Nutritional Status Assessment Before, During, and After Long-Duration Head-Down Bed Rest

Zwart, Sara R.; Oliver, Susan A. Mathews; Fesperman, J. Vernell; Kala, Geeta; Krauhs, Jane M.; Ericson, Karen L.; Smith, Scott M.

doi:10.3357/asem.br07.2009

Cited by 58 publications

(56 citation statements)

References 34 publications

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“…It is well documented that microgravity per se, as experienced during space flight, affects the nutritional status and body composition of astronauts (Smith et al 2005;Smith and Zwart 2008;Zwart et al 2009b). Terrestrial studies simulating the effects of microgravity in Space, by rendering participants inactive and unloading their weight-bearing limbs using the bed rest experimental model, have observed similar changes in body composition and nutritional status (Smith and Zart 2008;Smith et al 2005).…”

Section: Introductionmentioning

confidence: 80%

“…Although it is known that individually microgravity and hypoxia significantly alter nutritional status and body composition (Boyer and Blume 1984;Zwart et al 2009b), there is a paucity of data regarding their combined effect (Stevens et al 1966;Loeppky et al 1993a). The planned environmental conditions in future planetary habitats merit further investigations, with particular emphasis on the evaluation of the current guidelines regarding energy and nutrient intake levels.…”

Section: Introductionmentioning

confidence: 97%

“…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).…”

Section: Introductionmentioning

confidence: 99%

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

Debevec

McDonnell

Macdonald

et al. 2014

Appl. Physiol. Nutr. Metab.

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Future planetary habitats will expose inhabitants to both reduced gravity and hypoxia. This study investigated the effects of short-term unloading and normobaric hypoxia on whole body and regional body composition (BC). Eleven healthy, recreationally active, male participants with a mean (SD) age of 24 (2) years and body mass index of 22.4 (3.2) kg·m(-2) completed the following 3 10-day campaigns in a randomised, cross-over designed protocol: (i) hypoxic ambulatory confinement (HAMB; FIO2 = 0.147 (0.008); PIO2 = 93.8 (0.9) mm Hg), (ii) hypoxic bed rest (HBR; FIO2 = 0.147 (0.008); PIO2 = 93.8 (0.9) mm Hg), and (iii) normoxic bed rest (NBR; FIO2 = 0.209; PIO2 = 133.5 (0.7) mm Hg). Nutritional requirements were individually precalculated and the actual intake was monitored throughout the study protocol. Body mass, whole body, and regional BC were assessed before and after the campaigns using dual-energy X-ray absorptiometry. The calculated daily targeted energy intake values were 2071 (170) kcal for HBR and NBR and 2417 (200) kcal for HAMB. In both HBR and NBR campaigns the actual energy intake was within the targeted level, whereas in the HAMB the intake was lower than targeted (-8%, p < 0.05). Body mass significantly decreased in all 3 campaigns (-2.1%, -2.8%, and -2.0% for HAMB, HBR, and NBR, respectively; p < 0.05), secondary to a significant decrease in lean mass (-3.8%, -3.8%, -4.3% for HAMB, HBR, and NBR, respectively; p < 0.05) along with a slight, albeit not significant, increase in fat mass. The same trend was observed in the regional BC regardless of the region and the campaign. These results demonstrate that, hypoxia per se, does not seem to alter whole body and regional BC during short-term bed rest.

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Section: Introductionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Debevec

McDonnell

Macdonald

et al. 2014

Appl. Physiol. Nutr. Metab.

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“…A low intracellular antioxidant level PMO Postmenopausal osteoporosis, MDA Malondialdehyde, GPX Glutathione peroxidase, SOD Superoxide dismutase, nmol: nanomole, ml milliliter, U unit, min Minimum, max Maximum, IQR Interquartile range *P \ 0.05; when compared with the control group a when compared to the levels after the treatment increases osteoclastogenesis due to uncontrolled ROS formation. Increased N-telopeptide excretion and decreased antioxidant levels in patients bedridden for a long time with resultant increased bone loss have been shown to be associated [36]. A marked decrease in urinary cross-linked N-telopeptides of type I collagen (NTx) levels with risedronate use has previously been shown in PMO patients, and it has been postulated that it could provide earlier data than other methods during treatment monitoring [37].…”

