Histamine intolerance is often associated with digestive problems, nasal congestion or skin reactions. But histamine affects considerably more parts of the body than that, and some symptoms are easy to attribute to entirely different things. If you suspect an intolerance, these four signs may be worth keeping an eye on.
To begin with: What is histamine? On the one hand, it is a substance we take in through food. But it is also a substance that the body itself both produces and uses - among other things, it is involved in the immune system, the regulation of stomach acid and communication in the brain.
Histamine from food is normally broken down in the intestine, partly with the help of the enzyme DAO, diamine oxidase. With histamine intolerance, the body is thought to have more difficulty handling the amount of histamine to which it is exposed. One possible explanation may be reduced activity of the DAO enzyme, but researchers still do not have the full picture.
What symptoms can histamine intolerance cause?
Bloating, diarrhea, stomach pain, headaches, itching, skin flushing and nasal congestion are some of the best-known symptoms, but there are considerably more than that. Why? Histamine has functions, and therefore receptors, in many different organs and tissues throughout the body.
In other words, the symptoms can appear in several places, in different combinations.
In a study of people with suspected histamine intolerance, almost all participants had more than three different symptoms. On average, they reported as many as eleven.
And some of them are easy to miss or attribute to other possible causes.
1. Dizziness
Dizziness was actually one of the most common symptoms in the study above, and was reported by as many as 66 percent of the participants. One possible explanation is that histamine can dilate the blood vessels and affect blood pressure. As a result, the reaction can sometimes feel more like a problem related to blood circulation than something you would associate with food.
2. Palpitations
In the same study, palpitations also turned out to be common, and were reported by 47 percent of the participants. Histamine can affect both the blood vessels and heart rate.
Occasional palpitations can of course have many other causes. But if they repeatedly occur together with, for example, flushing, digestive problems or dizziness after you have eaten certain foods, it is a pattern that may be worth investigating.
3. Menstrual cramps
This connection is less well known. Histamine can affect smooth muscle, the type of muscle found, among other places, in the uterus, and menstrual cramps are described among the symptoms of histamine intolerance.
But just like palpitations, this symptom is not something you should attribute solely to histamine intolerance. If you have severe menstrual cramps, try to see whether you can identify common threads alongside other recurring symptoms.
4. Sleep problems
Sleep difficulties can also occur with histamine intolerance, such as finding it harder to relax and fall asleep. It may sound like a rather unexpected connection, but in the brain histamine functions as a neurotransmitter that helps you stay awake and alert.
That is also why some antihistamines can make you sleepy, because they block histamine’s effects in the brain. If your body has difficulty handling the amount of histamine, it may therefore become harder to wind down when it is time to sleep.
How do you know whether your symptoms are caused by histamine intolerance?
Investigating histamine intolerance can be tricky because there is no single symptom that is “a sure sign”. Dizziness can have many causes. The same applies to palpitations, menstrual cramps, and stomach problems.
It is therefore better to look for patterns. Do several symptoms occur at the same time? Do they recur after you have eaten certain foods, perhaps foods that contain a lot of histamine? If you suspect that you react to a particular food, keeping a food and symptom diary can make it easier to identify any possible connections.
There is also no single blood test that can reliably provide the diagnosis. DAO can be measured in the blood, but the result is not enough to determine whether you have histamine intolerance.
A study examined 59 people who suspected that they had histamine intolerance. When the researchers tested them with both histamine and a placebo, the diagnosis not confirmed in 50 of the 59 people.
And this shows how difficult it still is to diagnose histamine intolerance.
Recognizing yourself in a symptom list is not enough. But if you notice that the same combination of symptoms recur in connection with certain foods, you have something much more useful to work with. Document the pattern and seek help from someone knowledgeable about histamine intolerance who can help you investigate possible causes and what actually triggers your particular symptoms.
Sources
- Schnedl WJ, et al. (2019). Evaluation of symptoms and symptom combinations in histamine intolerance. Intestinal Research.
- Reese I, et al. (2021). German guideline for the management of adverse reactions to ingested histamine. Allergo Journal International.
- Zhao Y, et al. (2022). Histamine Intolerance: Etiology, Clinical Manifestations, and Treatment. Nutrients.
- Bent RK, et al. (2023). Placebo-controlled histamine challenge disproves suspicion of histamine intolerance. Journal of Allergy and Clinical Immunology: In Practice.
- Thakkar MM. (2011). Histamine in the regulation of wakefulness. Sleep Medicine Reviews.
