Click to Enlarge: Source: U.S. Department of Veterans Affairs
WASHINGTON, DC — Veterans with Gulf War illness who followed a low glutamate diet for one month experienced significant improvements in migraine symptoms, according to new research presented at the Society for Neuroscience annual meeting.
The findings presented in November by researchers at Georgetown University Medical Center and American University, both in Washington, DC, also revealed that brain scans on patients who adhered to this diet showed decreased cortical thickness. The study, funded by the Department of Defense, indicates for the first time that improvement in symptoms was linked to measurable changes in the brain, a Georgetown Medical Center press release reported.1
Glutamate is found in high levels in processed foods as a component of flavor-enhancing food additives, and it also occurs naturally in some foods like tomatoes and mushrooms. A low glutamate diet aims to exclude foods naturally high in free glutamate and food additives containing glutamate, the most abundant excitatory neurotransmitter in the nervous system, where it’s known to play a role in mediating pain, according to the press release.
The results of this experimental study propose a potential, low-cost treatment option for veterans struggling with chronic neurological symptoms since the Gulf War. Gulf War Illness, a chronic condition that affects about one in four veterans who served in the 1990-1991 conflict, is characterized by musculoskeletal, gastrointestinal and neurologic symptoms including migraines, which are thought to be linked to central nervous system dysfunction from neurotoxic exposures during the war, the study authors explained.
This research stems from previous work by the investigators on the low glutamate diet.
“I had previously shown drastic improvement in fibromyalgia symptoms using this dietary approach,” Kathleen Holton, PhD, MPH, a professor in the departments of health studies and neuroscience at American University, told U.S. Medicine. “Since the symptoms of GWI [Gulf War illness] almost completely overlap with fibromyalgia and chronic fatigue syndrome, it made sense to study the diet as a potential treatment for GWI also.”
Because cortical thickening has been linked to migraines more broadly, a low glutamate diet could also provide relief to a much larger population, the study suggested.
In this study, the researchers first used brain scans to compare differences in cortical thickness between patients with GWI and a group of healthy patients. GWI patients had a significantly thicker right visual cortex and were significantly more likely to report experiencing migraines than the healthy group. In a follow-up study, the investigators had GWI patients follow a low glutamate diet. The brain scans showed that cortical thickness in this group was significantly reduced after one month.
The researchers also observed a significant drop in migraines and headaches. More than half of the Gulf War veterans had migraines before the diet, and after following the low glutamate diet for one month, the number of veterans dropped to under 20%, according to the press release.
“These results, when combined with other published data from my lab, suggest that the low glutamate diet may be addressing the underlying pathophysiology of Gulf War Illness (GWI), as it appears to lower all symptoms of the disorder,” Holton said. “The findings presented at the Society for Neuroscience support the idea that the diet is not only reducing headache/migraine, but that it appears to also be directly affecting brain structure (and function) as its potential mechanism of action.”
She noted that the results came from a small clinical trial that was conducted years ago.
“As such, we wouldn’t typically recommend a change to clinical practice without these findings being replicated,” Holton explained. “Luckily, we are currently finishing up a large confirmatory clinical trial in veterans with GWI, which is showing similar dramatic improvements across all of the symptoms, including headache/migraine. Once these findings are published (which should occur in the coming year), I am hoping to work with the VA to get this diet offered as a treatment option in the VA system.”
Holton pointed out that, if there’s interest in implementing the low glutamate diet in the Military Health System and Indian Health Service, she also looks forward to those partnerships.
“This is truly a ‘food is medicine’ approach, as it shows the power of dietary change for treating neurological and psychiatric symptoms (both of which improve on the diet),” she explained. “Physicians are often frustrated at the lack of treatment options that work for patients suffering from widespread chronic pain conditions like GWI, as they have a very high symptom load which doesn’t respond well to conventional medications. If we can get dietitians throughout the VA trained on how to administer this diet, then clinicians will be able to easily refer patients to a dietitian for treatment with the low glutamate diet.”
An ICD-10 code was recently approved for GWI, so additional training for physicians to make them more aware of the multisymptom illness, to aid diagnosis, would also be beneficial, Holton suggested.
The study’s findings support the research team’s theory that glutamate may contribute to GWI symptoms by driving excitotoxicity, neuroinflammation and oxidative stress in the brain. The researchers suggested these processes continue to trigger each other in an ongoing cycle.
“We think this is one of the reasons people who are susceptible to dietary glutamate tend to have prolonged symptoms over time,” Holton explained in the press release. Other symptoms in the low glutamate group also improved, including significant reductions in widespread pain, fatigue, mood issues and cognitive dysfunction, according to the press release.
The investigators have published an abstract on this research and plan to publish additional findings in a peer reviewed journal. They’re also following up on the migraine specific findings that were presented at the Society for Neuroscience annual meeting with a clinical trial specifically focusing on migraine patients, Holton said.
“We are actively recruiting for that study in the greater Washington, DC, area over the next year,” Holton said. “This will allow us to look at the effects on headache and migraine outside of patients with GWI, to see if any differences exist regarding the effects of the diet.”
- Crowder H, Booker DT, Dragol SM, Baraniuk JN, Holton KF, VanMeter AS. Migraine symptoms and visual cortex thickness are significantly reduced following a 1-month low glutamate diet in veterans with Gulf War Illness. Program No. PSTR219.25. 2025 Society of Neuroscience Annual Meeting, Nov. 15-19. San Diego, CA.
