US Navy Chaplain Deb Mariya had been struggling with PTSD and fibromyalgia for decades, unable to find relief despite trying every treatment she could find, from medication to acupuncture.

Then a new diet changed her life, she told Business Insider.

Maryia said that she had developed escalating symptoms after deploying to Kuwait in 1991’s Operation Desert Storm, amid black clouds of burning oil and debris-laden sandstorms.

In the more than 30 years since, persistent brain fog has prevented Maryia from thinking clearly. An autoimmune condition attacked her bones and joints, leaving her in need of hip replacement surgery, but unable to heal properly afterward, causing life-threatening complications.

Then in 2024, Maryia enrolled in an experimental clinical trial for veterans. The goal: to test whether cutting out a compound common in processed foods could alleviate symptoms of a mysterious condition known as Gulf War Illness. The syndrome is a collection of neurological issues like joint problems, severe fatigue, and mood disturbances.

After living on a low-glutamate diet for a month, Mariya was scheduled for another surgery. This time, she said, she healed rapidly and was walking within weeks. She said that her brain fog lifted, and she regained the energy to complete her physical therapy sessions.

“I couldn’t believe it,” Mariya said. “It was like an answer from God.”

Hundreds of veterans like Mariya have tried the diet program since 2020, led by Kathleen Holton at American University in Washington, DC. As many as 80% of them see improvements after following the diet, according to both their self-reports as well as data collected by Holton’s team: less chronic pain, fewer symptoms of depression, anxiety, and PTSD, and sharper cognitive function.

“The people who go onto this diet usually don’t come off it due to how much better they feel,” Holton, a nutritional neuroscientist, told Business Insider.

Her research suggests that reducing glutamate may help prevent nerve cell damage, offering a promising therapy for complex, difficult-to-treat conditions such as Gulf War Illness as well as a myriad of other health concerns, from chronic migraines to mood disorders.

Understanding how this diet works could open new doors to revealing how our highly processed food system may affect our bodies and minds over time.

What is glutamate?

Glutamate is an amino acid, a building block of protein. It’s naturally produced by our bodies and acts as a neurotransmitter, carrying chemical messages from the nervous system throughout the body.

It’s also found in many foods, and has been used as a food additive since the early 1900s. Commonly added as monosodium glutamate (MSG), it helps give an umami boost to soups, snacks, cured meats, and condiments.

“Glutamate is really the ultimate flavor enhancer in the diet,” Holton said. “It has the ability to excite neurons in your tongue.”

MSG has been linked to potential health risks, including headaches and nausea. But the FDA considers it safe, partly because the blood-brain barrier prevents glutamate in food from freely entering the brain.

Researchers have been studying the role of glutamate in the brain since the 1950s. Too much glutamate can cause the nerve cells to get overexcited, a state known as excitotoxicity, resulting in damage or cell death. This can occur in conditions like Parkinson’s disease, seizure disorders, and some types of stroke.

Holton is one of the few researchers specializing in nutritional neurology. Most neurological research doesn’t focus on food, and nutritional research rarely addresses the brain. As she carved out this niche in grad school around 2006, glutamate emerged as an area of untapped potential.

Holton’s approach is based on precision nutrition — the idea that individual people may be particularly sensitive to certain compounds.

For instance, in cases of brain injury or stress, that barrier, which controls how much glutamate enters the brain, can become more permeable, increasing the risk of overloading. Glutamate also interacts with the gut, which regulates neurotransmitters like serotonin.

In 2020, Holton published her first study on the low-glutamate diet for pain management in 40 veterans. The results were striking: 73% of them had improved symptoms after a month on the diet. Symptoms were ranked on a scale from 0 to 33, and the average score after the diet was 11.7, compared to 18.1 in the control group — statistically, a “very large” effect, the researchers wrote.

In 2022, she received a $6.4 million grant from the Department of Defense to conduct further research on more than 100 veterans, and more symptoms, including anxiety, depression, and migraines.

Treating the ‘neurotoxic triad’

For Holton, Gulf War veterans offered an exceptional opportunity to work with a population experiencing complex neurological symptoms and few effective treatment options.

