Glutamate Neuro-Excitotoxicity in GWI (GWI)

The objective of the proposed research is to examine whether dietary exposure to food additives containing glutamate may be contributing to symptoms in Gulf War Illness (GWI). The rationale for proposed study comes from data in the fibromyalgia field which suggests that reducing the consumption of dietary glutamate can reduce over-excitation in the nervous system, leading to symptom improvement. In prior research, a low-glutamate diet (restricting food additive consumption) was tested in fibromyalgia patients. After one-month on the diet, 84% of patients had >30% of their symptoms go away (with 11 symptoms remitting on average), and 8 subjects had complete remission of all symptoms. Subjects then had a significant return of symptoms upon challenge with monosodium glutamate (MSG) as compared to placebo. Since there is almost complete symptom overlap between fibromyalgia and GWI, it is of utmost importance to test this diet as a low-cost treatment option in GWI patients.

The findings from this research will ultimately be applicable to all GWI patients and potentially to other veterans with a similar symptom profile as well. The ultimate impact of this research could be quite profound, as it has the potential to impact all of the symptoms of GWI, as opposed to being a proposed treatment for only one of the symptoms. This dietary treatment has been shown to dramatically affect symptoms like fatigue, cognitive dysfunction, and pain; and thus, has the potential to dramatically improve quality of life for these individuals. Potential benefits of the treatment are great, and risks are minimal, as the treatment involves shifting the diet to a healthier, whole-food approach.

First, the study will confirm or negate the idea that abnormal glutamate signaling in the nervous system could be causing symptoms in GWI. Second, if found to be successful, then this will provide a low-cost, easy-to-implement treatment option for the many veterans suffering from this multi-symptom illness. Third, this research could lead to future studies to identify potential causes of this abnormal neurotransmission, to help prevent future illness onset.

Study Overview

• Status: Completed
• Conditions: Gulf War Syndrome
• Intervention / Treatment: Other: Low-glutamate diet

Detailed Description

Objective/ Hypothesis: The objective of this clinical trial is to test the effectiveness of a low-glutamate diet in GWI patients, as a way to mediate symptom occurrence by reducing excess glutamatergic neurotransmission.

Specific Aims:

Aim 1- Determine if GWI is a glutamate neurotoxicity disorder, by testing whether reduced exposure to dietary glutamate can modulate symptoms. Hypothesis: Dietary glutamate restriction will significantly reduce GWI symptoms, including fatigue, cognitive dysfunction, pain, problems sleeping, headache/migraine, and diarrhea; as measured by symptom questionnaire, dolorimetery, computerized cognitive testing, EEG and fMRI memory testing. Additionally, brain glutamate levels will be reduced after one month on the diet, as measured by magnetic resonance spectroscopy (MRS).

Aim 2- Confirm that altered dietary glutamate exposure was the cause of symptom improvement.

Hypothesis: Challenge with MSG, as compared to placebo, in a randomized, double-blind, placebo-controlled crossover challenge, will significantly increase the occurrence of symptoms, cause increased pain sensitivity as measured by dolorimetry, increased excitatory neurotransmission as measured by EEG, and a worsening of cognitive function as measured by computerized cognitive testing.

Study Design: 40 subjects will be recruited from around the US . After phone screening, eligible individuals will travel to Washington DC for their first visit, where subjects will undergo baseline testing, including assessment of symptoms, cognition, brain glutamate levels and working memory testing using fMRI. For phase 1, subjects will be randomized to a low-glutamate diet (n=20) or a waitlisted group (n=20 as controls), and symptom occurrence will be compared after one month. Waitlisted participants will follow the low-glutamate diet over the following month. At the end of phase 1, subjects will return to DC, will undergo post-diet assessment of symptoms (same as baseline), and then will move onto Phase 2 of the study, a randomized, double-blind, placebo-controlled crossover challenge, to test whether symptoms recur upon challenge with MSG and not with placebo. Subjects will be randomized as to which contingency (MSG or placebo) is received first, and will receive MSG for 3 consecutive days on one of the weeks and placebo for 3 consecutive days on the other week. Symptoms, EEG and cognition will be assessed on day 3 of challenges each week. All subjects will still be following the low-glutamate diet during the challenge period, so their only exposure to glutamate will be from the week they receive the MSG.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • District of Columbia
    • Washington, District of Columbia, United States, 20016
      • American University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Males & Females
• Served (and was deployed) in the Persian Gulf War
• Fulfill both Kansas and CDC definitions of GWI
• Stable medication regimen for 3 or more months

Exclusion Criteria:

• Active Duty Military
• Current substance use disorder
• Unwilling to change diet for 2 months
• Severe asthma requiring past hospitalization
• Seizure disorder

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; 5 g of placebo (sugar and salt) will be administered in veggie capsules	Other: Low-glutamate diet; The dietary intervention consists of a one-month low-glutamate diet, followed by a randomized crossover challenge with MSG and placebo to measure return of symptoms.
Experimental: MSG; 5 grams of MSG will be administered in veggie capsules	Other: Low-glutamate diet; The dietary intervention consists of a one-month low-glutamate diet, followed by a randomized crossover challenge with MSG and placebo to measure return of symptoms.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Symptom Score Change	The number and type of symptoms will be assessed with a symptom score measure	Baseline, 1 month, 5th week, 6th week

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cognitive Function	A computerized cognitive battery will measure cognitive function	Baseline, 1 month, 5th week, 6th week

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in EEG	Electroencephalography will be used to measure brain excitation	Baseline, 1 month, 5th week, 6th week
Change in Brain Glutamate Levels	Brain glutamate levels will be measured using magnetic resonsnance psectroscopy	Baseline, 1-month

Collaborators and Investigators

• Sponsor: American University
• Collaborators: Georgetown University; United States Department of Defense
• Investigators: Principal Investigator: Kathleen F Holton, PhD, American University

Study record dates

Study Major Dates

• Study Start (Actual): November 14, 2017
• Primary Completion (Actual): July 7, 2020
• Study Completion (Actual): August 31, 2020

Study Registration Dates

• First Submitted: November 9, 2017
• First Submitted That Met QC Criteria: November 13, 2017
• First Posted (Actual): November 17, 2017

Study Record Updates

• Last Update Posted (Actual): January 12, 2021
• Last Update Submitted That Met QC Criteria: January 11, 2021
• Last Verified: January 1, 2021

More Information

Terms related to this study

• Keywords: Gulf War Syndrome; Diet; Glutamate; MSG
• Additional Relevant MeSH Terms: Occupational Diseases; Persian Gulf Syndrome
• Other Study ID Numbers: IRB-2017-301

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

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