Brain images may offer clues to gluten sensitivity

December 8, 2020

Pilot study finds neurological signs in gluten sensitivity that can be measured after gluten exposure

By Amy Ratner, Director Scientific Affairs

The first brain imagining research involving gluten sensitive patients was part of a small pilot study that looked at neurological symptoms and how soon they occur after gluten exposure.

The study published in the journal Plos One by researchers at Sheffield University in the United Kingdom was prompted after 125 self-identified gluten sensitive patients commonly reported symptoms such as headaches, brain fog and balance issues. The patients had responded to a survey sent in the mail after they had been seen at a gastroenterology clinic in Sheffield. Headaches and brain fog were each reported by about half.

Survey as the first step

Those who responded to the survey said it took about 90 minutes after a gluten exposure for the symptoms to occur and the median time for them to resolve was 48 hours. The pattern of onset of symptoms was comparable to that reported by celiac disease patients who had also been seen at the gastroenterology clinic. Study authors noted that similarities in neurological and other symptoms in gluten sensitivity and celiac disease drew “further attention to the high degree of overlap between the two conditions.” Sheffield researchers have also investigated brain images of celiac disease patients in a much larger study done earlier this year.

Related: Brain images show celiac disease related damage

Responses to the survey regarding frequency and severity of neurological symptoms motivated researchers to do the gluten sensitivity brain imaging pilot study. The combined survey and brain imagining results revealed that typical gluten sensitivity involves significant neurological symptoms, which can be measured within two hours of gluten ingestion, according to the study.

First imagining data in gluten sensitivity

The researchers emphasized that as a pilot study, their work is preliminary and is mainly intended to provide the first imagining data related to gluten sensitivity and to introduce potential neurological biomarkers for larger scale studies.

Currently, there are no blood biomarkers for gluten sensitivity. If someone has symptoms of celiac disease but celiac disease blood tests or biopsy results are negative and the person still improves on the gluten-free diet, gluten sensitivity may be diagnosed. Scientists have been searching for a more definitive way to diagnose gluten sensitivity.

“It is an important ‘first’ kind of study,” Iain Croall, PhD, a study author, said of the brain imaging research. “I think it justifies the desire to look into things more deeply.”

Meanwhile, the study indicates that people with gluten sensitivity may suffer from neurological effects due to eating gluten, he added. Croall, a research fellow in the academic unit of radiology at Royal Hallamshire Hospital, noted that this reinforces the importance of the gluten-free diet for those with gluten sensitivity who may not see the need for the diet as clearly as those with celiac disease.

The brain imagining study included five participants who had said on the survey that they followed a strict gluten-free diet and experience brain fog and symptoms less than two hours after inadvertently ingesting gluten.

Anxiety, depression and headache

Participants rated anxiety, depression, headache, clear headedness and overall state of health and were given baseline brain MRI scans. The scans were designed to enable researchers to summarize how “healthy” participants’ brains appeared. Results showed that three participants had an abnormal amount of white matter lesions. Two had low levels of N-Acetylaspartate, which is usually one of the most abundant molecules in the brain. Croall noted that the more of the molecule the better in terms of brain health. Additionally, one type of scan measured the average amount blood being delivered to the grey matter of the brain.

The first round of scans was followed by a gluten challenge of each participant’s choosing. All five chose a sandwich, which researchers estimate contained about 3 grams of gluten in two slices of wheat bread.  Within a few hours after the challenge, a second scan was done to enable researchers to compare before and after results. Participants also answered questions about their symptoms again after the gluten challenge.

All participants reported that headache and brain fog worsened after the challenge. “Feelings of brain fog and headache each worsened in a consistent manner and by an overall significant magnitude after eating gluten,” the study says, though lack of a control group that received a placebo was noted as a limitation.

Slightly unwell brains

“Overall, our conclusions are that this is evidence that [gluten sensitive] patients potentially have slightly “unwell” brains in terms of our baseline measurements in ways which mirror what we see in celiac disease,” Croall said. “And eating gluten appeared to lead to worse neurological symptoms.”

Additionally, one patient’s scan after gluten exposure appeared to show an increased blood flow to the brain. Though it’s not clear precisely what this would mean, Croall noted that similar changes occur in migraines.

He noted that the study involved only a small number of people, making formal scientific conclusions difficult. “Ideally, we would want to do a larger version of the same sort of study,” he said.

You can read more about the study here.

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