an important step towards safeguarding astronaut health”.

Over 200 species of gut bacteria were shared between the crew, allowing scientists to observe these changes in a way that was previously not possible.

The discovery of these alterations is a ‘missing link’ between these symptoms and scientists understanding of how astronauts work and survive during long-duration spaceflight.

The study, titled “Reanalysis of the Mars500 experiment reveals common gut microbiome alterations in astronauts induced by long-duration confinement,” was published in the Computational and Structural Biotechnology Journal.

Nasa believes that a crewed mission to Mars could be possible in the next two decades, but it would currently take nine months to travel the 34 million mile distance between the Earth and the Red Planet – assuming that the journey is made when the planet’s orbit is most beneficial to humans.

Moreover, human faecal matter remains an important resource for space flight study. Nasa has historically funded projects to turn faeces into food, and is currently designing a better toilet for astronauts in anticipation of its Artemis moon mission in 2024.