Nutrition and Bone Health in Space

Abstract

The effect of weightlessness on the human skeletal system is one of the greatest concerns in safely extending space missions [ 1 -11 ]. The ability to understand and counteract weightlessness-induced bone mineral loss will be vital to crew health and safety during and after extended-duration space station and exploration missions [ 1 -7 ]. Research on bone mineral loss during space fl ight has gone on for more than half a century, and recent studies have shown signifi cant progress in developing countermeasures that have proved to be effective, including good nutrition and exercise. We review the history of this research here and provide a summary of recent and ongoing studies, including efforts to counteract bone and calcium loss resulting from weightlessness. Key Points• The effect of weightlessness on the human skeletal system is one of the greatest concerns in safely extending space missions.• The ability to understand and counteract weightlessness-induced bone mineral loss will be vital to crew health and safety during and after extended-duration space station and exploration missions.• Research on bone mineral loss during space fl ight has gone on for more than half a century, and recent studies have shown signifi cant progress in developing countermeasures that have proved to be effective, including good nutrition and exercise.

Gut Microbiome and Space Travelers’ Health: State of the Art and Possible Pro/Prebiotic Strategies for Long-Term Space Missions

“…Data from spaceflights has also shown that most space travelers do not achieve their required energy intake through the on-board rations and typically consume about 75–80% of their daily requirements ( Zwart et al, 2014 ). This is associated with a variety of effects on space travelers ranging from a decrease in cognitive ability to general microgravity-induced physiological responses, such as impaired cardiovascular performance, exacerbated muscle atrophy and diminished immune function ( Smith et al, 2014 ). For shorter spaceflights up to 6 months, these effects could be reversed but when moving on to exploration missions of 1 year and longer, the effects may be much more serious and lead to mission failure, i.e., early return because of malnourishment and consequent diseases or even survival of space travelers as has been seen with some pioneering expeditions on Earth.…”

Magnesium and Space Flight

“…Bed rest did not yield a significant increase in urinary or serum magnesium, which would have been expected as some bone loss occurred in those subjects, albeit less than in astronauts [ 9 , 44 , 45 ]. Nonetheless, the AUC of the serum and urinary magnesium response to bed rest was linearly related to the change in whole-body BMC after 60–90 days of bed rest, and was less than the response observed during space flight ( Figure 3 ).…”

“…Magnesium is a critical element, and its amount and concentration in the body have implications for many systems, including the cardiovascular and musculoskeletal systems, along with implications for the incidence of hypertension, stroke, migraine headache, diabetes, and other diseases [ 1 , 2 ]. Given the health risks of human space flight [ 3 ] along with a limited food system, adequate intake of magnesium is an important concern for ensuring astronaut health, especially on long-duration space missions.…”

“…Good-quality diets, rich in magnesium and potassium, have been associated with improved bone health [ 7 , 8 ]. Bone loss and negative calcium balance have traditionally been considered hallmarks of space travel [ 3 , 9 , 10 , 11 , 12 ], although recent evidence documents the ability of nutrition and exercise to mitigate bone mineral density losses after flight, albeit with remaining questions about the integrity and strength of the resulting remodeled bone [ 9 , 13 , 14 ]. Whether magnesium balance is similarly affected during space flight is unknown.…”

A taste for space

“…The European Space Agency (ESA) is supporting NASA in the Mars project and one issue they have highlighted is the decreased consumption of food during space flight. Nutritional studies of astronauts have shown that in the vast majority of missions, only around 80% of their recommended daily calorie intake is consumed [1] . Over the six‐ to 12‐month period that astronauts remain in space, this does not seem to affect their performance, but the Mars voyage will take around three years and there is concern that this under‐consumption could affect physical and mental performance, both of which are vital for a successful mission.…”