3 Things Microbes in Space Can Teach Us About Our Health on Earth

A 3D rendering of an astronaut in outer space.

(© lexaarts/Fotolia)

We all know the typical astronaut accessories—the EVA suit, the oxygen tanks, the radio assembly. But there's an invisible part of each space mission that's often overlooked: the trillions of microorganisms that hitch a ride.

Observing responses of pathogens in space could help scientists figure out how to outsmart them when they cause trouble on Earth.

Dr. Sarah Wallace is a NASA microbiologist who aims to keep microbes from causing problems for U.S. astronauts aboard the International Space Station. According to Wallace, research on microorganisms in space has more than cosmic importance. It can also reveal things about our health here on Earth:

1) Avoiding disease isn't all about maintaining a sterile environment.

NASA has a great track record of keeping the crew healthy on space missions. But surprisingly, it's not from having kept the space flight environment as sterile as possible.

Wallace says, "We [monitor] the environment but unless we find something that's medically significant, or [in] super high numbers, we're not going to do anything."

Not only is it impossible for astronauts to live in completely sterile quarters—crew members, after all, are microbe-shedding machines—but it may not even be desirable, given what we now know about the human microbiome. Scientists have found that the entire community of microorganisms (bacteria, archaea, fungi, and viruses) living in and on us likely have an active role in keeping us healthy. This means that down on the ground we need to let go of the germophobe idea that eradicating all microbes is always better for our health.

2) Disease-causing microbes change their behavior under different conditions.

Remember the recent E. coli O157:H7 outbreak linked to romaine lettuce? We're still grappling with a lot of pathogen problems here on Earth. One reason is that scientists are still learning which strategies these disease-causing microorganisms are capable of employing under different conditions.

Space missions are associated with a major shift in gut microbiome composition—as shown in NASA's twin study.

Wallace says experiments with Salmonella Typhimurium showed that the pathogen became more virulent in space. Yet curiously, the opposite seemed to happen to Staphylococcus aureus under space-flight-like conditions—it became more benign.

"The way these organisms have evolved, certain triggers [in the space flight environment] might be dictating how they're responding," Wallace says.

Observing these responses could help scientists figure out how to outsmart the pathogen when it causes trouble on Earth. "It's giving us some great insights into how we could target them differently in the future," she explains.

3) Major shifts in the gut microbiome could affect health in specific ways.

Scientists still have a lot to learn about which changes in an adult's gut microbiome actually cause a change in health status. In fact, microbiome-focused therapeutics companies are in hot pursuit of these connections.

Space missions are associated with a major shift in gut microbiome composition—as shown in NASA's twin study, which followed astronaut Scott Kelly during a year aboard the ISS while his identical twin brother Mark (a retired astronaut) stayed on the ground. Scott experienced simultaneous changes in telomere length and bone formation; were these related to the gut microbial differences?

Wallace says a soon-to-be-published study of nine additional astronauts could help answer this question. The research may reveal how closely gut microbiome shifts track health outcomes, and the reversibility of the changes.

She emphasizes the science from her lab isn't meant to help only the small minority of humans who will ever go to space: "That's always our goal—that our research is helping people on Earth."

Kristina Campbell
Kristina Campbell is a Canadian writer who covers microbiome science for digital and print media around the world. She is author of The Well-Fed Microbiome Cookbook (Rockridge Press, 2016) and co-author of an academic textbook for health professionals, Gut Microbiota: Interactive Effects on Nutrition and Health (Elsevier, 2018).
Get our top stories twice a month
Follow us on

On the left, a Hermès bag made using fine mycelium as a leather alternative, made in partnership with the biotech company MycoWorks; on right, a sheet of mycelium "leather."

Photo credit: Coppi Barbieri and MycoWorks

A natural material that looks and feels like real leather is taking the fashion world by storm. Scientists view mycelium—the vegetative part of a mushroom-producing fungus—as a planet-friendly alternative to animal hides and plastics.

Products crafted from this vegan leather are emerging, with others poised to hit the market soon. Among them are the Hermès Victoria bag, Lululemon's yoga accessories, Adidas' Stan Smith Mylo sneaker, and a Stella McCartney apparel collection.

Keep Reading Keep Reading
Susan Kreimer
Susan Kreimer is a New York-based freelance journalist who has followed the landscape of health care since the late 1990s, initially as a staff reporter for major daily newspapers. She writes about breakthrough studies, personal health, and the business of clinical practice. Raised in the Chicago area, she holds a B.A. in Journalism/Mass Communication and French from the University of Iowa and an M.S. from the Columbia University Graduate School of Journalism.

From a special food to a vaccine and gene editing, new technologies may offer solutions for cat lovers with allergies.

Photo by Pacto Visual on Unsplash

Amy Bitterman, who teaches at Rutgers Law School in Newark, gets enormous pleasure from her three mixed-breed rescue cats, Spike, Dee, and Lucy. To manage her chronically stuffy nose, three times a week she takes Allegra D, which combines the antihistamine fexofenadine with the decongestant pseudoephedrine. Amy's dog allergy is rougher--so severe that when her sister launched a business, Pet Care By Susan, from their home in Edison, New Jersey, they knew Susan would have to move elsewhere before she could board dogs. Amy has tried to visit their brother, who owns a Labrador Retriever, taking Allegra D beforehand. But she began sneezing, and then developed watery eyes and phlegm in her chest.

"It gets harder and harder to breathe," she says.

Animal lovers have long dreamed of "hypo-allergenic" cats and dogs. Although to date, there is no such thing, biotechnology is beginning to provide solutions for cat-lovers. Cats are a simpler challenge than dogs. Dog allergies involve as many as seven proteins. But up to 95 percent of people who have cat allergies--estimated at 10 to 30 percent of the population in North America and Europe--react to one protein, Fel d1. Interestingly, cats don't seem to need Fel d1. There are cats who don't produce much Fel d1 and have no known health problems.

Keep Reading Keep Reading
Temma Ehrenfeld
Temma Ehrenfeld writes about health and psychology. In a previous life, she was a reporter and editor at Newsweek and Fortune. You can see more of her work at her writing portfolio (https://temmaehrenfeld.contently.com) and contact her through her Psychology Today blog.