Histamine Intolerance

Posted by Karen Carswell on

Histamine Intolerance


What is Histamine and Histamine Intolerance?

Best known for its role in allergic response, histamine is biogenic amine that is involved in a variety of normal processes in the body such as immunity, inflammation, gastric acid secretion and neuromodulation. Histamine acts to protect the body from allergens and microorganisms such as bacteria and viruses.

In the response to a “foreign invader” the immune system signals the release of histamine which initiates an inflammatory response in an attempt to fight the invader off. Blood vessels dilate enabling your white blood cells to move quickly to attack the infection or problem. Histamine is produced and stored in mast cells within body tissues or basophils which circulate in the blood.  

Histamine balance in the body is key to maintaining allergic responses and gastrointestinal symptoms. When histamine accumulates in the body, an array of symptoms can occur.  Histamine intolerance is becoming more and more common and personally I see a lot of it in my clinic. It is difficult to diagnose and poorly understood. Histamine Intolerance is not caused by a reaction to the actual foods high in histamine; it is the body’s reaction to the histamine in or released from the food. It is cumulative, unlike food sensitivities or allergies.

The best way to describe histamine accumulation in the body is with the “histamine bucket” scenario. Imagine your body is a bucket. The more histamine that goes into that bucket the fuller it gets until eventually it overflows. It is then that symptoms will occur. When, for example, you avoid histamine foods and empty the bucket a little, then the bucket has room for more histamine until it overflows again and symptoms return. When the level of histamine in the body exceeds what the body can clear, symptoms will occur.

Symptoms of Histamine Intolerance

This may seem like a huge list but as I mentioned earlier, histamine intolerance can cause quite an array of symptoms:

  • pruritus (itching of skin, nose, ears and eyes)
  • hives
  • skin conditions (psoriasis, eczema)
  • tissue swelling (facial, oral, throat)
  • feeling of “throat tightening”
  • flushing
  • profuse sweating
  • difficulty regulating body temperature
  • headache
  • migraine
  • fatigue
  • nausea / vomiting
  • food allergies
  • abdominal pains
  • diarrhea or constipation
  • indigestion, heartburn or reflux symptoms
  • seasonal allergies
  • runny nose or congestion
  • blood noses
  • rapid heart rate
  • hypotension
  • dizziness or vertigo
  • menstrual pain
  • irritability
  • anxiety
  • panic attacks
  • insomnia
  • large swollen mosquito bites
  • motion sickness
  • asthma
  • chest tightness
  • and probably more!!!!

 Histamine Foods 

There are a variety of foods that naturally contain histamine, cause the release of histamine by mast cells or block the enzyme diamine oxidase (DAO) which breaks down histamine. It is sometimes difficult to decide which food is causing your symptoms as they don’t usually occur immediately after eating a particular food, it can be a delayed reaction.

After researching many histamine food lists on the internet, I have found the following list written by Alison Vickery to be the most precise and easiest to understand. Her list is compiled using scientific test results from a paid scientific database and her own clinical experience.  She provides this editable pdf list free on her website:  https://alisonvickery.com.au/ and has given me permission to share this with you. Please read this thoroughly as it provides key information to assist with the avoidance of foods high in histamine.  Remember that people’s tolerance to different foods varies greatly and so use the list as a guide only.  Being in pdf form you can then easily customize the diet to suit yourself. 

What Causes Histamine Intolerance?
  • Ingestion of histamine-rich foods or histamine liberating foods
  • Bacterial overgrowth - SIBO (many bacteria produce histamine)
  • Gut microbiome imbalances
  • Leaky gut (permeability of the tight junctions of the small intestine)
  • Alcohol
  • GI bleeding, IBD
  • Allergies (IgE reactions)
  • Nutrient deficiencies (esp. B1, B2, B6, B12, folate, zinc, copper, vitamin C, omega3 and more)
  • Protein excess
  • DAO (Diamine Oxidase enzyme deficiency)
  • Genetic susceptibility
  • Undermethylation
  • Hormone excess (estrogen)
  • Hormone insufficiency (adrenal)
  • Medications
  • Stress
  • Environmental exposure to pollens, dust, mould etc.

As you can see there are many causative factors which contribute to Histamine Intolerance. Finding and addressing the possible causes of your histamine intolerance is the key to reducing symptoms. Following a low histamine diet is a good place to start (see above) and ensure you find a practitioner experienced with histamine intolerance, gut health, methylation and nutrigenomics to support you on your journey.

Gluten + Histamine = Zonulin

Tight junctions regulate what passes through the lining of the small intestine into the blood. Our bodies make a protein molecule called zonulin that regulates the permeability of these tight junctions. Zonulin is released in response to foreign bacteria, an overgrowth of ‘bad’ bacteria, certain medications, mercury and gluten. If an individual has a healthy immune system then the gluten triggered release is not a problem as the body will deal with the gluten and close the junctions. Increased levels of zonulin however affects gut function, health and associated immune response. Zonulin may be a contributing factor in the development of leaky gut, inflammation and autoimmune disorders such as coeliac disease, diabetes, MS and rheumatoid arthritis. Elevated zonulin also damages the villi in the small intestine that produce the DAO enzyme responsible for processing histamine. This makes us more sensitive to histamine foods. Removing gluten from the diet downregulates zonulin pathways and the gut lining can heal. This is an important part of healing from histamine intolerance and reducing symptoms. Nutritional support to heal the gut lining and reduce inflammation, removal of food allergens and high histamine foods, replacing digestive enzymes and hydrochloric acid if needed and restoring the beneficial microbial balance is important.

