Histamine intolerance
The short answer
A proposed reaction to histamine in food, usually explained by reduced activity of the enzyme that breaks histamine down in the gut. It sits closer to the contested end of this site than most of the other labels here.What is not settled
There is no agreed confirmatory test, and the blood test most often sold for it measures enzyme activity at a single moment rather than what happens to a meal. The food lists are the more practical problem: they are widely circulated, they disagree with each other substantially, and a large share of the foods excluded by them have no measured histamine finding behind the exclusion.
What it gets confused with
Each of these takes one pair and separates them on what can actually be measured.
- Is it MCAS or histamine intolerance?
One is cells releasing mediators. The other is difficulty handling a compound in food. They feel similar, and one set of criteria is still disputed.
- Is it SIBO or histamine intolerance?
Gut bacteria can produce histamine. That is a real mechanism and a routinely overstated one: shared mechanism is not the same as one causing the other.
How it gets tested
What each test physically measures, and what a negative does not rule out.
- The DAO blood test
A national allergy guideline says serum diamine oxidase testing cannot be considered conclusive. It remains one of the most commonly sold tests in this space.
What people try
What each intervention is, and how much is behind it.
- DAO supplements
Porcine and plant products publish potency figures that differ by a hundredfold. That gap is an assay artefact, not potency, and almost nobody says so.
Eating with it
Where the food advice comes from and where it contradicts itself.
- Why the food lists disagree
Researchers compared ten low-histamine diets. Only fermented foods were on every list, and 68% of excluded foods had no significant histamine.
Where this sits on the site
This page is an index rather than an article. It exists so that a label has one place to start from, and so the 5 pages above are reachable without knowing which section we filed them under. The pages themselves are where the work is.
Common questions
- Is this page a diagnosis of Histamine intolerance?
- No. Nothing here can tell you what you have. What these pages do is show you what separates one label from another, what each test can physically measure, and where the published sources disagree, so that the conversation you have with a clinician is a better one.
- What is genuinely unsettled about Histamine intolerance?
- There is no agreed confirmatory test, and the blood test most often sold for it measures enzyme activity at a single moment rather than what happens to a meal. The food lists are the more practical problem: they are widely circulated, they disagree with each other substantially, and a large share of the foods excluded by them have no measured histamine finding behind the exclusion.
Related
- Small intestinal bacterial overgrowthAn overgrowth of bacteria in the small intestine, diagnosed in practice by a breath test that measures gases rather than bacteria. Where that gap matters, and what it does not rule out.
- Mast cell activation syndromeA syndrome with two competing sets of diagnostic criteria that do not agree. What each one requires, what that disagreement means for you, and what it overlaps with.
- Irritable bowel syndromeIBS is defined by symptom criteria and by ruling other things out, not by a test that confirms it. Why that makes overlapping labels so common.
- Food intoleranceA reproducible reaction to a food that does not use the immune mechanism of an allergy. Which means the common tests are answering a different question.