Do you have unexplained symptoms like asthma, wheezing, runny nose or headaches?
Perhaps you’ve stumbled upon “histamine intolerance” in your pursuit for answers on the internet?
Or maybe, your doctor has diagnosed you with it. Or, like gluten-free and low FODMAP diets, you’ve jumped on the bandwagon yourself after a bit of “self-diagnoses”. Whichever the case, histamine intolerance is real but like most nutrition-related topics, there’s a lot of confusion about it.
You might be surprised to learn what histamine intolerance is, what causes it and what can really be done about it. This article will cover it all and help you understand what your next best steps are to feeling better.
What is histamine?
Histamine is a chemical (biogenic amine) in your body that serves a few roles:
- Tells your stomach to release acid to help with digestion
- Works like neurotransmitters in your brain, allowing your neurons to talk to each other
- Stimulates the immune system as part of the healing process after an injury or allergic reaction
Normally, your body gets all the histamine it needs from its own cells but histamine is also found in some foods.
Histamine in food
A typical healthy diet contains some histamine but there are some foods that contain more histamine than others. If you’re eating a lot of higher-containing histamine foods, your intake will obviously be higher. This may trigger symptoms.
Histamine can be produced from the amino acid histidine (amino acids are the breakdown product of protein digestion). Because certain bacteria and yeasts can do this conversion, aged and fermented foods tend to be higher in histamine (1).
Histamine in your body
As stated above, histamine naturally occurs in your body where it performs different roles. This includes directing digestion, aiding in neuron to neuron cross-talk and it’s involved in your immune system’s response to infections (2).
Where histamine intolerance is concerned, your ability to break histamine down/degrade it, influences your risk for developing symptoms.
Histamine is broken down by two enzymes: 1] diamine oxidase (DAO) which breaks down histamine in the digestive tract, and 2] histamine-N-methyltransferase (HNMT) which breaks down histamine inside cells. (2).
DAO is produced throughout the body by epithelial cells which act as a reservoir; supplying histamine when needed. What will make more sense later in this post, as it relates to gut health, is how gut health itself is a key player in histamine metabolism.
What is histamine intolerance?
It sounds counter-intuitive but histamine intolerance is not sensitivity to histamine (like lactose intolerance), but rather it means you’ve got to much of it.
When histamine levels get too high or when it can’t be broken down adequately, it affects normal bodily functions. The symptoms that occur are very similar to an allergic response. It’s for that reason that people commonly mistake histamine intolerance for other conditions. Because there’s a reaction after eating, people mistakenly conclude they have food allergies/intolerance and/or gastrointestinal diseases/disorders.
The actual prevalence is unknown, but it’s estimated to be about 1% of the population (3).
What causes histamine intolerance?
Histamine intolerance occurs when there is a buildup of histamine in the body. Drugs, medical conditions, medications, the environment, nutritional deficiencies, and diet can lead to histamine intolerance. Risk factors for histamine intolerance result in the following:
- Ingesting/consuming too much histamine
- A decrease in the effectiveness or amount of the enzymes DAO and HNMT (4, 5, 6).
- An overproduction of histamine in the body
Regarding point two, there are different factors that interfere with how well DAO and HMNT work, or how much of DAO is present in the gut.
Common factors that interfere with DAO and HMNT levels include many prescription drugs:
- Airway medications, such as theophylline
- Heart medications
- Muscle relaxants
- Pain medications
- Gastrointestinal medicines
- Acid reducers (H2 antagonists and PPIs)
- Malaria drugs
- Tuberculosis medications
Over-the-counter (OTC) and prescription anti-inflammatory (NSAIDs) and painkillers meds:
- Acetylsalicylic acid (aspirin)
- Ibuprofen (Advil)
- Indomethacin (Indocin)
- Diclofenac (Voltaren)
Other factors influencing DAO/HMNT function include:
- Intestinal conditions or injuries that compromise the gut lining and affect digestion
- Liver conditions
- Vitamin B-6, vitamin C, copper, or zinc deficiencies
- Extreme or chronic stress
- Injury or trauma
What’s the gut and histamine intolerance connection?
Here we are again with the gut. It’s amazing how this organ is involved in so many health conditions. Poor gut health can be a trigger for histamine intolerance too. This makes sense since the gut has a humongous surface area made up of an almost immeasurable amount of epithelial cells; full of histamine (7, 2). Gut damage and inflammation can cause histamine release.
As well, any disease or disorder of the gut (IBS, IBD, gut inflammation, gut barrier dysfunction) that can cause damage to the intestinal cells can/may interfere with DAO activity (8, 9). Damage to enzymes that line the villi (surface of the intestines), a.k.a. “brush board enzymes” can cause trouble.
For example, this is seen with fructose or lactose intolerance; gut infections, gut damage, and gut disorders can lead to deficiencies in enzymes along the surface of the digestive tract make digestion problematic. This can happen with the DAO enzymes too.
