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 body systems are affected accordingly:
- 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 the seasonal allergies so many people experience.
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 stimulate the body to produce more histamine. We’ll talk more about all of this in a little bit!
What is histamine intolerance?
Histamine intolerance generally refers to a person’s inability to tolerate high-histamine or histamine-producing foods in the diet. Unlike an 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. Think of it like 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 resulting in eating fish with excess bacteria. We all have a limit to the amount of histamine we can tolerate without symptoms, but those with histamine intolerance just have a lower threshold, or a smaller “glass.”
Those experiencing histamine intolerance experience fewer symptoms when avoiding foods that they know trigger symptoms. This can be tricky as high-histamine and histamine-producing foods do not create the same symptoms in everyone, making it necessary for everyone to determine their own threshold of certain foods (much like what we do with the elimination/reintroduction on the Autoimmune Protocol!).
What causes histamine intolerance?
If you are experiencing the symptoms of histamine intolerance, it is important to look into potential causes as treatment can sometimes resolve the issue or at least make it more manageable. Here are some root 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.
- Methylation — 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.
- 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?
There are many foods that either contain histamine, cause the body to release it’s own 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 the unpleasant symptoms that can transpire, and careful reintroduction can help you determine your threshold of tolerance.
- 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
Those who are incredibly sensitive to histamine will also react to leftover proteins in bone broth. It is important to remember that not all histamine intolerance looks the same, and that many people that experience histamine intolerance 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.
My experience with histamine intolerance
A certain flavor 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 eaten in larger than a bite-size quantity. 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 we have some 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, and use this DAO supplement any time I eat a high-histamine food to help break things down just in case. 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.
6/2017 Edit: I’ve found out that the manufacturer of the supplement above changed the formulation and it does not contain DAO. A reader has let me know that the only manufacturer of DAO in the US is Umbrellex DAO, although I have not tried their product and it contains non-AIP ingredients.
If you think you’re suffering from histamine intolerance, what should you do?
First, try a low-histamine and histamine-producing diet 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.
Next, seek out your root cause of histamine intolerance and get treated for it, if possible. This might mean asking your doctor to test you for SIBO, getting tested for methylation issues, and examining any medications you are on to see if they are impacting your tolerance to histamine.
Lastly, if you have found your root cause and are undergoing treatment, your histamine intolerance is likely to improve. This is very common in the case of SIBO — many people have symptoms of histamine intolerance appear when they develop the overgrowth, and disappear when it is successfully treated. It is time to reintroduce these high-histamine and histamine-releasing foods slowly and methodically, as to determine your personal threshold, and experiment with DAO supplementation if needed. You may find that like me, there are only certain histamine foods that cause an issue, and in specific quantities. You can 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!