Histamine Intolerance: The Ultimate Guide

Are you curious about histamine intolerance and the symptoms it can cause, such as digestive issues, skin problems, and neurological symptoms?

If so, you are in the right place.

Today, I will discuss the symptoms of histamine sensitivity, its nature, and its prevalence.

Key Takeaways

• It’s important to note that histaminosis is not a rare condition. It affects a significant portion of the population, with 30-55 percent of people with digestive issues potentially having this intolerance.

• Biogenic amines, including histamine, play a significant role in histamine overload and can be found in various foods. They impact dietary choices and health outcomes.

• Histamine is an inflammatory mediator in the body and acts as a signalling molecule for the immune system.

• Histamine receptors exist in various body cell types, glands, and organs, and symptoms can affect virtually all systems in the body.

• There is no definitive lab test for histamine intolerance. Diagnosis usually requires a comprehensive clinical evaluation, elimination diets, and various tests to rule out similar disorders or allergies. The diagnosis can be challenging due to the nonspecific nature of symptoms and the absence of validated diagnostic tools. A positive response to dietary changes can help confirm the diagnosis.

• Causes of histamine sensitivity include gut, oral and systemic infections and medications.

• The starting point for treatment should be diet, triggers, gut health and supplements.

What is Histamine Intolerance?

Histamine overload, also known as histamine sensitivity, histaminosis, histamine reaction, or histamine overload, is a condition with an excess of histamine in the body. An excess of histamine occurs when the rate at which the cells release histamine is greater than the rate at which the body enzymes breakdown histamine, particularly diamine oxidase.

The Prevalence of Histamine Intolerance

According to the Canadian Journal of Gastroenterology and Hepatology, 30% to 55% of individuals with digestive issues may have histamine sensitivity. However, this does not imply that those without digestive symptoms are free from histamine-related problems. In fact, histamine could be the root cause of many symptoms, including gastrointestinal issues.

Let’s now look at the main symptoms of histamine.

Symptoms of Histamine Intolerance

Histaminosis affects many systems in the body, from digestion to cardiovascular. Below is a list of some of the most common symptoms:

Digestive

• Bloating

• Diarrhea

• Abdominal pain

• Reflux

Excessive dietary histamine can overwhelm the body’s ability to break down food, causing digestive issues such as bloating and diarrhea.

Histamine stimulates the release of acid in the stomach, which is why heartburn medications called H2 blockers are effective; they reduce histamine release and consequently lower stomach acid levels. Some commentators suggest that individuals experiencing acid reflux may have low acid levels. While this perspective has merit, it’s important to note that those suffering from histamine overload can actually produce excess stomach acid.

Excess histamine can also impact the motility of smooth muscle in the intestinal lining, resulting in diarrhea, constipation, bloating, and food reactivity.

There is a connection between carbohydrate malabsorption and histamine intolerance. A 2016 study found that 55% of patients with carbohydrate malabsorption had low levels of diamine oxidase (DAO) in their blood. This suggests that more than 55% of individuals experiencing carbohydrate malabsorption may also be sensitive to histamine.

Let us look at the neurological symptoms of histamine overload.

Neurological

• Brain fog

• Depression

• Anxiety

• Insomnia

• Fatigue

• Headaches

Taking in outside histamine can make neurological symptoms worse, such as headaches and brain fog. This highlights the need to study more about how histamine intolerance plays a role in these symptoms.

Histamine, a neuromodulator, regulates the release of other neurotransmitters like acetylcholine, norepinephrine, and serotonin. Excess levels can cause neurological symptoms such as headaches, dizziness, insomnia, brain fog, mood fluctuations, and cognitive issues.

Let us look at respiratory symptoms.

Respiratory

• Runny nose

• Sneezing

Because histamine receptors line the nose and sinuses, individuals with histaminosis may experience symptoms similar to seasonal allergies, including a runny nose, congestion, sneezing and difficulty breathing. Consuming foods high in histamine, such as canned tuna, could trigger these symptoms.

Let’s look next at skin symptoms.

Skin

• Hives

• Rashes

The skin has histamine receptors, so an excess of histamine can cause skin symptoms such as inflammation, hives, itchiness, and flushing.

Let’s finally look at cardiovascular symptoms.

Cardiovascular

• Heart palpitations

Because histamine can have either vasoconstrictive or dilatory effects, an excess in the blood can lead to heart palpitations, a racing heart and, in extreme cases, it may lead to Postural orthostatic tachycardia syndrome (POTS).

