Gut microbiota shifts in spaceflight: a case study evidence and countermeasures for microbial homeostasis

The gut microbiota is a crucial component in maintaining overall human health since it has been found to influence not only metabolism but also neurobehavioral function and immunity. The extreme conditions of space, for example, cosmic radiation, microgravity, and confinement, can severely disrupt the functioning and alter the composition of gut microbiota. In fact, this will predispose the immune system to be dysfunctional, lead to psychological and metabolic disorders that are accompanied by a decrease in the diversity of beneficial microbes and change in the pattern of metabolite production. The spaceflight analog and ground, based studies have produced important findings concerning the mechanisms and reasons for gut microbial dysbiosis in extreme conditions. Different research works have been carried out, such as dietary intervention and high fiber to support the growth of healthy microbes. Further, advanced microbial monitoring using wearable sensors to identify the microbial and proinflammatory biomarkers will mitigate dysbiosis and safeguard the crew's health for longer-duration missions. This wearable sensor will not only help monitor astronauts' microbial status continuously, but it will also provide a significant feature for designing personalized dietary plans and probiotic supplements. This article provides a comprehensive understanding of astronaut health, including disturbances to the gut microbiome during space travel, space-analogue studies conducted by many researchers to unravel mechanisms, countermeasures to stabilize the gut microbiome, and its prospects.