NASA found a pair of twins that were both astronauts and sent one into space while the other stayed home. As space travel increasingly becomes more feasible, this study examing the gut microbiome is significant.

Here’s what happened:

You probably didn’t know that in 2015, Scott Kelly was sent into space, and in 2016, became the first American astronaut to spend almost one full year in space. Scott has a twin brother Mark Kelly who is a retired astronaut (yes, two astronauts in one family); Mark remained on Earth during his brother’s trip to space to act as a control for the study.

Turek and Vitaterna, two researchers that worked on the Twin Study from NASA’s Human Research Program, examined Scott and the changes in his gut once he returned. They also collected 2 fecal samples before he left for space, 4 samples during the year, and 3 once he returned.

Turek says the comparison between Scott’s fecal samples before and after the trip is more valuable to the study than the comparison between Mark and Scott.

Researchers found that Scott’s gut bacteria shifted while in space. 90% of gut bacteria are classified as Firmicutes or Bacteroidetes; Scott’s post-space trip fecal samples found that Firmicutes increased and Bacteroidetes decreased but returned to normal when he returned to Earth. Vitaterna says this was a “shift in the remodeling of the structure of this community of microorganisms.” Researchers don’t know if this is good or bad. However, going forward, they are going to investigate microgravity as the main suspect.

Image result for scott kelly astronaut

“On Jan. 19, 2015 Expedition 45/46 Commander, Astronaut Scott Kelly along with his brother, former Astronaut Mark Kelly at the Johnson Space Center speak to news media outlets about Scott Kelly’s 1-year mission aboard the International Space Station.” 19 January 2015  Photograph by Robert Markowitz

So what is the gut and why does it matter anyway? The gut microbiome is home to a complex and diverse community of microorganisms. The microorganisms such as bacteria, viruses, and fungi, live in the digestive tract. Vitaterna mentions how powerful bacteria is to our body and says, “There are studies that link changes in the gut microbiome with neurological and physiological conditions, like Alzheimer’s disease, Parkinson’s disease, autism, and schizophrenia.” Vitaterna believes that we can protect other parts of our body by protecting the gut. The gut has a huge influence on digestion, metabolism, and immunity, especially. Researchers have only recently found that when the gut microbiome experiences changes, bones, muscles, and the brain do as well.

This research can be used to protect astronauts and “space tourists” in their travels using lithium hydride. Earth’s planetary magnetic field can no longer protect humans from radiation from solar and cosmic particles once travelers leave earth’s orbit. However, this research into the microbiome will provide more insight into what scientists can do to make space travel safe.