Biochemical and physiological evaluation of human subjects in a life support systems evaluator
Biochemical and physiological evaluation of human nutritional requirements under simulated aerospace conditions
NUTRITIONAL REQUIREMENT↗
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Nutritional problems
Nutritional requirements and effects of other media factors in influencing metabolic activity of plankton cultures
CULTURE /BIOL/↗
Planning strategies for development of effective exercise and nutrition countermeasures for long-duration space flight
Exercise and nutrition represent primary countermeasures used during space flight to maintain or restore maximal aerobic capacity, musculoskeletal structure, and orthostatic function. However, no single exercise, dietary regimen, or combination of prescriptions has proven entirely effective in maintaining or restoring cardiovascular and musculoskeletal functions to preflight levels after prolonged space flight. As human space flight exposures increase in duration, identification, assessment, and development of various effective exercise- and nutrition-based protective procedures will become paramount. The application of adequate dietary intake in combination with effective exercise prescription will be based on identification of basic physiologic stimuli that maintain normal function in terrestrial gravity, and understanding how specific combinations of exercise characteristics (e.g., duration, frequency, intensity, and mode) can be combined with minimal nutritional requirements that mimic the stimuli normally produced by living in Earth's gravity environment. This can be accomplished only with greater emphasis of research on ground-based experiments targeted at understanding the interactions between caloric intake and expenditure during space flight. Future strategies for application of nutrition and exercise countermeasures for long-duration space missions must be directed to minimizing crew time and the impact on life-support resources.
Review↗
Consideration in selecting crops for the human-rated life support system: a Linear Programming model
A Linear Programming model has been constructed which aids in selecting appropriate crops for CELSS (Controlled Environment Life Support System) food production. A team of Controlled Environment Agriculture (CEA) faculty, staff, graduate students and invited experts representing more than a dozen disciplines, provided a wide range of expertise in developing the model and the crop production program. The model incorporates nutritional content and controlled-environment based production yields of carefully chosen crops into a framework where a crop mix can be constructed to suit the astronauts' needs. The crew's nutritional requirements can be adequately satisfied with only a few crops (assuming vitamin mineral supplements are provided) but this will not be satisfactory from a culinary standpoint. This model is flexible enough that taste and variety driven food choices can be built into the model.
NASA Center JSC↗
Nutrition for Space Exploration
Nutrition has proven to be critical throughout the history of human exploration, on both land and water. The importance of nutrition during long-duration space exploration is no different. Maintaining optimal nutritional status is critical for all bodily systems, especially in light of the fact that that many are also affected by space flight itself. Major systems of concern are bone, muscle, the cardiovascular system, the immune system, protection against radiation damage, and others. The task ahead includes defining the nutritional requirements for space travelers, ensuring adequacy of the food system, and assessing crew nutritional status before, during, and after flight. Accomplishing these tasks will provide significant contributions to ensuring crew health on long-duration missions. In addition, development and testing of nutritional countermeasures to effects of space flight is required, and assessment of the impact of other countermeasures (such as exercise and pharmaceuticals) on nutrition is also critical for maintaining overall crew health. Vitamin D stores of crew members are routinely low after long-duration space flight. This occurs even when crew members take vitamin D supplements, suggesting that vitamin D metabolism may be altered during space flight. Vitamin D is essential for efficient absorption of calcium, and has numerous other benefits for other tissues with vitamin D receptors. Protein is a macronutrient that requires additional study to define the optimal intake for space travelers. Administration of protein to bed rest subjects can effectively mitigate muscle loss associated with disuse, but too much or too little protein can also have negative effects on bone. In another bed rest study, we found that the ratio of protein to potassium was correlated with the level of bone resorption: the