Effect of Tyrosine Supplementation on Cognitive Performance and Mood During Military Stress

The objective of this research is to determine if tyrosine, an amino acid found in protein-containing foods, will mitigate the cognitive deficits and adverse effects on behavior and mood produced by exposure to military stress. This study was conducted at the US Navy Survive, Evade, Resist, Escape (SERE) school at Brunswick, Maine (ME).

Tyrosine is the dietary precursor of the catecholamine norepinephrine, a key brain neurotransmitter that is critical for the central nervous system (CNS) response to various types of acute stress. Psychological stress increases catecholamine turnover in the brain, increasing the requirement for tyrosine to support synthesis of norepinephrine. Animal and human studies have shown that tyrosine supplementation can produce beneficial effects on cognitive and physiological functions during exposure to a variety of acute stressors.

This project will determine if volunteers treated with supplemental tyrosine during stressful phases of SERE training experience less degradation in cognitive performance and mood than volunteers treated with placebo. Tyrosine or placebo will be administered in a specially developed food bar provided to volunteers. The bar is part of a prototype of ration-component designed for use during assault operations. A between-subjects, double blind experimental design will be employed. Tyrosine, an amino acid found in most protein-containing foods, has been tested in hundreds of volunteers without adverse effects.

Approximately 100 volunteers will be recruited from several SERE classes to ensure up to 80 volunteers complete the study. They will be tested during several portions of SERE. A comprehensive but brief battery of cognitive tests, as well as saliva samples, and heart rate data will be collected in a manner that does not interfere with ongoing training.

Hypotheses:

1. Exposure to the stressors of SERE school will adversely impact cognitive performance and mood of volunteers.
2. The adverse effects of psychological stress on cognitive performance and mood during SERE school will be reduced when volunteers are given supplemental tyrosine compared to placebo treatment.

Study Overview

• Status: Completed
• Conditions: Reaction to Severe Stress, Unspecified
• Intervention / Treatment: Other: Tyrosine-Containing Food Bar; Other: Placebo Bar

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maine
    • Brunswick, Maine, United States, 04011
      • US Navy SERE School

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 39 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Active duty military enrolled in the US Navy SERE School, Brunswick, ME.
• Fluent in English (non-native English speakers can be enrolled).

Exclusion Criteria:

• None.

[All volunteers enrolled in SERE school require a medical clearance. No additional inclusion or exclusion criteria are necessary.]

Study Plan

How is the study designed?

Design Details

• Primary Purpose: OTHER
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: DOUBLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
ACTIVE_COMPARATOR: Tyrosine-Containing Food Bar; 150 mg/kg dose of tyrosine per administration, administered twice	Other: Tyrosine-Containing Food Bar
PLACEBO_COMPARATOR: Placebo bar; 0 mg/kg dose of tyrosine per administration, administered twice	Other: Placebo Bar

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
change from baseline cognitive function compared to cognitive function as measured following treatment administration	baseline and final week of training (approximately 1 week later)

Collaborators and Investigators

• Sponsor: United States Army Research Institute of Environmental Medicine
• Investigators: Principal Investigator: Harris R. Lieberman, PhD, United States Army Research Institute of Environmental Medicine

Study record dates

Study Major Dates

• Study Start: July 1, 2009
• Primary Completion (ACTUAL): October 1, 2009
• Study Completion (ACTUAL): October 1, 2009

Study Registration Dates

• First Submitted: July 30, 2013
• First Submitted That Met QC Criteria: July 30, 2013
• First Posted (ESTIMATE): August 1, 2013

Study Record Updates

• Last Update Posted (ACTUAL): November 3, 2020
• Last Update Submitted That Met QC Criteria: November 2, 2020
• Last Verified: November 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Trauma and Stressor Related Disorders; Stress Disorders, Traumatic; Stress Disorders, Traumatic, Acute
• Other Study ID Numbers: H08-05