An Integrated Low-Volume Nutritional Countermeasure to Maintain Muscle Mass and Function During Space Exploration

Metadata Updated: November 12, 2020

Mechanical unloading, an inherent characteristic of spaceflight, results in a loss of muscle mass and muscle strength. These losses threaten the integrity of space missions and crew health upon return to Earth's gravity. Nutrition-based countermeasures represent one of the few viable intervention strategies available during long-duration spaceflight. We added leucine (0.06 g / kg lean mass / meal-1; LEU) to the regular meals served 3 • d-1 to middle-aged adults (45-60 y, representative of long-duration crew members) during 14 d of horizontal bed rest (BR) and 7 d of rehabilitation. Changes in muscle mass were assessed by dual-energy X-ray absorptiometry (DEXA); strength was evaluated with standard isokinetic dynamometry. Stable isotope tracer methodology was used to quantify muscle protein synthesis pre-BR, post-BR, and post-rehabilitation. Ongoing analysis of muscle samples for measures of protein metabolism and cell signaling continues to be batched. All subjects have tolerated the supplement (leucine or placebo) well, with no complaints.
Primary findings were: 1) leucine attenuated the loss of whole body lean mass during the first 7 d of BR compared to control subjects (LEU: -0.6±0.2 kg vs. CON: -1.1±0.2 kg, p<0.05) and reduced or prevented decrements in knee extensor strength (LEU: -8±3% vs. CON: -15±3%, p<0.05), ankle extensor strength (LEU: -13±5% vs. CON: -20±5%, p<0.05), and knee extensor endurance (LEU: -2±4% vs. CON: -14±3%, p<0.05) during 14 d BR; 2) LEU maintained both post-absorptive and post-prandial MPS during BR; in contrast, BR decreased post-absorptive MPS (pre-BR: 0.061% / h-1 vs. post-BR: 0.043% / h-1, p<0.05); 3) insulin area under the curve during an oral glucose tolerance test was unchanged in LEU after BR (21±8%) but elevated in CON (52±23%, p<0.05) and whole body insulin sensitivity in LEU was significantly increased above pre-BR values after 7 d rehabilitation (17±10% vs. CON: -9±9%, p<0.05).

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Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date November 12, 2020
Metadata Updated Date November 12, 2020

Metadata Source

Harvested from NASA Data.json

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Resource Type Dataset
Metadata Created Date November 12, 2020
Metadata Updated Date November 12, 2020
Publisher Space Technology Mission Directorate
Unique Identifier Unknown
Identifier TECHPORT_23273
Data First Published 2013-06-01
Data Last Modified 2020-01-29
Public Access Level public
Bureau Code 026:00
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Homepage URL
Program Code 026:027
Source Datajson Identifier True
Source Hash b05f09b3e87316ca157870cb676f7375d8ff8dc0
Source Schema Version 1.1

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