higher the ratio, the more bone resorption. These relationships warrant further study to optimize the beneficial effect of protein on both bone and muscle during space flight. Omega3 fatty acids are currently being studied as a means of protecting against radiation-induced cancer. They have also recently been implicated as having a role in mitigating the physical wasting, or cachexia, caused by cancer. The mechanism of muscle loss associated with this type of cachexia is similar to the mechanism of muscle loss during disuse or space flight. Omega3 fatty acids have already been shown to have protective effects on bone and cardiovascular function. Omega3 fatty acids could be an ideal countermeasure for space flight because they have protective effects on multiple systems. A definition of optimal nutrient intake requirements for long-duration space travel should also include antioxidants. Astronauts are exposed to numerous sources of oxidative stress, including radiation, elevated oxygen exposure during extravehicular activity, and physical and psychological stress. Elevated levels of oxidative damage are related to increased risk for cataracts, cardiovascular disease, and cancer. Many groundbased studies show the protective effects of antioxidants against oxidative damage induced by radiation or oxygen. Balancing the diet with foods that have high levels of antioxidants would be another ideal countermeasure because it should have minimal side effects on crew health. Antioxidant supplements, however, are often used without having data on their effectiveness or side effects. High doses of supplements have been associated with bone and cardiovascular problems, but research on antioxidant effects during space flight has not been conducted. Much work must be done before we can send crews on exploration missions. Nutrition is often assumed to be the simple provision of food items that will be stable throughout the mission. As outlined briefly above, the situation is much more complex than food provision. As explorers throughout history have found, failure to truly understand the role of nutrition can be catastrophic. When huns are in environments unlike any they have seen before, this is more true than ever.
Smith, Scott M.↗
Nutritional Status Assessment
Nutritional Status Assessment (Nutrition) is the most comprehensive inflight study done by NASA to date of human physiologic changes during long-duration space flight; this includes measures of bone metabolism, oxidative damage, nutritional assessments, and hormonal changes. This study will impact both the definition of nutritional requirements and development of food systems for future space exploration missions to the Moon and Mars. This experiment will also help to understand the impact of countermeasures (exercise and pharmaceuticals) on nutritional status and nutrient requirements for astronauts.
Smith, Scott M.↗
Legume Organoleptic and Nutritional Analysis
Long-duration missions beyond low Earth orbit will encounter challenges in maintaining adequate nutrition and acceptability in the food system. In situ production of fresh produce can supplement nutrients deficient in the stored diet. Currently there is a limited number of crops that can be reliably grown for space crop production. Recent challenges with Veggie plant growth technical demonstrations (i.e. Tokyo Bekana Chinese cabbage interveinal chlorosis and necrosis when grown under elevated CO2 (~3000ppm) and narrow-band LED lighting) have highlighted the necessity to conduct rigorous ISS-relevant crop screening on the ground. Additionally, crops must be selected to address specific nutritional deficits as identified by HRP, with an emphasis on having a large diversity of crops available to meet nutritional requirements and crew acceptability. A variety of crop types are necessary to address known nutritional deficits in the stored astronaut diet, to include leafy greens (vitamin C, vitamin K, potassium), tomatoes and peppers (vitamin C, potassium, lycopene), and legumes (vitamin B1).Legumes are being evaluated for biological performance and suitability under ISS-like environmental conditions as well as nutritional content and acceptability. Legumes are one of the few pick and eat crop types that is an excellent source of Vitamin B1.In FY21-22 Biological and Physical Sciences (BPS) is funding screening of 32 legume crop cultivars at KSC, 16 of which will be down-selected based on horticultural performance and informal taste testing for further horticultural assessment and analysis. HRP in FY21-22 is funding organoleptic and nutritional analysis of these 16 down-selected legume cultivars to determine the most promising candidates for future space applications. Nutritional analysis will include full elemental, proximate (fat, protein, calories, carbohydrates, ash), and vitamins B1, C, K. This new work is currently postponed due to Covid-19.
