Dietary Intake Modifications to Protect Against Changes in Bone Metabolism

NCT ID: NCT01713634

Last Updated: 2015-11-16

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 17 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2009-01-31
• Study Completion Date: 2015-11-30

Brief Summary

Bone loss is not only a well-documented effect of spaceflight on astronauts, but also a condition that affects millions of men and women on Earth each year. Many countermeasures to bone loss have been proposed, and many have been evaluated to some degree. To date, those showing potential have focused on either exercise or pharmacological interventions, but none have targeted dietary intake alone as a factor to predict or minimize bone loss during spaceflight. The investigators proposed to document how the ratio of acid precursors to base precursors in the diet is related to directional changes in markers of bone resorption and formation during flight and recovery from flight. There is a high likelihood for success in predicting the extent of bone loss from dietary intake patterns of astronauts during spaceflight, given that this concept is strongly anchored in data obtained from ground-based experiments in our laboratory and others. The notion of manipulating diet to minimize bone loss could also have significant social and economic impacts for NASA and for the general public - especially given the increasing trends for diets that are high in animal protein and low in fruits and vegetables. The results of the proposed experiments will lead to development of a dietary countermeasure for bone loss consisting of a balanced diet with no associated risks for side effects that might be present with pharmaceuticals or supplements, no requirement for payload mass, and no additional crew time necessary during flight.

Conditions

Bone Resorption

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: PREVENTION
• Blinding Strategy: NONE

Study Groups

Low Apro/K Diet

Subjects consume a prescribed diet for 4 days with a low ratio of animal protein to potassium (0.3-0.6 g/mEq).

Group Type: EXPERIMENTAL

Preflight

Intervention Type: OTHER

4-d controlled diet sessions will occur twice before flight.

In-flight

Intervention Type: OTHER

4-d controlled diet sessions will take place on flight days 15, 60, 120, and 180. Flight day 30 will only be monitored intakes (subject consume nominal intake)

High Apro/K Diet

Subjects consume a prescribed diet that has a high ratio of animal protein to potassium (1.0-1.3 g/mEq) for 4 days.

Group Type: EXPERIMENTAL

Preflight

Intervention Type: OTHER

4-d controlled diet sessions will occur twice before flight.

In-flight

Intervention Type: OTHER

4-d controlled diet sessions will take place on flight days 15, 60, 120, and 180. Flight day 30 will only be monitored intakes (subject consume nominal intake)

Interventions

Preflight

4-d controlled diet sessions will occur twice before flight.

Intervention Type: OTHER

In-flight

4-d controlled diet sessions will take place on flight days 15, 60, 120, and 180. Flight day 30 will only be monitored intakes (subject consume nominal intake)

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Astronauts flying on long-duration (3-6 months) spaceflights

Exclusion Criteria

• Non-astronauts

• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

National Aeronautics and Space Administration (NASA)

FED

Sponsor Role: lead

Responsible Party

Scott M. Smith

Manager for Nutritional Biochemistry

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Scott M Smith, PhD

Role: PRINCIPAL_INVESTIGATOR

National Aeronautics and Space Administration (NASA)

Locations

Johnson Space Center

Houston, Texas, United States

Countries

United States

References

Zwart SR, Hargens AR, Smith SM. The ratio of animal protein intake to potassium intake is a predictor of bone resorption in space flight analogues and in ambulatory subjects. Am J Clin Nutr. 2004 Oct;80(4):1058-65. doi: 10.1093/ajcn/80.4.1058.

Reference Type: BACKGROUND

PMID: 15447920 (View on PubMed)

Zwart SR, Davis-Street JE, Paddon-Jones D, Ferrando AA, Wolfe RR, Smith SM. Amino acid supplementation alters bone metabolism during simulated weightlessness. J Appl Physiol (1985). 2005 Jul;99(1):134-40. doi: 10.1152/japplphysiol.01406.2004. Epub 2005 Feb 3.

Reference Type: BACKGROUND

PMID: 15691900 (View on PubMed)

Zwart SR, Rice BL, Dlouhy H, Shackelford LC, Heer M, Koslovsky MD, Smith SM. Dietary acid load and bone turnover during long-duration spaceflight and bed rest. Am J Clin Nutr. 2018 May 1;107(5):834-844. doi: 10.1093/ajcn/nqy029.

Reference Type: DERIVED

PMID: 29722847 (View on PubMed)

Other Identifiers

Pro0225

Identifier Type: -

Identifier Source: org_study_id