What is Histamine?

Histamine is an inflammatory mediator in the body and acts as a signalling molecule for the immune system. Many individuals with seasonal allergies take antihistamines to relieve symptoms.

A healthy gut is crucial for a healthy gut lining and microbiota, which directly affects the proper function of histamine-producing mast cells in the gut. You may have heard of mast cell activation syndrome (MCAS), a condition where mast cells release excess histamine and other inflammatory molecules into the body, causing various symptoms. According to Dr. Michael Ruscio, a functional medicine practitioner, histamine overload and MCAS are interchangeable terms.

In contrast, dysbiosis and a leaky gut lining stimulate the mast cells to release excess histamine. The gut lining releases an enzyme known as Diamine oxidase (DAO) that metabolizes histamine. When there is dysbiosis and a leaky gut, the gut lining is damaged, disrupting the production of DAO; hence, histamine levels can rise. Impaired histamine degradation due to reduced enzymatic activity, particularly involving DAO and histamine-N-methyltransferase (HNMT), can contribute to gastrointestinal and inflammatory diseases.

Improving gut health can reduce the release of histamine from the mast cells and increase DAO production and histamine metabolism.

Let us now examine why histamine intolerance symptoms occur throughout the body.

Why do histamine sensitivity symptoms occur throughout the body?

Histamine receptors are present in various body cell types, glands, and organs, including neurons in the brain, vascular smooth muscle cells, the thymus, hepatocytes, intestinal epithelial cells, immune cells, bone marrow, and mast cells.

Let us take a closer look at the role of histamine receptors and the symptoms of histaminosis.

Understanding Histamine Receptors

Histamine receptors are specialized proteins crucial in the body’s response to histamine. There are four main types of histamine receptors: H1, H2, H3, and H4, each with distinct functions and involvement in various physiological processes.

H1 receptors are primarily found in smooth muscle cells, endothelial cells, and neurons. They regulate smooth muscle contraction, vasodilation, and increased vascular permeability. These receptors are also key players in mediating allergic reactions, which can lead to symptoms like itching, sneezing, and a runny nose.

H2 receptors are located in the stomach, intestines, and blood vessels. They regulate gastric acid secretion, gut motility, and blood vessel dilation. H2 receptors also contribute to allergic reactions, manifesting increased heart rate and blood pressure.

H3 receptors are predominantly found in the brain and regulate neurotransmitter release, appetite, and sleep. These receptors can also mediate allergic reactions by increasing histamine release.

H4 receptors exist in immune cells, such as T and dendritic cells. They regulate immune responses, including inflammation and allergic reactions.

Understanding the roles of these histamine receptors is essential for diagnosing and treating histamine oveerload and developing new treatments for allergic diseases.

Let us now look at some health conditions associated with histamine overload.

Histamine Intolerance and Other Diseases

Histamine sensitivity is often associated with other diseases and conditions, complicating diagnosis and treatment. Some of these related conditions include:

1. Food allergy: Histaminosis can be mistaken for a food allergy, as the symptoms can be similar.

2. Irritable bowel syndrome (IBS): Histamine overload can exacerbate IBS symptoms, such as abdominal pain, bloating, and diarrhea.

3. Migraines: Histamine intolerance can trigger migraines in some individuals.

4. Allergic rhinitis: Histamine sensitivity can worsen allergic rhinitis symptoms, such as congestion, sneezing, and a runny nose.

5. Asthma: Histamine overload can trigger asthma symptoms, including wheezing, coughing, and shortness of breath.

6. Chronic fatigue syndrome: Histamine overload can contribute to chronic fatigue syndrome symptoms, such as fatigue, muscle pain, and brain fog.

7. Fibromyalgia: Histamine intolerance can exacerbate fibromyalgia symptoms, including pain, fatigue, and sleep disturbances.

Diagnosing and treating sensitivity is crucial for managing these associated conditions and improving overall health.

Let’s explore how to test options for histaminosis and their merits, starting with genetic testing.

Diagnosing Histamine Overload: Testing Options

Genetic testing

According to Dr. Michael Ruscio, individuals with genetic variations in histamine who suffer from histamine intolerance often believe they will always have this condition. There are over 50 genetic variances in histamine, with four main ones. However, the authors of a 2024 study looking at the prevalence of DAO variants in patients with histamine sensitivity symptoms concluded that “the mere presence of an altered variant would not serve as a diagnostic marker for histaminosis.”

