Is cheese an MAOI inhibitor? Debunking the Dietary Interaction

October 11, 2025 •

3 min read

In the early 1960s, a pharmacist's discovery about his wife's headaches when combining cheese with her medication led to the famous 'cheese effect'. The critical question, however, is not if cheese is an MAOI inhibitor, but what makes it dangerous for people on these specific medications.

Quick Summary

This article clarifies the difference between an MAOI medication and the foods that interact with it, focusing on why certain cheeses pose a risk. It explains the role of tyramine and the potential for a hypertensive crisis in individuals taking MAOI drugs.

Key Points

Correction of the Myth: Cheese is not a monoamine oxidase inhibitor (MAOI), but it contains tyramine, which interacts with MAOI medications.
MAOI's Mechanism: MAOI drugs block the enzyme that breaks down tyramine, leading to a buildup of the substance in the body.
Hypertensive Crisis Risk: This tyramine buildup can cause a hypertensive crisis (a sudden, dangerous increase in blood pressure) in individuals taking MAOIs.
Tyramine in Cheese: Aged and fermented cheeses contain high levels of tyramine, while fresh cheeses generally have low levels.
Broader Dietary Restrictions: The tyramine restriction applies to many other foods, including cured meats, fermented soy products, and certain alcoholic beverages.
Importance of Medical Advice: Individuals on MAOIs must consult their healthcare provider for specific dietary guidance due to the risks involved.

Understanding the MAOI-Tyramine Interaction

Contrary to a common misconception, cheese is not an MAOI inhibitor. The danger associated with cheese consumption for individuals on Monoamine Oxidase Inhibitor (MAOI) medications is due to an indirect, but serious, interaction. MAOIs are a class of antidepressants that block the enzyme monoamine oxidase, which is responsible for breaking down a substance called tyramine in the body. Cheese, particularly aged and fermented varieties, contains substantial amounts of this naturally occurring tyramine. When the MAO enzyme is inhibited by medication, the body cannot process the dietary tyramine effectively, leading to a dangerous buildup.

The Role of Tyramine and the 'Cheese Reaction'

Tyramine is a byproduct of the amino acid tyrosine and is found in many aged and fermented foods and beverages. For most healthy individuals, tyramine is quickly metabolized and poses no threat. However, for those taking MAOIs, the failure to break down excess tyramine can trigger a sudden and severe spike in blood pressure, known as a hypertensive crisis.

Symptoms of this "cheese reaction" can include:

Severe headaches
Heart palpitations or rapid heartbeat
Stiffness or soreness in the neck
Nausea and vomiting
Shortness of breath

If not addressed quickly, a hypertensive crisis can lead to more serious complications like stroke, organ damage, or even death.

Why Aged Cheeses Are the Main Culprit

The tyramine content in cheese varies significantly depending on the production process, particularly the aging and fermentation period. The longer a cheese is aged, the more time microorganisms have to break down proteins into tyramine. This explains why a fresh cheese like cottage cheese or mozzarella is safe, while a well-aged Parmesan or Cheddar is not. The type of milk, bacterial cultures, and storage conditions also play a role in determining the final tyramine level.

A Comparative Look at Tyramine in Cheeses

To help navigate dietary choices while on MAOIs, it is useful to compare cheeses based on their tyramine content.


Cheese Category	Examples	Tyramine Level (MAOI Risk)
Low Tyramine	American cheese, Cottage cheese, Ricotta, Cream cheese, Fresh Mozzarella	Very Low
High Tyramine	Aged Cheddar, Blue cheese (Stilton, Gorgonzola), Parmesan, Swiss, Gruyère, Feta	High
Variable/Moderate Tyramine	Commercially made processed cheeses, some fresh goat cheese	Varies (Consume with caution)

Extending the Diet: Other Foods to Avoid

The MAOI-tyramine restriction extends beyond just aged cheese. Several other foods and beverages must also be avoided to prevent a hypertensive crisis. These include:

Cured or processed meats: Salami, pepperoni, dry sausages, hot dogs, and smoked or cured fish.
Fermented soy products: Tofu, miso, and soy sauce.
Fermented sauces: Teriyaki sauce, fish sauce, and shrimp sauce.
Certain alcoholic beverages: Draft or unpasteurized beer, sherry, and some red wines.
Other fermented foods: Sauerkraut and kimchi.
Yeast extracts: Marmite and Vegemite.
Dried or overripe fruits: Raisins, overripe bananas, and overripe avocados.

Evolving Dietary Recommendations and Safe Practices

Over the decades since the discovery of the "cheese effect," dietary guidelines have been refined. Modern food production and storage methods have made some foods safer than they were in the past. However, because tyramine levels can vary unpredictably, it is crucial for anyone taking an MAOI to follow their doctor's specific dietary instructions and to be vigilant about food sourcing and freshness. Always consult a healthcare professional for the most current and accurate dietary advice regarding MAOI medications. For more detailed information on MAOIs and diet, you can refer to authoritative sources like the Mayo Clinic's guidance on the topic.

Conclusion: The Critical Distinction

In summary, the statement that is cheese an MAOI inhibitor is factually incorrect. Cheese does not inhibit the MAO enzyme; rather, it contains a compound, tyramine, that becomes hazardous when the MAO enzyme is inhibited by medication. The resulting hypertensive crisis is a serious health risk. By understanding this crucial distinction and adhering to a strict, low-tyramine diet, individuals on MAOI therapy can manage their condition safely.

Frequently Asked Questions

People taking MAOI medications cannot properly break down tyramine, a substance found in aged cheeses, because the medication inhibits the enzyme responsible for this process. This can lead to dangerously high blood pressure.

Yes, fresh cheeses such as cottage cheese, ricotta, cream cheese, and fresh mozzarella typically contain very low levels of tyramine and are generally considered safe for those on MAOI medication.

The 'cheese effect' refers to the hypertensive crisis that can occur when a person on an MAOI medication consumes foods high in tyramine, such as aged cheese.

Many fermented foods are high in tyramine, but not all. The amount depends on the specific food, fermentation process, and aging time. It is best to avoid fermented foods altogether unless a healthcare provider confirms their safety.

The dietary restrictions for MAOIs should be continued for several weeks after stopping the medication, as advised by your healthcare provider. This is to allow the MAO enzyme activity to return to normal levels.

Symptoms can include severe headache, rapid or pounding heartbeat, chest pain, stiffness in the neck, and shortness of breath. Immediate medical attention is required for these symptoms.

While modern food production and storage have reduced tyramine levels in some products, the risk is not eliminated, especially with aged, artisan, and raw milk cheeses. Vigilance and consultation with a doctor are still essential for individuals on MAOIs.

Most MAOIs require dietary restrictions to avoid tyramine interaction. However, some newer, selective MAO-B inhibitors may have less stringent restrictions, particularly at lower doses. Always follow the specific instructions from your prescribing doctor.