Tyramine (4-hydroxy-phenethylamine) is an amino acid that is derived from tyrosine. It acts as a neurotransmitter. Tyramine occurs widely in plants and animals, and is metabolized by the enzyme monoamine oxidase. In foods, it is often produced by the decarboxylation of tyrosine during fermentation or decay. Foods containing considerable amounts of tyramine include meats that are potentially spoiled or pickled, aged, smoked, fermented, or marinated (some fish, poultry, and beef); most pork (except cured ham); chocolate; alcoholic beverages; and fermented foods, such as most cheeses (except ricotta, cottage, cream and Neufchâtel cheeses), sour cream, yogurt, shrimp paste, soy sauce, soybean condiments, teriyaki sauce, tempeh, miso soup, sauerkraut, kimchi, broad (fava) beans, green bean pods, Italian flat (Romano) beans, snow peas, edamame, avocados, bananas, pineapple, eggplants, figs, red plums, raspberries, peanuts, Brazil nuts, coconuts, processed meat, yeast, and an array of cacti.
Tyramine is also thought to have a possible causal connection to migraines in some people. Scientific studies, however, have provided mixed results. Supposedly, since it affects the vascular system through the release of catecholamines, it is thought to indirectly cause a constriction of blood vessels in the head. Then, as the effect wears off, the blood vessels dilate, which can potentially lead to a migraine occurring in individuals prone to them. Sometimes, if a migraine sufferer avoids foods containing tyramine, he or she may experience them less frequently.
If a person is repeatedly exposed to it over a prolonged amount of time, tyramine can be converted to octopamine. This can occupy the same storage spaces in the human body, known as synaptic vesicles, that some of the catecholines do before they are used. It is thought that since octopamine somewhat replaces the fight or flight hormones, where they are usually stored, it may be responsible for a lowering of blood pressure, and possibly lead to a condition called orthostatic hypotension. This is sometimes seen in people taking MAOIs. More research needs to be done, however, to understand the role of octopamine in the human body.
