If you have a histamine intolerance, working with a nutritionist and keeping to a low histamine diet is important to manage unpleasant symptoms. This article is a comprehensive guide on what histamine is, what causes histamine intolerance and a list of high histamine foods to limit in your diet.


Histamine is a chemical that is predominantly manufactured by our immune cells and released by white blood cells into the blood when the immune system wants to get rid of what it deems to be harmful to the body such as an allergy trigger or allergen (e.g. food, pollen, dust etc). When an allergen is encountered by the body the immune system triggers a cascade of chemical signals which activates mast cells in the skin, lungs, nose, mouth, gut and blood. This activation leads to the release of histamine which is stored in mast cells. This release leads to symptoms such as: sneezing and an itchy, runny or blocked nose (allergic rhinitis) itchy, red and watering eyes (conjuctivitis) wheezing, chest tightness, shortness of breath and a cough a raised, itchy, red rash (hives) swollen lips, tongue, eyes or face tummy pain, feeling sick, vomiting or diarrhoea dry, red and cracked skin. After histamine has done it’s job it is broken down by 2 enzymes – diamine oxidase (DAO) and histamine-N-methyltranserase (HNMT) and recycled.


Histamine is a monoamine neurotransmitter. Monoamine neurotransmitters are responsible for a range of functions in the body including modulation of psychomotor function, cardiovascular, respiratory and gastrointestinal control, sleep mechanisms, hormone secretion, body temperature and pain. Histamine is responsible for the stimulation of 4 post-synaptic receptors. These are concentrated in the brain, smooth muscles, gastric cells and in bone marrow. Histamine is also known as a neuromodulator as it regulates the release of other neurotransmitters, including serotonin.


Histamine intolerance results from an imbalance of accumulated histamine in the body and the capacity of the body to break it down. Histamine receptors are distributed widely throughout the different organs and tissues of the body so symptoms are wide ranging.


There are a diverse range of symptoms of histamine intolerance:

  • headaches or migraines
  • dizziness
  • nasal congestion or sinus issues
  • fatigue
  • hives, rashes, swelling, itchy skin, skin flushing and eczema
  • racing heart, palpitations and arrhythmia
  • low blood pressure
  • digestive issues
  • irregular menstrual cycles
  • nausea, vomiting, diarrhoea, bloating, flatulence, abdominal pain, constipation

If you are suffering from a few of these symptoms, it may be worth going to see a holistic nutritionist to uncover a potential histamine intolerance and if a low histamine diet is necessary.


Excess histamine in the body can be caused by the following issues:

A genetic single nucleotide polymorphism (SNP) on the diamine oxidase (DAO) gene.

As mentioned above, DAO is the enzyme that breaks down histamine in the body and reduces the histamine response. It is estimated that 10-13% of the population have a genetic SNP on the DAO gene. That means that their ability to produce the DAO enzyme can be significantly reduced and their ability to breakdown histamine can be hampered. The good news is DAO can be supplemented, bringing relief to those with a deficiency.

Medications that block DAO enzyme function.

Medication such as antibiotics, anti depressants, NSAIDS such as ibuprofen, aspirin etc can block DAO enzyme function leading to histamine overload.

Dybiosis (a dysfunctional mix of gut bacteria).

The gut microbiome is composed of trillions of bacteria. The microbiome has evolved along with us and therefore there are many functions in the body that wouldn’t work without it. When gut bacteria goes out of balance excess histamine accumulates in the gut and the production of the DAO enzyme is unable to keep up with it. Causes of bacterial imbalance include: frequent and/or long-term use of antibiotics, long term use of medications, stress, long term illness or infection, poor diet, toxin exposure or digestive issues such as leaky gut.

Leaky gut.

The lining of the gut is only one cell thick and held together by tight junctions. When food is digested and broken down into its most basic components (carbs, amino acids etc.) the nutrients are small enough to pass through the tight junctions leaving the waist products to pass through the digestive tract. If the tight junctions loosen, partially digested foods can get through into the blood stream, triggering an immune response. At first the food is able to get through without being attacked, but as more and more “invaders” come across the immune system retaliates. It tags this food as dangerous (common response to cows milk, dairy and gluten). Whatever you eat frequently can trigger immune responses. While your gut is leaky your body is generating extra histamine, which is intended to calm the inflammatory process but too much of it can cause a vicious cycle, retriggering the immune system and causing the release of more histamine. All of this makes it hard for your leaky gut to heal, as you now have at least three vicious cycles (gut, immune system and histamine) each of which makes the other two worse and further burdens your DAO. The DAO enzyme is stored in the gut wall and if your gut wall is distressed, with fewer cells and less integrity you will have less of the DAO enzyme and therefore less resources to process the histamine. Causes of leaky gut include gluten and other food allergies and sensitivities, excess alcohol consumption, stress, various medications, poor diet, toxin exposure, over exercising, antibiotics etc.

