Low-Glutamate Diet Linked to Fewer Migraines
/By Pat Anson
A diet low in glutamate significantly reduced migraines in U.S. veterans with Gulf War Illness, according to a new study that documents for the first time that a reduction in migraine symptoms is linked to changes in the brain.
Glutamate is an amino acid used in food additives like monosodium glutamate (MSG), which is widely used in processed food and soups as a flavor enhancer. Previous studies have shown that a low glutamate diet reduces pain and other symptoms from fibromyalgia.
Researchers at Georgetown University Medical Center observed a “big, big decrease” in migraines in 40 veterans with Gulf War Illness a month after they were put on a low-glutamate diet. Like fibromyalgia, Gulf War illness causes an array of musculoskeletal, gastrointestinal, and neurologic symptoms, including migraines. It is thought to be caused by exposure to toxic chemicals during the war.
“More than half of the Gulf War veterans had migraines before the diet, and that dropped to under 20% after following the diet for one month,” said senior author Ashley VanMeter, PhD, Professor of Neurology at Georgetown University School of Medicine. “So it was a very significant drop.”
In addition to fewer migraines, veterans on the low-glutamate diet also had significant reductions in widespread body pain, fatigue, mood issues, and cognitive dysfunction.
Findings from the study were recently presented at the annual meeting of the Society for Neuroscience in San Diego. The research, funded by the U.S. Department of Defense, grew out of a collaboration with Kathleen Holton, PhD, a nutritional neuroscientist at American University, who has been researching the low-glutamate diet as a way to manage neurological conditions.
In addition to food additives, glutamate occurs naturally in foods like tomatoes, cheese, mushrooms and nuts. Glutamate acts as a neurotransmitter in the brain and is believed to stimulate nerve cells that process pain signals.
In the Georgetown University study, researchers used brain scans to compare differences in the visual cortex – the part of the brain that processes visual information – in patients with Gulf War Illness and a group of healthy patients. Those with Gulf War Illness had a thicker right visual cortex and were more likely to report migraines than the healthy control group.
But after being put on a low glutamate diet, the brain scans of Gulf War Illness vets showed a significant reduction in cortical thickness.
Holton says the findings support the theory that glutamate may damage nerve cells, causing a repetitive cycle of neuroinflammation and oxidative stress in the brain.
“We think this is one of the reasons people who are susceptible to dietary glutamate tend to have prolonged symptoms over time,” said Holton.
Thickening of the visual cortex is common among migraine sufferers, especially those whose migraines occur with aura, or visual disturbances. That raises the question of whether a low-glutamate diet could be an inexpensive treatment option for patients with migraine or fibromyalgia..
“This is a very doable diet,” VanMeter said. “It’s a healthy diet, it’s not that hard to follow, and it’s a very low-cost way of treating what for some individuals is a chronic and debilitating condition.”
Holton noted that the study also adds to a growing body of evidence about how processed foods impact health.
“This speaks to the fact that diet can not only make us sick, but can also acutely treat our symptoms,” she said.
The FDA considers MSG to be “generally recognized as safe,” although some people are sensitive to it and experience short-term, mild symptoms, such as headache, numbness, flushing, tingling, palpitations, and drowsiness.
“Over the years, FDA has received reports of symptoms such as headache and nausea after eating foods containing MSG. However, we were never able to confirm that the MSG caused the reported effects,” the agency says.
