Probiotics on Immune Function and Intestinal Microbiota in Astronauts Under Closed Microgravity Environment

Study for Evaluating the Impact of Continuous Consumption of Probiotics on Immune Function and Intestinal Microbiota in Astronauts Under Closed Microgravity Environment

Human immune function and intestinal microbiota are suggested to be altered within long-duration stay in space. Accumulated evidences on earth support that Lacticaseibacillus paracasei strain Shirota (LcS) is a promising probiotic strain on improvement of immune function and intestinal microbiota. This study aims to investigate the impact of long-duration spaceflight as well as intake of LcS on the international space station (ISS), on immune system and intestinal microbiota in astronauts.

Inclusion Criteria:

• Individuals who are scheduled to stay on the ISS for at least 3 months
• Individuals who fully understand the study protocol and provide written informed consent for the study participation

Exclusion Criteria:

• Individuals who routinely use antibiotic, laxative, and/or bowel regulating medicine
• Individuals who participate in other research that competes with this study in terms of the purpose and field, e.g., study with dietary management or intake of bifidobacteria/lactic acid bacteria, oligosaccharides, antibiotic, laxative, and/or bowel regulating medicine