4-hydroxy-phenethylamine
Related Terms
4-hydroxy-phenethylamine, diet, MAO, MAOI, monoamine oxidase, monoamine oxidase inhibitor, para-tyramine, p-tyramine, tyramine.
Background
The tyramine-free diet is a way of eating that eliminates consumption of tyramine-containing foods. Tyramine is a substance derived from the amino acid tyrosine and commonly ingested as a component of a variety of foods, particularly aged cheese and wine. In normal quantities and without interference from other chemicals, consumption of tyramine does not produce any bothersome symptoms and helps to sustain normal blood pressure.
Tyramine is metabolized by an enzyme called monoamine oxidase (MAO). Certain individuals taking MAO inhibitors (MAOIs) such as phenelzine (Nardil) and isocarboxazid (Marplan) for depression or other psychiatric conditions are not able to metabolize dietary tyramine and are therefore instructed to avoid all tyramine-containing foods to prevent hypertensive crisis
Excessive amounts of tyramine may initially cause headache, heart palpitations, nausea, and vomiting and may lead to a hypertensive crisis that can be fatal.
Migraine sufferers often link headache episodes to consumption of foods rich in tyramine. The National Headache Foundation has published tyramine-free diet guidelines for this population of patients. Although few well-designed clinical trials exist studying the effects of tyramine intake in patients suffering from migraine headaches, clinicians often recommend the tyramine free diet to patients if other treatment methods have failed.
Theory / Evidence
When present in large quantities, tyramine displaces noradrenaline (a chemical in the brain), which causes activation of the sympathetic nervous system, leading to possible fatal increases in blood pressure and constriction of blood vessels.
The use of monoamine oxidase inhibitors (MAOIs) has decreased with development of newer antidepressants that do not require diet modification. If a MAOI is prescribed, patients must strictly adhere to the tyramine-free diet throughout treatment and for an additional 2-4 weeks after the drug is discontinued.
Although the tyramine free diet needs more long-term research to conclusively prove its benefits in patients suffering from migraine headaches, it is possible that some individuals may experience fewer migraine episodes when this diet is followed.
Author information
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
Bibliography
Low tyramine diet. 20 June 2006.
Mosnaim AD, et al. Apparent lack of correlation between tyramine and phenylethylamine content and the occurrence of food-precipitated migraine - reexamination of a variety of food products frequently consumed in the United States and commonly restricted in tyramine-free diets. Headache Quart 1996;7(3):239-49.
Diet outline
In the tyramine-free diet, individuals do not consume any foods that contain tyramine. Examples of tyramine containing foods include anchovies, avocados, bananas, bean curd, beer (alcohol-free/reduced), caffeine (large amounts), caviar, champagne, cheese (particularly aged, processed, or strong varieties such as camembert, cheddar, and stilton), chocolate, dry sausage/salami/bologna, fava beans, figs, herring (pickled), liver (particularly chicken), meat tenderizers, papaya, protein extracts/powder, raisins, shrimp paste, sour cream, soy sauce, wine (particularly chianti), yeast extracts and yogurt.
Identifying and avoiding ingredients containing tyramine is often a challenge. The table below includes some examples of foods that are considered safe to eat and which foods are typically avoided. A qualified healthcare provider should be consulted before making decisions about diets and/or health conditions.