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Histamine intolerance – or what might be the silent cause of your unresolved symptoms

Do you often have a runny nose, itchy eyes or other body parts? Have seasonal allergies or your mosquito bites swell up more than in other people? Do you find yourself irritable after certain foods, or are unable to loose weight? Histamine intolerance might be at the root of it.

Histamine is an important molecule in the body, as it helps assist the immune system. However, when overproduced, or as a result of a decreased breakdown, it can circulate in the system and produce severe reactions, such as:

  • Asthma – sneezing, chest tightness, itching, runny nose as a result of inhaled allergens
  • Seasonal allergies
  • Dust allergies
  • Hives and eczema
  • Diarrhea
  • Irritability
  • Increased reaction to insect bites
  • Generalised itching, rashes runny nose.

As mentioned above, these symptoms can result from 1) an overproduction in the body of histamine, or 2) a slowed breakdown of ingested and internally produced histamine.

1. An overproduction of histamine and increased immune reaction can be due to several factors:

  • Leaky gut
  • Food allergies
  • Lack of vitamin D, which is an important immune system regulator
  • Chemical exposure such as
    • Food additives and synthetic coloring exposure
    • Chemical body care products
    • Chemical cleaning products
    • Pesticides and fertilizers on food product
    • Chemical dyes on clothing, bedding, furniture

2. A slowed breakdown of histamine can be due to

  • A genetic mutation which slows one or both of the 2 major histamine break-down enzymes down. One works mainly to break down histamine in the gut (DAO), the other mainly in the cell and brain (HNMT). If you have a mutation here, you might have to limit high histamine foods lifelong. However, as there are a lot of otherwise ‘healthy’ foods on the histamine food list, goal is to heal the gut and balance the immune system, which further augment histamine load, and then slowly reintroduce medium level histamine foods. If your system is completely balanced, you might even be able to start tolerating high histamine foods again in moderation.
  • An imbalanced gut. A leaky gut not only overproduces histamine, but also slows down DAO, the enzyme responsible in the gut. IBS, SIBO, and inflammatory bowel disorders all can lead to a reduced action of DAO and hence a slowed breakdown of histamine.
  • Too little fat in the diet, as fat increases DAO enzyme activity and helps histamine to be broken down.
  • An estrogen-progesterone imbalance, also called estrogen dominance. Estrogen downregulates DAO which makes for more histamine, progesterone upregulates DAO, which decreases histamine load. This also explains why some women experience more symptoms during the early stages of their cycle, and improvements just after ovulation and during pregnancy.
  • Stress, inflammation and hormonal issues all influence each other, and ultimately lead to a cycle of overload of histamines and other neurotransmitters (especially also in the brain), and an overload to HNMT in the body.

So, what can you do about it? Follow these simple steps to reduce histamine load when you feel you are having symptoms, like a runny nose, itchy eyes or seasonal allergies.

  • Reduce high histamine foods (see list below)
  • Reduce allergens such as foods you are allergic to, mold.
  • Practice deep breathing and meditation to help balance neurotransmitters and inflammatory load in the body.
  • Heal your gut and with it, your immune system.
  • Getting plenty of vitamin D

Once your symptoms have gone, your gut has healed, your immune system is back in balance, and your brain chemicals are back on track, you can slowly start to re-introduce moderate histamine foods again and see how you feel. Know that often in your body, we are ok to tolerate small amounts, but as they build up, and you have more of it, all of the sudden the tipping point is reached, and the system goes into alarm again. So make sure to only add in small amounts every other day, and see how you feel.

If you have genetic mutations in DAO and HNMT, especially if homozygous, you might have to limit your high histamine food intake for life. Especially if in conjunction with a gut flora mutation (FUT), neurotransmitter mutations such as GAD, COMT, MAOB, methylation defects in MTHFR, and genetic predispositions towards gluten and other food intolerances that augment the immune system’s sensitivity.

High histamine foods

Fermented foods such as sauerkraut, kimchi, kombucha

Wine, beer, champagne, vinegar

Left-over foods (the older, the more histamine has already developed)- same goes for ready made meals and canned foods

Matured cheeses

Smoked products

Walnuts and cashew nuts


Snacks and other foods with preservatives and artificial food colourings.

Vinegar containing foods such as mayonnaise, pickles

Cured meats such as lunch meats, sausages, salami, peperoni, hot dogs.

Moderate histamine foods (they liberate histamine in the body)





Citrus fruits

Wheat germ

Beans and pulses

DAO blockers:


Black tea

Energy drinks

Green tea

Mate tea

Not sure what that means for you, how to heal your gut, or whether you have a genetic mutation in your histamine genes? We offer online (skype/facetime video) consultations worldwide with our Functional Medicine Practitioner Mirthe. Contact us for details. X

What are your symptoms and how do you deal with it? Comment below, we’d love for you to help each other.

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It is my goal to empower you to become the CEO of your health trajectory, preventing and optimising with precision and science backed strategies to live your best life & thrive.

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It is my goal to empower you to become the CEO of your health trajectory, preventing and optimising with precision and science backed strategies to live your best life & thrive.

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