What is histamine?Histamine is one of the chemicals that is produced by your body when you have an allergic reaction to something. It also occurs naturally in certain foods, while other foods can signal to your cells that they should release any histamine they happen to be storing at the moment – without your having an allergy to that food.
What is a histamine intolerance?For most people, histamine is broken down naturally by enzymes (including in particular the diamine oxidase or “DAO” enzyme) in the body and the histamine is then absorbed back into the blood stream.
However, if at any given moment in time you have more histamine in your system – whether from food or from allergic reactions – than you do DAO enzyme then the excess histamine will instead build up as a toxin in every tissue in your body that has a histamine receptor. This includes your gut, your heart, your lungs and your brain.
What foods need to be avoided on a low histamine diet?In general, histamine levels in foods increase as the food ages or if it is cultured, fermented or smoked. In addition, there are many foods that are “histamine liberators”: they signal to your cells to release any histamine they are storing back into your blood stream.
One of the things that makes histamine intolerance challenging is that there are many conflicting lists out there, in part due to the fact that different people will have different tolerance thresholds or trigger foods. This is a food intolerance where you will likely have to do some experimenting to figure out what your own tolerance level is.
To make this process easier for you, we have published freedible’s collated list, indicating what foods tend to appear on most if not all high histamine food lists, and which appear only on certain lists. (Alas, since we aren’t food scientists ourselves that’s the best we can do for you!).
Here are a few common examples though to help explain the different ‘buckets’ of high histamine foods – note that this is only a partial list; please refer to our cheat sheet for a more complete list.
|Aged & processed foods
||Hard cheeses, leftovers, canned foods, some packaged goods, deli or processed meats
||Beer & wine (which are also DAO inhibitors), pickled foods, anything made with vinegar or with yeast
||Dry sausages, smoked fish
|Examples of DAO enzyme inhibitors
||Alchohol, certain pharmaceuticals
|Examples of histamine liberators
||Citrus, papaya, tomatoes, strawberries, pineapple, nuts, peanuts, spinach, chocolate, pumpkin, spinach, eggplant, avocado, fish, crustaceans, pork, egg whites, additives, liquorice, spices
What are the symptoms?Because histamine can build up in so many different organs of the body, it can cause a very wide range of symptoms – some of which you would never expect to be related to your foods!
These symptoms can include:
· upper-respiratory symptoms like getting a runny or stuffy nose, asthma or wheezing, while or after eating particular foods;
· cardio-vascular symptoms like hypotension, arrhythmia, tachycardia (a suddenly-fast heart beat), blood pressure changes and even anaphylaxis;
· mental health symptoms like depression, panic attacks, anxiety disorders and even schizophrenia;
· skin changes like hives (urticaria or pruritis) or flushing (sudden red flush in your cheeks or other parts of your body);
· digestive tract reactions like diarrhea, stomach aches, gas, colic
· female reproductive reactions like dysmenorrhea;
· central nervous system reactions like vertigo, headaches (including migraine headaches), nausea, vomiting and difficulty with sleeping, learning and memory.
Of course, there are many other conditions that could cause those same symptoms so it is important to work with your doctor to ascertain whether histamine intolerance may be a contributing factor in your case. In consultation with your doctor, it may make sense for you to consider trying a low-histamine diet for a limited period of time to see if any of your symptoms subside, and/or to discuss whether any medications you take may inhibit DAO production. You should never stop taking a medication prescribed to you without consulting with your doctor.
How do you diagnose a histamine intolerance?Unfortunately, because the symptoms are so wide-ranging and appear similar to a number of other intolerances and diseases (including food allergies, sulfite intolerance and irritable bowel syndrome), it is often mis-diagnosed. Because a histamine intolerance shares symptoms with many other diseases including food allergies, some of which can have life-threatening consequences, it is important to work with your doctor to rule out other conditions.
If you have two or more symptoms of a histamine intolerance, your doctor may test your tryptase levels and then have you do a trial for several weeks of eating a low histamine diet and taking a daily antihistamine, to see if your symptoms improve. If they do, your doctor may do further testing to determine your DAO levels through a serum or tissue biopsy.
That sounds like me - how could I have gotten a histamine intolerance?First and foremost, the amount of the critical DAO enzyme that you produce is at least partly determined by your genetics, and we humans tend to produce less and less of the enzyme as we age. Sorry to give you the bad news. Thus, histamine intolerance is more common in adults middle aged and over, although some cases have been reported in children (including freedible founder Cheryl Viirand’s own kids).
