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What Causes IBS? How Bacterial Histamine in the Gut May Be the Key to Relief

Irritable Bowel Syndrome (IBS) affects millions worldwide, presenting a complex array of symptoms like chronic abdominal pain, motility issues, and discomfort that can significantly impact daily life. Despite its prevalence, effective, long-term solutions have remained elusive, leaving many patients searching for better answers. However, new research is shedding light on an unexpected player in IBS management: bacterial histamine produced by the gut microbiome.

Amy Chalker, a dietitian specializing in the intersection of eating disorders and complex chronic gastrointestinal (GI) issues, recently highlighted this exciting development. With years of experience in private practice, Amy is well-versed in evidence-based approaches to GI care and is passionate about helping patients navigate the complexities of their conditions. In this post, we'll explore the groundbreaking findings she discussed and their potential to revolutionize IBS treatment.

Understanding IBS and its Challenges

IBS is one of the most common functional gastrointestinal disorders, affecting roughly 10-15% of the global population. It is characterized by symptoms such as abdominal pain, bloating, diarrhea and/or constipation, and other changes in bowel habits. IBS significantly impacts quality of life, often interfering with daily activities, work, and emotional well-being.

One of the greatest challenges with IBS is its complexity and variability. The exact cause remains unclear, but it is widely understood to involve a miscommunication between the gut and the brain, known as a disorder of gut-brain interaction (DGBI). Additionally, IBS symptoms are influenced by factors such as diet, stress, gut microbiome imbalances, and even genetic predispositions.

As Amy explains, "Rarely is IBS straightforward. Some people might have a bacterial or fungal infection that, once treated, resolves many of their symptoms. But more often, IBS is tied to a complex web of unknowns—factors like co-occurring chronic GI illnesses or visceral hypersensitivity that we're still learning to fully understand."

Current treatment options, including dietary changes, medications, stress management, and lifestyle adjustments, can help manage symptoms but often fall short of providing long-term relief. For many, the journey to find effective solutions involves trial and error, leading to frustration and uncertainty. "One of the biggest challenges in my work," Amy notes, "is sitting with clients in the unknown—acknowledging that we might not have all the answers yet, but working together to find strategies that help them move forward."

This is why research into new therapeutic targets, such as bacterial histamine, is so exciting—it offers hope for more precise and effective treatments tailored to the unique needs of IBS patients.

What is Histamine?

Histamine is a naturally occurring compound in the body that plays a critical role in immune responses, digestion, and communication between the brain and gut. Most people associate histamine with allergies, as it's released by the immune system to fight off allergens, causing common symptoms like sneezing or itching. However, histamine also has important functions in the gastrointestinal (GI) system, influencing motility (the movement of food through the gut) and sensitivity to pain.

What's particularly fascinating is the discovery that histamine isn't just introduced to the body through external sources like food or allergens—it's also produced internally by the bacteria living in our gut.

How is Histamine Related to IBS?

In IBS patients, histamine may play a key role in several symptoms. As a recent literature review suggests, it can impact gut motility, either speeding it up (causing diarrhea) or slowing it down (leading to constipation). Additionally, histamine may contribute to visceral hypersensitivity, a condition where the gut becomes overly sensitive to objectively normal stimuli. Amy describes this as "a situation where your stomach expanding after a meal might cause extreme pain, instead of just feeling like the light pressure that people without visceral hypersensitivity experience."

This emerging research highlights just how interconnected the gut, microbiome, and immune system really are—and why histamine is gaining attention as a therapeutic target.

What This Could Mean for IBS Patients

The discovery of bacterial histamine as a potential therapeutic target offers new hope for IBS patients who have struggled with limited treatment options. By focusing on the role histamine plays in gut motility, visceral hypersensitivity, and immune system regulation, researchers are uncovering ways to address the root causes of IBS symptoms, rather than just managing them.

For patients, this could mean more individualized and effective treatments. "If we can better understand how bacterial histamine contributes to IBS," Amy explains, "we might be able to develop targeted interventions—whether that's through specific dietary changes, supplements, or even medications—that directly reduce pain and discomfort."

While these findings are still in the early stages, they represent a significant step forward in IBS research. For patients, it's a reminder that science is constantly evolving, and new solutions may be closer than ever. This breakthrough underscores the importance of staying informed and working with practitioners who are up-to-date on the latest research to create personalized, evidence-based care plans.

How can I stay up to date on IBS research?

As science continues to uncover the complexities of IBS and its connection to the gut microbiome, keeping up-to-date on emerging research can empower patients to make informed decisions about their care.

Amy recommends several resources for those looking to stay current:

  • Monash University: "Monash University in Australia is a leader in IBS research," she shares. "They're at the forefront of studies on topics like gut hypnotherapy and dietary interventions, and their website and newsletter are excellent tools for staying updated."
  • Google Scholar alerts: Amy recommends setting up keyword alerts on platforms like Google Scholar. By searching terms such as "IBS new research," "visceral hypersensitivity," or "bacterial histamine," you can get notified about the latest studies relevant to your condition.
  • Heather Van Vorous' newsletter: "This mailing list is a great way to learn about new studies and evidence-based solutions," Amy notes.

By leveraging these resources, patients can stay informed about advancements in IBS research and work collaboratively with their healthcare providers to explore new, science-backed approaches to care.


Amy Isabella Chalker, RDN, CEDS has been a Registered Dietitian Nutritionist for 19 years. Her current specialities are in Clinical Eating Disorders, Disordered Eating behaviors, Child/Family Feeding, and co-occurring gastrointestinal conditions/complex chronic illnesses.

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