Nutrition Requirements, Standards, and Operating Bands for Exploration Missions Nutritional Biochemistry Laboratory Human Adaptation and Countermeasures Office Space Life Sciences Directorate NASA Johnson Space Center Initial Release (rev 1), December 2005 Executive Summary The challenge was brought forward in early 2005 to define the nutritional requirements for Exploration missions, and to define the relevant standards and associated operating bands related to nutrition. This document is the result of this charge. An extensive review of existing knowledge was conducted with participation of intramural and extramural experts, and the findings are summarized herein. In short, the approach taken was to define the nutrient intake requirements, that is, the amount of each nutrient expected to be available in the food system. The standards are defined as markers of nutritional status, with optimal (green), sub-optimal (yellow), and critical (red) levels for each. For many of the nutrient requirements, it is not known if they are altered during space flight. Furthermore, in many cases the intake of a nutrient may act as a countermeasure to one or more negative effects of space flight, but these potential countermeasures, too, are not well defined. Thus, we have also documented herein the areas where further research is required. Accordingly, while this document is intended as a comprehensive summary of our knowledge to date, it is expected that this is the first edition of these requirements and standards. As we learn more about space-flight nutrition, and as relationships between disease and nutrients are further defined in Earth-based populations, this document, and the approach to nutrition in the space rogram, will need to be updated accordingly. 1 Table of Contents Executive Summary_________________________________________________ 1 Introduction ______________________________________________________ 4 Document Organization _____________________________________________ 6 Macronutrients ____________________________________________________ 8 Energy and Body Composition _______________________________________ 8 Protein________________________________________________________ 15 Carbohydrate___________________________________________________ 20 Fat ___________________________________________________________ 23 Fiber _________________________________________________________ 26 Fluid, Electrolytes and Renal Stone Risk _______________________________ 28 Fluid__________________________________________________________ 28 Sodium________________________________________________________ 32 Potassium______________________________________________________ 35 Renal Stone Risk ________________________________________________ 37 Fat-Soluble Vitamins _______________________________________________ 40 Vitamin A ______________________________________________________ 40 Vitamin D ______________________________________________________ 43 Vitamin K ______________________________________________________ 46 Vitamin E ______________________________________________________ 49 Water-Soluble Vitamins_____________________________________________ 53 Vitamin C ______________________________________________________ 53 Vitamin B12_____________________________________________________ 56 Vitamin B6 _____________________________________________________ 58 Thiamin _______________________________________________________ 60 Riboflavin______________________________________________________ 62 Folate ________________________________________________________ 64 Niacin_________________________________________________________ 68 Biotin _________________________________________________________ 70 Pantothenic Acid ________________________________________________ 72 Minerals_________________________________________________________ 74 2 Calcium _______________________________________________________ 74 Phosphorus ____________________________________________________ 81 Magnesium _____________________________________________________ 84 Trace Elements ___________________________________________________ 86 Iron __________________________________________________________ 86 Copper ________________________________________________________ 92 Manganese _____________________________________________________ 94 Fluoride _______________________________________________________ 96 Zinc __________________________________________________________ 98 Selenium _____________________________________________________ 101 Iodine________________________________________________________ 103 Chromium ____________________________________________________ 105 General Chemistry and Supporting Analytes ___________________________ 107 Special Issues ___________________________________________________ 109 Supplements __________________________________________________ 109 Nutrient-Drug Interactions _______________________________________ 110 Nutritional Recommendations for Extravehicular Activity _______________ 114 APPENDIX A. Abbreviations, Acronyms, Definitions _____________________ 115 APPENDIX B. Requirements ________________________________________ 117 References _____________________________________________________ 119 3 Introduction Nutrition has been critical to every phase of exploration, from the early sea voyages on which seafarers were plagued by scurvy to polar expeditions in which explorers died from under-nutrition, or in some cases nutrient toxicities. The role of nutrition in space exploration will be no different, except that space explorers will lack the opportunity to obtain food from the local environment, making their missions even more challenging than the exploration of Earth. The altered gravity environment will also likely alter nutrient requirements, making it even more difficult to meet these requirements. It is very clear that humans on a 1000-day exploration-class mission will require adequate nutrition, and deficiency of any one of the required nutrients could be catastrophic. To serve as a tool for defining the role of nutrition in exploration is the purpose of this document. The ultimate goal is to define requirements for nutrient intake and standards for assessing nutritional status. To this end, we will define a set of values, or operating bands, that can serve as a guide for setting both required intake levels and nutritional status assessment standards. Use of these operating bands will help NASA to maintain the health and well-being of crew members who explore beyond the surface of Earth. This document is based on many sources of information that were reviewed at a Nutrition Standards/Operating Bands workshop held March 23–24, 2005 in Houston, Texas. The documents reviewed included the set of nutritional requirements defined in 1991 for Space Station Freedom missions, plus the updated set of requirements developed in 1995 (in collaboration with Russian partners) for Mir flights. The activities of workshop participants included evaluation of the limited data from short- duration Space Shuttle flights, and longer Mir and International Space Station (ISS) flights. The findings from the MR016L/Clinical Nutritional Assessment profile of the first 10 ISS missions were also reviewed, to provide background information about the changes seen in flights of 4 to 6 months (during which time resupply by at least one Progress vehicle occurred). In many cases in this document, we have extrapolated from ground-based space analog studies, and in others we have only the ground-based nutrition literature for support, knowing nothing of the effects of space travel. In this document we also highlight the areas where we are at highest risk, with no evidence base to support the requirements and recommendations. For these areas, targeted research areas are identified as part of the requirement for exploration. The supporting and detailed information have been expanded herein, but the recommendations are based on the panel discussion. Nutrition is a cross-cutting science, one that influences and is influenced by many other disciplines, and because nutrients are required for the structure and function of every cell and every system, the pervasiveness of nutrient requirements for the adaptation to space travel is no surprise. Key areas of clinical concern for long- duration space flight include loss of body mass (general inadequate food intake), bone and muscle loss, increased radiation exposure, and general depletion of body nutrient 4 stores because of inadequate food supply, inadequate food intake, increased metabolism, and/or irreversible loss of nutrients. Cardiovascular and/or immune system changes noted during and after space flight may also be related to nutritional issues, but conclusive data are not yet available. The primary objectives of this document are Definition of requirements related to nutrition. This includes nutrient intake requirements as well as other aspects of nutrition. Definition of techniques that will be used to evaluate whether the requirement has been met (that is, the standards that must be met). For each standard, identification of the operating bands (including success/failure criteria for each) for potential mission impact and severe mission impact. Identification of potential differences in operational standards for different mission types (for example, low Earth orbit, lunar, Mars) and durations (6, 12, or 36 months) Identification of the effect of mission design elements (such as a traverse, extravehicular activity, or gravity field) on the standards Identification