A high histamine diet.

We manufacture histamine in our body but many commonly consumed foods are high in histamine. Also, some foods encourage the release of histamine or block activity of the DAO enzyme therefore increasing the amount of histamine floating around the body. The accumulation of histamine in food is the result of transformation of amino acids, the building blocks of proteins, by microorganisms and depends on various factors such availability of proteins and environmental conditions favourable for growth. It’s difficult to measure the exact levels of histamine in foods as it varies greatly even in the same type of food. Histamine levels in food increases as it ages. For example, you can cook some fresh chicken, salad and potatoes at lunchtime and it is a low histamine meal. Store it and have it later in the day or as leftovers the next day and the histamine will have gradually increased. Many of my histamine intolerant clients cannot eat leftovers. Anything that has been preserved such as fermented and aged foods usually have higher levels of Histamine, so it’s best to avoid them if you have a histamine intolerance.


Low Histamine Foods

  • Fresh meat
  • Certain fresh/frozen fish (e.g. Hake, Trout or Plaice)
  • Chicken
  • Egg
  • Fresh fruits with the exception of plantains
  • Fresh vegetables with the exception of tomatoes, eggplant and spinach
  • Grains (e.g. rice noodles, white/rye bread, oats or pasta)
  • Fresh pasteurised milk and milk products
  • Milk substitutes (e.g. Goat milk and Sheep milk)
  • Cream cheese, mozzarella and butter
  • Most cooking oils
  • Most leafy herbs
  • Most fruit juices without citrus fruits
  • Most herbal teas

Foods High In Histamine

  • Alcohol
  • Eggplant
  • Pickled/canned foods
  • Matured cheese
  • Smoked meat products (e.g. ham, salami, sausages)
  • Shellfish
  • Beans and pulses (e.g. chickpeas and soy flour)
  • Long stored nuts
  • Chocolates and other cocoa based products
  • Seitan
  • Rice vinegar
  • Any ready made meals
  • Salty snacks
  • Sweets with preservatives and artificial colours.

Foods That Encourage Histamine Release

  • Most citrus fruits – lemons, limes, oranges
  • Cacao and chocolate
  • Walnuts, peanuts
  • Papaya, pineapples, plums, kiwi and bananas
  • Legumes
  • Tomatoes
  • Wheat germ
  • Most vinegars
  • Additives – benzoate, sulphites, nitrites, glutamate, food dyes

Foods That Block The Diamine Oxidase (DAO Enzyme)

  • Alcohol
  • Black tea
  • Energy drinks
  • Mate tea
  • Yeast extract


  • Cut out all high histamine foods, histamine liberators and foods that block the DAO enzyme for at least a week. Reintroduce on a gradual basis until you have found your level of histamine intake that you can tolerate.
  • Work on stress management. Stress is damaging to the gut lining.
  • Eat as fresh food as possible. Avoid leftovers and ready made meals which are high histamine meals.
  • Heal the gut wall. There are many reasons for the occurrence of leaky gut. Book a consultation with me to identify your issues and help you get your gut back to optimal health.
  • Keep your gut bugs happy. Feed them lots of low histamine fruits and vegetables (half a plate with every meal). Bear in mind some of these might be your allergy triggers (see next step below).
  • Find out your allergy triggers. In the Physical Nutrition clinic we can arrange some very comprehensive allergy and sensitivity testing that will help you to heal the gut lining.
  • Supplement the diamine oxidase enzyme. There are a few supplements on the market. However, they are quite expensive. It would be more efficient to work on the root causes first.


What HIT Me? By Genny Masterman

Food Intolerances: Fructose Malabsorption, Lactose and Histamine Intolerance By Michael Zechmann and Genny Masterman

Histamine Intolerance: Histamine and Seasickness By Dr. Reinhart Jarisch

Dirty Genes By Dr Ben Lynch


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