title: The nutritional status of astronauts is altered after long-term space flight aboard the International Space Station.
abstract: Defining optimal nutrient requirements is critical for ensuring crew health during long-duration space exploration missions. Data pertaining to such nutrient requirements are extremely limited. The primary goal of this study was to better understand nutritional changes that occur during long-duration space flight. We examined body composition, bone metabolism, hematology, general blood chemistry, and blood levels of selected vitamins and minerals in 11 astronauts before and after long-duration (128-195 d) space flight aboard the International Space Station. Dietary intake and limited biochemical measures were assessed during flight. Crew members consumed a mean of 80% of their recommended energy intake, and on landing day their body weight was less (P = 0.051) than before flight. Hematocrit, serum iron, ferritin saturation, and transferrin were decreased and serum ferritin was increased after flight (P < 0.05). The finding that other acute-phase proteins were unchanged after flight suggests that the changes in iron metabolism are not likely to be solely a result of an inflammatory response. Urinary 8-hydroxy-2'-deoxyguanosine concentration was greater and RBC superoxide dismutase was less after flight (P < 0.05), indicating increased oxidative damage. Despite vitamin D supplement use during flight, serum 25-hydroxycholecalciferol was decreased after flight (P < 0.01). Bone resorption was increased after flight, as indicated by several markers. Bone formation, assessed by several markers, did not consistently rise 1 d after landing. These data provide evidence that bone loss, compromised vitamin D status, and oxidative damage are among critical nutritional concerns for long-duration space travelers.
authors.affiliation: Human Adaptation and Countermeasures Office, NASA Lyndon B. Johnson Space Center, Houston, TX 77058, USA. scott.m.smith@nasa.gov
authors.forename: Scott M
authors.initials: SM
authors.lastname: Smith
authors.forename: Sara R
authors.initials: SR
authors.lastname: Zwart
authors.forename: Gladys
authors.initials: G
authors.lastname: Block
authors.forename: Barbara L
authors.initials: BL
authors.lastname: Rice
authors.forename: Janis E
authors.initials: JE
authors.lastname: Davis-Street
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000209:Acute-Phase Proteins / Q000378:metabolism; D000328:Adult; D018480:Astronauts; D015415:Biomarkers / Q000652:urine; D001823:Body Composition; D002112:Calcifediol / Q000097:blood; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000652:urine; D019587:Dietary Supplements; D002149:Energy Intake; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D006801:Humans; D007391:International Cooperation; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D018384:Oxidative Stress; D013026:Space Flight; D013482:Superoxide Dismutase / Q000097:blood; D013997:Time Factors; D014807:Vitamin D
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; D014807:Vitamin D; D000080242:8-Hydroxy-2'-Deoxyguanosine; D013482:Superoxide Dismutase; D003849:Deoxyguanosine; D002112:Calcifediol