Histamine intolerance symptoms
The list of symptoms seems long but when you consider that histamine is a molecule that influences the brain, the digestive tract, and the immune system, histamine is far-reaching when it comes to affecting different body parts and systems (10, 11, 12).
The symptoms of histamine intolerance will vary from person to person but can include any of the following:
- Diarrhea or chronic constipation
- Chronic headache, congested, runny or itchy nose
- Flushing around the head & chest
- Red, itchy or watery eyes
- Sneezing, shortness of breath
- Hives, or red, raised, itchy bumps
- Very itchy skin
- Irregular or increased heart rate
- Very dry, patchy or scaly skin
- Unexplained exhaustion
- Nausea, vomiting, gas, bloating.
People with histamine intolerance tend to have a variety of symptoms that can make it difficult to determine the source. Because it’s not common, histamine intolerance is often overlooked when people seek help for these broad and somewhat vague symptoms. The immediate assumptions is…”allergies”.
Histamine intolerance test
Because is no single, conclusive way that doctors can diagnose histamine intolerance. Ruling out all other potential medical causes is how they diagnose most people. Start from the most likely explanation and work from there.
An allergist or immunologist will often begin by testing someone for food allergies and intolerances and rule those out if they suspect they may have histamine intolerance. Researchers have proposed a skin-prick test for diagnosing histamine intolerance, but it is not widely used and has not been proven repeatedly reliable despite some interesting results (13).
A gastroenterologist might be consulted to assess for common intestinal conditions that might explain any digestive symptoms.
If everything else has been ruled out, and histamine intolerance is suspected, an elimination diet (low histamine diet) will be explored. This involves removing histamine-rich foods from your diet for 4 weeks and slowly adding them back in, one at a time. A step-wide elimination and reintroduction diet can help you determine whether histamine is the problem.
Some naturopathic doctors and other health practitioners will use a simple test using blood spot samples. This can be done in-office or a person can do it at home.
An example of one of these tests is below; a client of mine shared his. He had it tested with another health practitioner. The result indicated adequate DAO levels, low levels of histamine and an ideal ratio of DOA: histamine. Of note, he and I did a low histamine challenge which good or bad, support these findings
Histamine intolerance treatment
Aside from dietary changes, there is no standardized treatment for histamine intolerance.
However, for those who try, they find relief from their symptoms with a few tweaks. What steps to take will depend on each individual’s situation; whether or not it applies to them etc.
Some of the most common medical treatments include:
- Taking antihistamine medication
- Switching prescription medications as needed
- Avoiding or limiting medicines associated with histamine intolerance (NSAIDs)
- Minimizing use of corticosteroids
Histamine intolerance diet
Like the low FODMAP diet, a low histamine diet is not meant to be permanent. Like the low FODMAP diet which is recommended for almost anything gut related these days, the low histamine diet seems to be overly prescribed and recommended.
A low histamine diet is meant to be used short term to assess if histamine might be the cause of your symptoms. If needed, it could be followed longer term with the guidance of a nutrition professional to ensure nutritional adequacy.
Not only are there lower-containing and higher-containing histamine foods to consider with this diet, but some foods can trigger, or stimulate, the release of histamine that’s found in mast cells (2).
FUN FACT: mast cells are a type of cell that is filled with basophil (white blood cell) granules. The granules contain histamine (12).
High histamine foods to avoid
As stated above, fermented and aged foods tend to have a lot of histamine due to the fermentation by bacteria (2). Generally speaking, any and all of the following should be avoided/limited.
- Alcohol and other fermented beverages (kombucha)
- Fermented dairy products
- yogurt, kefir, sour cream, buttermilk, ricotta & cottage cheese
- Dried fruits
- Aged/cured meats
- salami, pepperoni, hot dogs, bacon, sausages & lunch meats
- Soy sauce and tamari
- Fermented vegetables
- sauerkraut, kimchi, miso & natto
- Tea (white/oolong/green/black)
- Processed or smoked meats
- Aged cheeses
Foods that trigger histamine release
- Wheat germ
- Citrus fruits
- Nuts, specifically walnuts, cashews and peanuts
- Food dyes and other additives
There are some foods that block the production of DAO. When there is less DAO available, less histamine will be broken down leading to higher levels of histamine in your body (12).
- Black tea
- Mate tea
- Green tea
- Energy drinks
Low histamine foods to include
Getting more lower histamine-containing foods can help to reduce symptoms. As stated, all foods have histamine, so there’s no such as thing as a histamine-free diet. Lower histamine-containing foods are:
- Fresh meats, fish, poultry
- Non-citrus fruit; fruits not listed as high in the list above
- Eggs (cooked yolk)
- Flash frozen meats/fish
- Fresh vegetables (except tomatoes & eggplant)
- Butter, coconut & rice milk
- Most leafy vegetables except spinach
- Whole grain noodles, breads, crackers & pasta
Histamine intolerance supplements
Several vitamins and minerals are necessary for proper DAO activity. People with histamine intolerance would benefit from including more foods rich in these DAO enzyme-specific nutrients. Because the low histamine diet is so restrictive, a good multivitamin with minerals would be prudent.