Let’s now look at blood testing.

So genetics could determine some but not all histamine overload cases. In such cases, you can not change your genes, but you can control the healthy functioning of your body by improving gut health. We could conclude that genetic testing is a poor diagnostic tool for histaminosis.

Blood Testing

A blood test for histamine sensitivity measures the levels of the enzyme DAO in the blood. This test can help with a diagnosis, but it is not definitive. One reason is that different clinical trials examining DAO use various diagnostic values. Another reason is that DAO activity in the blood does not necessarily indicate activity in the rest of the body.

Let’s now look at using a low histamine diet to test.

Low Histamine Diet

Following a low-histamine diet is a simple and effective way to test for histaminosis. A 2021 review paper concluded this.

A histamine-free diet is crucial for individuals suffering from histamine overload, as it can significantly alleviate symptoms such as headaches and skin conditions. This dietary approach is important in clinical settings for diagnosing and managing histamine-related issues.

The good part about using the diet is that you can see results quickly, from a couple of days to one week.

According to Dr. Ruscio, if you do not see any change in symptoms in the second week, then the low histamine diet is not the right fit for you.

Now, look at foods you should avoid on a low-histamine diet.

Low Histamine Foods

Fermented foods are high in histamine. Many cultures view fermented foods as beneficial because they are rich in probiotics. Examples of fermented foods are kefir, kimchi, sauerkraut, and tempeh. However, we recommend avoiding these foods when following a histamine diet.

Food Groups	Safe	Avoid
Vegetables	Fresh vegetables (except avocados, eggplant, spinach and tomatoes).	Avocados, eggplant, spinach and tomatoes.  Sauerkraut and other fermented vegetables.
Fruit	Fresh fruit (except citrus, banana, papaya, pineapple and strawberries).	Citrus, banana, papaya, pineapple and strawberries.  Dried fruit: apricots, prunes, dates, figs and raisins.
Grains	Gluten-free grains such as rice and quinoa.	Baked foods made from wheat flour, including sourdough bread.
Nuts	Brazil nuts, pecans, pistachios and walnuts.	Almonds, cashews and peanuts.
Dairy	None.	All dairy products made from cows’ and goats’ milk.
Dairy Alternatives	Coconut, rice, hemp and almond milk.	Coconut, rice, hemp and almond yogurt.
Protein	Freshly cooked red meat and poultry. (frozen or fresh)  Freshly caught fish.  Eggs.	Cold cuts.  Cured meats: bacon.  Processed meats: sausages and hot dogs.  Shellfish.  Mackerel, mani and tuna.  Smoked fish.  Anchovies and sardines.
Fats	Olive oil and coconut oil.
Treats		Chocolate
Herbs and spices	Leafy herbs.	Spices
Condiments	Salt and pepper.	Soy sauce, miso, vinegar, mayonnaise, pickles and olives.
Food Additives	None.	Artificial additives, colours, dyes, preservatives and sweeteners.
Drinks	Herbal tea.	Black and green tea. Mate.
Alcohol	None.	Alcohol in general, especially beer, champagne and wine.

There is no need to avoid high-histamine foods altogether. Instead, focus on moderation to help manage symptoms better.

Another advantage of the diet is that it boosts DAO activity in the gut. This finding emphasizes that an appropriate diet can promote healing and restoration but is short-term.

Leftovers are food not listed on the table. If they are more than 24 hours old, they are high in histamine. Consistent consumption of these foods will likely cause problems.

Gluten and dairy are included in the diet because they tend to be inflammatory, which will prevent the healing of the gut lining and the restoration of DAO production.

Let us explore histamine intolerance and gut types.

Histamine Sensitivity and Gut Types

The concept of gut types originates from Dr. Michael Ruscio, who classifies his clients into bacterial and fungal types in his functional medicine practice. For example, an individual with a histamine issue may not thrive on a vegetable diet if they have a bacterial gut type. On the other hand, someone who struggles with a high-carb diet may fall into the fungal gut type category. This observation highlights that there is always an underlying reason for histaminosis, which does not occur in isolation.

So, if an individual with a histamine issue bloats when they eat vegetables, that may indicate a bacterial problem. This individual may respond better with a low histamine/low fodmap diet. Conversely, an individual may do well on a low-carb paleo-style diet, indicating a fungal problem.

