Cheese is a hugely popular food worldwide, but did you know it can be dangerous for some people? If you’re taking a certain type of antidepressant called a monoamine oxidase inhibitor (MAOI), consuming cheese could lead to serious health risks. The culprit is tyramine, a naturally occurring compound in many aged cheeses. Here’s why it matters and how to stay safe.
SEE ALSO: The most common cheese-medication interactions you have to watch out for →
What are MAOIs?
Monoamine oxidase inhibitors (MAOIs) are a class of antidepressants used to treat mood disorders such as depression, anxiety and sometimes Parkinson’s disease. These medications work by inhibiting the activity of an enzyme called monoamine oxidase (MAO), which breaks down neurotransmitters like serotonin, dopamine, and norepinephrine. By blocking this enzyme, MAOIs help increase the levels of these neurotransmitters, improving mood and emotional balance.
Some common examples of MAOIs include:
- Generic Names: Phenelzine, Tranylcypromine, Isocarboxazid, Selegiline
- Brand Names: Nardil (Phenelzine), Parnate (Tranylcypromine), Marplan (Isocarboxazid), Emsam (Selegiline, in patch form)
While effective for some patients, MAOIs require dietary restrictions to avoid complications like hypertensive crises, making awareness of tyramine-rich foods crucial.
What is tyramine?
Tyramine is a compound found in various foods, particularly aged or fermented ones. It forms when the amino acid tyrosine breaks down during the ageing or fermentation process. Tyramine is present in many cheeses, especially those that have been aged for extended periods, such as Cheddar, Parmesan and blue cheeses.
Why aged cheeses contain tyramine
The high tyramine content in aged cheeses is due to biochemical changes that occur during the ageing process. When cheese is aged, proteins within the cheese—primarily casein—undergo a breakdown process known as proteolysis. This involves enzymes and bacteria breaking down proteins into smaller peptides and amino acids, including tyrosine.
During this process, some tyrosine is further converted into tyramine by bacterial activity. Specific strains of bacteria present during fermentation and ageing, such as Lactobacillus and Brevibacterium, produce enzymes that facilitate this conversion. The longer a cheese is aged, the more time these bacterial enzymes have to generate tyramine, resulting in higher levels.
Environmental factors like temperature, humidity and pH during ageing can also influence tyramine levels. Cheeses aged in controlled conditions with optimal bacterial activity, such as blue cheeses and aged Cheddar, often have particularly high concentrations of tyramine.
How MAOIs interact with tyramine
Monoamine oxidase inhibitors (MAOIs) are a class of antidepressants prescribed to treat mood disorders such as depression. These drugs work by inhibiting the activity of an enzyme called monoamine oxidase (MAO). This enzyme is responsible for breaking down certain neurotransmitters in the brain, including serotonin, dopamine and norepinephrine, which are crucial for mood regulation.
However, MAO is also responsible for breaking down tyramine. When someone takes an MAOI, this enzyme is inhibited, leading to reduced ability to process tyramine. As a result, tyramine can build up in the bloodstream if consumed in high amounts.
What is hypertensive crisis?
Excess tyramine can trigger the release of norepinephrine, a neurotransmitter that causes blood vessels to constrict. This can result in a sudden and dangerous spike in blood pressure, known as a hypertensive crisis. Symptoms of a hypertensive crisis include:
- Severe headaches
- Chest pain
- Nausea and vomiting
- Rapid heartbeat
- Blurred vision
- Confusion
In extreme cases, a hypertensive crisis can lead to a stroke, heart attack or other life-threatening conditions. This is why tyramine-rich foods, including many types of cheese, are often listed as “off-limits” for individuals taking MAOIs.
Tyramine levels in cheese
The amount of tyramine in cheese varies significantly depending on the type and ageing process. Here’s a breakdown:
High tyramine cheeses:
- Aged Cheddar: 100–250 mg per 100 grams
- Blue cheeses (e.g., Roquefort, Gorgonzola, Stilton): 300–500 mg per 100 grams
- Parmesan: 200–500 mg per 100 grams
- Aged Gouda: 150–250 mg per 100 grams
Moderate tyramine cheeses:
- Swiss cheese (Emmental): 50–150 mg per 100 grams
- Gruyère: 50–200 mg per 100 grams
Low tyramine cheeses:
- Fresh Mozzarella: 0–5 mg per 100 grams
- Ricotta: 0–5 mg per 100 grams
- Cottage Cheese: 0–10 mg per 100 grams
- Cream Cheese: 0–10 mg per 100 grams
Fresh cheeses typically contain little to no tyramine because they are not aged. In contrast, aged and fermented cheeses are much higher in tyramine content due to the extended breakdown of proteins during the ageing process.
How to stay safe
If you are taking MAOIs, it is essential to avoid or limit foods with high tyramine content. Here are some tips:
- Check food labels: Look for information on whether a cheese is aged or fresh.
- Stick to fresh cheeses: Mozzarella, Ricotta, cream cheese and cottage cheese are low in tyramine and are generally safe options.
- Consult your doctor: Always ask your healthcare provider for a comprehensive list of foods to avoid while on MAOIs.
- Be cautious at restaurants: When dining out, inquire about the cheeses used in dishes to ensure they are low in tyramine.
Why only MAOIs?
It’s worth noting that the tyramine-cheese interaction is specific to MAOIs. Most other types of antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs), do not interfere with the breakdown of tyramine and therefore do not pose the same risk.
Examples of SSRIs include:
- Generic Names: Fluoxetine, Sertraline, Citalopram, Escitalopram, Paroxetine
- Brand Names: Prozac (Fluoxetine), Zoloft (Sertraline), Celexa (Citalopram), Lexapro (Escitalopram), Paxil (Paroxetine)
Examples of SNRIs include:
- Generic Names: Venlafaxine, Duloxetine, Desvenlafaxine
- Brand Names: Effexor (Venlafaxine), Cymbalta (Duloxetine), Pristiq (Desvenlafaxine)
Conclusion
While cheese is a delightful food enjoyed by many, its tyramine content can make it hazardous for individuals taking MAOIs. By understanding which cheeses are high in tyramine and taking precautions, those on these medications can minimise their risk of serious complications. Always consult your doctor or dietitian to tailor dietary recommendations to your specific needs.
References
- Shulman, K. I., & Hermann, N. (1996). “Tyramine content of previously restricted foods in monoamine oxidase inhibitor diets.” Journal of Clinical Psychopharmacology, 16(5), 383–388. doi:10.1097/00004714-199610000-00008
- Gillman, P. K. (2011). “Monoamine oxidase inhibitors: A review concerning dietary tyramine and drug interactions.” Psychopharmacology Bulletin, 44(2), 115–129.
- Mayo Clinic Staff. “Monoamine oxidase inhibitors (MAOIs): What they are and how they work.” Mayo Clinic. Accessed December 2024. https://www.mayoclinic.org
- US Food & Drug Administration (FDA). “Consumer information on monoamine oxidase inhibitors.” Accessed December 2024. https://www.fda.gov
- Fenelon, M. A., & Guinee, T. P. (2020). “Primary proteolysis and its importance to the development of flavour and texture in cheese.” In Cheese: Chemistry, Physics and Microbiology (4th ed.), edited by Fox, P. F., McSweeney, P. L. H., Cogan, T. M., & Guinee, T. P. Academic Press.
Cheese lover. Scientist. Created a website and a Youtube channel about cheese science because he could not find answers to his questions online.
