The low glutamate diet improves cognitive functioning in veterans with Gulf War Illness and resting-state EEG potentially predicts response

• Published in: Nutritional neuroscience Vol. 25; no. 11; pp. 2247 - 2258
• Main Authors: Kirkland, Anna E., Baron, Michael, VanMeter, John W., Baraniuk, James N., Holton, Kathleen F.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 02.11.2022
• Subjects: Cognition; cognitive functioning; Diet; dietary intervention; Electroencephalography; electroencephalography (EEG); glutamate; Gulf War Illness; Humans; Persian Gulf Syndrome - drug therapy; Sodium Glutamate; Veterans; electroencephalography (EEG); Gulf War Illness; cognitive functioning; glutamate; dietary intervention
• ISSN: 1028-415X; 1476-8305
• DOI: 10.1080/1028415X.2021.1954292

Objectives: Gulf War Illness (GWI) is a chronic, multi-symptom disorder with underlying central nervous system dysfunction and cognitive impairments. The objective of this study was to test the low glutamate diet as a novel treatment for cognitive dysfunction among those with GWI, and to explore if baseline resting-state electroencephalography (EEG) could predict cognitive outcomes. Methods: Cognitive functioning was assessed at baseline, after one-month on the diet, and across a two-week double-blind, placebo-controlled crossover challenge with monosodium glutamate (MSG) relative to placebo. Results: Significant improvements were seen after one-month on the diet in overall cognitive functioning, and in all other domains tested (FDR p < 0.05), except for memory. Challenge with MSG resulted in significant inter-individual response variability (p < 0.0001). Participants were clustered according to baseline resting-state EEG using k-means clustering to explore the inter-individual response variability. Three distinct EEG clusters were observed, and each corresponded with differential cognitive effects during challenge with MSG: cluster 1 had cognitive benefit (24% of participants), cluster 2 had cognitive detriment (42% of participants), and cluster 3 had mild/mixed effects (33% of participants). Discussion: These findings suggest that the low glutamate diet may be a beneficial treatment for cognitive impairment in GWI. Future research is needed to understand the extent to which resting-state EEG can predict response to the low glutamate diet and to explore the mechanisms behind the varied response to acute glutamate challenge.