A personalized elimination diet changed the gut microbiome in people with migraine

By Hugo Francisco de SouzaReviewed by Susha Cheriyedath, M.Sc.Aug 31 2026

Researchers tracked gut bacteria, zonulin, and migraine-related biomarkers to test whether personalized food elimination could influence pathways connecting the gut and brain.

Study: IgG positive food elimination diet altered gut microbiota, decreased zonulin in migraine adults: a pilot dietary intervention trial. Image Credit: Juliya Shangarey / Shutterstock

In a recent randomized controlled trial published in the journal Frontiers in Nutrition, researchers investigated how food-specific immunoglobulin G (IgG)-guided elimination diets affected the gut microbiota and serum zonulin levels in adults with migraine. The study comprised a single-blind, sham-controlled trial involving 98 randomized migraine patients conducted over 12 weeks.

The study specifically aimed to assess whether eliminating IgG-reactive foods affects the gut microbiota and serum zonulin levels, and whether these changes are associated with inflammatory biomarkers and migraine symptoms.

Study findings revealed that adherence to the true elimination diet was associated with changes in gut microbial composition and diversity. The analyses also identified a decrease in serum zonulin, a circulating marker associated with intestinal permeability, while prior findings from the same trial reported reduced concentrations of calcitonin gene-related peptide (CGRP) and interleukin-6 (IL-6).

These findings suggest that targeted dietary elimination may be associated with improvements in migraine symptoms and comorbid sleep disturbances alongside changes in gut microbiota, zonulin, and inflammatory biomarkers, although the proposed microbiota-gut-brain mechanism remains speculative.

Background

Migraine is clinically defined as a debilitating neurovascular disorder characterized by extreme sensitivity to light and sound, which usually manifests symptomatically as severe, throbbing head pain, often accompanied by nausea.

Extensive research in the field has established that migraines are frequently accompanied by substantial psychological and physiological comorbidities, including depression, anxiety, gastrointestinal dysfunction, and sleep disorders.

Despite extensive research, the biological mechanisms underlying its incidence and progression remain elusive. Previous studies by the researchers have associated food-specific IgG responses with migraine and its comorbidities. These studies also suggest that bidirectional communication within the microbiota-gut-brain axis may influence neuroinflammation and may also modulate gut permeability and neuronal excitability.

Parallel biochemical research indicates that intestinal dysbiosis (disruption of normal gut microbial communities) may affect tight junction integrity and contribute to zonulin release, a regulatory protein that helps regulate the epithelial and blood-brain barriers. Zonulin’s release, in turn, has been proposed to increase intestinal permeability, potentially allowing intestinal bacteria and incompletely digested nutrients to enter the systemic circulation.

However, the underlying microbiological mechanisms and their direct correlations with barrier permeability and neurovascular pain biomarkers remain uncharacterized.

About the study

The present study aimed to address these knowledge gaps and inform future migraine-associated research and clinical interventions by systematically investigating changes associated with food-specific IgG-guided dietary elimination, including gut microbial composition and serum zonulin, and their relationships with migraine symptoms and inflammatory biomarkers.

The researchers initially recruited 129 adults with migraine, of whom 98 demonstrated at least one food-specific IgG antibody elevation and were randomized. These 98 individuals were subsequently randomized into two cohorts: 1. A “true diet” group (n = 52) in which IgG-positive foods were eliminated from the participants’ diets, and 2. A “sham diet” group (n = 46) in which an equivalent number of IgG-negative foods were eliminated.

At 12 weeks, 84 of the 98 patients completed endpoint questionnaires and provided blood and fecal samples. Study outcomes were evaluated across three main assessment domains, specifically: 1. Serum biomarker concentrations measured via enzyme-linked immunosorbent assays (ELISA), 2. Gut microbiota diversity and taxonomic abundance were assessed using 16S rRNA amplicon sequencing on the Illumina MiSeq platform, and 3. Participants’ questionnaire-based migraine symptoms and comorbidities. CGRP, IL-6, and clinical symptom outcomes from this cohort had been reported previously.

Study findings

The analyses showed that the true elimination diet was associated with changes in gut microbial structure. While most measures of within-sample microbial diversity remained stable, the Simpson alpha-diversity index changed over the 12-week intervention period.

Measures of differences in microbial community composition, including Bray-Curtis and weighted and unweighted UniFrac analyses, also changed between baseline and week 12 in the true-diet group.

Genus-level analyses showed increased abundance of several taxa, including Bifidobacterium, Butyricicoccus, and Ruminococcus. At the same time, Prevotella abundance decreased.

Serum zonulin levels in the true-diet group decreased from 399.5 pg/mL at baseline to 253.3 pg/mL after 12 weeks. No comparable statistically significant reduction was observed in the sham-diet group, and the magnitude of change differed between the groups.

Finally, exploratory correlation analyses found that increases in Bifidobacterium abundance were associated with reductions in CGRP and changes in migraine-specific quality-of-life scores.

Conclusions

The study provides preliminary evidence that food-specific IgG-guided elimination diets are associated with changes in gut microbial composition and serum zonulin in adults with migraine. It also provides hypothesis-generating clues about possible mechanisms by linking specific microbial changes with zonulin, CGRP, IL-6, and clinical measures, although these correlations do not establish causality.

While larger, adequately powered studies using contemporary microbiome analyses are needed to validate these findings and investigate the pathways linking dietary responses to migraine, the authors cautioned that the proposed mechanism remains speculative.

The small sample size, baseline microbiota imbalances, moderate correlations, and lack of correction for multiple comparisons mean that the findings are exploratory and require validation before the microbiota-gut-brain axis can be considered an established therapeutic target for migraine management.