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Evidence Based

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Can I Take Quercetin for Histamine Intolerance?

Written by Dr. Michael Ruscio, DC on January 20, 2025

Written by Dr. Michael Ruscio, DC on January 20, 2025 — Reviewed by Hilary Watts

• What is Quercetin?|
• How Does Quercetin Work?|
• How to Take Quercetin|
• Other Ways to Improve|
• A Multi-Step Approach|

Allergic reactions can range from mildly uncomfortable (runny nose, rash) to dangerous and deadly (anaphylaxis). It’s important to understand your own profile when it comes to allergies and your own body’s histamine response so that you can be prepared if you accidentally get exposed.

About 1 in 50 people have deadly allergies—serious reactions that could result in anaphylaxis—which can cut off airways and require an intervention like an EpiPen 1. But many people experience seasonal allergies, mild to moderate food allergies, food intolerances, hives, and allergic reactions to things like bee stings and poison ivy. 

It’s also true that a small percentage of people experience histamine intolerance, which can lead to uncomfortable symptoms like nausea, bloating, diarrhea, cardiovascular changes or heart palpitations, low blood pressure, and headaches 2. 

Histamine intolerance, which research suggests originates in the gut, might happen if you become deficient in the enzyme that breaks down histamines in common foods 3. That enzyme is called diamine oxidase (DAO) 4. Histamine intolerance supplements and over-the-counter antihistamines may help your body handle histamine. 

We’ll be focusing on the research supporting the use of quercetin supplements, a plant flavonoid, for histamine intolerance. I’ll explain what quercetin is, how it works, how to take it, and other ways to improve histamine intolerance with supplements and diet.

What is Quercetin?

Quercetin is a flavonoid in fruits and vegetables that has antihistamine and anti-inflammatory effects 5. Flavonoids (also called bioflavonoids) are phytochemicals with powerful antioxidant properties. They offer immune health benefits and neutralize harmful free radicals in the body. Quercetin is available in supplement form (capsule usually) in most health food stores, but you can also boost your intake by eating foods that are high in quercetin.

Some of the main food sources of quercetin are 6 7:

• Capers
• Arugula
• Dill
• Coriander (cilantro)
• Fennel
• Juniper berries
• Elderberries
• Bee pollen
• Okra
• Onion
• Asparagus
• Red lettuce
• Cocoa powder
• Hot peppers
• Lingonberries
• Blueberries
• Apple
• Tomato

According to cell and animal studies, quercetin might work by reducing the release of histamine, the chemical that causes itchiness and swelling. This seems to be why quercetin helps alleviate allergy symptoms like itching and sneezing 6. Quercetin may also reduce allergy severity because it has anti-inflammatory properties and inhibits mast cell mediators, which could help reduce allergy severity 6. 

Flavonoids like quercetin can stop the release of histamine from mast cells, a key factor in allergic reactions. Mast cells are a type of white blood cell that release histamine and other inflammatory chemicals. This is a natural part of your immune system reaction. 

Mast cells are found in connective tissue across your whole body, especially under the skin, near blood vessels, lymph vessels, nerves, and in the gut 6. These areas tend to be where you might experience an allergic reaction (rash, lymph node swelling, digestive issues). Sometimes mast cells release too much histamine, which leads to disproportionate reactions. That’s where flavonoids can help.

Flavonoids can also suppress the production of IL-4 and IL-13, which are inflammatory cytokines involved in allergies, and influence immune cell development 6. Cytokines are signaling proteins that activate as part of an immune response.

Quercetin also has the potential to treat asthma and food allergies, as shown in studies with rats and human cells, with no noted side effects 6. Rats who regularly ate quercetin stopped having allergic reactions, such as peanut-induced anaphylaxis 6. 

While this is quite impressive, it may not exactly translate to humans. So, please don’t swap out your EpiPen for quercetin. Adding quercetin into your supplement regimen may be beneficial in reducing the intensity of a reaction; however, we need more research to confirm this for sure. 

How Does Quercetin Work To Reduce Histamine Intolerances?

There isn’t direct research looking at quercetin’s role in reducing histamine intolerance, but preliminary research suggests that quercetin is a promising treatment for any allergic and inflammatory conditions that involve histamine release 8 9 10 11.

This may include things like seasonal allergies, topical skin reactions like rashes or hives, and food sensitivities.

The results seem to be more pronounced in females (who experience histamine intolerance symptoms more often than males) and people with diagnosed diseases. 

Human clinical trials have shown that quercetin can reduce symptoms of seasonal allergies, contact dermatitis, and sun sensitivity 8 12.

How to Take Quercetin for Best Results

At our clinic, we always recommend that our clients start by setting themselves up for success with an altered diet and supportive probiotics. Then we have them add in quercetin. It’s important to talk with your own healthcare provider before embarking on a new supplement protocol. It’s not our goal to replace your doctor or provide medical advice in this article.

Here’s the standard protocol our clients receive:

• Start with a dietary intervention, like a low FODMAP diet or a low histamine diet. 
• Add in probiotics like Triple Therapy Probiotic Sticks.
• Add in quercetin at 500 mg for 2 weeks. (Our Quercetin product has 500 mg per 2 capsules.)
• If there is no difference, increase the dose to 1,000 mg for another 2 weeks. 

We’ve seen our clients experience the best results when following this protocol and adding in additional antihistamine supports, specifically probiotics and DAO enzyme. More on that in the next section.

