Chances are you’ve heard of antihistamines - medications used to control allergic reactions and allergy symptoms. But have you heard of histamine intolerance? I hadn’t either and learned a lot from the mother of one of my patients. Now I regularly treat patients with this problem and the improvements can be dramatic if you’re suffering with the symptoms.
A Determined Mom Paves the Way
I first learned about the impact of histamine intolerance not in medical school, but from the dedicated mother of one of my patients. Her teenaged daughter was struggling with a host of seemingly disconnected, and to her doctors somewhat bizarre, symptoms: racing heart and severe weakness and dizziness after eating, extreme low blood pressure that sometimes cause fainting, skin rashes and hives, severe abdominal pain, and debilitating anxiety. She’d been seen by a whole host of practitioners who largely dismissed her as making them up, and she was ultimately diagnosed with an anxiety disorder. When I met her she was 14 years old, weak and underweight because every food she ate seemed to make her worse. This previously high achieving student had now missed her entire first year of high school due to disability. In fact, she was so weak she was barely able to get out of bed.
Desperate to find an answer, her mother became a ‘citizen scientist,’ and when she brought her daughter in for her first appointment with me, she asked if I’d ever hear of histamine intolerance. I explained to her that I’d learned a great deal about the impact of histamine on the body as a medical student, and was familiar with mastocytosis and allergic reactions, but not histamine intolerance as a medical condition per se. But I’ve learned to learn from my patients, did my homework, and sure enough, this mom, who’d previously been told by several of her daughter’s doctors in no uncertain terms that she was too pushy (she was pretty sure she’d heard the term ‘pain in the ass’ get used about her in a doctor’s office) did in fact figure out what was going on with her daughter.
In the years since I’ve seen and treated many patients with HIT and while it’s not common in the general population, it’s often a hidden cause of symptoms that should be taken seriously and that your doctor might not know anything about. It’s especially important to consider if you’ve tried an elimination diet and it just hasn’t done the trick for you, because there are very specific dietary changes that are necessary to make.
The Lesser-Known Food Intolerance
The term “food intolerance” refers to foods to which you are sensitive and that can therefore cause you symptoms when you eat them. Lactose intolerance is one of the most common, and gluten intolerance is another that’s been on the rise in that past decade. Food intolerances can cause myriad symptoms that often get chalked up to “normal” facts of life, like seasonal allergies, headaches, and aches and pains (none of which actually are ‘just normal’ – they are reflect deeper imbalances going on). Food intolerances can also cause more serious illness, for example, diabetes and autoimmune disease.
In fact, many foods can cause intolerance in an individual for a variety of reasons, often having to do with imbalances in the gut or over-activation of the immune system, though they are not true food allergies.
One of the lesser-known types of food intolerances is called histamine intolerance (HIT). It appears to be on the rise and can cause a range of symptoms. The good news is that most often, it is readily treatable.
Wait, What is Histamine?
Histamine is a chemical your immune system releases from a variety of cells in which it is stored, in response to a variety of allergic and toxic exposures, for example, bee stings and certain foods like peanuts in those with peanut allergies. When such an exposure happens, histamine-containing cells (mostly mast cells and basophils) dump histamine into your bloodstream leading to a rapid inflammatory reaction that causes the blood vessels to become more permeable, allowing the immune system’s white blood cells to reach the area where the ‘invasion’ has occurred. Its also activates nerves that stimulate your respiratory passages to constrict, your eyes to water, and nose to run. Because cells throughout your body including your digestive system, heart and vascular system, skin, and lungs respond to histamine as part of its protective response, the response occurs widely throughout the body and can be multi-systemic causing all of the symptoms I list in the next section. Histamine produced in the brain acts as a neurotransmitter – a chemical involved in signaling in your nervous system; in the stomach, histamine stimulates the production of gastric acid necessary for digestion.
Do You Have Histamine Intolerance?
While histamine intolerance is not a true food allergy, and thus not usually considered life threatening, the symptoms can be quite severe and have led many people to the emergency department! If you’re experiencing any of the following symptoms, it could be that you, too, have HIT. Here are the most common symptoms:
- Abdominal cramps, diarrhea
- Difficulty falling asleep or staying asleep
- Dizziness, vertigo
- Feeling too hot or frequently chilled for now reason
- Fatigue or weakness
- Low of high blood pressure (can be extreme in either direction)
- Migraines or headaches
- Hives, Itching, Eczema
- Menstrual cramps or premenstrual headaches
- Nasal congestion, sneezing, itchy eyes, difficulty breathing
- Nausea or vomiting
- Puffiness, swelling
- Racing heart, especially but not always after eating certain foods
- Skin flushing, especially but not always after eating certain foods
- Wine/alcohol intolerance
When you have impaired histamine breakdown, excess histamine can build up, resulting in symptoms that mimic an allergic reaction – which are many of those I’ve just listed.
