This article was originally posted in June 2016, but has since been updated and expanded to accommodate new research.
What is histamine?
Histamine is a natural substance that our immune cells produce as a part of the stress response, usually after encountering an allergen.
When histamine is released, the following symptoms can be experienced:
- Skin — itching, swelling, rashes, hives
- Eyes — itching, burning
- Nose — itching, sneezing, runny
- Lungs — wheezing, coughing
- Digestive — cramps, diarrhea
- Vascular — headache
You may have experienced a histamine response if you’ve ever been bitten by a mosquito or received a bee sting. The swelling, redness, and itchiness that you get is a direct result of histamine being released at the site of the wound. Histamine is also involved in allergic reactions, like seasonal allergies.
It is important to note that histamine is both produced by the body, as well as a substance that can be consumed in food. Making things more confusing, some foods don’t contain histamine, but actually stimulate the body to produce more histamine. We’ll break all of this down later in this guide!
What is histamine intolerance?
Histamine intolerance is the inability to tolerate high-histamine or histamine-producing foods in the diet.
Unlike a food allergy, however, histamine intolerance can come in varying degrees of severity. For most people with a histamine intolerance or sensitivity, their symptoms are produced when the histamine level passes a certain threshold. For some people, their threshold is very low, while others can tolerate more.
Think of your histamine tolerance level being like the top of a glass of water. All of the high-histamine and histamine-producing foods you consume add water to the glass, but you only experience symptoms of excess histamine when that glass overflows. Even healthy people without any day-to-day issues with histamine can experience scombroid poisoning, or an extreme histamine reaction that comes from eating fish with excess histamine-creating bacteria.
Everyone has a limit to the amount of histamine they can tolerate without symptoms, but those with histamine intolerance just have a lower threshold, or a smaller “glass.” Even among those who regularly experience histamine intolerance, experiences can range from mild to severe, and tolerances to foods can vary wildly.
How is histamine intolerance managed?
Those with histamine intolerance experience fewer symptoms when avoiding foods that trigger their symptoms, whether they be high-histamine or histamine-producing foods.
This can be tricky as high-histamine and histamine-producing foods do not create the same symptoms in everyone, making it necessary for each person with histamine intolerance to determine their own threshold of certain foods (much like what we do in general with the elimination and reintroduction phases of the Autoimmune Protocol!).
This might look like changing the diet to remove high-histamine and histamine-producing foods, and then reintroducing them one at a time, in varying quantities and combinations, to assess tolerance.
In addition to symptom management through dietary changes, those with histamine intolerance can sometimes find a relief of symptoms through the successful treatment of underlying health conditions that may be causing it in the first place.
What causes histamine intolerance?
Anyone experiencing the symptoms of histamine intolerance should work with a healthcare provider to look into potential root causes and to see if there are any treatment options available for issues that come up.
Some common causes to look into:
- SIBO (small intestine bacterial overgrowth) — SIBO can be an underlying cause of histamine intolerance due to the overgrowth of bacteria producing excess histamine from undigested food. You can read more in our article SIBO: The Definitive Guide.
- Dysbiosis – Other infections like bacterial or yeast overgrowths and parasite infections can also cause histamine intolerance.
- Methylation dysfunction — We’ve talked about methylation on the blog before (for more info start here), and sometimes those who have impaired methylation, whether from genetics or another cause, can have issues or changes in their tolerance to histamine.
- Genetics — In addition to the genetic component to methylation, some people have mutations on the enzymes that degrade histamine (like diamine oxide, or DAO). Less enzyme activity means that these people are likely to tolerate histamine less than the general population.
- CIRS – Chronic inflammatory response syndrome is a condition many who have been exposed to mold toxicity develop, and can cause histamine intolerance.
- Heavy Metal Toxicity – Those who have high levels of heavy metals can develop histamine intolerance.
- Medications — Some medications inhibit DAO enzyme activity and can cause symptoms of histamine intolerance.
Which foods are high in histamine or inhibit the breakdown of histamine?