Section: Discussionmentioning

confidence: 99%

Prospective evaluation of free radicals and antioxidant activity following 6-month risedronate treatment in patients with postmenopausal osteoporosis

et al. 2011

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In addition to the well-described implications of estrogen deficiency in postmenopausal osteoporosis (PMO), free radicals are also effective on bone metabolism. The antioxidant vitamins C and E play an important role in the production of collagen, mesenchymal cell differentiation into osteoblasts, and bone mineralization. Therefore, the incidence of osteoporosis and the risk of fractures were decreased with vitamin C and E. It was proposed that free oxygen radicals are responsible for biological aging, atherosclerosis, carcinogenesis, and osteoclastic activity via their negative effects on the cell and DNA. In this study, we aimed to investigate and compare the levels of free radicals and serum antioxidant activity in patients with PMO and healthy subjects before and after six-month treatment with risedronate, which is an inhibitor of bone resorption. Twenty-three postmenopausal patients aged between 52-83 (mean [± standard deviation] 67.6 ± 8.17) with T scores below -2.5 in femur neck or L1-L4, and 23 postmenopausal healthy subjects were enrolled into the study. Patients who had received any medications within the last 6 months that could alter bone metabolism were excluded. Serum malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) levels were analyzed in both groups. The patients with PMO were commenced on 5 mg of risedronate, 1,200 mg of calcium, and 800 IU of vitamin D daily. The patients were reevaluated at the end of the sixth month. MDA and SOD levels were similar in patients with PMO when compared to the healthy group before the treatment, while the GPx levels were lower in patients with PMO (P = 0.014). GPx (P = 0.028) and MDA (P = 0.04) levels were increased in patients with PMO after the treatment. In contrast, SOD levels were decreased when compared to the initial levels (P = 0.006). There may be an insufficiency in different steps of the enzymatic antioxidant systems in patients with PMO without treatment. We observed an increment in lipid peroxidation levels and GPx levels with risedronate. We think that the decrement in SOD levels may be related with the utilized antioxidants due to the increased free radicals and the compensatory increment in the other steps of the antioxidant system.

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“…They were monitored to ensure round-the-clock compliance. Details have been reported elsewhere (34)(35)(36). In this study, 12 subjects (8 male subjects and 4 female subjects) with an age range of 25-49 y and an average age of 32 ± 8 y were enrolled.…”

Section: Methodsmentioning

confidence: 99%

Rapidly assessing changes in bone mineral balance using natural stable calcium isotopes

Morgan

Skulan

Gordon

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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121

104

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The ability to rapidly detect changes in bone mineral balance (BMB) would be of great value in the early diagnosis and evaluation of therapies for metabolic bone diseases such as osteoporosis and some cancers. However, measurements of BMB are hampered by difficulties with using biochemical markers to quantify the relative rates of bone resorption and formation and the need to wait months to years for altered BMB to produce changes in bone mineral density large enough to resolve by X-ray densitometry. We show here that, in humans, the natural abundances of Ca isotopes in urine change rapidly in response to changes in BMB. In a bed rest experiment, use of high-precision isotope ratio MS allowed the onset of bone loss to be detected in Ca isotope data after about 1 wk, long before bone mineral density has changed enough to be detectable with densitometry. The physiological basis of the relationship between Ca isotopes and BMB is sufficiently understood to allow quantitative translation of changes in Ca isotope abundances to changes in bone mineral density using a simple model. The rate of change of bone mineral density inferred from Ca isotopes is consistent with the rate observed by densitometry in long-term bed rest studies. Ca isotopic analysis provides a powerful way to monitor bone loss, potentially making it possible to diagnose metabolic bone disease and track the impact of treatments more effectively than is currently possible.osteopenia | biomarker | medical geology | biosignature | spaceflight

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Nutritional Status Assessment Before, During, and After Long-Duration Head-Down Bed Rest

Abstract: These changes are similar to some of those observed during spaceflight, and further document the utility of bed rest as a model of spaceflight.

Cited by 58 publications

References 34 publications

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

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

Prospective evaluation of free radicals and antioxidant activity following 6-month risedronate treatment in patients with postmenopausal osteoporosis

Rapidly assessing changes in bone mineral balance using natural stable calcium isotopes

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