L E Spencer↗
Meal Replacement Mass Reduction and Integration Acceptability Study
NASA, in planning for long-duration missions, has an imperative to provide a food system with the necessary nutrition, acceptability, and safety to ensure sustainment of crew health and performance. The Orion Multi-Purpose Crew Vehicle (MPCV) and future exploration missions are mass constrained; therefore the team is challenged to reduce the mass of the food system by 10% while maintaining product safety, nutrition, and acceptability. Commercially available products do not meet the nutritional requirements for a full meal replacement in the spaceflight food system, and it is currently unknown if daily meal replacements will impact crew food intake and psychosocial health over time. The purpose of this study was to develop a variety of nutritionally balanced breakfast replacement bars that meet spaceflight nutritional, microbiological, sensorial, and shelf-life requirements, while enabling a 10% savings in food mass. To date, six nutrient-dense meal replacement bars (approximately 700 calories per bar) have been developed, using traditional methods of compression as well as novel ultrasonic compression technologies developed by Creative Resonance Inc. (Phoenix, AZ). The four highest rated bars were evaluated in the Human Exploration Research Analog (HERA) to assess the frequency with which actual meal replacement options may be implemented. Specifically, overall impact of bars on mood, satiety, digestive discomfort, and satisfaction with food. These factors are currently being analyzed to inform successful implementation strategies where crew maintain adequate food intake. In addition, these bars are currently undergoing shelf-life testing to determine long-term sensory acceptability, nutritional stability, qualitative stability of analytical measurements (i.e. water activity and texture), and microbiological compliance over two years of storage at room temperature and potential temperature abuse conditions to predict long-term acceptability. It is expected that this work will enable a successful meal replacement strategy to be implemented that will maintain crew food consumption and health, while informing exploration missions with appropriate mass savings expectations.
Sirmons, T.↗
Nutritional models for space travel from chemically defined diets
Human nutritional requirements are summarized, including recommended daily intake and maximum safe chronic intake of nutrients. The biomedical literature on various types of chemically defined diets (CDD's), which are liquid, formulated diets for enteral and total parenteral nutrition, is reviewed. The chemical forms of the nutrients in CDD's are detailed, and the compositions and sources of representative commercial CDD's are tabulated. Reported effects of CDD's in medical patients, healthy volunteers, and laboratory animals are discussed. The effects include gastrointestinal side effects, metabolic imbalances, nutrient deficiencies and excesses, and psychological problems. Dietary factors contributing to the side effects are examined. Certain human nutrient requirements have been specified more precisely as a result of long-term use of CDD's, and related studies are included. CDD's are the most restricted yet nutritionally complete diets available.
Dufour, P. A.↗
Energy and thermal regulation during bed rest and spaceflight
This paper presents data available from bed-rest and flight studies on the energy metabolism and thermoregulatory parameters and their changes during long-duration space missions which may influence requirements of astronauts for food and water. It is calculated, on the basis of 3100 kcal and 2.2 l water a day, with 1 h/day moderate exercise, that the requirements for a 2-yr flight would be 2,263,000 kcal and 1606 l water for each astronaut. One daily 5-h-long extravehicular sortie would require an additional 529,250 kcal and 1,095 l of water per year. Changes in the efficiency of work or metabolism would affect these nutritional requirements for long spaceflights. Factors that would increase food and water requirements are discussed.
Greenleaf, John E.↗
Nutritional Status Assessment (SMO -16E)
The Nutritional Status Assessment Supplemental Medical Objective was an experiment initiated to expand nominal pre- and postflight clinical nutrition testing, and to gain a better understanding of the time course of changes during flight. The primary activity of this effort was collecting blood and urine samples 5 times during flight for analysis after return to Earth. Samples were subjected to a battery of tests, including nutritional, physiological, general chemistry, and endocrinology indices. These data provide a comprehensive survey of how nutritional status and related systems are affected by 4-6 months of space flight. Analyzing the data will help us to define nutritional requirements for long-duration missions, and better understand human adaptation to microgravity. This expanded set of measurements will also aid in the identification of nutritional countermeasures to counteract, for example, the deleterious effects of microgravity on bone and muscle and the effects of space radiation.
