Histamine is a key molecule in your body. You need it to survive. Histamine is produced by immune cells called mast cells. These immune cells are present in connective tissue and are part of the immune and neuroimmune systems. Histamine is also found naturally in many foods.

Your body needs histamine to:

  • Fight infection.
  • Act as a neurotransmitter.
  • Regulate sleep.
  • Helps in proper digestion.
  • Regulate hormones.
  • Help reproduction.

Too little histamine can cause serious problems. Your body cannot function properly without enough of this molecule. On the other hand, too much histamine can also wreak havoc. Since histamine is present throughout the body, high histamine can cause many different types of symptoms. Let’s take a look at those symptoms.

Signs and symptoms of high histamine levels.

These are common symptoms of high histamine levels:

  • Itchy eyes, ears, nose, throat, skin.
  • Redness of the skin.
  • Eruptions.
  • Nasal and sinus congestion.
  • Excess mucus.
  • Swelling and redness of the eyes.
  • Heartburn, reflux, indigestion.
  • Diarrhea.
  • Sleep problems: falling asleep or staying asleep.
  • Low blood pressure or high blood pressure.
  • Headaches or migraines.
  • Food sensitivities.
  • Fatigue.
  • Menstrual problems.
  • Breathing problems such as asthma.

Other symptoms of high histamine.

Symptoms get worse with fermented foods, wine, beer. Some people with high histamine levels may also experience these symptoms:

  • Palpitations or irregular heartbeat.
  • Problems regulating body temperature.
  • Dizziness.
  • Chest pain.
  • Nausea.
  • Vomiting.
  • Symptoms of anxiety or panic.
  • Depression.
  • Humor changes.
  • Swelling of the face, mouth, or throat.

You don’t have to experience all of the above symptoms to have histamine problems. However, if you have three or more of these symptoms, it could be a sign that you have a histamine intolerance.

What is histamine intolerance?

Histamine intolerance occurs when the body has more histamine than it can eliminate. The body removes histamine with specific enzymes, such as diamine oxidase (DAO) and histamine N-methyltransferase (HNMT). If you don’t have enough of these enzymes, histamine can build up to high levels.

Think of histamine intolerance like a sink with a drain. Histamine flows from the tap and enzymes are the drain that removes the histamine.

Think of histamine intolerance like a sink with a drain. Histamine flows from the tap and enzymes are the drain that removes the histamine. If you don’t have enough histamine-degrading enzymes, the sink will overflow and you’ll start to experience symptoms.

Likewise, if the flow of histamine from the tap is faster than the drain can follow, the sink will also overflow and cause symptoms.

You may not have enough of these enzymes due to a genetic predisposition or a lack of certain nutrients. Some of the nutrients that are important for breaking down histamine are:

  • B2, B5, B6, B12.
  • Folate (as methyl folate).
  • Vitamin C.

If you’re low on nutrients, your body could have trouble making these histamine-destroying enzymes.

Additional factors that can lead to high histamine levels

  • Hormonal imbalances.
  • Eating too many foods high in histamine.
  • Autoimmunity.
  • Intestinal infections (such as SIBO or Candida).
  • Chronic infections like Lyme or Epstein Barre.
  • Mold toxicity.
  • Certain medications.
  • Lack of deep sleep.
  • Stress.

The connection between histamine and hormones

Women prefer to have more histamine than men because women have more estrogen. Estrogen, progesterone, and histamine are closely related to the body. Estrogen stimulates mast cells to make more histamine.

This can cause a dangerous cycle when estrogen causes mast cells to release histamine and increasing levels of histamine produce more estrogen. In turn, estrogen causes mast cells to produce more histamine, creating a snowball effect.


This is also why you may have experienced more histamine problems at certain times in your cycle, probably when your estrogen levels were higher than your progesterone levels.

Estrogen dominance occurs when you have more estrogen than progesterone. So if you have estrogen dominant, chances are you have histamine problems.

It’s important to note that estrogen dominance doesn’t just happen with high estrogen levels. Even if you have a low estrogen level, you can have a dominant estrogen if you have more estrogen than progesterone.

On the other side of the coin, progesterone helps prevent mast cells from producing histamine. This is a big reason why the estrogen-progesterone balance is so important.

If you can maintain your progesterone, you likely have lower histamine activity. This results in lower histamine levels and fewer high histamine symptoms.

Histamine: menopause, SIBO, and low thyroid levels

There is also a great connection between histamine problems and menopause. Women are more likely to develop histamine intolerance during menopause.

This is because both estrogen and progesterone decrease during menopause. For many women, progesterone ends up being even lower than estrogen. Therefore, it can dominate estrogen during menopause.

High estrogen breaks down the DAO enzyme that breaks down histamine

Estrogen also causes another problem. In fact, it can reduce one of the important enzymes that break down histamine we talked about earlier, called diamine oxidase (DAO).

If you don’t have enough DAO, then you can get very high levels of histamine. DAO is also very vulnerable to intestinal infections like SIBO. Intestinal infections destroy the body’s ability to produce DAO. Therefore, the dominance of SIBO and estrogen together can wreak havoc on your histamine levels.

So balancing hormones should help, right? In theory, yes. However, the synthetic hormones used by many traditional practitioners in hormone replacement therapy often make histamine intolerance worse.

Research shows that the replacement of synthetic hormones is clearly related to the development of allergies and asthma. This is because synthetic hormones are harsh on mast cells, causing them to produce even more histamine.

Bioidentical hormones work better for women, fortunately. Make sure to do your research if you are considering taking synthetic hormones.

Low thyroid levels contribute to histamine problems

Low thyroid levels can also contribute to histamine problems. Research shows this is likely due to thyroid hormones that help regulate mast cells and reduce histamine production. If you don’t produce enough thyroid hormones, you could end up with much higher histamine levels.

Seeking to correct the root cause of your high histamine should be your first step, but in the meantime, fortunately there are very effective ways to balance that intolerance through enzymes that help to break down histamine and a proper diet with foods that are not high in histamine.


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