What Are the Symptoms of Histamine Intolerance?

What Are Histamines?

Histamine is a compound your body produces naturally, and it also occurs in many foods. Inside the body, histamine is stored mainly in mast cells and released as part of the immune response. Beyond immunity, histamine also plays a role in digestion (helping trigger stomach acid production) and in the nervous system, including your sleep-wake rhythm (1).

In food, histamine is a natural byproduct of fermentation and aging, which is why items like aged cheese, cured meats, wine, and sauerkraut tend to contain higher levels. Normally, the enzyme diamine oxidase (DAO) breaks down histamine from food before it builds up. Histamine intolerance symptoms appear when that breakdown process can’t keep pace with intake.

Histamine intolerance

Histamine intolerance is a condition where the body struggles to break down histamine effectively, leading to a variety of histamine symptoms often mistaken for allergies. Histamine is a natural compound involved in the immune and digestive systems, responsible for triggering responses to injuries or allergens. It is also present in various foods, especially aged or fermented items. When too much histamine accumulates, it can lead to symptoms resembling allergic reactions, causing significant discomfort for those affected.

What Is Histamine Intolerance?

How Is Histamine Intolerance Different From a Histamine Allergy?

Understanding histamine intolerance starts with distinguishing it from a histamine allergy. While both can cause similar reactions, histamine intolerance is a metabolic issue rather than an immune response. In histamine intolerance, the body lacks sufficient DAO enzyme activity to break down histamine. In contrast, a histamine allergy involves an immune reaction where the body perceives histamine as a harmful substance. This difference is crucial, as histamine intolerance symptoms stem from an inability to metabolize histamine rather than an allergic reaction, although they may appear similar.(1) There are also other histamine intolerance causes:

Imbalance in histamine-producing and -degrading bacteria
An imbalance in gut bacteria can increase histamine production or reduce its breakdown. Certain bacteria produce histamine, so an overgrowth can exacerbate symptoms.

High histamine foods
Foods like aged cheese, wine, fermented products, and certain vegetables contain high levels of histamine. Consuming these foods can overload the body’s ability to break down histamine, especially in those with reduced DAO activity. Consuming foods with lower levels in histamine might help. There are also several low histamine foods.

Medications
Some medications, like NSAIDs, antidepressants, and antihistamines, can inhibit DAO activity or promote histamine release, worsening symptoms in people with histamine intolerance.

Gastrointestinal disorders
Conditions like irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), or inflammatory bowel disease (IBD) can reduce DAO enzyme levels and impair histamine metabolism, leading to symptoms.

Hormonal fluctuations
Hormones like estrogen can influence histamine release and DAO levels, which may explain why some people experience increased histamine intolerance symptoms during certain points in the menstrual cycle.

What Happens During a Histamine Reaction?

A histamine reaction starts when histamine is released, either from mast cells as part of an immune response, or because it has built up faster than DAO can clear it after a meal. Once released, histamine binds to receptors found throughout the body: in blood vessels, the skin, the gut, the airways, and the brain.

This binding is what produces the symptoms people notice. In blood vessels, histamine causes them to widen and become more permeable, which shows up as flushing or swelling. In the gut, it can trigger smooth-muscle contractions and extra acid or mucus production, leading to cramping or bloating. In the skin and nerves, it can trigger itching. In the airways, it can cause congestion. Under normal circumstances, this is a short-lived, useful response. In histamine intolerance, low DAO activity means histamine lingers longer and the reaction is more prolonged or pronounced than it would otherwise be even without a true allergen involved.(1,2)

What Are the Common Symptoms of Histamine Intolerance?

• Gastrointestinal symptoms: Too much histamine in the digestive system can lead to bloating, stomach cramps, diarrhea, and discomfort. These symptoms may be mistakenly attributed to food allergies or irritable bowel syndrome.
• Skin reactions: One of the most visible signs of histamine intolerance, skin reactions include itching, flushing, hives, or eczema. Many people experience histamine allergy symptoms on their skin, leading to redness and swelling, particularly after consuming high-histamine foods.
• Respiratory symptoms: Histamine reaction symptoms in the respiratory system may involve congestion, sneezing, or a runny nose. These symptoms mimic seasonal allergies, making it challenging to differentiate between histamine intolerance and traditional allergies.
• Cardiovascular symptoms: Histamine intolerance can also impact cardiovascular health, causing headaches, migraines, irregular heartbeats, and even high blood pressure. Histamine response symptoms, such as migraines, can be particularly severe and may occur in response to specific foods or environmental factors.
• Other symptoms: Histamine response symptoms can cause fatigue, anxiety, and dizziness, further complicating diagnosis. Since these symptoms overlap with various conditions, identifying histamine as the cause is often difficult without proper guidance.

How to know if you have histamine intolerance

If you suspect histamine intolerance, several diagnostic approaches can help determine whether histamine is the source of your symptoms.

• Elimination diet: An elimination diet involves removing high-histamine foods from your diet and gradually reintroducing them. This approach allows you to monitor symptom improvement and identify specific triggers.
• Histamine testing: Blood tests can measure DAO enzyme activity and histamine levels in the blood. Low DAO activity is a significant indicator of histamine intolerance, as it suggests the body’s inability to break down histamine efficiently.
• Symptom diary: Keeping a symptom diary to track histamine symptoms can reveal patterns over time, particularly in response to diet and environment. This record can be valuable when working with a healthcare provider for an accurate diagnosis.

Managing histamine intolerance

Managing histamine intolerance involves dietary adjustments, supplements, and lifestyle changes to reduce histamine levels in the body. A low-histamine diet, which limits foods like aged cheeses, fermented products, and alcohol, can minimize symptoms. Supplements, such as DAO enzyme supplements, can help break down histamine to help reduce symptoms.* Additionally, lifestyle changes, including stress reduction and avoiding known triggers, play an essential role in controlling histamine reaction symptoms.

You can read more about the topic in our knowledge bank. If you suspect a food intolerance but are not yet certain you can contact one of our dietitians for personalized advice. If you’re looking for enzymes to support your situation you can try our supplement advisor below!:

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.