How Gut Health is Connected to Histamine Intolerance

Histamine intolerance and the gut are interconnected in many ways. The root cause of histamine intolerance can often be traced back to an issue or imbalance in the gut, including SIBO, dysbiosis, leaky gut, or a food sensitivity or intolerance. Similarly, histamine intolerance can contribute to and worsen gut problems, creating a vicious cycle. 

Getting to the bottom of histamine and/or mast cell issues inherently involves investigating gut health, and working towards a healthy gut is one of the most important things you can do to heal. 

Here, we will explore some of the many connections between histamine intolerance and the gut. For more background on histamine intolerance before you dive in, you can start with our primer here, and browse our entire library of histamine intolerance articles here. 

Does Histamine Intolerance Cause Gastrointestinal Symptoms? 

Histamine intolerance can be difficult to pinpoint. This is in part because it can manifest in so many different ways, and everyone presents with a different combination of symptoms. 

Many people who have histamine intolerance experience gastrointestinal symptoms of some kind, including bloating, constipation, diarrhea, stomach pain, or abdominal cramping. In some cases, these symptoms are more severe, and may lead you to a gastrointestinal diagnosis (like IBS) before uncovering histamine intolerance. In other cases, GI symptoms are present but do not interfere with day-to-day life as much as other symptoms. You might not even realize that your mild or moderate gastrointestinal symptoms are related to your histamine intolerance. 

Remember that issues in the gut (just like histamine intolerance) can also be behind symptoms in many other areas of the body.

How Gut Imbalances Influence DAO Levels 

Histamine is broken down in the gut by the enzyme DAO. A common cause of histamine intolerance is insufficient production of this enzyme, meaning that your body is ill equipped to handle your intake of dietary histamine, and you end up accumulating too much of it. 

When trying to get to the root cause of the problem, the next natural question is this: why would your DAO levels be low or insufficient? 

Most causes of and risk factors for low DAO involve gastrointestinal disease or gut imbalances. Imbalances like SIBO and dysbiosis are associated with inflammation in the gut wall, which can damage the cells that produce DAO. IBS, leaky gut, food intolerances and sensitivities including to gluten, Crohn’s disease, and colitis can also play a role in impaired DAO production and histamine intolerance. 

Certain medications including antibiotics and NSAIDs (such as ibuprofen, aspirin, and naproxen), as well as alcohol, and any substance with the potential to cause inflammation in the gut, can also block DAO production. 

Genetics may also play a role in DAO levels. Generally, it’s an interaction between genes and environment. Those with a genetic predisposition towards impaired DAO production may be more susceptible to dysfunction as a result of the same environmental risk factors (i.e. inflammation in the gut). 

The Gut and Mast Cells 

We’ve talked before about the difference between exogenous histamine (histamine that comes from outside the body/dietary sources) and endogenous histamine (produced within the body). 

Low DAO levels are a problem when it comes to breaking down exogenous (or dietary) histamine. When it comes to endogenous histamine, the major culprits are mast cells, whose job it is to release histamine in response to an allergen or threat. 

Histamine intolerance is often related to a mast cell disorder, in which these cells are either too abundant, or are activating and releasing histamine too often.  

Mast cells are major components of the immune system, and the majority of the immune system is housed in the gut. Mast cells cross paths with gut microbes all the time, and are influenced by whatever is going on in the gut, including infections, bacterial overgrowth, dysbiosis, fungus, parasites, and candida. 

Inflammation in the gut has been found to increase mast cell activation (and production of histamine). So, we can see that imbalance and inflammation in the gut spurs on histamine issues on both fronts: increasing levels of histamine released from mast cells in the body, and decreasing levels of DAO which means that we can’t break down enough dietary histamine. 

SIBO, Dysbiosis, and Histamine Intolerance 

We’ve learned that SIBO and dysbiosis create inflammation in the gut, which can both reduce DAO activity and increase mast cell activation. 

While a number of conditions can cause inflammation in the gut (and the rest of the body— inflammation is linked to just about every chronic disease you can think of), SIBO and dysbiosis, characterized by an overgrowth of bacteria, might be especially likely to be found at the root of histamine intolerance. 

