NASA conducts research while orbiting more than 200 miles above the Earth to learn how humans and materials behave outside of a gravity-influenced world. Research Summary: The Pro K investigation is NASA's first evaluation of a dietary countermeasure against bone loss associated with spaceflight. By providing a controlled diet to the astronauts and taking blood and urine samples, researchers will learn how the diet affects the loss of bone mass in flight, and the recovery of bone after landing. This study could result in a countermeasure against bone loss that has virtually no risk of side effects and does not require additional materials or crew time. Research Objective: The specific goal for the study is to determine if the ratio of animal protein acid precursors to potassium base precursors in the astronaut diet is correlated with bone metabolism and bone loss after spaceflight. Pro K investigators propose that a diet with a lower ratio of animal protein to potassium will decrease bone loss. Time Frame: Pro K operations on the International Space Station ISS began during Expeditions 21/22 in 2009 and is planned to continue through Expedition 27/28. Earth Application: The proposed research on the effects of diet on bone loss has direct public health significance, especially given the growing trend in the United States toward diets high in animal protein.
