NEWS ALERT! THE FASCINATING LINK BETWEEN IBS & HISTAMINES

With discussion around complex chronic illnesses like Mast Cell Activation Syndrome, POTS, Ehler’s Danlos Syndrome, Lyme Disease, Long COVID and others dominating the health landscape lately, including in my own clinical practice, long-recognized conditions like Irritable Bowel Syndrome (IBS) are slowly being pushed lower on the totem pole in conversation and in research.

Fortunately for the more than 11% of the global population who suffer from IBS, a new peer-reviewed literature review by Siraj et al, “Bacterial Histamine as a Therapeutic Target for Abdominal Pain in Irritable Bowel Syndrome” published in April’s edition of The Cureus Journal of Medical Science not only reminds us of the importance of keeping this notoriously nebulous condition on the forefront of our minds, but also makes a key link between the root causes of IBS and some of the aforementioned complex conditions. This is a major throughline as we continue to seek best treatment practices for debilitating gastrointestinal symptoms that span multiple diagnoses and tend to evade long-term relief.

It’s important to note that IBS is a functional GI disorder (FGID) of the brain-gut axis, as defined by Rome IV Criteria, that produces disruptive but not life-threatening symptoms like abdominal pain, intestinal gas, bloating/distention, and altered bowel habits. People who suffer from IBS, notably young women, typically endure a lower quality of life, increased depression, and poor body image.

Histamine, a chemical mediator secreted from immune cells in the body, including mast cells, in response to external stimuli, is responsible for a wide variety of actions across all organ systems, including the gastrointestinal system, where it regulates GI motility, gastric acid secretion, and mucosal ion transport through 4 distinct histamine receptors. The literature review notes that pharmacological inhibition of the H4R Receptor in the gut reduces visceral hypersensitivity (a hallmark of IBS) and decreases mast cell infiltration in the colon. The authors note, “Individuals with IBS have elevated levels of mast cells in the colon, often near enteric [intestinal] nerves, which correlates with the severity of abdominal pain. There is also a higher occurrence of histamine-producing bacteria.” In particular, gut-specific histamine-producing bacteria include Bacteriodes, Blostridium, Bifidobacterium, Fusobacterium, and Lactobacillus.

In a fascinating conclusion, the authors go on to say that, “These findings suggest that gas production and bowel distention are not the primary causes of pain in IBS patients on high fermentable diets [high-FODMAP diets],” but that it is instead the action of gut histamine activity that increases visceral hypersensitivity. In the eating disorder field, studies like this become key when implementing dietary strategies so that clients are not unnecessarily limited from eating foods that may not have a negative impact in the first place, and in fact may deprive them of key nutrients, like fiber, that are actually responsible for gut repair and optimal functioning.

While these correlations and connections provide rich material for developing treatment strategies for IBS and other conditions that span the GI-symptom/histamine continuum, it’s vital to keep in mind that this is emerging science. Anyone who tells you with certainty that simply following “3 easy steps” will rebalance your gut is likely optimistic at best and trying to sell you something at worst. It’s important to allow the science to catch up with practice and work closely with your clinician to determine the best dietary approach for you, with room for experimentation and patience along the way.

References:

Mohamed Siraj H, Usaid M, Shaikh S, et al. (April 12, 2025) Bacterial Histamine as a Therapeutic Target for Abdominal Pain in Irritable Bowel Syndrome: A Literature Review. Cureus 17(4): e82132. doi:10.7759/cureus.82132

Lacy BE, Patel NK. Rome Criteria and a Diagnostic Approach to Irritable Bowel Syndrome. J Clin Med. 2017 Oct 26;6(11):99. doi: 10.3390/jcm6110099. PMID: 29072609; PMCID: PMC5704116.

A BLOG ABOUT WEIGHT LOSS (EEK!)

What is an eating disorder dietitian doing writing a blog about weight loss!? In truth, I work with many clients who wish to lose weight. It is, after all, once of the defining characteristics of multiple eating disorders. And it would be ignoring reality to deny that the desire to lose weight is often on the minds of many, eating disorder clients or not, thanks to the social and psychological constructs of diet culture, patriarchal culture, racial injustice, trauma history, underlying illness, developmental interruption, unconscious defenses, and a host of other factors that drive thin ideals.

One of the reasons I do not use “HAES” or “Health at Every Size” language in my work is that to me, this is a value inherent in every human, akin to saying “respect at any size” or “humanity at any size”. The fact that there has been entire movement devoted to reminding people that everyone matters speaks to layers of complex oppression and narcissistic devaluing of the “other” that cannot easily be untangled. My clients are, first and foremost, human. And it is my job to know them, and if they want to discuss their weight loss wishes and goals and fantasies, is not my job to stop or deter them, but rather to understand them and approach their wishes with curiosity and inquiry.

I can’t make bodies lose weight. In fact, I can’t make bodies do anything! It reminds me of when I work with parents of younger children who come to me and say, “I can’t get my child to eat (vegetables/anything beyond pasta/fill in the blank) and often my first thought is, “of course you can’t!”. The only way we can “get” people to do something is usually through some kind of manipulation or cult-like adherence, neither of which are ethical or part of my value-system as a clinician and as a human.

