How To Clear Histamine From Your Body

How to Clear Histamine from Your Body

Why Histamine Clearance Matters

Histamine intolerance occurs when the body cannot adequately degrade histamine—either from dietary sources or released internally—leading to a wide array of symptoms affecting the skin, gut, cardiovascular, neurological, and respiratory systems. Unlike allergies, histamine intolerance is a non-IgE-mediated sensitivity due to impaired histamine degradation, primarily in the gastrointestinal tract.

Despite its under-recognition in medical settings, histamine intolerance is believed to affect 1–3% of Western populations, with recent research suggesting this may be an underestimate due to symptom overlap with IBS, non-celiac gluten sensitivity (NCGS), migraines, urticaria, and more (source). Many of these conditions may in fact represent undiagnosed histamine intolerance.

Understanding the Root Causes of Histamine Accumulation

Diamine oxidase (DAO), produced by intestinal epithelial cells, is the key enzyme responsible for breaking down histamine in the gut. Low DAO activity leads to systemic overload, even from normal histamine intake. DAO levels below 10 U/mL are suggestive of histamine intolerance, with levels below 3 U/mL indicating a more severe deficiency. Recent data suggests that intestinal disorders like IBD, Crohn’s disease, mucosal damage, SIBO, chemotherapy, and the use of various medications can impair DAO production. This highlights that DAO insufficiency is not always genetic in origin.

Histamine-N-methyltransferase (HNMT) inactivates histamine within cells, particularly in the central nervous system, liver, and lungs. A key SNP (genetic variation) can reduce its function, increasing symptoms such as eczema or asthma. Although not easily measured, genetic testing and symptom clusters may suggest impairment.

Histamine intolerance also originates from imbalances in the gut microbiome. Patients with histamine intolerance frequently harbour histamine-producing bacteria such as Clostridium perfringens and Enterococcus faecalis, while beneficial bacteria like Faecalibacterium and Ruminococcus are often depleted (source).

This microbial imbalance not only raises histamine levels but may also compromise gut barrier function, reducing endogenous DAO expression.

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Key Nutrients and Cofactors That Support Histamine Clearance

Several nutrients are essential for optimal function of histamine-degrading enzymes. Copper and vitamin B6 are direct cofactors for DAO, while S-adenosylmethionine (SAM-e) is a critical methyl donor for HNMT (and thus healthy methylation is a foundation for healthy histamine metabolism). Other nutrients such as magnesium, zinc, and folate support methylation pathways and general detoxification.

A brilliant supplement that provides many of these key nutrients is Histamine Nutrients.

Though not enzyme cofactors, vitamin C and quercetin stabilise mast cells and reduce histamine release. When used together, these compounds create a supportive biochemical environment for managing histamine intolerance.

Clinical pearl: Some people need to go much higher than the standard recommended dose of these nutrients to experience the benefit. My recommended product is Quercetin Ascorbate which comes in a powder allowing you to titrate the dose. A slighter cheaper but still effective option is Quercetin Plus. This is a nice product that contains liposomal quercetin along with additional nutrients such as vitamin C and Luteolin, another helpful nutrient for those with histamine issues.

You can also consider supplementing DAO directly. This, for some, is an absolute game changer but obviously depends on your DAO status (not everyone will have  a DAO deficiency). So in many ways this is a simple test that you can do on yourself – do you benefit from DAO or not? If not, then simply stop taking it and consider the other factors discussed in this blog.

Recommended product: Histamine Digest.

Probiotics and Microbiome-Based Strategies

Emerging research highlights the gut microbiome’s role in histamine metabolism. Certain strains, such as Lactiplantibacillus plantarum LP115, have demonstrated the ability to stimulate epithelial DAO release in vitro. I am not aware of a supplement with this strain in at this point in time. Other probiotic strains can directly degrade histamine or outcompete histaminogenic microbes. Patients with histamine intolerance often present with dysbiosis characterised by increased histamine-producing bacteria and reduced populations of species like F. prausnitzii and Ruminococcus, which are associated with anti-inflammatory effects.

A probiotic I have found incredibly helpful personally, and in clinic, is Lactobacillus Rhamnosus GG.

The Low-Histamine Diet: A Central Platform for Symptom Control

A low-histamine diet remains the cornerstone for managing histamine intolerance symptoms. I emphasis the symptoms as this is not solving the underlying issue, but can improve quality of life (as it improves symptoms). The first step is to eliminate common high-histamine and histamine-releasing foods. These include aged cheeses, cured meats, sauerkraut, wine, kombucha, canned or smoked fish such as sardines and tuna, and vegetables like tomatoes, spinach, and eggplant. Fruits such as citrus, strawberries, bananas, and avocados can also trigger symptoms. Alcohol, vinegar, soy sauce, and black tea may further block DAO function and should be avoided during the elimination phase.

It’s important to appreciate that people seem to have their own unique triggers – some respond to avocados, others don’t, for example. Keeping a symptom diary can be helpful in establishing what your triggers are.