Vitamins and minerals that may be good for people with histamine intolerance include:
- Vitamin B6, which helps DAO break down histamine (16, 2).
- Vitamin C to help lower histamine blood levels and help DAO break down histamine (17, 18).
- Copper, which helps raise DAO blood levels slightly and helps DAO break down histamine (19).
- Magnesium that can raise the allergic response threshold (20).
- Manganese that can enhance DAO activity
- Zinc to help DAO break down histamine (it may also have anti-inflammatory and anti-allergic properties) (21).
Probiotics for histamine intolerance
Some bacteria produce histidine decarboxylase (the enzyme that creates histamine), and others produce diamine oxidase (which breaks histamine down). In theory, bacterial strains might help but not all probiotics are created equal where histamine intolerance goes.
Regardless, some probiotic products are likely better than others for histamine-related symptoms. The trick is trying to figure out the exact strain of bacteria used in studies. Normally I advise clients that if a potential treatment is safe, is biologically and physiologically plausible, is ethical, cost effective and they have nothing to lose and possibly everything to gain, to go for it.
The challenge with probiotics is that they are classified by genus, species and strain. It’s at the strain level where effectiveness is determined. Most of the studies on probiotics and histamine intolerance list the genus and species of bacteria tested but not the strain.
This makes buying an effective probiotic difficult; a brand can’t be sourced without information the strain. For this reason, I can’t confidently recommend probiotics to clients.
These supplements support histamine breakdown in the gut. They don’t do anything for the histamine that’s in the other cells of your body.
They work locally, like digestive enzymes do, and help to breakdown the histamine that’s in the food you eat, and therefore reduce the amount of histamine that can be absorbed into your body.
Research is mixed but you can take the approach like I do with any approach to healing. One more time for the folks int he back…..If it’s biologically/physiologically plausible, if there’s some evidence, if it’s safe, won’t break the bank and you have nothing to lose and possibly everything to gain, what not give it a try? (22, 23, 24, 25).
Vitamins and minerals for histamine breakdown
Several vitamins and minerals play a role in histamine metabolism and breakdown.
Ensuring you’re getting enough of these nutrients would be a foundational approach to histamine intolerance management. Taking a good broad-spectrum multivitamin with minerals is a good start. A couple of good brand formulations can be found here* and here*.
Taking supplements of individual nutrients is possible but that’s something that’s best done with the guidance of licensed nutrition professional.
*As an Amazon Associate, I earn from qualifying purchases indicated with an asterisk (*)
Like the name suggests, these medications block histamine. Allergy sufferers know this. Many with histamine intolerance use them to try and get relief.
They do help but they don’t get to the root causes; they just mask the symptoms. The goal is to get to the bottom of the issue and addressing things like diet, medications, gut health issues etc ideally need to be assessed without the masking effects of antihistamines.
Pros and cons of a low histamine diet
Low-histamine diets can be extremely restrictive and, in the long run, may lead to malnutrition. There’s no evidence that a strict low-histamine diet will improve your quality of life in the long term.
The benefit of a low-histamine diet is that it helps to identify your personal tolerance. By eliminating histamine-rich foods from your diet for several weeks (under the supervision of professional) and then slowly adding them back in, you can learn how to personalize the right diet for you (26).
In most cases, making dietary changes, as well as taking anti-histamines or enzyme supplements, helps to manage symptoms within a few weeks.
People managing histamine intolerance will also need to avoid or limit the use of any potentially problematic medications known to trigger histamine release. This may mean working with your doctor to reduce dosages or find alternatives.
Don’t forget about your gut health either. Common foods, medications, alcohol, and gut disorders can reduce DAO activity or cause similar symptoms. Take an integrative approach.
Focusing on fresh, non-packaged or prepared foods more often is a good way to avoid excess histamines, as well as, limiting those foods you’ve found to be a challenge.
Consult with a doctor before beginning a low-histamine diet. If you have symptoms serious enough to consider an elimination diet, then it’s worth ruling out all other possible causes. Nutrient deficiencies are bad at any age, but this diet needs special attention for children who are very susceptible. If you suspect your child has food allergies or is experiencing symptoms of histamine intolerance, talk to your pediatrician.
Generally, a low-histamine diet is not a long-term treatment plan. It’s merely one tool in your toolkit to help you rule out other food intolerances or causes for your symptoms. Ultimately, you will need to determine your individual tolerance and customize a diet suited to your personal needs and goals.