Nutritional status assessment in semiclosed environments: Ground-based andspace flight studies in humans

Adequate nutrition is critical during long-term spaceflight, as is the abil ity to easily monitor dietary intake. A comprehensive nutritional status as sessment profile was designed for use before, during and after flight. It i ncluded assessment of both dietary intake and biochemical markers of nutrit ional status. A spaceflight food-frequency questionnaire (FFQ) was develope d to evaluate intake of key nutrients during spaceflight. The nutritional s tatus assessment protocol was evaluated during two ground-based closed-cham ber studies (60 and 91 d; n = 4/study), and was implemented for two astrona uts during 4-mo stays on the Mir space station. Ground-based studies indica ted that the FFQ, administered daily or weekly, adequately estimated intake of key nutrients. Chamber subjects maintained prechamber energy intake and body weight. Astronauts tended to eat 40-50% of WHO-predicted energy requi rements, and lost > 10% of preflight body mass. Serum ferritin levels were lower after the chamber stays, despite adequate iron intake. Red blood cell folate concentrations were increased after the chamber studies, Vitamin D stores were decreased by > 40% on chamber egress and after spaceflight. Mir crew members had decreased levels of most nutritional indices, but these a re difficult to interpret given the insufficient energy intake and loss of body mass. Spaceflight food systems can provide adequate intake of macronut rients, although, as expected, micronutrient intake is a concern for any cl osed or semiclosed food system, These data demonstrate the utility and impo rtance of nutritional status assessment during spaceflight and of the FFQ d uring extended-duration spaceflight.