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If you’ve already tried some of the typical diets or had food sensitivity testing and you haven’t improved, you may want to explore histamine intolerance. It can be the root cause of tricky health problems like migraines, skin irritation, and digestive upset.
Histamine intolerance symptoms can mimic other conditions, so it’s crucial to rule out other health issues before trying a low histamine diet. A low histamine diet isn’t the first thing you want to try to optimize your health.
What Is Histamine?
Everyone has histamine in their bodies. You’ve probably heard of antihistamines for allergic reactions. Made from the precursor amino acid, histidine, it has many roles in the body:
- Contracts smooth muscles (like for breathing)
- Dilates blood vessels
- Influences blood pressure
- Stimulates gastric juices
- Involved in immunomodulation
Histamine also helps the body heal from injuries and allergies by increasing blood flow to parts of the body. It’s also a neurotransmitter in the brain, relaying messages and regulating the wake-sleep cycle.
There are four types of histamine receptors in our bodies:
- H1 – are everywhere in the body
- H2 – are mainly in the gastrointestinal tract (stomach, duodenum, and small intestine)
- H3 – are in the nervous system
- H4 – are present in a small amount in certain tissues, like the skin, tonsils, and spleen
What Is Histamine Intolerance?
Histamine intolerance (HIT) is when a person cannot properly metabolize and degrade histamine in their digestive tract and in the rest of the body. It is not an allergy or food intolerance but more like a build-up or a bucket overflowing that causes symptoms.
Some hypothesize that the overuse of antibiotics has handicapped our microbiome and its ability to break down histamine. You’ll see that HIT is linked to other conditions, and we’re still learning exactly how.
Symptoms of Histamine Intolerance
The symptoms of histamine intolerance typically occur anywhere between 30 minutes to 72 hours after ingesting certain foods. People tend to experience different symptoms and may experience them from only one category, multiple categories, or all of them. An official diagnosis requires:
- an improvement or remission of symptoms with a low histamine diet
- at least one positive lab or genetic marker
- two or more symptoms once your doctor rules out other conditions (see symptoms below)
The four types of histamine receptors all over the body may explain the variability of symptoms. Here are the common HIT symptoms by body system:
- Redness and flushing
- Urticaria (hives)
- Pruritus (itchy skin)
- Hypotension (low blood pressure)
- Painful periods
- PMS symptoms like cramps, headache, nausea, vomiting, etc.
Histamine may be part of the cascade that creates uterus contractions during your period and it’s possible that HIT may be a significant player in hormonal migraines.
How does a person get to the point that their body can no longer metabolize histamine? There are a few different causes of HIT to explore.
First, it’s essential to rule out pharmaceuticals. Certain drugs can cause histamine intolerance by causing diamine oxidase (DAO) deficiency, so check with your pharmacist about that potential interaction.
Histamine has two main enzyme pathways in the body: histamine-N-methyltransferase (HNMT) and DAO. Genetic mutations called single nucleotide polymorphisms (SNPs) of amino acids can cause both of these to function abnormally. The next sections are a little dense but it’s essential to understand if you’re struggling with this.
HMNT breaks down histamine throughout the body. If you have the MTHFR mutation, you may struggle to break down histamine unless you supplement with a methylated vitamin B. This is important to watch carefully because too much vitamin B may be inflammatory, so you’ll need to work closely with a doctor on it and get regular bloodwork.
You can dig more into this research I’ve already done on MTHFR:
- What Is a MTHFR Mutation?
- 29: Methylation Problems & Gene Mutations
- 97: OB & Midwife Aviva Romm on PPD, Thyroid Problems, & MTHFR
- 135: Understanding Genetic Testing, Epigenetics & Genetic Polymorphisms with Dr. Ben Lynch
The DAO enzyme primarily breaks down histamine in the intestines, kidneys, and colon, keeping it from leaking into the bloodstream. Normal DAO levels keep histamine levels from rising above normal in the bloodstream. Some consider DAO activity like a bouncer in the mucosal lining of your digestive tract, keeping too much histamine from crossing.
