Metabolism and Nutrition

Nutritional requirements for crew members on extended flights have been derived largely by extrapolation from ground-based research, from the extensive metabolic studies conducted in the Skylab program, from measurements conducted on Spacelab missions, the Space Shuttle, the Russian space station Mir, and the International Space Station (ISS). Understanding the ways in which nutrients are metabolized by crew members under the unique conditions of space flight is essential for maintaining long-term crew health, particularly the development of strategies for preventing undesirable changes in lean body mass so as to maintain bone-mineral integrity and muscle performance. Such strategies must include the consumption of sufficient amounts of energy and protein, among other nutrients. Because foods and the food systems to be flown in space must meet the unusual constraints associated with space craft and space flight conditions, this chapter opens with descriptions of the food systems developed for the various U.S. space programs, including the ISS. Next follows an outline of planned food systems for vehicles to be used for return for very long-duration space flights, beyond low Earth orbit, and trips to other solar system bodies. The remainder of the chapter reviews the knowledge collected to date on nutrition.