The Gut–Brain Axis and Migraine: How Your Gut May Influence Your Head

For decades, migraine was primarily viewed as a neurological disorder involving abnormal activity in the brain and its surrounding pain pathways. Today, researchers are investigating a much broader system: the gut–brain axis, a two-way communication network connecting the gastrointestinal tract, immune system, gut microbiome, and nervous system. Increasing evidence suggests that this relationship may help explain why people with migraine frequently experience gastrointestinal symptoms—and why changes in the gut could potentially influence migraine susceptibility.

Importantly, the science is still developing. The gut–brain axis is a promising area of migraine research, but it does not mean that migraines are simply caused by an unhealthy gut or that changing the microbiome can cure migraine.

What Is the Gut–Brain Axis?

The gut–brain axis is a complex, bidirectional communication system between the gastrointestinal tract and the central nervous system. Communication occurs through several pathways, including the vagus nerve, immune signaling, hormones, microbial metabolites, and neurotransmitter-related pathways.

The gut is also home to trillions of microorganisms—including bacteria, fungi, and other microbes—collectively known as the gut microbiome. These organisms interact with food, intestinal cells, and the immune system and produce biologically active compounds that can influence processes elsewhere in the body.

This means communication does not travel exclusively from the brain to the gut. Signals can move in both directions.

Brain → gut: Stress and nervous-system activity can alter intestinal movement, secretion, and sensitivity.

Gut → brain: Microbial metabolites, immune signals, hormones, and neural pathways can influence nervous-system activity and inflammation.

What Does This Have to Do With Migraine?

Migraine is a neurological disorder involving complex interactions between the brain, blood vessels, sensory nerves, and inflammatory signaling. Gastrointestinal symptoms—including nausea and changes in digestion—are common during migraine attacks, and migraine is also associated with several gastrointestinal conditions.

Researchers have observed associations between migraine and conditions such as irritable bowel syndrome and other gastrointestinal disorders. However, an association does not necessarily prove that one condition causes the other.

One possible explanation is that migraine and gastrointestinal disorders share biological pathways involving the nervous system, immune system, and gut microbiome.

The Gut Microbiome: A Potential Missing Piece

The gut microbiome may be particularly important because its composition can influence immune activity and metabolism.

Studies comparing people with migraine and people without migraine have reported differences in the composition and diversity of their gut microbiomes. A 2025 systematic review found that several studies identified differences in microbial populations among people with migraine, although the specific organisms involved were not completely consistent across studies.

This inconsistency is important. Researchers have not identified a single “migraine microbiome” that can reliably predict who will develop migraine.

Instead, the evidence suggests that migraine may be associated with broader changes in the microbial ecosystem.

How Could Gut Bacteria Influence Migraine?

Several mechanisms are being investigated.

1. Inflammation

The gut and immune system are closely connected. Changes in the intestinal environment can influence immune signaling and the production of inflammatory molecules.

Because inflammation and neuroinflammatory signaling are involved in migraine biology, researchers are investigating whether gut-derived immune signals could influence migraine susceptibility.

2. The Intestinal Barrier

The intestinal lining acts as a selective barrier between the contents of the gut and the rest of the body.

Researchers are investigating whether changes in intestinal barrier function could allow greater interaction between microbial products and the immune system. This could potentially contribute to systemic inflammatory signaling that affects neurological pathways.

However, the exact importance of intestinal permeability in migraine remains uncertain and requires more research.

3. Microbial Metabolites

Gut bacteria produce molecules that can affect human physiology. One important group is short-chain fatty acids (SCFAs), which are produced when certain dietary fibers are fermented by intestinal microbes.

SCFAs can influence immune activity, metabolism, and communication between the gut and nervous system. Researchers are investigating whether differences in these microbial metabolites could contribute to neurological conditions, including migraine.

4. Serotonin and Other Signaling Molecules

The gut is heavily involved in serotonin biology. Serotonin is a signaling molecule that has important roles in both the gastrointestinal and nervous systems.

Researchers have proposed that interactions among gut microbes, serotonin pathways, and migraine-related neurological signaling could help explain some of the connections between gastrointestinal function and migraine.

5. The Vagus Nerve

The vagus nerve provides a major communication pathway between the gastrointestinal tract and the brain.

Signals originating in the gut can travel through this neural pathway and influence brain activity. This has led researchers to investigate whether microbiome-related changes could influence neurological processes involved in migraine.

Can Improving Gut Health Prevent Migraines?

This is where it is important to separate promising research from established treatment.

Researchers have investigated probiotics, prebiotics, and synbiotics as potential adjunctive approaches for migraine. Some clinical trials have reported reductions in migraine frequency, severity, or medication use.

However, results have not been uniform. Different studies use different bacterial strains, formulations, doses, populations, and treatment periods. A 2025 systematic review concluded that microbiome-targeted treatments show promise but that additional high-quality randomized trials are needed.

A recent review similarly concluded that microbiome-targeted approaches are biologically plausible but that their effects appear to depend on the specific intervention and population being studied.

Therefore, probiotics should not currently be viewed as a replacement for established migraine treatment.

What About Diet?

Diet is one of the most interesting connections between the gut microbiome and migraine because what we eat can influence both the microbiome and migraine triggers.

A balanced diet containing a variety of plant foods can provide dietary fiber that supports microbial fermentation and production of metabolites such as SCFAs. At the same time, migraine triggers are highly individual: a food that triggers symptoms in one person may have no effect on another.

Some dietary components, including caffeine and alcohol, have been investigated as potential migraine triggers, while nutrients such as magnesium and riboflavin have also been studied for their potential relationship with migraine.

This does not mean that people with migraine should follow extremely restrictive diets. In fact, unnecessary elimination of large groups of foods can create nutritional problems and make eating unnecessarily difficult.

The Bigger Picture

The gut–brain axis provides an exciting way to think about migraine as more than an isolated problem occurring inside the head.

The brain, gut, immune system, microbiome, and nervous system are constantly communicating. Changes in one part of this network may influence the others.

But scientists are still working out exactly what causes what. Does altered gut microbiota contribute to migraine? Can repeated migraine attacks alter the gut? Or do both result from shared biological and environmental factors?

The answer may ultimately be a combination of all three.

The Future of Migraine Research

Future research may move beyond simply asking whether people with migraine have different gut bacteria. Scientists are increasingly interested in identifying which microorganisms, metabolites, immune signals, and neurological pathways actually matter.

This could eventually lead to more personalized approaches to migraine prevention—potentially using a person’s symptoms, diet, microbiome, genetics, and other biological characteristics to determine which interventions are most likely to help.

For now, however, the strongest conclusion is more modest: the gut and brain clearly communicate, and the gut microbiome appears to be associated with migraine biology, but researchers are still determining exactly how significant that relationship is.

Understanding this connection could open an entirely new chapter in migraine research—one in which treating neurological disorders may involve paying considerably more attention to what is happening beyond the brain.