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.
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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.