Fermented Foods and Histamine

Time and microbes give Korean food much of its depth. Salted seafood ripens into jeotgal, soybeans become doenjang and cheonggukjang, and kimchi sours week by week in the refrigerator. The same processes that build flavor can also produce biogenic amines, small compounds such as histamine and tyramine. For most people these are not a concern. For a smaller group, including people with histamine intolerance and anyone taking certain antidepressants, they are worth understanding. The general picture of fermentation is covered in fermented foods and fermented soybeans; this page focuses on the amines.

What biogenic amines are

Biogenic amines form when bacteria strip a chemical group from amino acids, the building blocks of protein. Histidine becomes histamine and tyrosine becomes tyramine, while other amino acids give putrescine and cadaverine. Protein-rich foods that sit for weeks or months with active microbes, such as fish fermented in salt or soybeans fermented with bacteria and molds, tend to accumulate more of them.

In healthy people, enzymes in the gut wall break dietary amines down before much reaches the bloodstream. The main enzyme for histamine is diamine oxidase (DAO). Trouble can arise when a meal contains a very large dose, or when the enzymes are weak or blocked.

Where they turn up on the Korean table

Korean researchers have measured amines in many traditional foods, and levels vary enormously from one product to the next.

• Fish sauces and jeotgal: A 2019 review by Park, Lee and Mah found some of the highest histamine values in fermented anchovy sauce (myeolchi-aekjeot) and sand lance sauce (kkanari-aekjeot), often well above the 100 mg/kg level commonly suggested as a guideline. Salted shrimp (saeujeot) was usually far lower. A 2018 analysis of 12 commercial anchovy sauces found histamine in every sample, from about 370 to 2,110 mg/kg. See making jeotgal.
• Kimchi: Most kimchi samples are low, but results range widely, and some samples exceed the guideline. The review points to fish sauce and jeotgal in the seasoning as an important source. In a 2022 fermentation study, kimchi made without fish sauce had 42 to 63 percent less total amine content than kimchi with 5 percent fish sauce, while putrescine and tyramine rose sharply during the first week of fermentation. See making kimchi and baechu-kimchi.
• Fermented soy pastes: A 2023 survey of 292 samples from 50 commercial brands found the highest histamine and tyramine maximums in cheonggukjang, followed by soy sauce, doenjang and ssamjang. Stir-frying lowered amine levels in soy sauce and gochujang, while boiling changed them little.

Histamine intolerance

Histamine intolerance is the name given to symptoms thought to arise when the body cannot clear dietary histamine fast enough, usually because DAO activity is low. A 2020 review in Biomolecules by Comas-Basté and colleagues describes symptoms that are varied and nonspecific, most often digestive (bloating, fullness, diarrhea, abdominal pain), followed by headache, dizziness, palpitations, and skin or breathing complaints. It cites estimates that around 1 to 3 percent of people may be affected.

The review is frank about the uncertainty. There is no agreed diagnostic test, the reliability of blood DAO measurements is disputed, and published low-histamine diets disagree with one another about which foods to exclude. Other amines such as putrescine and cadaverine may compete for the same enzyme, some medications inhibit DAO, and alcohol may add to the effect. Research is ongoing, and anyone who suspects a problem should work it out with a clinician rather than cutting out whole food groups alone.

Tyramine and MAOI medications

Tyramine matters most for people taking monoamine oxidase inhibitors (MAOIs), an older class of antidepressants. These drugs block the enzyme that normally clears tyramine, and a tyramine-rich meal can then cause a dangerous reaction. MedlinePlus advice for phenelzine, one such drug, warns that tyramine is found in foods that are aged, fermented, improperly stored or spoiled, and says a doctor or dietitian will explain which foods to avoid. The 2023 Korean seasoning survey concluded that the products it tested were safe for the general population but specifically advised people on classical MAOIs to be careful with cheonggukjang. Anyone on these medicines should ask their prescriber about doenjang, cheonggukjang, jeotgal and well-aged kimchi.

Korean regulation

Korea's food code sets a histamine limit of 200 mg/kg for certain fish sold frozen, salted, canned or simply processed, such as fillets and dried anchovies. As of a 2018 study of anchovy sauce, no biogenic amine limit had been set for fermented seafood products such as fish sauce.

Practical notes

• Most people need not worry: Fermented seasonings are eaten in small amounts, and researchers judged typical intakes safe for the general population.
• Freshness matters for fish: Excess histamine in fish is linked to a food poisoning known as scombroid poisoning, which is one reason Korea sets a histamine limit for some fish. Keep fresh fish such as mackerel cold; see food safety at home.
• Lighter seasoning helps: Using less fish sauce in kimchi, or choosing lower-amine options such as saeujeot, is one practical lever for sensitive eaters.
• Talk to a professional: Recurring flushing, headaches or digestive upset after aged foods deserve a medical conversation, not self-diagnosis.