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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

The effect of diet, exercise, and 7,12-dimethylbenz(a)anthracene on food intake, body composition, and carcass energy levels in virgin female BALB/c mice

The effects of diet, exercise, and 7,12-dimethylbenz(a)anthracene (DMBA), a mammary-tumor carcinogen, on food intake, energy consumption, body weight, and body composition in virgin female BALB/c mice are investigated. Diet, exercise, and DMBA all had pronounced effects on energy consumption, which in turn affected body composition. These treatments may influence manifestations of breast cancer via their effects on body composition.

Lane, Helen W.↗
NASA NTRS1992

Energy requirements for space flight

Both the United States and the Soviet Union perform human space research. This paper reviews data available on energy metabolism in the microgravity of space flight. The level of energy utilization in space seems to be similar to that on earth, as does energy availability. However, despite adequate intake of energy and protein and in-flight exercise, lean body mass was catabolized, as indicated by negative nitrogen balance. Metabolic studies during simulated microgravity (bed rest) and true microgravity in flight have shown changes in blood glucose, fatty acids and insulin concentrations, suggesting that energy metabolism may be altered during space flight. Future research should focus on the interactions of lean body mass, diet and exercise in space, and their roles in energy metabolism during space flight.

Lane, Helen W.↗
NASA NTRS1997

Comparison of ground-based and space flight energy expenditure and water turnover in middle-aged healthy male US astronauts

Energy requirements during space flight are poorly defined because they depend on metabolic-balance studies, food disappearance, and dietary records. Water turnover has been estimated by balance methods only. The purpose of this study was to determine energy requirements and water turnover for short-term space flights (8-14 d). Subjects were 13 male astronauts aged 36-51 y with normal body mass indexes (BMIs). Total energy expenditure (TEE) was determined during both a ground-based period and space flight and compared with the World Health Organization (WHO) calculations of energy requirements and dietary intake. TEE was not different for the ground-based and the space-flight periods (12.40 +/- 2.83 and 11.70 +/- 1.89 MJ/d, respectively), and the WHO calculation using the moderate activity correction was a good predictor of TEE during space flight. During the ground-based period, energy intake and TEE did not differ, but during space flight energy intake was significantly lower than TEE; body weight was also less at landing than before flight. Water turnover was lower during space flight than during the ground-based period (2.7 +/- 0.6 compared with 3.8 +/- 0.5 L/d), probably because of lower fluid intakes and perspiration loss during flight. This study confirmed that the WHO calculation can be used for male crew members' energy requirements during short space flights.

STS Shuttle Project↗
NASA NTRS2012

Plasma Cytokine Levels During Long-Duration Spaceflight

Determine the in-flight status of immunity, physiological stress, viral immunity/reactivation. Specific measurements include leukocyte distribution, T cell function, cytokine production profiles (mRNA, intracellular, secreted, plasma), virus-specific T cell number/function, latent herpesvirus reactivation, stress hormone levels. Determine the clinical risk related to immune dysregulation for exploration class spaceflight, as well as an appropriate monitoring strategy for spaceflight-associated immune dysfunction, that could be used for the evaluation of countermeasures. Specific Study Objectives: Determine the nutritional status of astronauts before, during, and after spaceflight ensure adequate intake of energy, protein, and vitamins during missions. The Clinical Nutritional Status Assessment measures dietary intake, body composition, protein, bone, iron, mineral, vitamin, and antioxidant status (60 total analytes). Currently, it is a medical requirement for U.S. crewmembers on-board the ISS. The results of data analysis are used both to understand the connections between nutrition and human health during space flight, and to develop effective dietary strategies to reduce adverse health impacts (including bone loss, loss of important vitamins and minerals, and increased genetic damage from radiation).

