Recently there’s been a bit of a buzz about antihistamines as a treatment of IBS. Let’s find out why!
Histamine is a small protein, a biogenic amine that the body makes and uses in many processes. It influences acid secretion in the stomach, it takes part in allergic reactions and in controlling body temperature (to name a few). It is a highly necessary substance, not a toxin, though like anything else, in high amounts it can cause toxicity. There are cases of difficult histamine poisoning from eating certain fish very high in histamine.
That said, most of the histamine in the body is made by the body, and only about 5% comes from food. Our gut microbes can also make histamine. Inside the intestines, there is an enzyme called diamine oxidase (DAO) that breaks down histamine and prevents negative effects from arising when eating foods high in histamine.
An increase in histamine causes a wide array of symptoms, ranging from IBS-like symptoms of constipation, diarrhea, and nausea, to headaches, hives, flushing, heart palpitations, nasal congestion etc.
The more common causes of increased histamine include foods high in histamine, problems in the DAO enzyme, and increased production by gut microbes. Mast cells (part of the immune system) store histamine and are the main producers of histamine in the gut, and they can also be stimulated to release too much histamine, for example due to stress, infection, or eating certain foods. Alcohol can block DAO, and certain drugs, like antibiotics and NSAIDs, can do the same.
Some studies have found that people with IBS have higher levels of histamine (and in some cases mast cells) compared to people who don’t have IBS, so should histamine be something to consider for IBS? Perhaps avoiding histamine-rich foods, or taking DAO supplements, or antihistamines.
This is a good question.
If you are someone, who is already avoiding a lot of foods, and perhaps on a strict low FODMAP diet, adding a low histamine diet on top seems too much. I would really work on expanding your diet in these cases rather than restricting more, as sweeping diet restrictions can lead to malnutrition, decreased quality of life, food fears (which feed gut symptoms) and unwanted changes to the gut microbiota.
But if you’ve clearly noticed that a food or a few foods cause an array of symptoms that sometimes start even within minutes, trialing avoiding this food for a few weeks seems sensible. That said, research is very much lacking on the effectiveness of a low histamine diet, not just in IBS, but even in diagnosed histamine intolerance (btw, histamine tolerance is also a diagnosis of exclusion, without a test that you can just simply take). If you’d like to explore trying a low-histamine diet, I’d recommend working with a dietitian to avoid problems.
What about supporting histamine breakdown with DAO supplements? There are no studies that I could find that look specifically at IBS. Supplements in general are not well controlled (always choose a third party tested product) and may come with side effects, so it’s questionable whether they would be of help.
When it comes to antihistamines, H1 antihistamines could improve abdominal pain, as they block pain sensing receptors in the gut (they don’t reduce histamines). However, there are only two studies on this to date. H2 antihistamines are used widely for heartburn and gastroesophageal reflux as they reduce the acidity of the stomach.
Long story short, histamine may be playing a role in IBS, most likely through mast cell activation. But whether avoiding histamine containing foods, or taking antihistamines are good ideas, the evidence is still highly limited and drawing conclusions is difficult at this time. If you are wondering if histamine could be a problem for you, I’d advise you talk to your doctor.
If you feel like your life is being controlled by your gut problems, it’s time to do something about it. Schedule a free call with me to discuss your situation to see what your best next step toward IBS freedom would be.
Love,
Anna-Kaisa
PS. Have you already downloaded your free guide “5 Easy Ways to Beat the Bloat”?
PPS. I’m hosting a free webinar on March 4th on nutrition and stress to entrepreneurs (though anyone will get great insight into how stress and nutrition affect each other). It’s at 16:00 GMT+2 - to sign up, go here.