SIBO & Histamine Intolerance: What’s the Connection?

On a recent episode of the Gut Check Project, Dr. Ken Brown and Eric Rieger hosted naturopath Joanne Kennedy. Joanne is a specialist in MTHFR gene methylation and histamine intolerance.

This episode was especially interesting because of how histamine intolerance is often overlooked when helping people figure out the cause of their malaise. 

SIBO is a condition that when treated by conventional treatments, can remain an issue because histamine intolerance is causing the symptoms and not SIBO itself. 

In this article, we will bring to light some of the helpful facts that Joanne explained and integrate that information into gut health conditions.

But first, it’s helpful to understand what histamine is and how it affects your body. 

What is histamine and how does it affect your body?

You’re probably more familiar with antihistamines like allergy medicines. Histamine is a compound in your body that is released by cells when they’re responding to injury or an allergy. 

The activation of histamine causes contractions of your smooth muscles and dilation of the capillaries. 

Some of the common noticeable symptoms of heightened histamine action are runny nose, watery or itchy eyes, or sneezing. These symptoms are more easily recognized as histamine related because of seasonal allergens, but that isn’t the only time that histamine is released.

Histamine helps to send messages to your brain. And it triggers the release of stomach acid to help with digesting foods. 

Histamine is also used in the breakdown of serotonin. The inability to break down serotonin can cause an overabundance which can lead to depression. Or it can lead to insomnia because the serotonin molecules aren’t being broken down into melatonin as they should. 

Histamine intolerance: too much histamine

You can get too much histamine in your body for multiple reasons — which will be discussed later in this article. 

If your body has an overabundance of histamine, it can present with symptoms like:

• Headaches or migraines
• Sinus issues
• Fatigue
• Hives
• Digestive issues
• Irregular menstrual cycles

These symptoms aren’t your only problems, though. If you let histamine intolerance go untreated it can lead to problems like:

• Neurodegeneration and associated diseases like Alzheimer’s and dementia
• Gut health issues 
• Fatigue
• Autoimmune conditions
• Irregular menstrual cycle
• Heightened anxiety 
• High blood pressure

The name histamine intolerance can be confusing because your body isn’t intolerant of the histamine itself like when we use the term lactose intolerance. Rather, it explains that your body has a high level of histamine circulating throughout it. 

Histapenia: too little histamine

People experiencing too little histamine in their body — generally from overmethylation — will experience the following issues:

• Depression
• Anxiousness
• Inability to concentrate
• Increased levels of copper in the blood which can lead to psychosis
• Increased mental and psychological disorders
• Food sensitivities

What affects histamine levels?

There are multiple things that can affect your histamine levels. Some can be external and some internal. 

Some of the common things that can be checked that have an effect on histamine levels include:

• Homocysteine
  • Low will lead to histamine intolerance
  • High will lead to histapenia
• Seasonal allergens like pollen and mold
• DAO enzyme deficiency
• SIBO
• Overmethylation will lead to histapenia and undermethylation will lead to histamine intolerance

To understand most of these issues, it will be helpful to understand methylation as they all play a part in that cycle.

The Importance of Methylation

Methylation is important for your enzymes to be able to break down what they’re meant to. In the case of histamine, we need Histamine-N-Methyl-Transferase (HNMT) enzyme to degrade histamine. 

It also helps to regulate the enzymes that break down oestrogen in the liver. This helps to avoid mast cell stimulation and therefore the release of histamine. All this helps avoid histamine intolerance and all of its negative effects on our bodies. 

Some other things during the methylation process can affect your histamine levels. Homocysteine is an amino acid that in healthy quantities is used to create SAM which is the body’s major methyl donor (supporting the methylation process by donating methyls to the cells that need them). And it also creates glutathione, the body’s major antioxidant.  

What you’ll notice when looking at improper homocysteine levels is that you’ll get similar symptoms and problems as improper histamine levels. This is likely because of the out-of-whack methylation pathway. 

This pathway also affects your DAO enzyme levels which play a large role in the gastrointestinal symptoms people experience with histamine irregularities. (More on the DAO enzyme in a bit)

SIBO & Histamine Intolerance

Our gut needs bile acids to break down foods and kill off bacteria we may have been exposed to. Methylation has a large hand in the production of our bile acids because it produces phosphatidycholine. 

Insufficient bile acid can lead to SIBO so methylation is essential to avoid that.

If you already have SIBO, it can be exacerbated by methylation. The inflammation caused by the bacteria can cause damage to the soft tissues of the small bowel. This causes a histamine release in the small bowel and an overproduction of diamine oxidase (DAO) enzyme to try to break down the histamine. Unfortunately, your body cannot produce enough DAO enzymes to break it all down. 

Too low DAO enzyme levels lead to an excessive amount of histamine stagnating in your body leading to higher levels of inflammation to try and remove the buildup of histamine. This can cause increasing amounts of gastrointestinal and systemic disturbance.

The bacteria associated with SIBO can sometimes stop DAO enzyme synthesis which also prevents the body from creating enough DAO enzyme to remove the histamine buildup.

This phenomenon is sometimes mistaken for Mast Cell Activation Syndrome (MCAS) because of how it presents in the gut. But actually, it is the result of excessive histamine buildup. 

The problem in this instance isn’t the muscles — which is why mast cell stabilizers don’t work to treat the symptoms. So if you’ve been experiencing these symptoms and mast cell stabilizers aren’t working, you may be having an issue with SIBO and histamine overload.  

What to do about imbalanced histamine levels

If you suspect you may have a histamine problem, you can ask your doctor about checking any of these levels. Some of the treatments you may experience include improving homocysteine levels since that is often the beginning of the cycle. 

Your doctor will be able to best help you with your specific case. They’ll need to figure out whether you’re overmethylating or undermethylating and what your homocysteine levels are. 

Some common things that might be prescribed include:

• Methyl B12
• Hydroxycobalimin 
• Methylfolate
• Vitamin B6
• DAO enzymes
• Diet changes to include foods with these things in them or to remove foods that are high in histamine until levels are normalized

Ultimately working with your doctor to understand your specific condition more in-depth will help you the most. Working on reducing SIBO can help too so that the bacteria aren’t causing more histamine release. Atrantil can help with getting IBS/SIBO symptoms under control since it was created to target the bacteria that are causing the issue.

If you want to get your gut health under control while exploring options with your doctor, ask them about using Atrantil to improve your gastrointestinal issues and hopefully your recovery time. Grab a bottle here.