This video presents an interesting discussion of a test of whether nutrition can affect the bone density of crew members of the ISS:

Space Station Live commentator Pat Ryan conducts an interview with Dr. Scott M. Smith, the principal investigator of the Pro K experiment. The experiment is NASA’s first evaluation of a dietary countermeasure to lessen bone loss of astronauts. Pro K proposes that a flight diet with a decreased ratio of animal protein to potassium will lead to decreased loss of bone mineral. Read more…

http://www.nasa.gov/mission_pages/sta…