Crucian, Brian E.↗
NASA NTRS2000

Nutritional Biochemistry of Spaceflight

Adequate nutrition is critical for crew health and safety during spaceflight. To ensure adequate nutrition, the nutrient requirements need to be both accurate and available from the spaceflight food system. The existing nutritional requirements for extended-duration spaceflight have been defined largely by extrapolation from ground-based research. However, nutritional requirements are influenced by most of the physiological consequences of spaceflight, including loss of lean, adipose, and bone tissue; changes in blood composition; and increased risk of renal stone formation. This review focuses on key areas where information has been gained in recent years: dietary intake and energy metabolism, bone health, fluid and electrolyte homeostasis, and hematological changes. Areas in which specific nutrients have the potential to serve as countermeasures to the negative effects of spaceflight are also reviewed. Dietary Intake

Smith, Scott M.↗
NASA NTRS2001

Increased Body Weight Reduces Voluntary Movement to Maintain Energy Expenditure of Rats Exposed to Increases in Gravity

With the increase in obesity related diseases there is heightened interest in mechanisms regulating body weight. To assess the influence of increases in body weight on energy expenditure and intake in rats we employed variable levels of gravity. Our approach afforded the means to measure interactions of energy expenditure and intake in response to increases in body weight (body mass x gravity level). We found a dose relationship between rapid elevation of body weight and reduction of voluntary movement, such that the energy requirements for activity are unchanged, and total energy expenditure and intake maintained. Reduction of movement appears to be a response to increased body weight, rather than a contributing factor, suggesting a new regulatory pathway.

Wade, C. E.↗
NASA NTRS2015

An Updated Look at the Pro K Experiment: Urinary Acid Excretion Can Predict Changes in Bone Metabolism During Space Flight

Mitigating space flight-induced bone loss is critical for space exploration, and diet can play a major role in this effort (1). Previous ground-based studies provide evidence that dietary composition can influence bone resorption during bed rest (2). In this study we examined the role of dietary intake patterns as one factor that can influence bone mineral loss in astronauts during space flight. Crew members were asked to consume, for 4 days at a time, prescribed menus with either a low (0.3-0.6 g/mEq) or high (1.0-1.3 g/mEq) ratio of animal protein to potassium (APro:K). Menus were developed for each crewmember, and were designed to meet both crew preferences and study constraints. Intakes of energy, total protein, calcium, and sodium were held relatively constant between the two diets. The order of the menus was randomized, and crews completed each set (low and high) once before and twice during space flight, for a total of 6 controlled diet sessions. One inflight session and three postflight sessions (R+30, R+180, R+365) monitored typical dietary intake. As of this writing, data are available from 14 crew members. Two subject's samples are awaiting return from ISS via Space-X, and the final subject has one more collection session planned in November 2014. On the last day of each of the 4-d controlled diet sessions, 24-h urine samples were collected, along with a fasting blood sample on the morning of the 5th day. Preliminary analyses will show the relationships between diet and flight on markers of bone metabolism. The results from this study, which represent healthy individuals in a unique environment, will be important to better understand diet and bone interrelationships during space flight as well as on Earth. These data will be important as nutritional requirements and food systems are developed for future exploration-class missions. This study was funded by the Human Health Countermeasures Element of NASA Human Research Program.

Zwart, Sara R.↗
NASA NTRS2015

Dietary and Urinary Sulfur can Predict Changes in Bone Metabolism During Space Flight

Mitigating space flight-induced bone loss is critical for space exploration, and diet can play a major role in this effort. Previous ground-based studies provide evidence that dietary composition can influence bone resorption during bed rest. In this study we examined the role of dietary intake patterns as one factor that can influence bone mineral loss in astronauts during space flight. Crew members were asked to consume, for 4 days at a time, prescribed menus with either a low (0.3-0.6 g/mEq) or high (1.0-1.3 g/mEq) ratio of animal protein to potassium (APro:K). Menus were developed for each crewmember, and were designed to meet both crew preferences and study constraints. Intakes of energy, total protein, calcium, and sodium were held relatively constant between the two diets. The order of the menus was randomized, and crews completed each set (low and high) once before and twice during space flight, for a total of 6 controlled diet sessions. One inflight session and three postflight sessions (R+30, R+180, R+365) monitored typical dietary intake. As of this writing, data are available from 14 crew members. The final three subjects' inflight samples are awaiting return from the International Space Station via Space-X. On the last day of each of the 4-d controlled diet sessions, 24-h urine samples were collected, along with a fasting blood sample on the morning of the 5th day. Preliminary analyses show that urinary excretion of sulfate (normalized to lean body mass) is a significant predictor of urinary n-telopeptide (NTX). Dietary sulfate (normalized to lean body mass) is also a significant predictor of urinary NTX. The results from this study, will be important to better understand diet and bone interrelationships during space flight as well as on Earth. This study was funded by the Human Health Countermeasures Element of the NASA Human Research Program.