What Causes Histamine Intolerance?
Histamine intolerance results from an imbalance between the amount of histamine that is released from your cells in response to certain triggers, or builds up in your body as a result of foods you eat – and your body’s ability to break it down and clear it out, which it does using two naturally occurring enzymes your body is supposed to produce – Diamine oxidase (DAO) and histamine N-methyltransferase (HNMT).
However, due to either genetics or acquired reasons, your body might not produce enough of one or the other, or both of these. HNMT is produced inside the cells and is usually more genetically influenced. DAO, however, is produced in the intestine, and is also the enzyme responsible for breakdown of ingested histamine, so if there has been intestinal damage, DAO production might be reduced. This can occur as a result of:
- Leaky gut
- Crohn’s disease or ulcerative colitis
- Celiac disease and non-celiac gluten intolerance
- Small intestinal bacterial overgrowth (SIBO)
- Certain medications including: NSAIDS (ibuprofen), Antidepressants (Cymbalta, Effexor, Prozac, Zoloft), Antihistamines (Allegra, Benadryl ,Zyrtec), Histamine (H2) blockers (Pepcid, Zantac0, Immune modulators (Enbrel, Humira, Plaquenil), Antiarrhythmics/Calcium channel blockers (amlodipine, diltiazem, propanolol, metoprolol)
DAO-blocking foods including alcohol can also lead to decreased availability of DAO to break down histamine, resulting in elevated levels. Consuming high histamine foods can also cause a problem, especially if your enzyme system is impaired.
HIT is more common in people with Inflammatory Bowel Disease (IBD – Ulcerative colitis and Crohn’s), celiac disease, and SIBO, as well as eczema, all conditions that have been associated with intestinal inflammation.
Dysregulation in the stress response system – whether adrenal overdrive with high cortisol, or inhibited adrenal function with low cortisol – can also impair the immune system leading to increased reactivity to foods, and stress seems to worsen HIT in many individuals.
Can I Get Tested to See If I Have Histamine Intolerance?
There are currently no tests that are proven to diagnose histamine intolerance, and though blood and urine levels of histamine can be measured, because histamine levels are so naturally variable depending on time of day and also when you’ve eaten, it’s just not a reliable way to test for this problem. Similarly blood levels of DAO can be measured, but these levels don’t really correlate neatly with symptoms. Because it’s not a true allergic condition, allergy testing, including food allergy testing, is not useful.
The best way to ‘test’ for histamine intolerance is through a low histamine diet, which I describe below. A reduction in symptoms on the diet, and a return of symptoms when higher histamine foods are re-introduced, suggests that there is histamine intolerance.
It’s also important to remember that you can get checked for true allergies and other medical conditions that may lead to similar symptoms.
Can I Treat This?
Depending on the root cause of your histamine intolerance it can be reversed (usually if there’s gut damage causing the problem), reduced dramatically (if there’s low DAO production), or reduced to a tolerable extent (genetic). Most of my patients go on to live completely normal healthy asymptomatic lives, but usually do have to pay attention to food triggers. There are 3 steps to treating histamine intolerance:
- Eat a low histamine diet
- Heal your root causes
Let’s explore these.
The Low Histamine Diet
A low histamine diet is the first line of treatment. The best approach is to remove all high histamine containing foods, as well as foods that cause the release of histamine, as well as avoiding all DAO blocking foods and whatever DAO blocking medications you can also avoid (work with your prescribing doctor to come off of medications) for 30 days. During this time keep a food journal to record how you feel (you can download a sample food journal here) both immediately and about 2-3 hours after each meal. Symptoms don’t always appear immediately, they may appear when your body accumulates histamine over the course of the day. So paying close attention throughout your day during this 1-month period is very important, but it’s not always 100% possible to identify the individual triggers for you. That said, sometimes it is. For example, I had one patient who discovered that popcorn shot her blood pressure up sky high and caused her to break out in hives.
If during this 30-day period you notice that your symptoms have disappeared or have been dramatically reduced, I highly recommend sticking with the low-histamine diet for 3 months total before trying to reintroduce foods from the lists below. If and when you do reintroduce foods you’d removed, do so slowly, adding in foods from one group at a time over 3 days each, so for example, you might add in higher histamine fruits for 3 days and record any symptoms if they arise. If they do, you are probably sensitive to those fruits, and omit them for now. Wait until the symptoms have passed before introducing the next group, for example, nuts, and again track, and so on.