As I explained before, foods can either contain histamine, cause the body to release histamine, or inhibit the breakdown of histamine in the body. For those who are histamine intolerant, modifying the diet to exclude or minimize these foods can help lower unpleasant symptoms.
- Alcoholic beverages (esp. beer and wine)
- Cheeses (esp. those that are aged)
- Dried fruit
- Fermented foods (sauerkraut, kombucha, kefir, yogurt)
- Cured or processed meat products (bacon, salami, deli meat)
- Smoked meats (esp. seafood)
- Seafood (unless caught, cooked, and eaten very quickly)
- Vinegar-containing foods (pickles, olives)
- To a lesser degree — some fruits and vegetables like citrus, avocado, eggplant, mushrooms, spinach, and tomatoes
- Alcoholic beverages
It is important to remember that not all histamine intolerance looks the same, and that many people that experience its symptoms have foods that really trigger their symptoms, and others that may be on the above lists that they are able to eat in smaller quantities. This is why you won’t find a resource for low-histamine recipes that accommodates every type and severity of histamine intolerance – it really can vary a lot from individual to individual.
When to modify AIP to accommodate histamine intolerance
In general, if you don’t notice an issue eating high-histamine or histamine-producing foods, there is no reason to avoid these foods while in the elimination phase of the Autoimmune Protocol.
Exceptions are those with conditions that directly affect the skin (like psoriasis) or those that cause symptoms similar to histamine intolerance (like autoimmune urticaria). This is why in the AIP Psoriasis/Eczema study, the researchers asked participants to avoid the highest-histamine foods (fermented foods and cured meats) in their implementation of the Autoimmune Protocol, as there is a lot of anecdotal evidence that histamine intolerance is much more common in these groups.
My experience with histamine intolerance
A certain type of histamine intolerance runs in my family — my mother, sister and I all get headaches when we drink red wine or eat chocolate. I’m also sensitive to cured, smoked, or fermented meat products, all of which produce a headache if I eat more than a few bites. Most of the other foods on the high histamine list, including fermented vegetables, probiotic drinks like kombucha, and dried fruit have never given me issues, even in large quantities. Since this runs in my family, I suspect that my family members and I have a genetic predisposition to a mild dysfunction in the ability to break down histamine.
While I can easily avoid the meat products that cause me issues at home, traveling presents a problem as I have less access to fresh food and these preserved proteins are very convenient. I am careful to moderate my intake while on the road. I don’t avoid any of the high-histamine foods that haven’t caused me problems in the past, and I don’t avoid any of the histamine-releasing foods. I don’t consider myself as having a full-blown histamine intolerance, but I’m mindful not to overdo it with the foods I know cause me issues in certain quantities.
What to do if you experience histamine intolerance
First, try a low-histamine and low-histamine-producing food diet for a short while to see if that resolves your symptoms. If so, you likely have some form of histamine intolerance, and knowing this information can help you manage your symptoms better through dietary modification.
Next, reach out to your healthcare provider to seek out your root cause of histamine intolerance and get treated for it, if possible. This might look like asking your doctor to test you for SIBO or other gut issues, getting tested for methylation issues, or examining any medications you are on to see if they are impacting your tolerance to histamine.
Lastly, if you have identified your root cause and are undergoing treatment, your histamine intolerance is likely to improve. This is very common in the case of SIBO — many SIBO patients have symptoms of histamine intolerance appear when they develop the overgrowth, and disappear when it is successfully treated. Same with those that have CIRS or heavy metal toxicity.
Once you treat an underlying cause, you may be able to try reintroducing some of these high-histamine or histamine-releasing foods slowly and methodically, to determine your new food list and threshold. Some people find supplementing with DAO can be helpful, although be cautious as it is difficult to find brands that don’t have unwanted fillers (I don’t have any specific recommendations, sorry!).
If you are one of the people who has a genetic issue (like me!), and there are only certain histamine foods that cause an issue, and in specific quantities. You can then use this information to avoid symptoms in the long run.
Have you experienced histamine intolerance? I’m curious if you’ve found your root cause and if treatment brought any change to your symptoms!