Zwart, Sara R.↗
NASA NTRS1977

Skylab nutritional studies

Precise nutritional specifications arising from both physiological and experimental requirements necessitated a comprehensive study of the chemical composition of the Skylab food supply. Each of the approximately seventy different food items was analyzed for digestible and non-digestible carbohydrate, and for protein, amino acids, fat, fatty acids, vitamins and minerals. Menus were formulated to provide at least the National Research Council's Recommended Dietary Allowance of all essential nutrients and, in addition, to provide constant daily intakes of calcium, phosphorus, magnesium, sodium, potassium and protein. In general, the crew members adhered to their programmed menus. The ability to swallow and digest food was unaffected by prolonged weightlessness. Taste acuity also appeared to be undiminished in flight. The bone and muscle changes which occurred in previous flights were more pronounced in Skylab. It is concluded that these changes did not develop as a result of nutritional deficit. If such changes are nutritionally related, they point to the existence of nutritional requirements in weightlessness which differ quantitatively from those observed on earth.

long duration↗
NASA NTRS1979

Quantitation of tissue loss during prolonged space flight

Data from Skylab missions related to tissue loss in space were analyzed. Significant changes in gross body composition occur during spaceflight, these include: alterations in water balance resulting from headward shifts of fluid, loss of musculoskeletal tissue, and alterations in fat depending upon the balance between caloric intake and energy expenditure. An effort was made to control the more essential components of body weight on the Skylab missions.

Leonard, J. I.↗
NASA NTRS2002

Determinants affecting physical activity levels in animal models

Weight control is dependent on energy balance. Reduced energy expenditure (EE) associated with decreased physical activity is suggested to be a major underlying cause in the increasing prevalence of weight gain and obesity. Therefore, a better understanding of the biological determinants involved in the regulation of physical activity is essential. To facilitate interpretation in humans, it is helpful to consider the evidence from animal studies. This review focuses on animal studies examining the biological determinants influencing activity and potential implications to human. It appears that physical activity is influenced by a number of parameters. However, regardless of the parameter involved, body weight appears to play an underlying role in the regulation of activity. Furthermore, the regulation of activity associated with body weight appears to occur only after the animal achieves a critical weight. This suggests that activity levels are a consequence rather than a contributor to weight control. However, the existence of an inverse weight-activity relationship remains inconclusive. Confounding the results are the multifactorial nature of physical activity and the lack of appropriate measuring devices. Furthermore, many determinants of body weight are closely interlocked, making it difficult to determine whether a single, combination, or interaction of factors is important for the regulation of activity. For example, diet-induced obesity, aging, lesions to the ventral medial hypothalamus, and genetics all produce hypoactivity. Providing a better understanding of the biological determinants involved in the regulation of activity has important implications for the development of strategies for the prevention of weight gain leading to obesity and subsequent morbidity and mortality in the human population.

Review↗
NASA NTRS1998

Alteration of renal function of rats following spaceflight

Following spaceflight, changes in renal function of humans have been suggested. To assess the effects of readaptation on renal function, urine was collected from male rats ( approximately 245 g) over a 2-wk period following a 14-day spaceflight. Rats were assigned to three groups: flight animals (n = 6), flight controls (n = 6) housed in the flight cages on the ground, and vivarium controls (n = 5) housed in standard shoe box cages. Animals were placed into individual metabolic cages for urine collection. Urine output was significantly increased for 3 days following flight. Excretion rates of Na+ and K+ were increased, resulting in an increased osmotic excretion rate. Creatinine excretion rate increased over the first two postflight days. Glomerular filtration rate increased immediately following spaceflight without changes in plasma creatinine, Na+, K+, or osmolality. Increased excretion of solute was thus the result of increased delivery and a decreased percent reabsorption of the filtered load. Osmolal clearance was increased immediately postflight while free water clearance was decreased. In growing rats, the diuresis after short-duration spaceflight is the result of an increase in solute excretion with an accompanying reduction in free water clearance.

