Contribution of L-Tyrosine to Recovery From Operational Strain on Return From External Operation (USOP)

Operational conditions amplify soldier's constraints and stress factors, upsetting individual and collective adaptive landmarks. The soldier's resistance is strained by the high intensity of stressors, by the long duration of exposure and by their cumulative effect.

This may lead to a state of "operational strain" that refers to chronic stress and the allostatic load imposed by operational constraint.

The investigators believe that operational strain could manifest itself by a kind of accelerated aging of the organism due to the increased allostatic load without sufficient resource restoration (neurotransmitter precursors, partial and repeated sleep deprivation, etc.).

This aging mechanism would be reversible after a sufficient period of resource restoration (sleep, physical activity, adapted diet, etc.).

Study Overview

• Status: Completed
• Conditions: Stress, Psychological
• Intervention / Treatment: Biological: Blood collection; Drug: L-Tyrosine 500 Mg; Behavioral: Psychological questionnaires; Device: Photoplethysmography; Drug: Placebo

• Study Type: Interventional
• Enrollment (Actual): 116
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Brétigny-sur-Orge, France, 91223
    • Institut de Recherche Biomédicale des Armées

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 61 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• From 18 to 65 years of age

Exclusion Criteria:

• Tyrosine intake within the previous 15 days
• History of neurological or psychiatric disorder
• History of nephrological or endocrine disorder or liver failure
• Hereditary tyrosinemia

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Tyrosine - External Operation; 1-month L-Tyrosine treatment following 4-month external operation	Biological: Blood collection; A blood sample will be collected before during and after the treatment.; Drug: L-Tyrosine 500 Mg; The participants will be administered 4 capsules of L-Tyrosine 500 mg per oral route daily over 1 month.; Behavioral: Psychological questionnaires; The participants will fill in several psychological questionnaires before, during and after treatment administration: Life Event Checklist; Moral injury; Posttraumatic Checklist; Burnout Assessment Tool; State-Trait Anger Expression Inventory-2; Ruminative Response Scale - Reconsidered; Deployment Risk and Resilience Inventory-2; Questionnaire about tobacco use; Device: Photoplethysmography; Photoplethysmography recording will be performed before during and after the treatment.
Experimental: Placebo - External Operation; 1-month Placebo treatment following 4-month external operation	Biological: Blood collection; A blood sample will be collected before during and after the treatment.; Behavioral: Psychological questionnaires; The participants will fill in several psychological questionnaires before, during and after treatment administration: Life Event Checklist; Moral injury; Posttraumatic Checklist; Burnout Assessment Tool; State-Trait Anger Expression Inventory-2; Ruminative Response Scale - Reconsidered; Deployment Risk and Resilience Inventory-2; Questionnaire about tobacco use; Device: Photoplethysmography; Photoplethysmography recording will be performed before during and after the treatment.; Drug: Placebo; The participants will be administered 4 capsules of Lactose 500 mg (placebo) per oral route daily over 1 month.
Experimental: Tyrosine - Rear Base; 1-month L-Tyrosine treatment following 4 months at rear base	Biological: Blood collection; A blood sample will be collected before during and after the treatment.; Drug: L-Tyrosine 500 Mg; The participants will be administered 4 capsules of L-Tyrosine 500 mg per oral route daily over 1 month.; Behavioral: Psychological questionnaires; The participants will fill in several psychological questionnaires before, during and after treatment administration: Life Event Checklist; Moral injury; Posttraumatic Checklist; Burnout Assessment Tool; State-Trait Anger Expression Inventory-2; Ruminative Response Scale - Reconsidered; Deployment Risk and Resilience Inventory-2; Questionnaire about tobacco use; Device: Photoplethysmography; Photoplethysmography recording will be performed before during and after the treatment.
Experimental: Placebo - Rear Base; 1-month Placebo treatment following 4 months at rear base	Biological: Blood collection; A blood sample will be collected before during and after the treatment.; Behavioral: Psychological questionnaires; The participants will fill in several psychological questionnaires before, during and after treatment administration: Life Event Checklist; Moral injury; Posttraumatic Checklist; Burnout Assessment Tool; State-Trait Anger Expression Inventory-2; Ruminative Response Scale - Reconsidered; Deployment Risk and Resilience Inventory-2; Questionnaire about tobacco use; Device: Photoplethysmography; Photoplethysmography recording will be performed before during and after the treatment.; Drug: Placebo; The participants will be administered 4 capsules of Lactose 500 mg (placebo) per oral route daily over 1 month.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference between the change in Burnout Assessment Tool (BAT) score following 1-month treatment in each arm	The Burnout Assessment Tool (BAT) is used to assess burn-out risk. The score ranges from 1 to 5, with higher scores indicating a higher risk of burn-out.	After 1-month treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference between the change in catecholamine level following 1-month treatment in each arm	Catecholamine level will be measured in blood before during and after 1-month treatment.	After 1-month treatment
Difference between the change in aminoacid level following 1-month treatment in each arm	Aminoacid level will be measured in blood before during and after 1-month treatment.	After 1-month treatment
Difference between the change in zonulin level following 1-month treatment in each arm	Zonulin level will be measured in blood before during and after 1-month treatment.	After 1-month treatment
Difference between the change in Brain-Derived Neurotrophic Factor (BDNF) level following 1-month treatment in each arm	BDNF level will be measured in blood before during and after 1-month treatment.	After 1-month treatment
Difference between the change in gamma-aminobutyric acid (GABA) level following 1-month treatment in each arm	GABA level will be measured in blood before during and after 1-month treatment.	After 1-month treatment
Difference between the change in Tumor Necrosis Factor Alpha (TNFα) level following 1-month treatment in each arm	TNFα level will be measured in blood before during and after 1-month treatment.	After 1-month treatment
Difference between the change in Interleukin-6 (IL6) level following 1-month treatment in each arm	IL6 level will be measured in blood before during and after 1-month treatment.	After 1-month treatment

Collaborators and Investigators

• Sponsor: Direction Centrale du Service de Santé des Armées

Study record dates

Study Major Dates

• Study Start (Actual): September 9, 2020
• Primary Completion (Actual): June 30, 2021
• Study Completion (Actual): June 30, 2021

Study Registration Dates

• First Submitted: September 8, 2020
• First Submitted That Met QC Criteria: September 8, 2020
• First Posted (Actual): September 16, 2020

Study Record Updates

• Last Update Posted (Actual): November 25, 2022
• Last Update Submitted That Met QC Criteria: November 23, 2022
• Last Verified: November 1, 2022

More Information

Terms related to this study

• Keywords: L-tyrosine
• Additional Relevant MeSH Terms: Behavioral Symptoms; Stress, Psychological
• Other Study ID Numbers: 2019PBMD06; 2020-A01658-31 (Other Identifier: IDRCB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No