Nutritional Status Assessment in Semiclosed Environments: Ground-Based and Space Flight Studies in Humans

Abstract

Adequate nutrition is critical during long-term spaceflight, as is the ability to easily monitor dietary intake. A comprehensive nutritional status assessment profile was designed for use before, during and after flight. It included assessment of both dietary intake and biochemical markers of nutritional status. A spaceflight food-frequency questionnaire (FFQ) was developed to evaluate intake of key nutrients during spaceflight. The nutritional status assessment protocol was evaluated during two ground-based closed-chamber studies (60 and 91 d; n = 4/study), and was implemented for two astronauts during 4-mo stays on the Mir space station. Ground-based studies indicated 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 requirements, 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 are difficult to interpret given the insufficient energy intake and loss of body mass. Spaceflight food systems can provide adequate intake of macronutrients, although, as expected, micronutrient intake is a concern for any closed or semiclosed food system. These data demonstrate the utility and importance of nutritional status assessment during spaceflight and of the FFQ during extended-duration spaceflight.

Amino acid supplementation alters bone metabolism during simulated weightlessness

“…Serum bone-specific alkaline phosphatase (BSAP) was measured by a commercially available ELISA (Quidel). Urinary creatinine was measured as previously described (44).…”

Whole body and regional body composition changes following 10-day hypoxic confinement and unloading–inactivity

“…It is assumed that allowing ad libitum energy intake would cause an increase in body mass, primarily due to gains in fat mass outweighing the loss in lean mass as has already been shown (Gretebeck et al 1995). Therefore, abulatory and best rest studies employ PAL for dietary intake calculations that usually range between 1.4 and 1.6 for the ambulatory and between 1.1 and 1.3 for bed rest conditions (Smith et al 2001;Lane and Feeback 2002;Zwart et al 2009a). The PAL factors used in the present study (1.4 and 1.2) are, hence, at the lower part of the spectrum.…”

“…Significant decreases in the whole body mass as well as changes in the regional body composition, mostly within the lower limbs, have been reported previously (Krebs et al 1990;LeBlanc et al 1992;Blanc et al 1998;Inniss et al 2009). As nutritional responses to weightlessness and bed rest have been shown to be qualitatively similar (Zwart et al 2009b), the application of the bed rest model seems suitable for investigating the effects of microgravity on nutritional status, dietary intake, and body composition (Smith et al 2001).…”

Effects of Dietary Antioxidant Supplementation on the Development of Malignant Lymphoma and Other Neoplastic Lesions in Mice Exposed to Proton or Iron-Ion Radiation

“…With the oxidative stress associated with space travel, it is conceivable that astronauts may deplete their vitamins and mineral stores more rapidly than other individuals and may need considerably higher amounts of antioxidant vitamins/minerals than the established Recommended Dietary Allowances (RDAs). There is some evidence that astronauts do deplete their vitamins during space flight, because there is a decrease of bioreduction capacity [measured as plasma total antioxidant status (TAS)] in astronauts after long-duration space flights (13). Thus supplementation with antioxidant vitamins is likely to reduce the radiation-induced damage associated with space travel.…”