(P09-019-25) Improving Widespread Chronic Pain and Overall Symptoms in Gulf War Illness With the Low Glutamate Diet

Objectives: Gulf War Illness (GWI) is a chronic, multi-symptom disorder characterized by widespread chronic pain, fatigue, cognitive impairments, and mood disturbances. Evidence suggests that GWI is driven by excitotoxicity resulting from excessive levels of glutamate. Our lab has shown that the low glutamate diet, which eliminates free glutamate and emphasizes healthy whole foods, alleviates symptoms of GWI, including chronic pain. This study analyzes preliminary data from a phase III clinical trial evaluating the diet’s effects on symptom number, severity, and widespread chronic pain in veterans with GWI.

Methods: Data were collected from 52 veterans with GWI before and after one month on a low glutamate diet. Outcomes included a total symptom score (0–33) capturing typical GWI symptoms and a symptom severity score (sum of individual symptoms rated 0–4). Widespread pain was assessed with a tender point exam across 18 tender points, yielding a tender point count, myalgic score (each point ranked 0-3), and dolorimetry measurements (pain threshold). Dietary compliance was evaluated using an excitotoxin food frequency questionnaire (FFQ). Pre- and post-diet comparisons were analyzed using paired t-tests or Wilcoxon Signed Rank tests. Multivariable linear regression assessed the adjusted association between pain threshold and dietary adherence; significance level p ≤ 0.05 in SPSS.

Results: Dietary adherence was high during the intervention, as reflected by significant reductions in FFQ scores (p < 0.001). After one month on the diet, the mean (SD) total symptom number decreased from 19(7) to 13(6), p < 0.001, and symptom severity was significantly reduced from 44(20) to 27(17), p < 0.001. For widespread chronic pain, significant reductions (mean difference, p-value) were observed for the myalgic score (-6.1, p < 0.001) and tender point count (-2.4, p < 0.001), with a significant increase in pain threshold (0.42 kg, p < 0.001). Improvements in pain threshold held in multivariable linear regression after adjusting for age, sex, and change in BMI, (β=-0.28, p=0.05).

Conclusions: These preliminary findings align with previous evidence that the low glutamate diet significantly reduces symptom burden and overall pain in veterans with GWI.

Funding Sources: Department of Defense