A no-jargon guide to what histamine intolerance is, how the SIGHI food scale works, which foods are safer, and why freshness matters more than almost anything else.
Histamine is a natural compound your body makes and uses for many jobs — immune responses, stomach acid, even waking you up. Usually an enzyme called DAO (diamine oxidase) breaks dietary histamine down in the gut.
Histamine intolerance happens when histamine builds up faster than your body can clear it — most often because DAO activity is low. The result is a pile of allergy-like symptoms (headaches, flushing, hives, digestive upset, fatigue) that seem to appear after certain meals.
Important: histamine intolerance overlaps with but is distinct from mast cell activation syndrome (MCAS) and from IgE food allergies. If symptoms are severe or unexplained, work with a doctor or registered dietitian.
The most widely used reference for low-histamine eating is the SIGHI Food Compatibility List from the Swiss Interest Group Histamine Intolerance. It sorts foods by tolerance on a 0–3 scale:
| Score | Meaning | Typical examples |
|---|---|---|
| 0 | Well tolerated | Fresh poultry, eggs, rice, apples, most fresh vegetables |
| 1 | Moderately tolerated | Green peas |
| 2 | Poorly tolerated | Dry / yellow peas, some individual triggers |
| 3 | Very poorly tolerated | Aged cheese, cured meats, smoked/canned fish, sauerkraut, alcohol |
Two other mechanisms matter: liberators (e.g. citrus, strawberries, chocolate, shellfish) trigger your own mast cells to release histamine even if the food is low in it; DAO blockers (alcohol, mate tea, some medicines) slow the drain. Our calculator scores both as added histamine pressure.
This table matches the foods in our calculator, so what you tick there lines up with what you read here.
| Category | SIGHI | Foods |
|---|---|---|
| Safest | 0 | Fresh chicken/turkey, fresh pork/lamb, eggs, fresh milk, mozzarella/ricotta/cream, apples/peaches/melon, rice/corn/potatoes, zucchini/carrots/green beans, herbal tea, water |
| Use with care | 1 | Green peas (dry/yellow peas rate ~2) |
| High histamine — avoid | 3 | Aged/hard cheese, yogurt/sour milk, salami/bacon, smoked/canned fish (tuna, mackerel), shellfish, sauerkraut, vinegar, soy sauce, alcohol |
| Poorly tolerated | 2 | Tomato, spinach, eggplant, avocado |
| Liberators | — | Citrus, strawberries, chocolate, nuts (release stored histamine) |
| DAO blockers | — | Alcohol, mate tea, energy drinks (slow breakdown) |
Source: SIGHI Food Compatibility List. Always read labels — processed foods hide triggers like yeast extract, vinegar, or soy sauce.
Unlike fibre (which is stable), histamine climbs as food sits. Bacteria convert the amino acid histidine into histamine over time, especially in protein-rich foods. Practical rules:
Some people take DAO enzyme supplements (e.g. products built on diamine oxidase) about 15 minutes before meals to help break down dietary histamine. Clinical research suggests they can reduce symptoms in people with low DAO activity.
Supplements are not a free pass to eat high-histamine foods, and they are not suitable for everyone. Discuss with a healthcare provider, especially if you take medications (NSAIDs, some antidepressants, antibiotics, PPIs can affect DAO).
No. A true food allergy involves the immune system (IgE) and can be life-threatening. Histamine intolerance is about accumulation and slower clearance — usually dose-dependent and variable day to day.
Reliable per-food histamine mg values aren't established — levels swing with freshness, bacteria, and preparation. That's why our tool uses SIGHI tolerance scores, not invented milligram numbers. It's a self-awareness guide, not a lab report.
Often not. A structured elimination (typically 2–4 weeks) to calm symptoms, then a careful reintroduction, helps you find your personal tolerance. Over-restriction long term can cause its own problems — work with a dietitian.
Because your "bucket" fills from many sources. A high-histamine meal on a low-stress, well-slept day may be fine; the same meal during an infection or poor sleep can overflow it.
This guide is for educational purposes only and is not medical advice. It does not diagnose, treat, or prevent any condition. Histamine intolerance is individual — always consult a qualified healthcare provider or registered dietitian before changing your diet or starting supplements. Data based on the SIGHI Food Compatibility List and publicly available summaries of low-histamine diet guidance.