Smith, Scott M.↗
Metabolic energy requirements for space flight
The international space community, including the USSR, Japan, Germany, the European Space Agency, and the US, is preparing for extended stays in space. Much of the research planned for space will be tended by humans, thus, maintaining adequate nutritional status during long stays in space has lately become an issue of much interest. Historically, it appears that minimum nutritional requirements are being met during stays in space. Thus far, crewmembers have been able to consume food adequate for maintaining nominal performance in microgravity. The physiological data obtained from ground-based and flight research that may enable us to understand the biochemical alterations that effect energy utilization and performance. Focus is on energy utilization during the Apollo lunar missions, Skylab's extended space lab missions, and Space Shuttle flights. Available data includes those recorded during intra- and extravehicular activities as well as during microgravity simulation (bed rest). Data on metabolism during flight and during bed rest are discussed, with a follow-up on human gastrointestinal function.
Lane, Helen W.↗
Novel Microgreen Crop Testing for Space
Long-duration missions beyond low-Earth orbit will encounter challenges in maintaining adequate nutrition and crew acceptability in the food system. In situ production of fresh produce can supplement nutrient deficiencies in the prepackaged diet. Currently, there are a relatively small number of crops that can be reliably grown in space for space crop production efforts. An intriguing area of new investigation involves novel types of microgreens that have the potential to be sources of calories, fat, carbohydrates, and protein. These sources of nutrition are not obtainable in significant quantities with current pick and eat crops. Many microgreen cultivars are also sources of nutrients of interest, such as Vitamins B1, C, and K, and elements such as potassium. Microgreens should be selected to address specific nutritional deficits, as identified by NASA’s Human Research Program, with an emphasis on having a diversity of crops to meet nutritional requirements and crew acceptability. To achieve this, the concept of Crop Readiness Level (CRL) has been developed to gauge readiness of crops for spaceflight applications. CRL includes assessing environmental compatibility, food safety considerations, relevant nutritional analysis, and sensory analysis. Recent testing at Kennedy Space Center has focused on advancing the CRL of a variety of novel microgreens. These varieties were grown under 150 µmol m -2 s -1 PPFD from LED lights, 3000 ppm CO 2 , and 23°C to simulate an ISS environment. Crops were harvested and yield was assessed. Then, baseline microbiological and nutritional analysis (Vitamins B1, C, K; mineral analysis; proximate analysis) and sensory evaluation were performed. These baseline data are essential to selecting candidate crops for future missions and assessing crop production hardware and changes in environmental conditions on future crop performance and nutritional quality.
nutrition↗
Legume Crop Testing for Space
Long-duration missions beyond low-Earth orbit will encounter challenges in maintaining adequate nutrition and crew acceptability in the food system. In situ production of fresh produce can supplement nutrient deficiencies in the prepackaged diet. Currently, there are a relatively small number of crops that can be reliably grown for space crop production efforts. Recent challenges with Veggie plant growth technical demonstrations, such as interveinal chlorosis and necrosis of Tokyo Bekana Chinese cabbage when grown under elevated CO 2 (~3000 ppm) and narrow-band LED lighting, have highlighted the necessity to conduct rigorous ISS-relevant crop screening on the ground. Additionally, crops should be selected to address specific nutritional deficits, as identified by NASA’s Human Research Program, with an emphasis on having a diversity of crops to meet nutritional requirements and crew acceptability. To achieve this, the concept of Crop Readiness Level (CRL) has been developed to gauge readiness of crops for spaceflight applications. CRL determination includes assessing environmental compatibility, food safety considerations, relevant nutritional analysis, and sensory analysis. Recent testing at Kennedy Space Center has focused on advancing the CRL of a variety of legumes. Twenty-four varieties of peas ( Pisum sativum ) and beans ( Phaseolus vulgaris ) were grown under 300 μmol m -2 s -1 PPFD from LED lights, 3000 ppm CO2, and 23 °C to simulate an ISS environment. Crops were harvested and size and yield were assessed. Then, baseline nutritional analysis (Vitamins B1, C, K; elemental analysis; proximate analysis) and sensory evaluation were performed on eight down-selected varieties. These baseline tests will help in selecting candidate crops for future missions and assessing crop production hardware and changes in environmental conditions on future crop performance and nutritional quality.
