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Histamine Intolerance

Most people know histamine as the chemical produced during an allergic reaction that results in swelling and inflammation. However, histamine is actually a chemical messenger associated with many other functions in the body, specifically with gut health.

It regulates our gastric acid, the movement of food through our gut, and is involved in the complex communication between the gut and the brain where it acts as a neurotransmitter in the central nervous system, affecting mood, the wake-sleep cycle and is required for arousal, alertness, learning and memory. It also regulates appetite, other neurotransmitters and the perception of pain.

Amazingly, histamine is released from cells present in every tissue of our body and, in particular, our ovaries and uterus.

Histamine levels can rise due to production in the digestive tract and from gut flora, as well as from ingesting histamine-rich foods. Levels are kept in balance by an enzyme called diamine oxidase, also known as DAO. DAO breaks down histamine for clearance from the body.

In certain individuals, this enzyme either does not work properly due to a genetic defect or SNP, or they have a DAO deficiency due to poor gut health. This is because DAO is produced in the intestinal lining of the gut.

Both situations can leave people with what's known as histamine intolerance.

Common Symptoms

Histamine intolerance is unlike a typical allergy response where just a minor encounter sets off a serious reaction. When histamine symptoms show up it's the result of a slow build-up. Remember it is the quantity of histamine relative to your own capacity to clear it, which translates into symptoms. They include:

  • Red flush with alcohol consumption

  • Arrhythmias (irregular heart beat)

  • Waking with a racing heart

  • Food intolerances

  • Diarrhoea

  • Swelling

  • Headaches

  • Anxiety

  • Motion sickness

  • Painful bloating

  • Prickly heat

  • Rashy skin

  • Insomnia

  • Brain fog

  • Low libido

  • Nasal congestion

  • Phlegmy throat

  • Allergies

  • Sweaty feet

  • Itchy throat

Nb this list is not exhaustive.

People can expect an exacerbation of symptoms after eating leftovers, fermented foods or fermented drinks or other high-histamine foods. You may also experience an exacerbation at certain times in your menstrual cycle when oestrogen peaks and or progesterone declines.

As mentioned above one of the most common causes of histamine intolerance is poor digestive health; more specifically a compromised gut microbiome (dysbiosis), and poor integrity of your gastrointestinal mucous membranes.

But What Worsens A Histamine Intolerance?

  • Menstrual cycle issues (sex hormone imbalances)

  • Excessive exercise

  • Chronic stress

  • Alcohol intake

  • A diet high in histamine

  • A high protein diet

  • Exposure to mould

  • Anything that worsens digestive health

  • Genetic susceptibility (single nucleotide polymorphisms - aka "SNPs")

  • Nutrient deficiencies (B vitamins, zinc, copper, C, methionine)

A little more on 'Genetic Polymorphisms'

These commonly occur in diamine oxidase (DAO), histamine-n-methyl- transferase (HNMT), monoamine oxidase (MAO), phosphatidylethanolamine N-methyltransferase (PEMT), N-acetyltransferase 2 (NAT2) and methylenetetrahydrofolate reductase (MTHFR).

Eg. Insufficient histamine-n-methyl- transferase (HNMT) in the nervous system and lungs can lead to histamine overload.

How? Any of these genes can be ‘down-regulated’, which means the pathway that breaks down histamine is slowed. We offer genetic testing via the Kiyah Clinic.

A little more on 'Nutrient Deficiencies'

Both poor diet and malabsorption of nutrients in the gut can lead to nutrient deficiencies.

DAO and other enzymes involved with histamine degradation either rely on the nutrients listed above or work closely with them to break down histamine. If you’re deficient in any of them, your DAO enzyme will not function as it should. Moreover, low vitamin C levels in the blood also promote the synthesis and release of histamine.

Managing Your Symptoms Through Food

Some individuals find improvement in their symptoms just by eliminating the foods highest in histamine or those foods which are known to liberate histamine or block the action of DAO.


There is no such thing as a histamine-free diet.

What is important, is to determine your own threshold.

  • Canned vegetables. 

  • Canned or smoked seafood. (i.e. shellfish, mackerel, mahi-mahi, tuna, anchovies, sardines)

  • Cured, deli or smoked meats. 

  • Bone broth.

  • Fresh vegetables including spinach, eggplant, mushrooms, tomatoes, curry, avocados, olives.

  • Beans and pulses (legumes).

  • Most citrus fruits, strawberries, papaya, pineapple, raspberries, banana, kiwi, pears, papaya, guava.

  • Overripe fruits.

  • All dried fruits.

  • Chocolate.

  • Dairy. 

  • Peanuts, walnuts, cashews and other nuts stored for long periods.

  • Yeast.

  • Spices.

  • Pickled, soured and fermented foods like kimchi, sauerkraut, yogurt and kefir, kombucha, aged cheese, vinegar, soy sauce, sour cream. Mustard. 

  • Leftover meals.

  • Packaged foods.

  • Ready-made meals.

  • Anything with preservatives or additives: benzoate, sulphites, nitrites, glutamate, food dyes, MSG.

  • All alcohol, especially wine, champagne, cider and beer.

‘Blockers’ such as alcohol, smoked or fermented foods, black tea, green tea and some medications such as non steroidal anti-inflammatory medications (ibuprofen or aspirin). can also lead to histamine overload.

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

These lists will vary across the internet. Everyone has different levels of sensitivity. Figuring out what is OK for you or not OK for you is something to determine with your practitioner.

Moderating your intake of these will lower your histamine load and help to relieve you of symptoms BUT remember that removal of nutritious foods from your diet long-term is NOT the answer. Lists like this should be considered but not strictly adhered to.


Because removing some foods without professional guidance may cause you to lean heavily on other foods which may end up creating other symptoms. The other more important reason is that histamine rich foods are not the problem. The problem is poor gut health and or defective DAO enzyme.

This is what needs to be addressed and it's what we address in the KIyah Clinic with the 'Heal Your Gut' package. If you have questions connect with us for a free 10 in call here.


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