Can probiotics keep space travelers healthy during long journeys? Scientists say it holds great promise
Microgravity causes bone and muscle loss in astronomers and exposure to radiation increases the risk of cancers
Life in space takes a heavy toll on human bodies, affecting bones, muscles, immunity and mental health. These effects are likely to impede future explorations to Mars and beyond. But scientists think we might have one solution: boosting gut health through beneficial microorganisms. They arrived at this after reviewing previous studies on the link between gut microbes and health in space.
Previous studies have suggested that space travel alters gut microbiota. "It is therefore not surprising that its alterations have been related to several disorders," Dr Silvia Turroni of the University of Bologna, one of the authors of the review, told MEA WorldWide (MEAWW). In other words, changes in the microbial population are likely to reduce the number of beneficial microbes, thereby enriching potentially harmful bacteria. The human gut is home to trillions of microbes, most of which are linked to our well-being. The microbial population changes with age, physical condition, diet, or lifestyle, Turroni explained. Certain stress factors could alter the natural balance of tiny residents in the gut, potentially leading to disorders.
The same can happen in space too. Radiation, microgravity, dietary constraints, constant noise induce stress, Turroni added. Microgravity causes bone and muscle loss in astronomers and exposure to radiation increases the risk of cancers. Explorers tend to witness a decreased sensitivity to insulin, which may lead to high blood sugar levels, weak immune system, mental illness and cognitive decline.
In space, studies have documented steady changes in the gut microbiome: some microbes increase in numbers while others decrease. For instance, one study found that space travelers from the same mission developed a similar population of gut microbes during their journey. "The results of spaceflight and analog studies are quite consistent with each other and also with what is already available on Earth," Prof Martina Heer of the University of Bonn, who conceived the review, said. But more further studies on long-term missions can add weight to these findings, the researchers said.
Can prebiotics and probiotics help?
Probiotics and prebiotics, which help in manipulating gut microbiota, may help space travel maintain their health during long missions. Studies suggest they hold great promise to protect explorers, Dr Turroni explained. They are widely used on Earth to promote good health. Probiotics are ingesting beneficial bacteria — through food like yogurt or pills. Prebiotics, on the other hand, involves eating fiber-rich food, which could boost beneficial bacteria in the gut. They appear to keep the stomach, intestine, heart, bone and mind healthy. Based on this evidence, both strategies could protect space travelers from stress-inducing factors such as disrupted metabolism, immune function, and sleep patterns, loss of bones and muscles, as well as neurobehavioral disorders, Dr Turroni explained.
However, there are still questions about their use to treat various health conditions. Dr Turroni suggested that studies should explore and verify the effects of probiotics and prebiotics during long-term stay under microgravity conditions. "The well-being of the gut microbiome of space travelers should be among the primary goals of long-duration exploratory missions," said Heer. "To ensure the success of the mission, we must not overlook the myriad of microorganisms that reside in our gastrointestinal tract and make sure they are in balance."
The study is published in Frontiers in Physiology