LaShelle E Spencer↗
Dietary Support of Extended-Duration Bed Rest Studies
Dietary control and nutrient intake are critical aspects of any metabolic study, but this is especially true in the case of bed rest studies. We sought to define nutrient requirements, develop menus, and implement them in a series of three long-duration bed rest studies. With regard to energy intake, the goal was to maintain subject body weight to within 3% of their body weight on day 3 of bed rest (after fluid shift had occurred). For other nutrients, intakes were based on the NASA space flight nutritional requirements (with some adaptations based on the ground-based model used here). A secondary goal was to develop menus with foods similar to those expected to be approved for space flight (however, this was relaxed to attain desired nutrient intakes). This paper also describes the role of the research dietitian as part of the multi-disciplinary team and the importance of the metabolic kitchen staff. It also provides insight into some of the dietary challenges that arise during extended-duration bed rest studies. Regardless of the overall objective of the study, nutrition must be carefully planned, implemented, and monitored for results to be uncompromised.
Inniss, A. M.↗
Nutrition and Stresses of Short Term Space Flight
The nutritional requirements for short-term space flights which are most likely to be affected by the expected stressors and operational malfunctions or both, especially that of the Environmental Control System, are water and calories. Evidence accumulated under simulated or analogous situations on Earth would indicate that calcium and protein imbalance may occur. Experiments have been proposed to study selected nutritional parameters during Gemini missions of increasing duration.
Nutrition↗
Bioregenerative food system cost based on optimized menus for advanced life support
Optimized menus for a bioregenerative life support system have been developed based on measures of crop productivity, food item acceptability, menu diversity, and nutritional requirements of crew. Crop-specific biomass requirements were calculated from menu recipe demands while accounting for food processing and preparation losses. Under the assumption of staggered planting, the optimized menu demanded a total crop production area of 453 m2 for six crew. Cost of the bioregenerative food system is estimated at 439 kg per menu cycle or 7.3 kg ESM crew-1 day-1, including agricultural waste processing costs. On average, about 60% (263.6 kg ESM) of the food system cost is tied up in equipment, 26% (114.2 kg ESM) in labor, and 14% (61.5 kg ESM) in power and cooling. This number is high compared to the STS and ISS (nonregenerative) systems but reductions in ESM may be achieved through intensive crop productivity improvements, reductions in equipment masses associated with crop production, and planning of production, processing, and preparation to minimize the requirement for crew labor.
Non-NASA Center↗
Practical and clinical nutritional concerns during spaceflight
Experience with space exploration to date has raised more questions regarding nutritional requirements for astronauts than it has answered. As mission lengths continue to increase, nutrient imbalances due to alterations in intake, dietary requirements, bioavailability, or excretion, may become more important. Factors adversely affecting intake include those as straightforward as stress and as complex as space-adaptation syndrome. Metabolic alterations induced by shifts in fluid and electrolyte balance, neuroendocrine function, and changes in hepatic protein synthesis and skeletal muscle type that result in nutrient partitioning to different biochemical pathways may also affect dietary requirements. Food processing effects on nutrient stability and digestibility, which apply to limited quantities of our usual diet on Earth, may become more important for diets that contain little fresh food during extended-length missions. Whereas nutrient and water recycling through ecosystems is taken for granted on Earth, specific effects of trace contaminant accumulation will require greater attention for prolonged space flights. Human factors, esthetics, and user-friendly operations will be necessary to facilitate the psychological as well as physiological health of the astronauts.
Review, Tutorial↗