Other Ways to Improve Histamine Intolerance

We touched on foods that are high in quercetin. But it’s also a good idea to reduce high-histamine foods in your diet, focus on gut-healing foods, and take other supplements that support the gastrointestinal tract. Examples of gut-supporting additions are probiotics and a DAO supplement, as well as other immune supports like vitamin C and vitamin B6.

High-histamine foods to cut back on include things like fermented foods (sauerkraut, kimchi), aged red wine, aged cheeses and meats, canned fish, shellfish, spinach, eggplant, and alcohol 13 14.

Histamine liberators (foods that activate the release of histamine into your bloodstream) to avoid include things like citrus fruits, legumes, chocolate, alcohol, nuts, and seeds 13.

Low histamine foods to eat more of include fresh meat; gluten-free grains like rice, quinoa, or millet; fresh veggies, green tea, berries, apples, and pears; and healthy fats like coconut oil and olive oil 13.

These are not exhaustive lists. It’s also good to note that a permanent elimination of these foods may not be necessary. Your personal tolerance is unique to you. You may want to work with your healthcare provider to come up with a diet plan to test out your own reactions to these foods. 

For a more complete guide, download our Low Histamine Diet eBook.

Support Your Gut Microbiome with a Probiotic

Research seems to show that poor gut health is a root cause of histamine intolerance. So, improving gut health could reduce reactions to allergens and histamine-rich foods over time 3.

We don’t have direct clinical evidence directly linking probiotics with lower histamine levels, but we’ve seen real change with our clients. We’ve found that probiotics likely help improve histamine intolerance through their gut-healing properties. Histamine intolerance may arise from a leaky gut or gut dysbiosis, and probiotics can help repair both. 

In terms of the available research, it’s likely that probiotics can reduce excess histamine, but some controversy exists, and more research in this area is needed. 

Again, between my clinical experience and the overwhelming research on the efficacy of probiotics in improving gut health, we can make some educated inferences:

Multiple studies make a connection between histamine intolerance and gut conditions:

• One study found that 30–55% of patients with digestive symptoms may also have histamine intolerance 15. 
• In another study, patients with histamine intolerance were more likely than controls to test positive for gut bacteria imbalances and leaky gut 16. 
• The digestive tract is full of histamine receptors, and people with GI diseases often have altered expressions of these histamine receptors 17.
• Low DAO levels have been associated with Crohn’s disease and ulcerative colitis, the two most common inflammatory bowel diseases 18 19.

Research clearly shows that probiotics are effective against gut conditions, like:

• SIBO (small intestine bacterial overgrowth) 20
• H. pylori, fungus, protozoa, and parasitic infections 21 22 23 24 
• Leaky gut 25 26

Preliminary evidence suggests that probiotics might be effective against histamine-type symptoms:

• A 2022 meta-analysis found that multi-strain probiotics reduced common symptoms related to histamines (allergic rhinitis), suggesting probiotics may reduce symptoms of histamine intolerance 27. 
• An older meta-analysis and a more recent clinical trial concluded that probiotics significantly reduced symptoms and clinical markers in patients with allergic rhinitis 28 29.
• In a randomized controlled trial, Lactobacillus probiotics improved the quality of life in people with seasonal allergies 30. 
• The use of probiotics for the prevention and/or treatment of allergies have shown promising results 31, but we need more research to confirm.
• An in vitro study found that probiotics reduced the expression of histamine receptor genes on human mast cells, reducing the amount of histamine released 32.
• A mouse study found that probiotics reduced mast cell degranulation in mice 33. Mast cells are a type of immune cell that release large amounts of histamine when they degranulate, aka release their contents into the bloodstream. 

In our clinic, we see the best results with our Triple Therapy approach. The Triple Therapy approach includes all three categories of probiotics, taken daily for 2–3 months, to maximize the efficacy of the probiotic.

DAO Supplements to Reduce Histamine Response

While there’s not yet any direct research on supplemental DAO for treating histamine intolerance, some studies have shown it may be helpful for treating certain symptoms that often occur in people with histamine intolerance. 

For example, randomized controlled trials have found that DAO supplements can:

• Reduce migraine patients’ need for migraine medication 34
• Improve fatigue, anxiety, and depression in fibromyalgia patients 35
• Reduce the severity of hives and the need for antihistamines in hives patients 36

These are all promising findings. There’s no mention of side effects in these studies, but it’s always a good idea to talk to your doctor before trying something new, especially if you have pre-existing health conditions or are already taking other medications or supplements.

Vitamin C and B6 to Support Your Immune Health

Vitamin C and B6 have both been shown to offer antioxidant properties, and vitamin C also provides antihistamine benefits 37. 

A 2013 clinical study found that patients with infectious or allergic diseases (upper respiratory tract infection, viral infection, eosinophilic esophagitis, rhinoconjunctivitis, eczema, or asthma) who received intravenous ascorbic acid (vitamin C) had reductions in serum histamine 38. 

This means that, in the presence of an active immune response, vitamin C reduces the inflammatory response of histamine release.

Studies have also shown that vitamin B6 is connected to the DAO enzyme. Vitamin B6 deficiency may reduce levels of DAO enzyme, which suggests this vitamin has the potential to support DAO levels and reduce histamine intolerance 39 40.

A Multi-Step Approach

Quercetin can be an excellent supplement for reducing histamine intolerance, but it’s most effective when you combine it with a low-histamine diet, probiotics, and possibly a DAO enzyme supplement as well. 

It’s a good idea to pay attention to the foods you’re eating so that you might be able to draw a connection between your diet and your symptoms, but reducing the most common irritants in your food should be your first step.

We would love to help you discover the best way to reduce your histamine response. Reach out to our clinic to set up an appointment.

The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.