Sigma: 2021-09-21

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The Gut Microbiome – Implications for Health on Earth and in Space

Amina R. Zeidan

Sepember 21, 2021 at 7:30 P.M. at


Each human hosts a microbiome in their gut that is home to more than 1,000 species of bacteria, archaea, viruses, and eukaryotic microbes. This gut microbiome weights about 3 – 4 pounds in total – but these are pounds you won’t want to lose. These gut microorganisms are highly involved in numerous metabolic reactions that influence normal host physiology and metabolism. Additionally, an enormous portion of the body’s immune function is positioned in the human gut, i.e., nearly 70% of the body’s lymphocytes reside in gut-associated lymph tissues. This means that the bacteria living in your gastrointestinal tract (everything from your mouth to your rectum) play numerous roles in maintaining your health. Specifically, the health of your gut can influence your risk of cardiovascular disease, cancer, and the development of neurodegenerative diseases, such as dementia.

What is the relevance of the gut microbiome to human health and astronauts? There are several stressors of space travel, including: microgravity, radiation exposure, isolation, anxiety, sleep deprivation, and isolation from medical care, all of which can potentially negatively impact the gut, and therefore, impact overall human health. With several unknowns regarding how these changes can alter human health in the long-term, it is critical for researchers to further their understanding of space travel stressors effects on the gut microbiome so that we may ensure the health and safety of our astronauts during mission time and after their return home.


Amina Zeidan is a Research Fellow with NASA Langley’s Space Radiation Risk Research Group. As a translational scientist, she conducts research on the human gut microbiome and gut responses to infectious diseases, environmental exposures, and stressful environments, such as those experienced by astronauts. Dr. Zeidan has presented her research both nationally and internationally, notably being a returning presenter at the European Congress of Clinical Microbiology & Infectious Diseases. Some of her previous work has focused on the response of the human gut microbiome to Clostridioides difficile infection, the recovery process, and short- and long-term health outcomes associated with infection. A native Missourian, she received her BS from George Mason University (Community Health & Preventive Medicine), two MPH degrees from the University of South Florida College of Public Health (Epidemiology & Global Communicable Diseases), and her PhD from the University of Texas at Austin and UT Health Science Center at San Antonio (Translational Science). She is currently board certified by the National Board of Public Health Examiners. Dr. Zeidan is adjunct faculty at George Mason University in Fairfax, Virginia and guest lectures for public health courses at several colleges and universities.

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