We do know that the body needs copper to make DAO. A common first step is to do blood tests for copper, zinc, and a copper/zinc ratio. You can accidentally overdose on zinc and deplete your copper, which prevents the proper breakdown of histamine. For some, simply adding a copper supplement can reduce their HIT symptoms.
Researchers have identified over 50 SNPs in DAO genes that alter its activity and may lead to histamine intolerance. If your tests come back normal, or if you supplement with copper and it doesn’t alleviate any of your symptoms, talk to your doctor about taking a DAO enzyme like this one by Seeking Health.
Interestingly, the placenta produces high amounts of DAO, which may lead to some women finding relief during pregnancy. This doesn’t happen for everyone with HIT though.
Why It’s Hard to Diagnose HIT
In order to get a HIT diagnosis, your doctor must rule out the following:
- Skin prick food allergy test
- Tryptase levels for systemic mastocytosis
- DAO inhibiting drugs
- SIBO or another infection that could be releasing histamine with a breath test (Listen to my interview with Sarah Kay Hoffman to learn more about the links between histamine intolerance, SIBO, and IBS)
Once all of those have been ruled out, some doctors will try to measure:
- DAO – in the blood plasma
- Histamine – in the blood plasma (but you should know that an accurate measure requires immediate freezing (cold centrifuged) to be accurate, so call the lab beforehand to ask if they do this, but don’t be surprised if they say no…. Just know that the levels of histamine may not be accurate.)
- Urinary-N-Methyl Histamine – to rule out mast cell activation disorders and mastocytosis
- Vitamin B12 & B9 – to rule out MTHFR and HMNT issues
- Copper and zinc – to ensure the body can adequately make DAO
- Genetic SNPs – like DAO and HNMT with a test like the StrateGene DNA Kit
Ideally, you’ll want to get these tests done before limiting histamine in your diet so that you get an accurate picture of your health.
How to Do a Low Histamine Diet
The primary treatment for HIT is to reduce your histamine intake as much as possible so your body can calm down. Some practitioners will recommend a short-term low histamine diet to see if symptoms reduce, especially if the patient lacks the resources to get tests or can’t access them. (It’s impossible to do a totally histamine-free diet.)
It’s usually a good idea to follow a low histamine elimination diet for 4-8 weeks to see if it lowers your symptoms. Some will continue to stay on the first phase for six months if they also struggle with mast cell activation syndrome.
Once you have completed your elimination diet, you can start a test phase. Reintroduce foods into your diet and see how you react for 3-4 days before introducing the next one. As always, I suggest focusing on healthy foods such as vegetables and produce that are in season.
From there, find the right long-term balance for you. It’s best not to stay low histamine for too long because histamine is needed for certain biological functions such as daytime waking, normal healing cycles, and stomach acid production.
High Histamine Foods
This list contains some general trends. There isn’t a consensus among sources on which foods are actually high in histamine since the way foods are grown, stored, and transported can highly affect the amount of histamine.
The well known histamine-rich foods are:
- Fermented foods – sauerkraut, alcohol, kimchi, yogurt, kombucha, and vanilla extract
- Aged meats and dairy – beef (it’s typically aged for 2 weeks unless you specifically ask the butcher not to), fish (it typically sits on a boat in the fridge for days or weeks), jerky, and aged cheeses
- Ground meats
- Canned foods – beans, lentils, fish, vegetables, and fruit
- Refrigerated meats – any meat that hasn’t been immediately frozen and recently thawed
- Slow-cooked foods – bone broth, chili, and other crockpot meals
- Nuts – peanuts, walnuts, and cashews
- Artificial dyes and colors
- Artificial sweeteners
If you eat something and you think you react, make a note of it. You may want to do some research to see if some sources suggest it may have more histamine than you realized.
Ways to Reduce Histamine Levels in Foods
In order to be low histamine, you must handle foods a certain way. Here are the main ones:
- Frozen meat – Buy meat that you know they immediately freeze, like ButcherBox and Vital Choice.
- Flash thaw – Soak meats in warm water to defrost them quickly. This works best for thinner cuts like salmon filets.