Your production of the critical DAO enzyme can also be affected by drinking alchohol and taking certain pharmaceuticals, both of which can inhibit your DAO production. It can also be affected by irregularities in your mast cells, the cells which actually produce the histamine, including “mast cell activation disorder or syndrome” (MCAD/MCAS) and mastocytosis. Gastrointestinal bleeding and some bacterias are also cited in the literature as possible causes of over-producing histamine.
In addition, if you have a lot of seasonal or food allergies, you are more likely to be producing histamine through allergic reactions, thus increasing your overall histamine levels. Similarly, if you eat a diet that is very high in high histamine foods then you should expect that your baseline level of histamine could be fairly high.
For women, histamine production is also tied to your hormonal cycle and you may find that your histamine reactions get worse when you are menstruating (add it to the list of unfair female realities, folks!). Interestingly, pregnant women produce dramatically more DAO enzyme (up to 500 times more according to one article!) than they do otherwise. Thus, some pregnant women actually get a break from their food intolerances while they’re pregnant – something to make up for all that coffee and wine you don’t get to drink!
Is this the same as an allergy?No – the word “allergy” refers to a very specific cellular reaction, driven by a particular antibody-driven mechanism. If you have any allergies they may make you more likely to develop histamine intolerance because they contribute towards the overall level of histamine to be broken down and, conversely, there is some evidence that a poor ability to break down histamine may also contribute to the pathogenesis of food allergies. In theory, you could have a histamine intolerance without having any allergies, and allergy testing will not tell you whether you have a histamine intolerance.
How can I manage this? Do anti-histamines help?Yes – over the counter anti-histamines, if recommended by your doctor, help to break down the amount of histamine in your system. However, for some people the anti-histamine alone is not enough: it must be combined with a strictly low-histamine diet to manage their symptoms.
For many with histamine intolerance, some or all of their symptoms respond well to maintaining a low histamine diet. In addition, some patients have found that certain foods, including pomegranate, can actually help to break down histamine levels, and there is evidence that vitamins C and B-6 can increase DAO enzyme activity.
What’s the deal with histamine and alchohol?Alcohol can deliver a double-whammy to the histamine-challenged. First, all alcohol decreases your production of the critical DAO enzyme, thus amplifying any histamine reactions you might otherwise have. In other words, sitting down to a lovely cocktail followed by a high histamine meal may not be your best move!
Second, any alcohol that is fermented (such as wine and beer) is already high-histamine itself, although different alcohols or even different varietals of wine can have notably different histamine levels. As if figuring out that you have a histamine sensitivity wasn’t already complicated enough!
It is also important to note that some people who react to wine are actually reacting instead or in addition to the sulfites contained in the wine (and in other foods as well). Sulfite-triggered reactions can be caused by low production of the enzyme needed to break down the wine but they can also be caused by an (IgE-mediated) allergy and sulfites are added as a preservative and antioxidant to a range of foods, so it is important to work with your doctor to get a proper diagnosis of the cause behind any wine reactions you might have.
How do you manage a low-histamine diet? Do I have to go “cold turkey”?Here at last we have some good news. The list of foods to be avoided on a low-histamine diet is undoubtedly daunting. However, unlike an IgE-mediated allergy in which anaphylaxis can be caused by exposure to even the minutest exposure, like most intolerances here it is a question of quantity. Check out our Guide to Getting Started on a Low Histamine Diet for concrete tips on how to get started.
And, being freedible, we’re here to help! Check out our Histamine Intolerance Cheat Sheet and our Guide to Getting Started on a Low Histamine Diet, leave us a comment, join our histamine intolerance group, check out histamine intolerance blog posts in our blog posts, or reach out to Cheryl via her profile. And rest assured that the freedible team has a very personal stake in developing the site as a resource that works for people with histamine intolerance and other complicated food restrictions with large buckets of restricted foods!
We are indebted for this FAQ – and for the ways our own histamine intolerance diagnoses have truly transformed our lives – to Laura Mintz & Natalija Novak for their article on “Histamine and histamine intolerance” appearing in The American Journal of Clinical Nutrition, and to Dr. Anne Maitland, M.D., PhD., who handed that article to freedible founder Cheryl Viirand one day with instructions to “read this and tell me if it reminds you of anyone in your household – and I mean all y’all!” How to say thanks for giving us back our health? Hopefully spreading the word to help others is a starting point.