National Aeronautics and Space Administration HUMAN ADAPTATION TO SPACE FLIGHT: THE ROLE OF NUTRITION Scott M. Smith Nutritionist; Manager for Nutritional Biochemistry Nutritional Biochemistry Laboratory Biomedical Research and Environmental Sciences Division NASA Johnson Space Center Houston, Texas USA Sara R. Zwart Senior Scientist; Deputy Manager for Nutritional Biochemistry Nutritional Biochemistry Laboratory Biomedical Research and Environmental Sciences Division NASA Johnson Space Center Houston, Texas USA Martina Heer Nutritionist Adjunct Professor of Nutrition Physiology University of Bonn Institute of Nutritional and Food Sciences Bonn, Germany Table of Contents Preface .......................................................................................................................... iv 1. Introduction .............................................................................................................. 1 Conducting Nutrition Research on ISS .......................................................................... 2 Blood Collection .......................................................................................................... 2 Urine Collection ........................................................................................................... 3 Biological Sample Stowage and Return ..................................................................... 4 Food Intake Monitoring ............................................................................................... 5 Body Mass .................................................................................................................. 6 2. Energy and Fuel Metabolism .................................................................................. 7 Energy Expenditure and Requirements .......................................................................... 7 Energy Intake .................................................................................................................. 8 Implications for Inadequate Energy Intake ..................................................................... 9 Carbohydrate ............................................................................................................... 13 Fat (and Fatty Acids) .................................................................................................... 14 Cofactors in Energy Metabolism .................................................................................. 15 3. Muscle and Protein ............................................................................................... 17 Protein Intake ............................................................................................................... 17 Vitamin B6 .................................................................................................................... 18 Muscle Loss and Protein Turnover in Microgravity ...................................................... 18 Ground Analog Studies ................................................................................................ 19 Muscle Loss Countermeasures .................................................................................... 21 Mechanical ................................................................................................................ 21 Pharmacological ....................................................................................................... 22 Nutritional .................................................................................................................. 25 Protein and Bone ...................................................................................................... 26 4. Bone ........................................................................................................................ 29 Bone Loss .................................................................................................................... 29 Bone Metabolism ......................................................................................................... 30 Bone Loss Countermeasures ....................................................................................... 31 Exercise ..................................................................................................................... 31 Gravity ....................................................................................................................... 35 Vibration .................................................................................................................... 35 Pharmacological Agents ........................................................................................... 35 Nutritional Countermeasures .................................................................................... 36 i Nutrients and Bone Health ........................................................................................... 37 Calcium ..................................................................................................................... 37 Vitamin D ................................................................................................................... 37 Vitamin K ................................................................................................................... 40 Phosphorus ............................................................................................................... 40 Magnesium ................................................................................................................ 41 Zinc (and Lead) ......................................................................................................... 42 Unique Aspects of Calcium and Space Flight .............................................................. 42 Urine Processing and Water Reclamation ................................................................ 42 Natural Calcium Isotope Composition of Bone ........................................................ 43 5. Iron and Hematology ............................................................................................. 45 Iron ............................................................................................................................... 45 Copper ......................................................................................................................... 48 6. Cardiovascular Health ........................................................................................... 51 Energy .......................................................................................................................... 51 Magnesium ................................................................................................................... 53 Ongoing and Future Research ..................................................................................... 53 Oxidative Stress ........................................................................................................ 53 Omega-3 Fatty Acids ................................................................................................ 54 Healthier Diets ........................................................................................................... 54 7. Sodium, Potassium, Fluid, and Renal Stone Risk .............................................. 55 Sodium and Chloride .................................................................................................... 55 Potassium ..................................................................................................................... 58 Fluid .............................................................................................................................. 59 Renal Stone Risk .......................................................................................................... 61 8. Space Flight Ophthalmic Changes and Nutrition ............................................... 63 Ophthalmic Changes .................................................................................................... 63 One-Carbon Metabolism .............................................................................................. 63 Folate ............................................................................................................................ 65 Vitamin B12 ................................................................................................................... 66 Biotin ............................................................................................................................ 67 Vitamin A ...................................................................................................................... 67 9. Immune Function, Inflammation, and Nutrition .................................................. 71 Energy Intake ................................................................................................................ 71 Protein and Amino Acids .............................................................................................. 71 Vitamin D ...................................................................................................................... 72 ii Vitamin B12 ................................................................................................................... 73 Sodium ......................................................................................................................... 73 Vitamin A .....................................................................................................................