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7 Surprising Histamine Triggers

Many people deal with histamine intolerance, histamine overload or even mast cell activation syndrome (MCAS). For these people, eating foods high in histamine can cause reactions. When we think of histamine, we usually just think typical allergy symptoms. But histamine goes way beyond that!

There are two types of histamine reactions: internal and external.

Internal reactions (endogenous) usually are food related. These can come from foods that are naturally high in histamines, fermented foods, leftovers, aged foods or even processed foods. These reactions are even worse if you are deficient in the DAO enzyme, which is responsible for breaking down dietary histamines.

External reactions (exogenous) can be a bit more complicated. Mast cells (a type of white blood cell) can release histamine as a part of an immune response. But in some cases (like in MCAS) these histamines are released too frequently, causing a host of reactions. Certain types of gut bacteria can produce histamines, which means certain things that affect the microbiome (traditional probiotics, antibiotics, etc) can cause reactions in some people.

Symptoms of histamine overload:

  • traditional allergic type reactions

  • hives, itching

  • flushing of the face & hot skin

  • panic attacks

  • motion sickness

  • chronic pain

  • miscarriages or infertility

  • PMS & intense periods

  • ovulation pain

  • dizziness & fainting

  • fear & anxiety

  • low blood pressure

  • rapid or irregular heartbeat

  • estrogen dominance

  • bloating after every meal

  • abdominal pains

  • heat intolerance

  • migraines & headaches

  • acid reflux & heartburn

  • diarrhea or constipation

  • brain fog & fatigue

  • joint pain or stiffness

  • food intolerances

  • acne & eczema

So, it's easy to see histamine is NOT as straightforward as most people think! Symptoms can affect many different body systems, including the neurological, cardiovascular, digestive, reproductive, skin and more! But, it's important to realize histamine overload is NOT a root cause. It's actually caused by things like mold, bacteria, parasites, heavy metals, a sluggish liver, candida & yeast, nutrient depletion, oral contraceptives, hormonal imbalances, medications and antibiotics. Genetics CAN play a part, but as I like to say, genetics only load the gun.... lifestyle pulls the trigger.

There are many conditions linked to histamine overload, including: ADHD, OCD, POTS, MCAS, PMS, PMDD, Anxiety, Depression, Endometriosis, Celiac Disease, Lyme Disease, Eczema, Psoriasis, Insomnia, Interstitial Cystitis, Thyroid problems, IBS, IBD, Crohn's, Acid Reflux, Morning Sickness and MORE.

You might have histamine overload if you can't.... go a day without an antihistamine, can't eat dozens of foods, can't eat fermented or aged foods, can't eat without feeling "off" after, can't tolerate alcohol or vinegar, can't tolerate vitamins, can't go in a car without being car sick, can't stand hot weather, can't stand scented products, can't get up without being dizzy, can't find your libido, can't have a tolerable menstrual cycle, or can't find out what's wrong with you!

Now that we have a better understanding of what histamine looks like, what are some surprising triggers of histamine overload that you might want to avoid if you deal with this condition?

1. Heat & Sunlight

When body temperature rises, it can trigger the activation of mast cells in the skin and muscles, leading to histamine release. This can happen when you're outside in the hot sun, or when you take a hot bath or shower.

2. Strenuous Exercise

For some, high intensity aerobic exercise may lead to symptoms like itchiness and redness or dizziness and weakness. This can be attributed to the muscular inflammation that occurs during exercise, along with an increase in body temperature, provoking a mast cell response and histamine release.

3. Stress

When we experience stress, our mast cells receive signals that lead them to activate and release histamine. Research has actually found that stress is the most common trigger for MCAS!

4. Medications

Many medications can actually block DAO (the enzyme that breaks down dietary histamine). These include Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) which include Advil and Aleve, antibiotics, antidepressants, antacids, diuretics, and immune modulators. Some of these medications, including NSAIDs and antibiotics, may also contribute to inflammation and dysbiosis within the gut, which may exacerbate the problem.

Some antihistamine medications can also lead to increased histamine levels by inhibiting DAO. While it may seem confusing that antihistamines would increase histamine levels, it’s important to understand that these medications generally work by blocking histamine receptor sites rather than actually decreasing levels of circulating histamine. So, while they may be effective for acute situations (like an allergic reaction), they are not necessarily helpful when it comes to lowering your overall histamine load.

5. Menstrual Cycle

If you are a menstruating woman, you may find that your histamine symptoms worsen before your period. Estrogen, which naturally increases when you are ovulating and just before your period, has been shown to increase mast cell activation and histamine levels. Histamine also increases the production of estrogen, which can create a vicious cycle. Furthermore, estrogen has been shown to inhibit levels of DAO.

6. Gut Imbalances

Different kinds of gut bacteria can either produce histamine or help to degrade it. Gut dysbiosis (an imbalance between helpful and harmful bacteria within the gut microbiome) can lead to excessive levels of histamine-producing bacteria. Gastrointestinal disorders including SIBO, leaky gut, gluten intolerance, dysbiosis, and IBS can also influence levels of DAO. Finally, the gut is a major component of the immune system and contains a high volume of mast cells, which are influenced by the gut bacteria that live among them.

7. Vitamin or Mineral Deficiencies

The body relies on adequate levels of certain vitamins and minerals in order to produce DAO. These include magnesium, vitamin B6, vitamin C (which is also a natural antihistamine), and zinc. Sometimes, in the cases of chronic inflammation, and especially when following a restricted diet due to sensitivities, levels of these vitamins and minerals may be too low, and can contribute to histamine intolerance.

The bottom line, is that living with a histamine intolerance is all about managing your overall histamine load and addressing the root causes behind it. The more we can understand about our triggers and factors that are contributing to this load, the better equipped we are to manage the condition and reduce the likelihood or severity of symptoms. It’s not a matter of being afraid of food, exercise, or stress, but of being aware and informed!

With love,


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