STS-58 Shuttle Project↗
NASA NTRS1997

Human skeletal muscle protein breakdown during spaceflight

Human spaceflight is associated with a loss of body protein. Excretion of 3-methylhistidine (3-MH) in the urine is a useful measurement of myofibrillar protein breakdown. Bed rest, particularly with 6 degrees head-down tilt, is an accepted ground-based model for human spaceflight. The objectives of this report were to compare 3-MH excretion from two Life Sciences shuttle missions (duration 9.5 and 15 days, n = 9) and from 17 days of bed rest (n = 7) with 6 degrees head-down tilt. The bed rest study was designed to mimic an actual Life Sciences spaceflight and so incorporated an extensive battery of physiological tests focused on the musculoskeletal system. Results showed that nitrogen retention, based on excretion of nitrogen in the urine, was reduced during both bed rest [from 22 +/- 1 to 1 +/- 5 mg N x kg(-1) x day(-1) (n = 7; P < 0.05)] and spaceflight [from 57 +/- 9 to 19 +/- 3 mg N x kg(-1) x day(-1) (n = 9; P < 0.05)]. 3-MH excretion was unchanged with either bed rest [pre-bed rest 5.30 +/- 0.29 vs. bed rest 5.71 +/- 0.30 micromol 3-MH x kg(-1) x day(-1), n = 7; P = not significant (NS)] or spaceflight [preflight 4.98 +/- 0.37 vs. 4.59 +/- 0.39 micromol 3-MH x kg(-1) x day(-1) in-flight, n = 9; P = NS]. We conclude that 1) 3-MH excretion was unaffected by spaceflight on the shuttle or with bed rest plus exercise, and 2) because protein breakdown (elevated 3-MH) was increased on Skylab but not on the shuttle, it follows that muscle protein breakdown is not an inevitable consequence of spaceflight.

STS-58 Shuttle Project↗
NASA NTRS1994

Spaceflight and protein metabolism, with special reference to humans

Human space missions have shown that human spaceflight is associated with a loss of body protein. Specific changes include a loss of lean body mass, decreased muscle mass in the calves, decreased muscle strength, and changes in plasma proteins and amino acids. The major muscle loss is believed to be associated with the antigravity (postural) muscle. The most significant loss of protein appears to occur during the first month of flight. The etiology is believed to be multifactorial with contributions from disuse atrophy, undernutrition, and a stress type of response. This article reviews the results of American and Russian space missions to investigate this problem in humans, monkeys, and rats. The relationship of the flight results with ground-based models including bedrest for humans and hindlimb unweighting for rats is also discussed. The results suggest that humans adapt to spaceflight much better than either monkeys or rats.

Review↗
NASA NTRS1997

Nutrition in space

The authors review studies conducted to define nutritional requirements for astronauts during space flight and to assess nutrition before, during, and after space flight. Topics include space food systems, research and limitations on spacecraft, physiological adaptation to weightlessness, energy requirements, dietary intake during space flight, bone demineralization, gastrointestinal function, blood volume, and nutrition requirements for space flight. Benefits of space-related nutrition research are highlighted.

