NASA Human Research Program Investigators' Workshop (2012)
NUTRITIONAL STATUS ASSESSMENT (SMO 016E)
S. M. Smith1, M. A. Heer2, and S. R. Zwart3
1
NASA Johnson Space Center, Houston, TX, 2University of Bonn, Germany, and 3Universities Space
Research Association, Houston, TX
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 in nutritional biochemistry during (and after) 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 (e.g., protein, vitamin, mineral), physiological (e.g.,
bone and muscle markers), general chemistry, and endocrinology indices.
These data will 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 longduration 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.
Findings to date:
Fish/Bone. Data from this experiment have documented a relationship between fish intake and
bone loss in astronauts (that is, those who ate more fish lost less bone). A similar relationship has
also been shown in ground-based studies, including bed rest and cell culture studies. We believe
the mechanism to be related to the fact that omega-3 fatty acids can inhibit the activation of the
cells responsible for bone breakdown. (J Bone Miner Res 25:1049-57, 2010)
Vitamin K. Data from the Nutrition SMO, along with data from ground-based studies, have
documented that in generally well-fed and otherwise healthy individuals, vitamin K status and
bone vitamin K-dependent proteins are unaffected by space flight (and bed rest). (J Bone Miner
Res 948-54, 2011)
Testosterone. Data from 15 participating crew members documented that blood concentrations of
testosterone were unchanged during flight, but a transient decline occurred after landing. Coupled
with some previously unpublished Skylab data on urinary testosterone (which increased during
flight), these data documented that testosterone secretion is largely unaffected by flight. (J Clin
Endo Metab in press)
Vision. Data from the Nutrition SMO provided evidence that biochemical markers (such as
homocysteine and methylmalonic acid) involved in folate-dependent one-carbon metabolism were
altered in crew members who experienced vision-related issues during and after flight. In Earthbased populations, these same changes have been associated with increased risk of stroke,
increased risk of migraine headaches, and increased risk of cerebral vascular incidents.
Beyond these research findings, data from the Nutrition SMO have contributed to the ISS Program
operationally as well. From documenting the effectiveness of 800-IU/d vitamin D supplementation in
flight to helping understand how and why the Urine Processing Assembly clogged with calcium sulfate
precipitate, data from this experiment have proven valuable to flight surgeons, engineers, and the ISS
Program in general. Continued data collection, sample analysis, and data evaluation will result in findings
with implications for individuals, future crew members, and the general population.
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