Physiology: Plumming the depths of spaceflight

Dietary supplementation with dried plums may help to prevent bone loss caused by ionizing radiation, which may be experienced during radiotherapy or spaceflight, according to a mouse study in Scientific Reports this week. The results may have implications for both astronauts and cancer patients.

Unlike radiation doses experienced on the International Space Station, long duration space missions outside the protection of the Earth’s magnetosphere - the magnetic field that envelops the planet - may lead to exposure to levels of ionizing radiation capable of causing bone loss.

To investigate the effects of different treatments on preventing bone loss and the expression of genes in bone marrow cells that lead to bone resorption (the breakdown of bone), Ruth Globus, Ann-Sofie Schreurs and colleagues assigned five to ten male mice to groups to evaluate interventions with antioxidant or anti-inflammatory activities, thought to prevent bone loss. The four interventions included an antioxidant diet cocktail, dihydrolipoic acid, Ibuprofen and dried plums - previously shown to mitigate age-related bone loss. Mice from each group were then exposed to ionizing radiation in the form of either gamma rays (as used in radiotherapy) or simulated space radiation. The authors found that dried plums were the most effective intervention in reducing expression of genes related to bone resorption. It was also found that this diet was equally effective at preventing bone loss after irradiation for both types of radiation.

Further studies are required to determine the active component in plums that is responsible for this protective effect and if the findings can be replicated in humans.