- Freeze leftovers – Immediately place them in the freezer in glass containers (not plastic) so that histamine-releasing bacteria can’t grow.
- Instant Pot – Use the pressure cooker function to infuse flavors in meals that you usually slow cook to reduce histamine.
- Fresh produce – Buy locally from your farmer’s market or health food store when they’re in season.
- Frozen produce – For foods that you can’t ensure how they’ve been handled, buy them frozen to reduce histamine.
- Tomatoes – Buy small tomatoes like cherry or grape as these have less histamine than the larger ones (only for later phases or when you want to indulge).
- Carrots – Look for carrots with fresh green tops, so you know they are fresh.
- Bone broth – Use the Instant Pot version in this recipe to keep histamine low. You may reduce the cooking time to 30 minutes to still glean some of its benefits.
Other Factors That Raise Histamine Levels in the Body
There are other influences on histamine you should know that are both food and lifestyle-related.
Some foods have amines that may increase histamine levels in the body. The foods that trigger this are:
- Citrus fruits
- Uncooked egg white (common on mayo)
- Olive oil
- Sugar – You may want to avoid sugar and any sugar substitutes that raise blood sugar (like coconut sugar, honey, maple syrup, agave, etc.) and stick with stevia and pure monk fruit
Some doctors hypothesize that oxalate poisoning can trigger an elevated histamine response, so if you’ve tried a low histamine diet, you may want to talk to your doctor about slowly reducing your oxalate intake.
In addition to bacterial infections, some probiotic strains may increase histamine levels. The main ones are in the Lactobacillus family, so talk to your doctor about switching to the suggested ones in the next section.
Stress raises cortisol and histamine levels in the body. Follow these tips to help reduce stress naturally.
Eating too Frequently
Every time you eat, your body expresses histamine. If you can, intermittent fast to reduce your eating window to 12 hours or less. This will help reduce your body’s histamine burden.
Natural Remedies for Histamine Intolerance Symptoms
Once a person has determined that histamines might be the issue, they can use these tools to help manage their symptoms in addition to a low histamine diet.
If you’re wondering whether or not you have enough diamine oxidase, you may want to talk to your doctor about taking Seeking Health’s Histamine Block. It’s a pork-based DAO enzyme that helps your body break down histamine in your intestines. They recommend taking it about 15 minutes before eating any histamine-rich foods. Some take it during their elimination phase to help them break down any excess histamine in their systems.
For additional support, they also have Histamine Block Plus. It not only has DAO but also additional nutrients, including a balance of copper and zinc, vitamin C, and vitamin B.
These probiotic strains may help break down histamine:
- Lactiplantibacillus plantarum
- Lacticaseibacillus rhamnosus
- Bacillus family
We’ve used Genexa’s Allergy Care, and it could help with symptoms of histamine intolerance, especially ones that mimic seasonal allergies.
Do not take any form of antihistamines if you are pregnant or nursing as it reduces milk supply and can interfere with hormones.
Before taking an OTC antihistamine, start with natural ones. The main ingredients you want to see are:
- Stinging Nettle
- Vitamin C
The best product I have found with many of these included is HistaminX.
When natural remedies aren’t enough, there’s no shame in using the best of conventional medicine. Even holistic practitioners will suggest OTC antihistamines to help alleviate severe symptoms during the elimination phase and as a bandaid during the reintroduction phase. They work on the H1 receptors. However, try to limit them to short-term use as many warn against long-term side effects. If myself or a loved one ever got to this point, I’d try a 2nd generation antihistamine like Zyrtec, Allegra, or Claritin.
- For more information, listen to my mast cell activation syndrome and histamine intolerance podcast interview with expert Beth O’Hara, FN.
- Check out the book The 4-Phase Histamine Reset Plan: Getting to the Root of Migraines, Eczema, Vertigo, Allergies and More by Dr. Becky Campbell.
This article was scientifically reviewed by Beth O’Hara, FN. She is a functional naturopath who specializes in histamine intolerance, mast cell activation syndrome, and mold toxicity. Find her work at mastcell360.com.
Have you tried a low histamine diet? Did it help alleviate any of your histamine intolerance symptoms?