What I can and do provide assistance with is developing and recommending emotional and behavioral interventions that provide sufficient energy and nutrients, alongside complex illness treatment recommendations, environmental stability and relational strength, so that the body can settle to a weight range where it is naturally (i.e. genetically, environmentally, psychologically) inclined. Whether or not clients accept and apply these recommendations is a complex journey, rarely linear, that may involve repeated return to restrictive food behaviors and more active weight loss pursuits. By helping clients to work through resistances to treatment and real health, I can in turn help clients know themselves and understand what drives potentially destructive behaviors and what motivates the pursuit of more meaningful, growth-oriented ones.

In discussing weight loss, it bears discussing what is meant by “health”, as many clients and clinicians alike often tout weight loss in the name of health. In my work, it is important to understand each individual’s definition of the word, and not simply apply my own understanding. For example, I am consistently reminded that the same clinicians who recommended 1200-calorie diets to their patients to lose weight in the name of “health” then deem the same clients "lazy" because they have (obviously) been unable to maintain such unsustainable intakes, don't have the literal energy to exercise, have poorer psychological functioning, and ultimately gain more weight than where they began. This constant "yo-yo" dieting has left many patients in larger bodies than when they began their journey, and no amount of dieting and exercise is going to correct years of poor guidance by clinicians and laypersons alike, from a weight perspective.

What could help is focusing on factors besides weight like sufficient nutrient, fiber, and energy intake, cardiovascular stamina, weight-bearing exercise, and treatment and management of underlying illness that will vastly improve an individual's metabolic health markers, but not automatically move the needle on the actual scale in a meaningful way, at least by societal standards. Avoiding absolutisms about weight loss AND easing the myopic scrutinizing of numbers on the scale may very well be the most healthful approach - both are disrespectful to our clients at best and downright condescending at worst.

MEASURING WELLNESS: A MOVING TARGET

In our modern healthcare framework, measurable biomarkers of health are standards of care uniformly applied to patients, based on scientific precedent, and generally embraced by clinicians for clarity of diagnosis and direction of treatment. Relying on standards of treatment to match measurable tests - whether weight/BMI, blood tests, ultrasounds, or bone density scans - are widely considered a foundation of effective, efficient healthcare in America.

But what happens when this foundation reveals tiny fissures that lend uncertainly to the stability of the well-hewn structure? For example, when blood test results don’t show anything outside of normal range, despite patients reporting real and sometimes debilitating symptoms; or when a BMI chart places a patient in the “overweight” category, despite recovery from an eating disorder and other positive clinical markers of health. Who are we to rely on for clarity of direction then? The piece of paper showing a concrete data point or the individual sitting in front of us expressing their pain, or their satisfaction? And how can a clinician take both seemingly incongruous pieces of information into account, in an effort to help the patient improve their wellbeing and ultimately, ‘to do no harm’?

These intersections often appear in my work with chronic illness and eating disorders, especially with “invisible” conditions where an individual may appear conventionally healthy with no visible or laboratory signs of ill-health, but still express ongoing physical and mental anguish that prevents them from living a full, meaningful life. I am reminded of Leslie Jameson’s essay, “The Devil’s Bait” on the ambiguous Morgellons disease, and what it was like for her to attend a conference on the condition, not as an investigator for its scientific validation, but as an examiner of patients’ real-life experiences with the condition.

And perhaps that is the key to reconciling these two distinct paradigms: Seeking to understand patients’ experiences as paramount always to the facts on a page. In the end, it is individuals’ unique inner experiences that drive their behaviors, their fears, and their decision-making processes for treatment.

In recent months, the BMI chart has been in the news for its unreliable nature as a predictor of disease states, for all it doesn’t take into account: An individual’s muscular composition, genetic frame, fat distribution, race/ethnicity, history of disordered eating, childhood growth curve, and myriad other factors. In fact, the BMI chart with its arbitrary categories for overweight and obesity was originally developed in Europe in the 1800s by a male for males, for the purpose of establishing characteristics of “the normal man”. Over time, the chart was adopted into Western medicine to use as a “convenient” marker of disease risk, mistaking the quantifiable categories as telling the whole story about a person without any actual information about patients’ lives to support the conclusions.

And it’s not only clinicians who are susceptible to over-adhering to numbers on a scale or lab values within normal limits as solace that all is well. Patients too are often liable to feel physically and mentally sound, with well-established feeding and eating competency tools under their belt until they see a number on a scale that feels dissonant to their lived experience. Or they may be clear on their concerning symptomatology until labs show all-normal results and then begin to wonder if their condition is all in their heads. Numbers and data points often seem to wield disproportionate power to an individual’s authentic experience; it requires far less effort to trust an “authority” than to believe in what are bodies are uniquely telling us and move through a decision-making process accordingly.

This is not to say that scientific test results and measurements should be ignored; far from it. Sometimes it’s more a matter of finding the right tests, especially by asking the right questions, and listening closely to the patient, that leads to more ease and progress in the clinical encounter, and to a much more meaningful therapeutic relationship, one of the primary predictors of the successful treatment.