Monoamine oxidase inhibitors, or MAOIs, are a type of antidepressant that blocks the actions of the enzyme monoamine oxidase. Monoamine oxidase breaks down excess tyramine, an amino acid involved in blood pressure regulation. Consuming excess tyramine while on MAOIs can lead to a build-up of tyramine, potentially causing a rapid and dramatic spike in blood pressure. Therefore, while on MAOIs, following a low-tyramine diet is crucial.
A High Tyramine Diet
According to Stahl, et al., in "Trends in Psychopharmacology," a meal is considered to be high in tyramine if it contains around 40 mg of the amino acid. A person not taking MAOIs can handle up to 400 mg of tyramine before experiencing an increase in blood pressure. However, if you are taking a high dosage of certain nonselective irreversible MAOIs, as little as 8 to 10 mg of dietary tyramine may cause an increase in blood pressure.
Foods to Limit or Avoid
If you are prescribed an MAOI, your physician will provide you with specific dietary guidelines to follow. Make sure you clearly understand which foods you should avoid, as there are potential health risks associated with not following a low-tyramine diet. Foods to avoid or limit include aged cheeses; cured meats such as salami, pepperoni and sausage; banana peel extract; overripe and spoiled fruits; caviar; chicken and beef liver; dried, salted and pickled fish; broad bean or fava bean pods; soy sauce; sauerkraut; yeast-extract spreads such as Marmite; fermented soy-bean products such as tofu; tap or draft beer; unpasteurized beer; some wines; and improperly stored or spoiled foods. Keep in mind that the tyramine content of foods can differ based on their processing, storage and preparation.
Allowed Foods
As tyramine content is higher in foods that are close to spoiling or have been stored for a long period of time, your physician may recommend you consume a diet of primarily fresh foods. While on a low-tyramine diet, all cheese products need not be avoided. Processed cheeses as well as cottage cheese, cream cheese and ricotta cheese are safe to consume while using an MAOI. Furthermore, all fresh or frozen meats, fish or poultry are allowed on a low-tyramine diet. Milk, decaf coffee, decaf tea and carbonated drinks are typically permitted as well. With the exception of the few vegetable products you should avoid, all fresh, frozen, dried or canned vegetables and vegetable juices may be eaten while taking an MAOI. If you are ever unsure whether or not a food is safe for you to consume, consult your physician.
Risks of Not Restricting High-Tyramine Foods
MAOIs inhibit monoamine oxidase from breaking down excess dietary tyramine. If you consume high-tyramine foods while taking an MAOI, your body will not be able to process the tyramine rapidly enough, potentially leading to a narrowing of your blood vessels. This narrowing of the blood vessels may cause a dangerous increase in your blood pressure, requiring emergency medical attention. Watch out for signs and symptoms that may indicate a hypertensive crisis such as dilated pupils, nausea, vomiting, fast heartbeat, sweating and headaches.
References
- University of Pittsburgh Medical Center: MAOI Diet Facts
- MayoClinic: Monoamine oxidase inhibitors (MAOIs)
- MayoClinic: MAOIs and diet: Is it necessary to restrict tyramine?
- "Trends in Psychopharmacology"; Monoamine oxidase inhibitors: A modern guide to an unrequited class of antidepressants; Stephen M. Stahl et al.; October 2008
