The Microbiome: The Forgotten Organ of the Astronaut's Body — Probiotics Beyond Terrestrial Limits

Amir Ata Saei; Abolfazl Barzegari


Future Microbiol. 2012;7(9):1037-1046. 

In This Article

Abstract and Introduction


Space medicine research has drawn immense attention toward provision of efficient life support systems during long-term missions into space. However, in extended missions, a wide range of diseases may affect astronauts. In space medicine research, the gastrointestinal microbiome and its role in maintaining astronauts' health has received little attention. We would like to draw researchers' attention to the significant role of microbiota. Because of the high number of microorganisms in the human body, man has been called a 'supra-organism' and gastrointestinal flora has been referred to as 'a virtual organ of the human body'. In space, the lifestyle, sterility of spaceship and environmental stresses can result in alterations in intestinal microbiota, which can lead to an impaired immunity and predispose astronauts to illness. This concern is heightened by increase in virulence of pathogens in microgravity. Thus, design of a personal probiotic kit is recommended to improve the health status of astronauts.


Living in space has been a great desire for mankind, leading to the development of space stations for long-duration manned space missions. The design of a life support system is needed to maintain the minimum life requirements for humans in space by conserving a stable body temperature, a standard pressure on the body and by managing waste products. So far, the majority of research in this area has been devoted to the human primary requirements such as air, water and food. Furthermore, a life support system deals with astronauts' healthcare. Although health status of the astronauts such as immunological and physiological problems has been investigated, less attention has been paid to the intestinal microbiome and its significant role in the astronaut's health. Immunological and physiological health problems could occur when considering the identified increase in the virulence and antibiotic resistance of some infectious bacteria exposed to microgravity, along with possible weakening of the immune system during space flight.[1,2] Compensating for these alterations may not only enhance the health and immunity status of astronauts, but might have possible effects on enhancing the duration of space journeys.

For many years, the importance of intestinal flora in human health and disease has been known to man. Researchers have suggested a possible association between the changes in the balance of gut flora and several diseases.[3] At the end of the Human Genome Project, the aggregation of flora genes within the human genome was named the 'human metagenome', highlighting the crucial role of the microbiome in the maintenance of health.[4] This perspective highlights the crucial role of the microbiome in the health and/or disease status in astronauts. Considering astronauts' special health and nutrition needs in orbit, it could be advantageous to develop probiotics for each crew member. These healthy bacteria could then be consumed during long-duration missions to replenish the intestinal microbiome.