Irritable Bowel Syndrome (IBS) and Migraine

Irritable bowel syndrome (IBS) and migraine are two different pain-related disorders, and yet they share some features. Further, people with IBS have migraines more often than the general population and vice versa. This suggests a possible common origin. In fact, many experts suggest that both migraine and IBS are part of a category of illnesses that have been dubbed central sensitivity syndromes.

Pain, Sensitivity, and Your Nervous System

Central sensitivity syndromes are a family of conditions that are diagnosed by their symptoms, meaning that there isn't any sort of lab or imaging test to confirm the diagnosis. Rather there are criteria that healthcare providers use to determine whether you have the condition—sort of like a checklist of symptoms, but a bit more detailed.

"Central" refers to pain that arises from a change in your central nervous system, which comprises the brain and spinal cord.

"Sensitivity" refers to the fact that people with central sensitivity syndromes like migraine and IBS have a heightened sensitivity to both stimuli that should and should not hurt. For instance, they feel a higher level of pain than normal with something like a needle prick (hyperalgesia) or even discomfort with regular touch (allodynia). 

This sensitivity occurs because of a process called central sensitization, a gradual change in your central nervous system after (often repeated) exposure to certain stimuli like light, sound, odor, and touch. These triggers then cause you to feel more pain than you normally would.

Central Sensitivity in Migraine

No one knows exactly what causes migraine. It's possible that one of the mechanisms behind it is that migraine causes changes in your brain that activate a cranial nerve called the trigeminal nerve, releasing peptides like calcitonin gene-related peptide (CGRP). This, in turn, promotes inflammation and transmits pain signals to your brain, which is referred to as the trigeminovascular pain pathway.

Eventually, your brain becomes sensitized to your triggers, causing the nerve cells to more easily transmit messages through the trigeminovascular pain pathway because they've done it before. This is how central sensitization may work in migraine, possibly resulting in migraine attacks arising more easily with exposure.

Central Sensitivity in IBS

The hallmark of IBS is visceral hypersensitivity, meaning that your internal organs (e.g., your intestines, stomach, and bladder) cause an increase in your pain sensation. This is why mild stomach bloating or distension can be excruciating and debilitating when you have IBS.  

Experts believe that the visceral hypersensitivity of IBS eventually leads to central sensitization. This would explain why many people with IBS suffer from extraintestinal pain-related symptoms, such as migraines and joint and muscle pain, while some do not.

The Estrogen Link

IBS and migraine are more common in women. This suggests that sex hormones, especially estrogen, also influence these pain disorders.

Migraine and Estrogen

In migraine, women typically have improvement in their migraines during the second and third trimesters of pregnancy, when their estrogen levels are high. Menstrual migraines are common in female migraineurs and are believed to be triggered by an estrogen drop, which occurs just before menses.

By the same token, many women experience more migraines as they approach menopause, when their ovarian function begins declining and estrogen levels in the body start falling. Overall, migraines seem to improve after menopause—a somewhat confusing fact that suggests there are a number of factors at play. 

IBS and Estrogen 

In IBS, estrogen not only modulates the pain and stress response in your brain, but it also affects the sensitivity of your gut to pain, the motility of your gut's contents, and even the type of bacteria that grow in your gut.

However, the role of estrogen in IBS is complex. This is why studies are conflicting as to whether certain hormone-sensitive stages in a woman's life help or worsen her IBS symptoms. For example, studies mostly show that the incidence of IBS (like migraine) is lower after menopause when estrogen levels in the body are very low. That being said, some women report worsening GI symptoms, especially constipation and bloating, after menopause.

Other Commonalities

It's common for mental health disorders like depression, anxiety, and/or post-traumatic stress disorder (PTSD) to co-occur with IBS and migraines. Having a mental health disorder in addition to a pain disorder is an intricate cycle of one triggering the other.

It's often difficult to ascertain which came first, sort of the "chicken or the egg" theory. Regardless, the combination of bodily pain along with psychological disturbances can worsen quality of life and daily functioning if left untreated.

There's also the potential role of the brain-gut axis in both conditions. This bidirectional relationship involves communication between the central nervous system and the enteric nervous system, which is responsible for gastrointestinal functions.

Studies have found that the microorganisms in your gut could influence the brain-gut axis and that chronic inflammation, found in both migraine and IBS, may also play a role.

Treating IBS and Migraine

Healthcare providers often recommend a combination of therapies that may help treat both IBS and migraine.

Medications

Antidepressants, particularly tricyclic antidepressants, are used as treatment strategies in both conditions, so your healthcare provider might try one of these to see if it helps them both.

Examples of tricyclic antidepressants are Pamelor (nortriptyline), Tofranil (imipramine), and Elavil (amitriptyline).

Complementary and Alternative Medicine (CAM)

There are a handful of CAM therapies that you can try to treat migraine and IBS, including:

• Acupuncture: Research has found that acupuncture may be helpful for both conditions.
• Biofeedback: This technique uses sensors to teach you how to be aware of and control specific responses your body has to stress, helping you learn to relax.
• Cognitive-behavioral therapy (CBT): CBT is a type of psychotherapy that has also shown some promise in treating both conditions.
• Probiotics: Taking these supplements every day can help restore the number of good bacteria in your gut, which can, in turn, relieve some of your IBS symptoms. Because of the potential role of the brain-gut axis, it's possible that probiotics may also help reduce the frequency and/or severity of migraines as well, since they can decrease inflammation and improve the gut microbiome.

Elimination Diet

Scientists are also looking into single treatments that can help both conditions, one of which is diet therapy.

In one small 2013 study in the journal Headache, participants with both migraines and IBS underwent an elimination diet; they were selected because of high immunoglobulin G (IgG) levels in their blood when exposed to certain foods. (IgG is an antibody and a marker for inflammation in the body.)

The diet reduced both symptoms of IBS and migraine in the participants.

Future Research

A connection between two disorders does not mean that one causes the other, or that having one means you will you eventually develop the other. It simply means that there's a link.

Continuing to examine the links between IBS and migraine helps scientists better understand why these pain disorders develop and how healthcare providers can best treat them—a slow process that requires careful and delicate study and interpretation.

A Word From Verywell

If you have migraine and you've been diagnosed with IBS or you have symptoms of gastrointestinal distress, be sure to see your healthcare provider for a firm diagnosis and to get both conditions treated. Research shows that treating underlying gastrointestinal conditions like IBS can help decrease the frequency and severity of your migraines as well, so it's worth looking into.