Mast Cells, Histamine, and IBS

Updated: Mar 18

Feeling bloated and gassy? Are you dealing with constipation, or perhaps, the opposite? You are not alone. Up to 20 percent of people have irritable bowel syndrome (IBS) (1).

Many doctors feel that IBS is a mysterious condition without a real solution. They may offer dietary strategies or medication that may or may not offer relief. Your mast cells and histamine may be the missing link to your IBS. This is not surprising, since IBS and IBS-like symptoms are a common complaint with histamine intolerance.


What Is IBS?


Before we get into the connection between mast cells, histamine, and IBS, I want you to understand what IBS is. IBS is a common chronic digestive condition that affects your large intestines. Though they may share some similar symptoms, IBS is a different condition from inflammatory bowel diseases (IBDs). It’s also not linked to any other bowel condition. IBS generally refers to a group of digestive symptoms without another bowel condition being present.


You may be experiencing IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), or IBS with mixed bowel habits (IBS-M) with both diarrhea and constipation. Other symptoms beyond constipation and/or diarrhea you may be dealing with are abdominal pain, bloating, gas, cramping, nausea. Your symptoms, their duration, and their severity may vary.


Histamine Intolerance and IBS


In my practice, I’ve seen hundreds of patients with histamine intolerance complaining about IBS. Likewise, IBS patients often experience symptoms after eating high-histamine or histamine-releasing foods. It’s not just a coincidence. There is growing research suggesting that there is, in fact, a connection between your mast cells, histamine, and IBS.


Gluten, IBS, and Histamine


If you have IBS, you might’ve noticed that certain foods are more triggering than others (2). You may find gluten or wheat to be a problem. The symptoms of histamine intolerance and symptoms of non-celiac gluten sensitivity can be surprisingly similar (3). Considering that many high-gluten foods are highly processed and high in histamine, it may be difficult to tell what causes the problem: gluten or histamine intolerance.


However, gluten may increase the release of zonulin, a protein that regulates the permeability of tight junctions in your gut lining. Increased zonulin may lead to leaky gut syndrome, which can increase your risk of both histamine intolerance and IBS-like digestive symptoms (4, 5, 6, 7).


Higher Levels of Mast Cells


Your mast cells are white blood cells found in tissues throughout your body. They contain granules with histamine inside them. When your body experiences an allergic reaction, infection, or disease, among other triggers, your mast cells are activated and release these granules triggering inflammation.


Individuals with IBS tend to have more mast cells in their gut than those without IBS. Not surprisingly, they also show higher histamine levels than those who do not have IBS (8). More masts cells and increased histamine production may be the culprit behind your IBS-related gut irritations.


Stress, Mast Cells, and IBS


You may find that stress can trigger your IBS symptoms. Both acute and chronic stress can increase mast cell production and/or activation, and lead to histamine release in your gut (9, 10, 11). Chronic stress can also disrupt your gut microbiome health, worsen gut infections, and increase inflammation (13). This can lead to a vicious cycle of histamine intolerance, gut inflammation, and IBS symptoms.


DAO Enzyme and IBS


The diamine oxidase (DAO) enzyme plays an enormous part in histamine metabolism by breaking down excess histamine in your body. It helps to balance your histamine levels and reduce symptoms of histamine intolerance.


Chronic gut inflammation and gut infections can cause decreased DAO enzyme levels and activity. Not having enough DAO enzymes can result in histamine buildup and histamine intolerance symptoms, including digestive issues. Research studies have linked low DAO enzyme levels and histamine intolerance to various digestive problems, including leaky gut syndrome, ulcerative colitis, Crohn’s disease, and IBS (14, 15, 16, 17). One study has found that the therapeutic use of vegetal DAO enzyme may help to reduce histamine-induced muscle contractions in your gut and as a result, alleviate IBS symptoms (18).


Histamine Intolerance and Visceral Hypersensitivity


Visceral hypersensitivity refers to a gut pain or gut sensitivity that IBS patients are very familiar with. Your gut pain doesn’t happen without a reason. Research suggests that histamine receptors in your gut make you more sensitive to histamine causing your IBS symptoms. Not only that, but mast cell activation can also increase visceral hypersensitivity. Researchers have also found that anti-histamine medications may be effective in treating IBS and visceral hypersensitivity (19, 20).


Low-FODMAP, IBS, and Histamine


The low-FODMAP diet is one of the most common dietary recommendations for IBS. Interestingly, the low-FODMAP diet may not only help to reduce your digestive symptoms, but also decrease histamine levels in your urine (21). This reduction in histamine may explain why patients with IBS feel better following a low-FODMAP diet.


Histamine-Producing Bacteria, SIBO, and IBS


Small intestinal bacterial overgrowth (SIBO) is a common root cause of IBS. It is also the culprit of histamine intolerance due to a build-up of histamine-producing bacteria in your small intestine (21). Certain bacteria, including L. casei and L. bulgaricus, have been associated with increased histamine production (23, 24, 25). This means that taking probiotic supplements with lactic acid-based bacterial strains can actually increase your histamine intolerance, SIBO, and IBS symptoms. Choosing soil-based probiotics is a safer idea.



Solutions for Histamine Intolerance and IBS


Addressing histamine intolerance and/or mast cell activation is essential for improving your gut health and IBS symptoms. I recommend avoiding high-histamine foods and following a low-histamine diet. You may find that following a low-FODMAP diet can be incredibly helpful as well for histamine intolerance, IBS, and underlying bacterial overgrowth (SIBO included). Focus on whole, fresh, nutrient-dense foods that nourish, nurture, and energize your body.


Think about reducing your histamine bucket by lowering your stress levels, getting 7 to 9 hours of restorative sleep at night, and choosing organic, natural products over chemical-filled conventional ones. In addition to these dietary and lifestyle strategies, you may find supplementation with natural antihistamines and mast cell stabilizers, such as quercetin, vitamin C, and DAO enzyme helpful.


Next Steps

1. Working with a healthcare practitioner knowledgeable in MCAS and histamine intolerance is the best way to get to the root cause of your symptoms and to create an individualized treatment plan. I welcome you to start a personalized functional medicine consultation with me. You may book your consultation here.


2. Check out my Histamine Intolerance Course here. Learn on your own time, from anywhere. Get an inside look at the most helpful functional medicine tests for pinpointing imbalances, ways to identify and manage the most common (and sometimes surprising) mast cell triggers, and learn what to eat, what to avoid, and why.