Histamine intolerance varies highly amongst different people – some can’t reintroduce some of the higher histamine provoking or containing foods at all, while some can include small amounts in their diets. You have to sort of experiment with it – and ideally, work with a knowledgeable practitioner who can help guide you. And hang in there – it can feel quite restrictive and like a long road when you eliminate all of these triggers, but chances are you won’t mind as much when you’re feeling better, and if gut damage was a component of your histamine intolerance, then once your gut is healed, you may be able to resume a diet that includes a broader variety of foods. Gut healing can take weeks to up to a year so you have to be patient with the process.
High Histamine Foods to Eliminate
Aged and fermented foods, leftover meats, poultry and fish, and wine are often the biggest triggers; however, any of the foods on this list may be a problem for you, so remove them all for 30 days.
- Alcohol: Champagne, red wine, beer, white wine
- Aged cheeses: Parmesan, Gouda, Swiss, and cheddar
- Grains: Wheat
- Legumes: Chickpeas, soybeans
- Fermented or smoked Meats/Fish: Sardine, mackerel, herring, tuna, salami
- Fermented and pickles vegetables: Pickles, sauerkraut, kimchi, relish, soy sauce/tamari
- Fermented milk products: Yogurt, kefir, and buttermilk
- Fruit: Dried fruit, citrus, strawberries
- Vegetables: Tomatoes and tomato products, spinach, avocado, and eggplant
- Also: Cinnamon, chocolate
Histamine Liberators to Avoid
Citrus, bananas, dairy products, chocolate (sorry ladies!), papaya, pineapple, nuts, strawberries, food additives, shellfish, artificial dyes and preservatives
DAO Inhibitors to Avoid
Alcohol, black and green tea, mate
What You CAN Eat
Now if you’re wondering what you can eat, rest assured, there’s still plenty, though admittedly, this is a more restrictive food plan than many.
Low-histamine foods you can enjoy include:
- Freshly cooked meat and poultry (fresh or frozen – no leftovers!)
- Freshly caught or flash frozen fish
- Gluten-free grains: rice, quinoa
- Peanut butter
- These fruits: mango, pear, watermelon, apple, kiwi, cantaloupe, grapes
- Most vegetables except those listed earlier
- Dairy alternatives: coconut milk, rice milk, hemp milk, almond milk
- Oils: olive oil, coconut oil
- Many of the non-caffeinated herbal teas
Note that methylated B vitamins, in my clinical experience, seem to aggravate some people with histamine intolerance; if you are taking methylfolate or methyl-B12 I recommend stopping these while you are on the 30 Day Low Histamine Diet and re-introducing them as a ‘food group’ to see how you respond. If you are planning to conceive, however, it is still important to be on folate or folic acid in some form for at least 30 days prior to conception and during pregnancy.
Heal the Root Causes
4R Gut Healing: Healing the gut is central to my work with patients with histamine intolerance and is described in detail in my book, The Adrenal Thyroid Revolution, in my 28-Day Gut Reset program, and you can read about it here in this article. It is usually done in conjunction with the 30-Day Low Histamine Diet, and continued for about 3 months or longer if needed (i.e., with celiac or IBD the damage is likely high).
Tame the Stress Response: As mentioned earlier, when your stress response system is disrupted, your immune response may also be over-activated. Include simple daily stress reduction practices in your lifestyle and head over here to see if you have symptoms of adrenal imbalances that suggest this area needs more attention. My book The Adrenal Thyroid Revolution will support you in a stress response reset.
While supplements for histamine intolerance have not yet been well studied, in addition those used for gut healing, several have shown promise, and have been quiet effective in my clinical practice. These include:
- Quercetin and Freeze Dried Stinging Nettles: this is a natural antihistamine duet, often found as a combination product, that does not block DAO and is very effective in preventing histamine reactions and calming mild to moderate reactions. Dose: A combination product that provides 250 mg quercetin or isoquercetin three times daily; quercetin should not be used in pregnancy or if you have kidney disease.
- Vitamin B6: 50 to 100 mg a day (do not exceed 100 mg/day)
- Buffered Ascorbic Acid: 500 mg 2 to 4 times daily
- Probiotics and Prebiotics: A daily combination of both a probiotic and a prebiotic helps to repair the intestinal wall, however, be avoid probiotics with Lactobacillus casei, a strain that may increase histamine.
- Direct DAO supplementation is often recommended, however, I’ve not found nearly as effective as the above combination, and therefore rarely recommend it anymore.
Living with the symptoms of histamine intolerance can be annoying in the least, debilitating when severe. I hope this article gives you yet another tool to be a Root Cause Revolutionary and start to take back your health. If you’ve found this article helpful, please LIKE and SHARE it, and make sure to leave a comment in the comments section below if you’d like to dialogue with me or other readers. To learn more about healing your gut and resetting your adrenals, get a copy of my latest book, The Adrenal Thyroid Revolution.
Maintz L, Novak N. Histamine and histamine intolerance. Am J Clin Nutr. 2007 May; 85(5):1185-96.