As many as 300,000 servicemembers who deployed to the Persian Gulf region during the early 1990s in Operations Desert Storm and Desert Shield went on to report chronic health conditions ranging from fatigue, dizziness, and headaches to joint pain, respiratory problems, and memory problems, according to the Department of Veterans Affairs.

While researchers are still trying to understand Gulf War Illness, the available evidence suggests it involves a cycle of three processes that wreak havoc on the central nervous system: inflammation, excitotoxicity, and oxidative stress.

“Currently, we don’t have any medications that can treat the neurotoxic triad, but nutrition is perfectly suited to do just that,” Holton said.

She and her team developed a dietary protocol that involved both reducing food sources of glutamate and increasing intake of nutrients that help reduce inflammation and protect the brain, such as omega-3 fatty acids and fresh produce.

Using randomized controlled trials, the gold standard for research, Holton tested whether the diet could reduce symptoms of Gulf War Illness among veterans, compared to a control group that didn’t try the diet.

One of her trial participants was 68-year-old Army veteran Wendy Fite, who developed multiple physical and psychological symptoms after serving in the Gulf.

Before starting a low-glutamate diet, Fite said she was assessed for PTSD and scored at about 40 — the clinical threshold for diagnosis is 31 to 33.

After 30 days of the program, Fite’s PTSD score dropped by 30 points. Typically, PTSD patients are considered responsive to treatment if their score decreases by at least 10 points. She said her relationship with her spouse improved, and her mind felt sharper, too — and extensive cognitive testing by Holton’s team confirmed it wasn’t only a subjective improvement.

Fite’s biggest change came after giving up pasta with cheese and tomato sauce, all high in glutamate and once a staple as she trained for more than 70 marathons. Instead, she eat beans as often as possible and takes cod liver oil to reduce inflammation. Two years after her study ended, she’s still sticking to the diet.

Robin Runkle, a 60-year-old Army veteran from Ohio, told Business Insider that cutting out snacks and sweets transformed her health. Since swapping cereal for yogurt, her migraines have dropped from several times a week to “once in a blue moon.” She also has better cholesterol, sleep, and energy, which she channels into trying new recipes that fit her plan.

Holton said the diet’s benefits can have “cascading effects,” improving lasting healthy habits. Veterans also share the plan with family and friends, thereby impacting communities. Mariya, a Navy chaplain, said she’s eager to share the diet widely, especially to her niece and VA-provided home health aides.

Mariyah still manages mobility issues and will likely need a wheelchair someday. For now, her world has expanded. She can complete a lap around the block, walk a flight or two of stairs without getting out of breath, and get her own mail.

“It changed my life,” she said. “I wish I had found it sooner.”

Tackling migraines, brain injuries, and psychiatric disorders

There is precedent for the idea that diet can directly influence mental and cognitive health, said Deanna Kelly, a psychiatry professor at the University of Maryland who has published work on gluten-free diets.

“You can imagine in a brain that’s just on the edge of not working so well, there are a variety of manifestations that could be seen or worsened if you had inflammation,” Kelly told Business Insider.

It’s a matter of picking apart which compounds might be overloading a sensitive brain.

The research on low-glutamate diets is still emerging, however. For Holton, the next step is to conduct further research on specific conditions such as migraines and traumatic brain injuries. Studies on both are underway. She’s also hoping to roll out more trials with veterans in partnership with the Department of Defense.

A major advantage of the diet is how closely it mirrors other basic healthy-eating advice: Stick to nutrient-dense whole foods and cut back on ultra-processed foods with unpronounceable ingredients. As such, there is little risk of side effects.

In the future, understanding how glutamate affects the brain could help provide more specific diet recommendations for a wide range of psychiatric and neurological conditions.

For now, Holton aims to expand access to the low-glutamate diet, including to service members with conditions similar to Gulf War Illness who were deployed in other conflicts.

“It’s all well and good that we publish scientific findings, but at the end of the day, we really need to get this out to the veterans, to the people that need it most,” Holton said.