Histamines are present in many foods, especially those that have been aged. Foods with the highest histamine levels are aged cheeses, yogurt, sour cream, meats, salami, bacon, wine, sauerkraut, pickles, soy sauce, and vinegar. However, they are also found in some fresh fruits and vegetables like spinach, tomatoes, papaya, pineapple, strawberries, eggplant, and citrus fruits. They can also form in meats that have been ground, cyovac’d, canned, smoked, frozen, and stored in the refrigerator after being cooked.

Some people – like myself – have histamine intolerance, and ingesting even the smallest amount can produce a wide variety of unpleasant and disabling symptoms. Some of these symptoms include:

Pruritus (itching of the skin, eyes, ears, and nose)

Urticaria (hives)

Rashes

Acne

Angioedema (swelling of the face, mouth, and throat)

Hypotension (low blood pressure)

Tachycardia (racing heart rate)

Arrhythmia

Chest pain

Panic attack

Asthma attack

Nasal constriction

Flushing of the face and skin

Nasal mucus production

Conjunctivitis (irritated and watery eyes)

Migraines and other types of headaches

Dysmenorrhea (painful menstruation)

Irregular menstrual cycle

Fatigue

Confusion

Vertigo (dizziness)

Balance problems

Irritability and impatience

Digestive upset

Heartburn or gastro-esophageal reflux

Nausea and vomiting

Diarrhea

The cause of histamine intolerance may be multifaceted. One of the most likely causes is a deficiency of one or both of the enzymes responsible for breaking down and eliminating histamines from the body. As Maintz and Novak explain in their comprehensive review article,

“Histamine intolerance results from a disequilibrium of accumulated histamine and the capacity for histamine degradation. Histamine is a biogenic amine that occurs to various degrees in many foods. In healthy persons, dietary histamine can be rapidly detoxified by amine oxidases, whereas persons with low amine oxidase activity are at risk of histamine toxicity. Diamine oxidase (DAO) is the main enzyme for the metabolism of ingested histamine. It has been proposed that DAO, when functioning as a secretory protein, may be responsible for scavenging extracellular histamine after mediator release. Conversely, histamine N-methyltransferase, the other important enzyme inactivating histamine, is a cytosolic protein that can convert histamine only in the intracellular space of cells.”

Many things can potentially interfere with the production of Diamine oxidase and N-methyltransferase. According to Dr. Amy Meyers in her blog post on this subject, these including Celiac disease, Crohn’s disease, Ulcerative colitis, Inflammatory bowel disease, leaky gut, gastointestinal infections, genetic mutations, mitochondrial dysfunction, and a wide variety of medications such as pain relievers, antidepressants, immune modulators, and even certain antihistamines.

The most powerful thing someone with histamine intolerance can do is to simply avoid foods that are known to be high in histamines. However, this can be a real challenge for someone who wants to do a low carb ketogenic diet or even a zero carb diet, as high-histamine foods often play a central role in low-to-no carb diets. And, if you are unaware that you are histamine intolerant, following the food recommendations espoused by most of the low and zero carb advocates can leave you feeling down right awful. When I first embarked upon a low carb ketogenic diet and then a more restricted zero carb approach, this is precisely what happened to me because almost everything I ate was high very in histamines. The only thing that did not make me feel too bad was raw egg yolks and heavy cream! I knew and felt that what my body really wanted was red meat, but every time I tried it I got a terrible migraine, severe digestive upset, and lots of mucus.

Fortunately, I did not have to flounder around in the dark for to long. Amber, a Zero Carb blogger with food sensitivities similar to mine referred me to an excellent article on histamine intolerance by Dr. Georgia Ede who – incidentally – also has a long history of bizarre reactions to a great many foods herself and eats a mostly meat diet as a result. I could not believe what I was reading! I had practically every symptom on the list. It was an incredible relief to finally understand why I was reacting badly to so many foods, but it was also stunning to me that no doctor I have consulted during the past 20 years every suggested histamine intolerance (or salicylate intolerance) as a possible cause of all my problems.

Now, the only thing I needed to do was find a source of unaged meat. However, that is easier said than done. It took me a few weeks, but I finally found a small local butcher shop that carries fresh-frozen, unaged, grassfed veal. It is likely that there are still some histamines present in this meat, as histamines continue to form even while meat sits passively in frozen storage. But the level must be considerably less because I respond to it way better than any of the other meats I tried previously. Discovering that I am histamine intolerant is just as huge as discovering that I am salicylate intolerant. It has provided me with enormous clarity regarding the path I need to follow, and I can finally move forward with confidence.

It may be possible to restore one’s ability to properly metabolize histamines, but the process is complex and may take years to accomplish. Nevertheless, if you feel that you may have histamine intolerance, I encourage you to read Joseph Cohen’s comprehensive blog post outlining the possible avenues for investigation. One of the easiest things you can do is a trial run with DAO enzymes to see if they make any difference in how you feel. I am planning to experiment with this myself in the near future. But for now, I am simply going to seek out and eat only those meats that have not been subjected to any intentional aging process. It is possible that my gut will heal on this diet, and one day I will be able to eat a wider variety of meats. Time will tell.