Review↗
NASA NTRS2011

Nutrition Research: Basis for Station Requirements

Prior to the Shuttle program, all understanding of nutritional needs in space came from Skylab metabolic research. Because Shuttle flights were short, most less than 14 days, research focused on major nutritional issues: energy (calories), protein and amino acids, water and electrotypes, with some more general physiology studies that related to iron and calcium. Using stable isotope tracer studies and diet intake records, we found that astronauts typically did not consume adequate calories to meet energy expenditure. To monitor energy and nutrient intake status and provide feedback to the flight surgeon and the astronauts, the International Space Station (ISS) program implemented a weekly food frequency questionnaire and routine body mass measurements. Other Shuttle investigations found that protein turnover was higher during flight, suggesting there was increased protein degradation and probably concurrent increase in protein synthesis, and this occurred even in cases of adequate protein and caloric intake. These results may partially explain some of the loss of leg muscle mass. Fluid and electrolyte flight studies demonstrated that water intake, like energy intake, was lower than required. However, sodium intakes were elevated during flight and likely related to other concerns such as calcium turnover and other health-related issues. NASA is making efforts to have tasty foods with much lower salt levels to reduce sodium intake and to promote fluid intake on orbit. Red blood cell studies conducted on the Shuttle found decreased erythrogenesis and increased serum ferritin levels. Given that the diet is high in iron there may be iron storage health concerns, especially related to the role of iron in oxidative damage, complicated by the stress and radiation. The Shuttle nutrition research lead to new monitoring and research on ISS. These data will be valuable for future NASA and commercial crewed missions.

Lane, Helen W.↗
NASA NTRS1994

Metabolic energy required for flight

This paper reviews data available from U.S. and U.S.S.R. studies on energy metabolism in the microgravity of space flight. Energy utilization and energy availability in space seem to be similar to those on Earth. However, negative nitrogen balances in space in the presence of adequate energy and protein intakes and in-flight exercise, suggest that lean body mass decreases in space. Metabolic studies during simulated (bed rest) and actual microgravity have shown changes in blood glucose, fatty acids, and insulin levels, suggesting that energy metabolism may be altered during flight. Future research should focus on the interactions of lean body mass, diet, and exercise in spaced and their roles in energy metabolism during space flight.

Lane, H. W.↗
NASA NTRS1999

Energy expenditure and balance during spaceflight on the space shuttle

The objectives of this study were as follows: 1) to measure human energy expenditure (EE) during spaceflight on a shuttle mission by using the doubly labeled water (DLW) method; 2) to determine whether the astronauts were in negative energy balance during spaceflight; 3) to use the comparison of change in body fat as measured by the intake DLW EE, 18O dilution, and dual energy X-ray absorptiometry (DEXA) to validate the DLW method for spaceflight; and 4) to compare EE during spaceflight against that found with bed rest. Two experiments were conducted: a flight experiment (n = 4) on the 16-day 1996 life and microgravity sciences shuttle mission and a 6 degrees head-down tilt bed rest study with controlled dietary intake (n = 8). The bed rest study was designed to simulate the flight experiment and included exercise. Two EE determinations were done before flight (bed rest), during flight (bed rest), and after flight (recovery). Energy intake and N balance were monitored for the entire period. Results were that body weight, water, fat, and energy balance were unchanged with bed rest. For the flight experiment, decreases in weight (2.6 +/- 0.4 kg, P < 0.05) and N retention (-2. 37 +/- 0.45 g N/day, P < 0.05) were found. Dietary intake for the four astronauts was reduced in flight (3,025 +/- 180 vs. 1,943 +/- 179 kcal/day, P < 0.05). EE in flight was 3,320 +/- 155 kcal/day, resulting in a negative energy balance of 1,355 +/- 80 kcal/day (-15. 7 +/- 1.0 kcal. kg-1. day-1, P < 0.05). This corresponded to a loss of 2.1 +/- 0.4 kg body fat, which was within experimental error of the fat loss determined by 18O dilution (-1.4 +/- 0.5 kg) and DEXA (-2.4 +/- 0.4 kg). All three methods showed no change in body fat with bed rest. In conclusion, 1) the DLW method for measuring EE during spaceflight is valid, 2) the astronauts were in severe negative energy balance and oxidized body fat, and 3) in-flight energy (E) requirements can be predicted from the equation: E = 1.40 x resting metabolic rate + exercise.

Non-NASA Center↗