Supplements to assist with histamine intolerance:   https://www.nutrienergy.co.nz/collections/histamine-intolerance


Histamine and SIBO

Small Intestinal Bacterial Overgrowth (SIBO) is an increase in the number of bacteria and / or an alteration in the type of bacteria in the small intestine.  Imbalances in the small intestine can be due to too many pathogenic bacteria producing gases, too many probiotic species which become detrimental to digestion and peristalsis or bacteria species traveling up from the large bowel into the small intestine due to a poorly functioning bowel or ileocecal valve which separates the small intestine from the colon. There are many causes of SIBO which need to be addressed to get this condition under control.

SIBO causes many symptoms similar to IBS and has been shown to significantly interfere with the digestion of food and the absorption of nutrients due to the damage to the cells lining the small intestine and the brush border enzymes.  The bacteria can also rob us of certain B vitamins (especially vitamin B12), iron, amino acids and also decrease fat metabolism leading to deficiencies in the fat soluble vitamins such as vitamin A and D.  The damage to the small intestine lining (mucosa) negatively affects the structure and function of the small intestine leading to impaired gut permeability otherwise known as a “leaky gut” (as mentioned above).  A leaky gut and a lack of enzymes can lead to food sensitivities, allergies, inflammation, immune reactions, auto-immune diseases and of course histamine intolerance.
For more information on SIBO please click below:


Histamine and Hormones

Histamine intolerance is becoming more and more common in females due to the link between histamine, estrogen, progesterone and cortisol. Estrogen stimulates the release of histamine from mast cells and the more circulating estrogen, the more histamine is released. At the same time, histamine can stimulate estrogen production. Estrogen can also down-regulate DAO activity influencing histamine levels.
Some women with histamine intolerance have reported to me that their tolerance levels to high histamine foods fluctuate depending on what stage of their cycle they are in. When estrogen dominates progesterone during the cycle, histamine symptoms worsen. Progesterone has an inhibitory effect on histamine release and so women who are low in progesterone and have elevated estrogen levels can be more susceptible to histamine intolerance, it can be a vicious cycle. Progesterone naturally declines as we age also resulting in many peri-menopausal women presenting with histamine intolerance. Menstrual headaches, migraines and dysmenorrhea are common symptoms in women with histamine intolerance.


Accurate hormone testing (I use the DUTCH test) is a good way to decipher hormone levels in the body. Supporting the body with a healthy diet, improving digestion, using correct supplementation to support the adrenals, the liver and estrogen clearance, avoiding Xenoestrogens and using progesterone cream to balance estrogen (if needed) can be helpful.

Histamine and Stress

Stress is another causative factor not to be forgotten. Stress results in poor digestion and absorption of nutrients, a leaky gut, mast cell degranulation and therefore higher histamine levels. Histamine can also stimulate cortisol synthesis via the adrenal cells (24 hour cortisol testing is also done through the DUTCH test). Also as you go into menopause the ovaries stop producing estrogen and the adrenals take over so if you have adrenal fatigue going into menopause, it makes that transition much more unpleasant. Addressing sources of stress, promoting relaxation techniques and supporting the adrenals with nutrients and adaptogenic herbs can be helpful.


During my studies with the NutriGenetic Research Institute and readings of Dr. Ben Lynch, I have learnt the importance of addressing the underlying causes of histamine intolerance and of the key genes involved in processing histamine. The two main genes include HNMT (requires SAMe as a cofactor) and an effective MTHFR enzyme to help produce SAMe) and DAO (AOC1) which requires vitamin B6 and copper as cofactors. Other important genes and nutrients are required for effective histamine degradation including MAO (requires B2), NAT2 (Acetyl CoA) and of course the MTHFR gene and methylation as mentioned above (a whole subject of its own)!

Recommended Testing

The following testing is available through my clinic to assist with finding the underlying causes of your histamine intolerance:

Genetic Testing assistance using Ancestry DNA – determine your genetic susceptibility to histamine intolerance. This is valuable to help determine if histamine intolerance is a high risk for you (if you are unsure if histamine intolerance is a cause of your symptoms) and where your genetic weaknesses may be.  Also a great guide to which supplemental cofactors you may need to support your histamine pathways.

Methylation Profile – evaluates the plasma levels of Methionine, Cysteine, SAMe, SAH, Hcys and Cystathionine to determine cellular methylation of DNA, proteins and neurotransmitters

Organic Acids Test (OAT test) – comprehensive test of 74 unique urinary metabolites - valuable to identify key vitamin and antioxidant levels, yeast and bacterial overgrowth, fatty acid metabolism, neurotransmitter levels, oxalate levels, inborn errors of metabolism, mitochondrial function, oxidative stress, detoxification and much more!

SIBO Breath Testing – accurate form of testing for SIBO (Small Intestinal Bacterial Overgrowth)

Comprehensive Stool Analysis (CSA) with Parasitology x3 – a great test for determining causes for a wide range of digestive and bowel complaints – identifies live bacteria, yeast, parasites, digestion efficiency, inflammation and immune function

DUTCH Complete – dried urine test for accurate testing of  hormones - cortisol (x4), cortisone (x4), cortisol metablolites (3), DHEAS, Melatonin (x1 overnight), Androgens (8), Progesterone Metabolites (2), Estrogens and Metabolites (8)

IgG Food Allergy Test with Complement - measures both IgG and immune complexes containing the complement fragment ‘C3d’ to multiple food antigens

Allergenics Food and Environmental Sensitivity test – tests for multiple food and environmental sensitivities, some bacteria and viruses


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