Low-histamine foods include freshly cooked meats and fish, gluten-free grains, and a wide range of fresh vegetables excluding those previously listed. Eggs, herbal teas, and fresh fruits like apples, pears, and melons are generally well tolerated. Cooking methods such as boiling or steaming are preferable, as grilling or frying can increase histamine content.

The diet is typically initiated with a strict 2 to 4-week elimination phase. This is followed by a gradual reintroduction phase, where foods are reintroduced one at a time, every few days, while monitoring for symptom recurrence. This approach enables individuals to identify personal thresholds and develop a sustainable, personalised dietary plan. Notably, even when DAO levels remain unchanged, studies such as Rentzos et al. (2024) report significant symptom improvement during dietary adherence.

Putting It All Together: A Practical Action Plan

Begin by assessing your histamine status. Serum DAO testing is a useful starting point, particularly when levels fall below 10 U/mL. Genetic testing for DAO and HNMT variants and ruling out mimicking conditions like food allergies or mastocytosis can further refine the diagnosis.

Once histamine intolerance is suspected or confirmed, initiate a strict low-histamine diet for 2 to 4 weeks, eliminating common triggers and DAO-blocking foods. During this period, maintain a detailed food and symptom journal to track patterns and responses. This log becomes an invaluable guide during the reintroduction phase.

Supporting enzyme activity through nutritional supplementation is another important step. Supplementing with copper, vitamin B6, magnesium, folate, SAM-e, and antioxidants like vitamin C and quercetin can bolster both DAO and HNMT function. Ideally, these should be used under professional supervision. You can also consider supplementing the enzyme DAO itself.

Next, introduce targeted probiotics such as Lactobacillus Rhamnosus GG. This strain can potentially help reduce histamine intolerance symptoms by down-regulating the IgE and histamine receptors, reducing intestinal permeability, and decreasing the adherence of harmful bacteria to the gut wall. Additional probiotic strains can be selected to rebalance the microbiome by suppressing histaminogenic species.

Following symptom stabilisation, begin the reintroduction phase. Add back individual foods one at a time every few days, noting any changes in your journal. This method helps establish personal histamine tolerance levels.

After several months, re-evaluate DAO activity and consider microbiome profiling to ensure restoration of beneficial gut flora. Finally, transition into an ongoing maintenance plan. This includes a personalised diet based on tolerated foods, continued micronutrient support, and periodic reassessment, especially during life changes or symptom flare-ups.

Commonly Overlooked Factors

Many medications are known to impair DAO function or trigger histamine release. These include NSAIDs like ibuprofen and aspirin, certain antibiotics like clavulanic acid, antidepressants such as amitriptyline, and mucolytics like acetylcysteine. Assessing long-term medication use is crucial when addressing histamine intolerance.

Furthermore, histamine intolerance often overlaps with conditions such as IBS, SIBO, NCGS, IBD, functional dyspepsia, migraine, urticaria, asthma, and mast cell activation disorders. In many cases, these conditions may share underlying mechanisms or be exacerbated by histamine overload.

Finally stress can really exacerbate the symptoms of histamine intolerance and so somatic and nervous system work can be helpful for many. This will look different for different people but might include breathwork, yoga, time in nature, findings things that make you laugh, a bath, more hugs, tai chi, reading (you get the picture!).

What Science Is Exploring Next

Research continues to advance in several key areas. Improved diagnostics, such as urinary methylhistamine profiling and more accurate DAO assays, are under development. Enzyme supplementation with plant- or microbe-derived DAO products is gaining traction, though standardisation and dosing remain challenges.

Another critical need is transparent labelling of histamine content in foods, which would aid consumer choices and dietary planning. Finally, expanding research into the gut-immune-histamine axis may shed light on histamine’s role in conditions like asthma, eczema, and even autoimmune disorders such as multiple sclerosis.

Frequently Asked Questions

Q: Will DAO serum levels rise with the diet?

Not consistently. In Rentzos et al.’s crossover trial, only around half of participants saw increased DAO with the low‑histamine diet; others remained unchanged or declined. Yet overall symptoms improved, underscoring that clinical improvement often precedes measurable increases in enzyme levels

Q: Can I rely on probiotics alone?

Not yet. While L. plantarum LP115 stimulated DAO release in vitro, human clinical trials are still needed before making firm recommendations. Other strains of probiotic including those mentioned, can also be helpful.

Q: What if I’m negative for DAO deficiency?

You may still have HNMT impairment or excessive histamine input via microbiome or mast cell overactivity. Continue with low‑histamine diet, nutrient support, and consider genetic testing and functional assessments.

Q: Should I take DAO enzyme supplements?

They may help as an adjunct, especially if gut health is compromised and endogenous DAO release is low; but current evidence remains preliminary.

Final Word: Why This Guide Matters

This comprehensive guide synthesises peer-reviewed research, including Schnedl and Enko’s landmark 2021 review, with clinical insights and actionable strategies. It integrates the latest understanding of histamine intolerances enzymatic, genetic, microbial, and dietary dimensions. By focusing on gut health, nutrient support, and careful food selection, it empowers individuals to take control of a condition that is frequently misunderstood or misdiagnosed. This guide is intended to serve as both a starting point and a long-term reference for those navigating histamine intolerance.