Histamine intolerance occurs when there is a buildup of histamine in the body. Many foods contain high histamine levels, and various health conditions and medications can contribute to an intolerance (See below for a list of common symptoms).
Histamine is a chemical that sends messages to the brain, signals the release of stomach acid for digestion, and is released as part of the immune system's response to an injury or allergic reaction.
An intolerance to this chemical happens when the body cannot break down enough of it in the intestines, causing histamine levels in the blood to rise.
This typically results from having low levels of an enzyme called diamine oxidase (DAO), which is the primary agent that breaks down digested histamine.
When histamine levels get too high or when it can't be broken down properly, it can adversely impact normal bodily functions.
Symptoms of histamine intolerance

• headaches or migraines
• nasal congestion or sinus issues
• fatigue
• hives
• digestive issues
• irregular menstrual cycle
• nausea
• vomiting

Additional symptoms may include:

• abdominal cramping
• tissue swelling
• high blood pressure
• irregular heart rate
• anxiety
• difficulty regulating body temperature
• dizziness

What causes high histamine levels?
The enzyme diamine oxidase (DAO) is responsible for breaking down histamine that you take in from foods.
If you develop a DAO deficiency and are unable to break down histamine, you could develop an intolerance.
Some individuals have altered DAO production due to a number of different factors including:
Small Intestinal Bacterial Overgrowth (SIBO): some gut microbes produce high amounts of histamines as a byproduct of their metabolism.
Leaky Gut Syndrome: Intestinal permeability creates major inflammatory stress in the body which can contribute to poor DAO function.
GI inflammatory conditions: Crohn's, Inflammatory bowel disease (IBS), colitis
Celiac disease and those with gluten intolerance
Certain drugs: NSAIDs, acid-blocking medications, anti-depressants, immune suppressants.
Nutritional Factors to Consider:
The DAO enzyme is dependent on vitamin B6, B12, iron, copper and vitamin C, so it makes sense to increase the intake of these compounds.
Copper and Vit C are crucial components of the DAO enzyme and B6 is a key cofactor that enables DAO to degrade histamine.
Copper deficiency is another possible cause for low DAO activity, as copper is a central atom of the DAO and thus essential for its function.
Controlling histamine levels with diet
Foods to avoid or at least limit.
Histamine-rich foods are:
alcohol and other fermented beverages
fermented foods and dairy products, such as yogurt and sauerkraut
dried fruits
avocados
eggplant
spinach
processed or smoked meats
shellfish
aged cheese
There are also a number of foods that trigger histamine release in the body, such as:
alcohol
bananas
tomatoes
wheat germ
beans
papaya
chocolate
citrus fruits
nuts, specifically walnuts, cashews and peanuts
food dyes and other additives
Foods to eat
If you have a histamine intolerance, the following low-histamine foods can help reduce symptoms.
Some foods low in histamine include:
fresh meat and freshly caught fish
non-citrus fruits
eggs
gluten-free grains, such as quinoa and rice
dairy substitutes, such as coconut milk and almond milk
fresh vegetables except tomatoes, avocados, spinach, and eggplant
cooking oils, such as olive oil
Diagnosing Histamine Intolerance
Your doctor might also take a blood sample to analyze if you have a DAO deficiency.
G-DAP from https://precisionpointdiagnostics.com is a good test to check your DAO and Histamine levels
Supplement Recommendation to Block Histamine and Replenish DAO
Histamine Block from Seeking Health
Additional Recommendations
Replenish the supplements necessary for the production of DAO: B6, B12, iron, copper and vitamin C.
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7463562/
Ideas obtained from https://mthfrsupport.com.au
Ideas and concepts obtained from Dr. Ben Lynch--https://mthfr.net

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