Let us look at some other causes of histamine overload.

Causes of Histamine Intolerance

As we can see from the two different gut types, histamine sensitivity does not occur in isolation.

Other causes, including nutrient deficiencies, interfere with the production of DAO, namely B6, vitamin C, and copper.

There are also hormonal fluctuations, namely estrogen, which impact the function of the DAO enzyme. This impact on histamine may explain why sometimes women experience cramping and headaches during their cycles.

An environmental cause of histaminosis could be chronic mould exposure. It’s important to note that mould is not usually a problem if found in small amounts, such as around windows. However, if there are significant amounts of mould in a home, a sign that it may be an issue is if symptoms improve when outside compared to inside.

Another cause of histamine overload is medications, including certain antibiotics, prokinetics, anti-inflammatories, and anti-depressants, which affect the activity of DAO. Histamine toxicity can occur when ingested histamine overwhelms the body’s histamine-degrading enzymes, leading to symptoms such as flushing, headache, and gastrointestinal distress.

Let’s now look at some supplements that can help with histamine intolerance.

What Supplements Might be Beneficial for Histamine Sensitivity?

Supplements may be beneficial for histaminosis; however, they should be used in addition to treating the underlying causes.

A few of the supplements that may help lower histamine include:

• Vitamin C

• Quercetin

• Resveratrol

• DAO enzymes

• Probiotics

• Over-the-counter antihistamine medications such as Claritin and Allegra

These supplements can also help manage acute symptoms of histamine intoxication, which is often caused by consuming high-histamine foods like spoiled fish.

Some other prescribed medications may be helpful, such as x and y.

If symptoms persist after following the low histamine diet, treating gut infections, and taking supplements, consider the presence of other underlying diseases.

One such infection is bacteria overgrowth of the nose and sinus cavities, known as SIBO of the nose. Individuals with this infection may have chronic nasal and sinus congestion or recurrent nasal infections.

Another common oral infection occurs around the teeth or in cavities. In such cases, it’s essential to consult with a qualified dentist.

Finally, and not least, are vector-borne infections. Historically, the label for these types of infections has been Lyme disease. However, this label is inaccurate because Borrelia, the bacterial infection associated with Lyme, is less common than Babesia. Such infections can lead to immune and digestive dysfunction, affecting histamine activity and metabolism. Interestingly, a 2021 scientific paper concluded that three or more digestive or body-wide symptoms increased the likelihood of a vector-borne infection.

Let us look at some lifestyle changes that can help manage symptoms of histamine overload.

How to Manage Symptoms of Histamine Intolerance

Managing symptoms of histamine sensitivity requires a comprehensive approach involving dietary adjustments, lifestyle changes, and stress management techniques. Here are some lifestyle modifications that can help alleviate symptoms:

1. Low histamine diet: Avoid foods high in histamine, such as fermented foods, fish, and citrus fruits. Instead, focus on eating fresh fruits, vegetables, lean meats, and whole grains.

2. Avoid histamine liberators: Avoid foods and substances that trigger histamine release, such as spicy foods, caffeine, and certain medications.

3. Stay hydrated: Drinking plenty of water helps flush out histamine from the body.

4. Exercise regularly: Regular physical activity can reduce stress and improve overall health.

5. Manage stress: Stress can exacerbate histamine intolerance symptoms. Practice stress-reducing techniques like meditation, yoga, or deep breathing exercises.

6. Get enough sleep: Lack of sleep can worsen histamine intolerance symptoms. Aim for 7-8 hours of sleep per night.

7. Avoid exposure to allergens: Minimize exposure to allergens such as dust, pollen, and pet dander, which can trigger allergic reactions.

By incorporating these lifestyle changes, individuals with histamine overload can better manage their symptoms and improve their overall quality of life.

Recap

The following points are a summary of this article:

• A multisystem collection of symptoms is suggestive of histamine sensitivity.

• Following the proper diet can make a big difference. Gut health is a vital component.

• A starting point for treatment is diet, reducing triggers gut health and antihistamine supplements and medications.

Now It’s Over To You

Do you have any histaminosis symptoms?

Let me know in the comments below.

Do You Need Help?

If you need help, I suggest you book a free functional medicine discovery session with me to determine whether my approach fits your needs.

Disclaimer

The information provided on this website is for educational purposes only and is not intended to diagnose or treat any disease. Please do not apply this information without first speaking with your doctor.