Category Archives: Health

Long-duration Space Missions May Affect the Human Gut Microbiome

Peter Lobner

On 23 November 2016, Dr. Stanley Maloy gave the presentation, “Beneficial Microbes and Harmful Antibiotics,” (Talk #107) to the Lyncean Group. The focus of this presentation was on the nature of the human gut microbiome, its relationship to personal health, disruption of the gut microbiome by antibiotics and other causes, and how to restore a disrupted gut microbiome. You can find his presentation on the Past Meetings tab on the Lyncean home page or use the following direct link:

In a story that’s related to Dr. Maloy’s presentation, a 3 February 2017 article by Megan Fellman entitled, “Changes in astronaut’s gut bacteria attributed to spaceflight,” provides the first results of a comparative analysis by Northwestern University researchers on changes in the gut microbiomes of NASA astronaut identical twins Scott and Mark Kelly. As part of a NASA experiment to examine the effects of long-duration space missions on humans, Scott Kelly was continuously in orbit on the International Space Station (ISS) for 340 days during 2015 – 2016, while Mark Kelly remained on Earth and served as the control subject.

Mark & Scott KellyMark (left) and Scott Kelly (right). Source: NASA

The key points reported by Northwestern University researchers were:

  • There was a shift in the balance between the two dominant groups of bacteria (Firmicutes and Bacteroidetes) in Scott Kelly’s gastrointestinal (GI) tract when he was in space. The balance returned to pre-flight levels when Scott Kelly returned to Earth.
  • Fluctuations in the same bacterial groups were seen in Mark Kelly, the control on Earth, but the fluctuations were not as great as those seen in Scott Kelly in space.
  • The surprise finding was that an expected change in diversity of gut microbes (the number of different species) was not observed in Scott Kelly while in space.
  • “Right now, we do not see anything alarming….”

You can read the complete article on this Northwestern University research at the following link:

So far, it looks like the human gut microbiome may not be a limiting factor in long-duration spaceflight.