Could Histamine Be The Reason for Your Lingering Symptoms?

 I wanted to write this blog post because we see many clients at the clinic suffering needlessly from histamine intolerance. Experiencing unexplained and frustrating symptoms? Could Histamine be the reason for your lingering symptoms?

Let’s have a look…

What is histamine?

Histamine is a chemical involved in your immune system, proper digestion, and your central nervous system. As a neurotransmitter, it communicates important messages from your body to your brain. It is also a component of stomach acid, which helps you break down food in your stomach.

If you’ve suffered from seasonal allergies or food allergies, you may have noticed that antihistamine medications provide relief to your symptoms. Why? Because histamine’s role in the body is to cause an immediate inflammatory response. It serves as a red flag in your immune system, notifying your body of any potential attackers.

Histamine causes your blood vessels to swell, or dilate so that your white blood cells can quickly find and attack the infection or problem. It is the histamine “buildup” that gives you a headache and leaves you feeling flushed, itchy, and miserable. It’s important to understand that it’s part of the body’s natural immune response, but when you can’t break down histamine properly, you can develop what we call histamine intolerance (HIT).

Because histamine travels throughout your entire body in your bloodstream, histamine can impact your gut, lungs, brain, entire cardiovascular system, and skin, contributing to a wide range of symptoms and making it difficult to identify.

What is Histamine Intolerance?

Histamine Intolerance is an intolerance of histamine ingested with food. It is caused by a deficiency of the histamine-degrading enzyme diamine oxidase (DAO), which is produced in your small intestine or an imbalance between histamine and DAO. It can be caused by genetic factors or is an acquired condition, often identified as a secondary condition to another.

Causes of High Histamine Levels

It is important to get a diagnosis, the exclusion of possible other causes such as genuine food allergy (IgE reactions), cross-reactions, non-allergic reactions such as fructose malabsorption, lactose intolerance sorbitol malabsorption, or Celiac Disease, and the exclusion of any other illnesses (such as cancer or a rare disease such as mastocytosis) from your GP or one of our Doctors at the clinic.

Other causes of high Histamine levels are:

Bacterial overgrowth (SIBO)
Dysbiosis- (i.e. histamine producing bacteria)
Leaky gut
GI bleeding
Fermented alcohol like wine, champagne, and b
Diamine Oxidase (DAO) deficiency
Histamine-rich foods

Do you see the link with your gut health? We find histamine intolerance in some individuals suffering from intestinal permeability, SIBO, and dysbiosis.


Some scientific researchers recommend taking supplements of Vitamin B6 and a higher dosage of Vitamin C as these are often deficient in individuals with HIT.

DAO food supplements

These contain the enzyme diamine oxidase but they do not in any way replace a low-histamine diet where you need to establish your threshold.

Some pharmaceuticals enhance symptoms

There are substances used in different pharmaceuticals that have a negative effect on the DAO. For someone with HIT, that means that symptoms get worse, not better. Do not change medication before you have talked to your doctor, otherwise, you may harm your health.

Only once you find out what is causing the symptoms in the first place can you start on the road to recovery.


Digestive tract
Diarrhea alternating with normal motions (irritable Bowel Syndrome – IBS)
Chronic constipation
Flatulence and feeling of fullness
Stomach cramps
Stomach ache
GERD/Acid Reflux
Symptoms affecting the head and face
Headaches, similar to migraine
Runny nose and weepy eyes, especially after eating although there is no clinical sign of allergies
Fits of dizziness/vertigo
Extreme tiredness, feeling knocked out
Edema (swellings mostly appearing around eyes and lips, sometimes in the area of the throat)
Flushing of face and/or chest
Skin problems
Skin rashes, itchiness
Acne (pimples)
Chest area
Cardiac arrhythmias, such as a fast beating or irregular heartbeat
Dysmenorrhoea (severe period pains)
HIT symptoms go away during pregnancy and return after the birth of a child

Other symptoms

Chills and shivers
Low blood pressure
Circulatory collapse
Sudden psychological changes (e.g. aggressiveness, inattentiveness, lack of concentration)
Sleep disorder

Here are some general guidelines:

Avoid or reduce eating canned foods and ready meals

Avoid or reduce eating ripened and fermented foods (older cheeses, alcoholic drinks, products containing yeast, stale fish)

Histamine levels in foods vary, depending on how ripe, matured or hygienic the foods are  

As much as it is possible, only buy and eat fresh products

Don’t allow foods to sit outside the refrigerator – especially meat products  

Don’t eat leftovers older than 2 days old

Everyone has their own threshold; you will need to find yours

Cook at home. It will reduce your exposure and help you feel better faster

Make sure the probiotics you are taking are not Histamine Producers!  

Eat Low Histamine Level foods

Avoid High Histamine Level Foods and Histamine Liberators.  

Yeast – even though it does not contain histamine as such, yeast serves as a catalyst for histamine generation during manufacture. There is no yeast in the end product.

It is important to eat foods that are low in histamine levels in accordance with your threshold. In that objective, a food and symptoms diary is essential. Please always remember that there is no such thing as a “histamine-free diet”! Based on each individual threshold will result in stricter dietary changes for some and less for others.
What can you do if you have Histamine Intolerance?

Remove the high histamine foods for 1-3 months. You can add in a supplement of DAO by taking two pills at each meal if needed.

You may not have to avoid these foods forever. It can be a short-term solution until your histamine or DAO levels return to their optimal ranges. Most importantly, find the root cause of histamine intolerance. Depending on your uniqueness, you may find that you tolerate some foods better than others, so don’t despair as you learn important information about your body and take charge of your health!

For more information, please call me at (416) 792-1100 or email me at the clinic

Yours in health,
Caroline Sabbah
Clinical Functional Nutritionist


Dr. Janice Joneja, “The Beginner’s Guide to Histamine Intolerance ”.


American Journal Clinical Nutrition, 2007; 85:1185–96.

Caroline Sabbah
Clinical Functional Nutritionist

Following a career in law and a move to Toronto, Caroline decided to pursue her true passions, holistic health and helping others. Caroline’s passion for holistic health grew through the years while searching for solutions for her personal health problems. Her personal successful journey towards health and vitality is a testament to the impactful contribution of nutrition. She practices clinical nutrition at VitalityMD.

Using a functional medicine approach, Caroline focuses on uncovering the root causes, the “why”, of your health issues by carefully listening to her client’s concerns, looking at the body as a whole, conducting detailed intakes, and delivering achievable and customized health programs to restore and maintain optimal health and vitality. #VitalityMD


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