Space Prunes for Healthy Astronaut Bones?

Astronauts, cancer patients and other people exposed to bone-zapping radiation may want to start eating prunes.

Astronauts, cancer patients and other people exposed to bone-zapping radiation may want to start eating prunes. Experiments on mice show that a diet including prunes, or dried plums, staved off bone loss after the animals were irradiated.

"We believe our findings are likely to be applicable to humans," said Ruth Globus, with the Space Biosciences Division at NASA's Ames Research Center in Moffett Field, Calif.


For the first set of experiments, which are detailed in a paper published in this week's Nature Scientific Reports, mice were fed the equivalent of 25- to 30 prunes per person per day. More work is needed to learn if smaller quantities still protect bones, Globus wrote in an email to Discovery News.

"Other human studies indicate lower amounts (of dried plums), roughly five to 12 per day, are beneficial for the bone health in post-menopausal women," a group that is particularly susceptible to osteoporosis, she said.

Other foods, including blueberries, have previously been reported to help counter the harmful effects of ionizing radiation, but the new study is the first to find a connection between protecting bones and any fruit.

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"Dried plums include a wide variety of vitamins, minerals, antioxidants, polyphenols and other bioactive components. It's possible that dried plums might have of a unique combination of nutrients that are radio-protective for bone, but more work is needed in this area," Globus said.

Other mice were fed various antioxidants -- a diet that previous studies found offered some protection against radiation -- but Globus and colleagues determined that they alone did not stem bone loss.

"We suspect antioxidant content alone probably does not account for the protective effects of dried plum that we observed," Globus said.

"It would be interesting to know whether or not dried plum protects tissues other than bone, such as the gut, and also to compare dried plum side-by-side with other fruits, to see which one is most effective," she added.

In related studies, researchers also are using mice to determine if dried plums offer protection from colon cancer.

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"The polyphonic molecules appear to work in concert with dietary fiber that is present in the plums," Nancy Turner, a nutritionist researcher with Texas A&M University, told Discovery News.

She suspects the combination promotes a beneficial population of gut microbes that is helping to protect the colon.

Globus' research was supported by NASA's National Space Biomedical Research Institute. The authors acknowledge that the California Plum Board donated dried plums for the study.

Prunes have a range of health benefits, but they could be also an unlikely hero in the fight against bone radiation damage for long-duration space travelers.

Between fixing toilets

and rescuing zinnias

, it turns out that Scott Kelly is a fun astronaut to hang out with. The NASA spaceman is currently spending a year aboard the International Space Station (double the usual stay) and he shared his experiences

in an "Ask Me Anything" (AMA) session on Reddit last week

. His answers were in part sweet, in part humorous, but all gave a fascinating behind-the-scenes look to the not-so-well known aspects of an astronaut's life in space. Read on to hear about his views on acid pee, Klingon technology and David Bowie.

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One of the AMA's youngest interviewers was Simon, who is five years old. He asked: "Could a rogue spaceship sneak up on the space station without being aware, and dock?" Kelly's answer made us worry about Klingons from Star Trek: "Maybe an alien spaceship with a cloaking device. But not your normal spaceship, no. Unless it had a cloaking device, which doesn't exist, the U.S. Air Force would see it coming."

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We think of astronauts as brave people, but perhaps their bravery doesn't come from the derring-do we see in movies such as "The Martian" and "Gravity." Kelly said the creepiest thing he ever does on the job "generally ... has to do with the toilet." "Recently I had to clean up a gallon-sized ball of urine mixed with acid," he said, adding, "The acid is added to the urine so the urine doesn't damage the machinery that moves it through the system. It keeps it from clogging up the system."

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Photo: The toilet in the Zvezda service module of the International Space Station, as photographed during Expedition 6 in 2002-03. Rotated counterclockwise.

With Kelly having a military background and all, perhaps you'd be forgiven for thinking he crosses his arms so often because he is a stern naval aviator. Turns out, though, that it's a matter of simple physics. And human physiology. "It feels awkward to have them floating in front of me. It is just more comfortable to have them folded," Kelly wrote. Another user responded, "Wow, this is something I legitimately never considered. I just thought you were being gangsta."

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Photo: Scott Kelly hangs out in his personal quarters on the International Space Station, along with the Reddit symbol.

We think of microgravity as being a very gentle environment for astronauts. They can push off walls with a simple touch, do somersaults effortlessly, and simply float in a sleeping bag to go to sleep. But besides hurting muscles and bones, the environment makes you develop weird calluses, Kelly said. "The top of my feet develop rough alligator skin because I use the top of my feet to get around here on space station when using foot rails," he wrote.

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Photo: Scott Kelly with a bunch of carrots, just hanging out in space.

With the passing of David Bowie earlier this month, space fans have been nostalgic about the many space references in his songs, from "Space Oddity" to "Starman". He even had an album with perhaps the neatest space reference of all time ("The Rise and Fall of Ziggy Stardust and the Spiders from Mars.") But what was Kelly's favorite song from the Brit's award-winning catalog? Turns out it's "Modern Love". The song appears to be about disillusionment with modern-day life, and especially working for a living. But we still think modern days and working would remain ever more awesome in space.

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Photo: File photo of David Bowie performing a concert at the Color Line Arena in Hamburg, Germany, on Oct. 16, 2003