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Sometimes, headache happens along with gastrointestinal (GI) symptoms. This can raise a “chicken and egg”-type of question: Is the headache causing the GI symptoms, or are the GI symptoms causing the headache?

The answer to this question is that it may be possible for either scenario to be true. While research is currently limited, there’s a link between headache and stomach trouble.

Keep reading as we explore this topic in more detail, the symptoms you can experience, and how your doctor may treat them.

Let’s dive deeper into the link between headache and GI symptoms. As we discuss this topic, it’s good to keep in mind that research into this area is still quite limited.

The gut-brain connection

In a developing fetus, the cells that will eventually make up the central nervous system and the nerves of your GI tract form around the same time. Afterwards, the brain and the GI tract remain linked through various biological pathways, including:

You may see this referred to as the gut-brain axis. Achieving a greater understanding of how the gut-brain access works and the ways in which it can impact our health is an area of intense research.

The link between headaches and GI symptoms

A connection between headache and GI symptoms has long been noted for some types of headache. In fact, the International Headache Society includes nausea and vomiting within the diagnostic criteria for migraine.

Additionally, abdominal migraine is a subtype of migraine that’s mostly seen in children. It causes GI symptoms like abdominal pain, nausea, and vomiting, as opposed to headache. Many children with this condition go on to experience migraine as adults.

A 2008 study asked 51,383 individuals to fill out two surveys: one about headache, and one about GI symptoms. Headache was found to be more prevalent in people with GI symptoms. This association rose significantly with increasing headache frequency.

Furthermore, a 2016 review noted that over the past 30 years, various studies have found several GI disorders to be associated with headache or migraine, including:

Does headache cause GI symptoms or do GI symptoms cause headache?

You may now be wondering if headache causes GI symptoms or vice versa. The answer to this question is currently unclear.

An older 2005 study looked at 378 people undergoing endoscopy for dyspepsia (indigestion). Another 310 individuals without dyspepsia symptoms were evaluated as controls. Researchers found that:

  • No difference in migraine prevalence was reported between the two groups.
  • No difference in migraine prevalence was seen in people with abnormal endoscopic findings, like ulcers, when compared to the control group.
  • A higher prevalence of migraine was found in individuals with dyspepsia due to motility problems, and symptoms like nausea and vomiting, when compared to the control group.

This result implies that for some individuals with migraine, GI symptoms could potentially be brought on by a migraine attack as opposed to a condition such as ulcers.

However, it’s also possible that people who experience frequent GI symptoms or distress may be more prone to headaches. Overall, additional investigation is needed to understand exactly how the two are connected.

What are the mechanisms linking headache to GI symptoms?

Researchers have several different ideas about how headache and GI symptoms may be linked. Let’s examine a few of them:

  • Hypersensitivity. Some people may be more sensitive to nerve signaling from the GI tract. Because of this, things like abdominal distention or acid reflux may cause the activation of pain pathways in the body, leading to headache.
  • Autonomic dysfunction. Your autonomic nervous system controls a variety of processes, including digestion. Dysfunction of the autonomic nervous system can cause GI symptoms and is also associated with some headache types.
  • Serotonin. Serotonin is important for nerve cell signaling and can be found in both the GI tract and the central nervous system. It may be possible that serotonin levels play a role in the headache-GI connection.
  • Food allergies. Food allergies can cause inflammation in the GI tract, leading to symptoms like abdominal pain, nausea, and diarrhea. It’s also possible that this inflammation may play a role in some types of headache.
  • Medications. People that have frequent headaches often take medications like nonsteroidal anti-inflammatory drugs (NSAIDs) to ease pain. NSAIDs can have side effects like indigestion, diarrhea, and ulcers.

The GI symptoms that are typically reported to occur along with a headache can include things like:

Several smaller studies have indicated that treating a GI disorder that occurs alongside headache may improve headache symptoms or reduce headache frequency. Some examples include:

  • A 2002 case study of two individuals looked at migraine associated with GERD. Increasing the dose of proton pump inhibitor medication lowered the frequency of headaches in both people.
  • A 2003 study found that out of 90 people with migraine, four had celiac disease, a significantly higher prevalence than the control group. Six months of gluten-free diet improved migraine frequency, length, and severity in these individuals.
  • A study from 2015 involved 24 children and adolescents with both constipation and headache. Receiving a treatment for constipation improved headache in all 24 individuals.

While these observations are very promising, additional research is needed in how to treat headache that happens with GI symptoms, especially when it comes to migraine.

Treatments that may also help to relieve headache and associated symptoms include the following.

Home remedies and lifestyle changes

There are various things you can do at home to help ease or prevent headaches. Examples include:

  • moving into a quiet, dark place to rest when a headache comes on
  • placing a cold compress or ice pack across your forehead
  • being sure to drink enough fluids, particularly if your headache happens with vomiting
  • avoiding things that may trigger your headaches
  • implementing healthy habits, such as exercising regularly, getting enough sleep, and eating regular meals

Over-the-counter (OTC) medications

Various OTC medications can help to alleviate headache pain. Examples include:

Prescription medications

Sometimes your doctor may prescribe medications that help prevent or ease headache symptoms, particularly if you have migraine or cluster headaches.

Complementary therapies

In some cases, complementary therapies (formerly known as alternative) may be beneficial for certain types of headache, such as migraine. Examples of these include:

Various types of headache, including migraine, have been associated with GI symptoms. These symptoms can include, but aren’t limited to, things like acid reflux, nausea, and abdominal pain.

Further research is needed to determine the exact nature of this link and the biological mechanisms involved.

Some research has found that treating GI symptoms may also improve headache. However, more research is needed into this topic.

Currently, medications, home remedies, and lifestyle changes are often used to treat headaches and their associated symptoms.