Food rating methodology for histamine intolerance
Last updated: April 2026
What is histamine intolerance?
Histamine intolerance (HIT) is impaired histamine breakdown in the body caused by reduced activity of diamine oxidase (DAO), or in some cases by histamine-N-methyltransferase (HNMT) pathways. Histamine is a biogenic amine naturally present in many foods and is formed especially through fermentation, aging, and microbial activity.
Estimated HIT prevalence in the population is 1-3% (Maintz & Novak, 2007). Diagnosis is based on excluding other causes and observing the clinical response to a low-biogenic-amine diet.
Food classification
Each food in the database has a primary rating and optional additional flags that describe the intolerance mechanism.
Primary rating
| Label | Description |
|---|---|
Suitable | Low histamine and low biogenic amine content; the food does not trigger histamine release from cells. Suitable for everyday use. |
Caution | The food may contain a moderate amount of histamine or may only be tolerated individually in small amounts. Track your own reactions. |
Unsuitable | High histamine content or high levels of other biogenic amines such as tyramine or putrescine. We recommend excluding it from the diet. |
Additional flags
A food can have a primary rating plus one or more additional flags. The flag describes why the food may be problematic, because different patients react differently to different mechanisms.
| Icon | Flag | Description |
|---|---|---|
| Liberator | The food can trigger histamine release from mast cells regardless of its own histamine content. Typical examples include strawberries, citrus fruits, tomato, avocado, egg white, and seafood. | |
| Biogenic amines | The food contains higher levels of other biogenic amines, such as tyramine, phenylethylamine, or spermine. They may act similarly to histamine and cause similar symptoms. Typical examples include chocolate, banana, walnuts, and cashews. | |
| DAO blocker | The food inhibits diamine oxidase, the enzyme that breaks down histamine in the digestive tract. This can slow histamine processing from all foods eaten at the same time, so the effect may multiply. Typical examples include alcohol, black tea, green tea, mate, and energy drinks. |
Flags are shown as small icons on the food card. Expanding the card shows the detailed explanation.
Data sources
Food ratings are based primarily on these sources:
- SIGHI list (Swiss Interest Group Histamine Intolerance) - the most widely used European reference list for histamine intolerance.
- Maintz L, Novak N (2007): Histamine and histamine intolerance. American Journal of Clinical Nutrition, 85(5), 1185-1196. DOI: 10.1093/ajcn/85.5.1185
- Jarisch R (ed., 2015): Histamin-Intoleranz. Thieme Verlag, Stuttgart. ISBN 978-3-13-116033-0
- Reese I et al. (2017): German guideline for the management of adverse reactions to ingested histamine. Allergologie Select, 1(1), 21-29.
- Czech dietology and allergology recommendations from Czech professional societies.
Rating process
For each food, the available sources are compared. When sources disagree, we use the more conservative rating, meaning the stricter classification. The Why field for each food gives a short explanation of the rating and points to the mechanism: histamine content, tyramine, liberator effect, DAO inhibition, or another relevant reason.
The database is updated when new scientific recommendations are published or when a mismatch with practice is found.
Individual tolerance
Histamine tolerance is highly individual. A food marked as caution may cause symptoms in one person and be tolerated by another. The database is an orientation aid, not a binding meal plan. For a personal diet plan, consult a physician or registered dietitian.
Source citations
- Maintz L, Novak N. Histamine and histamine intolerance. Am J Clin Nutr. 2007;85(5):1185-96.
- Jarisch R, ed. Histamin-Intoleranz. 3rd ed. Stuttgart: Thieme; 2015.
- Reese I, et al. German guideline for the management of adverse reactions to ingested histamine. Allergologie Select. 2017;1(1):21-29.
- SIGHI - Swiss Interest Group Histamine Intolerance. Compatibility list. Available at: sighi.ch