Gut bacteria can produce histamine. They can also degrade it, or they might have nothing to do with it. There are some bacterial strains in particular that are more likely to produce histamine, and if we end up with an overgrowth of these strains or an imbalance between the histamine producing strains and those that degrade it, we might start to see more reactivity and histamine intolerance symptoms. 

IBS and Histamine Intolerance 

There are many connections between IBS and histamine intolerance. Often people with histamine intolerance are first diagnosed with IBS, and it may not be discovered for quite some time that histamine and/or mast cells are part of the problem. 

Research is growing in this area. IBS patients can experience worsening of gastrointestinal symptoms when they eat high histamine or histamine-releasing foods. Individuals with IBS have also been found to have higher levels of mast cells in the gut than those who do not have IBS, as well as markers of higher histamine levels. 

We also know that SIBO is often the root cause of IBS, as well as commonly being behind histamine intolerance. 

Healing the Gut for Histamine Intolerance 

Investigating and improving gut health is essential if you have a histamine intolerance and/or a mast cell issue. 

A low histamine diet is often recommended. For many people, a low FODMAP diet (often recommended for SIBO and/or IBS) is also helpful, especially if histamine intolerance is being caused or worsened by bacterial overgrowth. You can read more about the low FODMAP diet for histamine intolerance here. Avoiding high histamine foods is still important in order to reduce overall histamine load. In general, you want to focus on whole, fresh, nutrient-dense foods. Avoiding alcohol as much as possible is also very helpful. 

We want to heal the gut, but remember that some of the foods we typically think of as gut health superstars (like fermented foods) are actually problematic in the case of histamine intolerance. 

There are some supplements that may be helpful, including mast cell stabilizers and natural antihistamines like quercetin and vitamin C, and DAO enzymes. Although there is some debate over probiotics for individuals with histamine intolerance, supplementing with the right strains can be very helpful. Of course, any and all supplements should be discussed with your practitioner first. 

Working with a knowledgeable practitioner is the best way to get to the root cause of your histamine intolerance, and investigate and treat any underlying issues within the gut. 

Summary of Key Points 

• ➢ There are numerous connections between histamine intolerance and the gut 
• ➢ The root cause of histamine intolerance can often be traced back to gut issues including SIBO, dysbiosis, leaky gut, IBS, or a food sensitivity 
• ➢ It is essential to investigate gut health and work towards a healthy gut in order to heal
• ➢ With histamine intolerance, gastrointestinal symptoms may be mild, severe, or not present; gut issues can lead to symptoms throughout the entire body 
• ➢ Dietary histamine is broken down in the gut by DAO; a deficiency in this enzyme is a common cause of histamine intolerance 
• ➢ Inflammation in the gut can damage the cells that produce DAO 
• ➢ Common causes of gut inflammation and low DAO include SIBO and dysbiosis 
• ➢ A genetic predisposition towards impaired DAO production may make an individual more susceptible to dysfunction as a result of the same environmental factors 
• ➢ Mast cells, which release histamine as part of the immune response, are also influenced by gut imbalances and inflammation 
• ➢ An imbalance/inflammation in the gut may lead to both reduced DAO production and increased mast cell activation & histamine release 
• ➢ Gut bacteria can also produce histamine; an overgrowth of histamine-producing strains may occur with SIBO or dysbiosis 
• ➢ Individuals with histamine intolerance may first be diagnosed with IBS 
• ➢ IBS patients can experience worsening of GI symptoms after eating high histamine or histamine releasing foods
• ➢ IBS patients have been found to have higher levels of mast cells in the gut; markers of higher histamine levels 
• ➢ A low FODMAP diet, often recommended for SIBO and IBS, may be helpful for histamine intolerance, as well as avoiding high histamine foods, alcohol, and fermented foods
• ➢ Some supplements, including mast cell stabilizers, natural antihistamines, DAO enzymes, and probiotics may be helpful and should be discussed with a practitioner 

If you have, or suspect you may have, histamine intolerance, or for more personalized guidance on anything mentioned here, request an appointment with Dr. Gannage.

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