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:

1. Check food labels: Look for information on whether a cheese is aged or fresh.
2. Stick to fresh cheeses: Mozzarella, Ricotta, cream cheese and cottage cheese are low in tyramine and are generally safe options.
3. Consult your doctor: Always ask your healthcare provider for a comprehensive list of foods to avoid while on MAOIs.
4. 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

1. 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
2. Gillman, P. K. (2011). “Monoamine oxidase inhibitors: A review concerning dietary tyramine and drug interactions.” Psychopharmacology Bulletin, 44(2), 115–129.
3. Mayo Clinic Staff. “Monoamine oxidase inhibitors (MAOIs): What they are and how they work.” Mayo Clinic. Accessed December 2024. https://www.mayoclinic.org
4. US Food & Drug Administration (FDA). “Consumer information on monoamine oxidase inhibitors.” Accessed December 2024. https://www.fda.gov
5. 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.

Jonah Kincaid

Cheese lover. Scientist. Created a website and a Youtube channel about cheese science because he could not find answers to his questions online. 

cheesescientist.com

The post Why High Tyramine Cheeses Can Interact With Antidepressants appeared first on Cheese Scientist.

Monoamine oxidase inhibitors (MAOIs)

Aged cheeses like Cheddar, Parmesan and blue cheese contain high levels of tyramine. This compound forms when proteins break down during ageing.

MAOIs, used to treat depression or Parkinson’s disease, inhibit the enzyme monoamine oxidase. This enzyme normally breaks down tyramine in the body. When MAOIs are taken with aged cheeses, tyramine levels can spike.

• Mechanism: Excess tyramine causes a rapid release of norepinephrine, a stress hormone. This can lead to dangerously high blood pressure, known as a hypertensive crisis.
• Examples: Common MAOIs include phenelzine (Nardil), tranylcypromine (Parnate) and selegiline (Emsam).
• Advice: Avoid aged cheeses like Cheddar, Parmesan and blue cheese while taking MAOIs. Fresh cheeses like Ricotta or Mozzarella are safer alternatives.

Tetracyclines and Quinolones (antibiotics)

Some antibiotics, particularly tetracyclines and quinolones, can interact with cheese. These drugs are used to treat bacterial infections.

• Mechanism: Calcium in cheese binds with antibiotics in the gut, forming insoluble complexes. These complexes cannot be absorbed, reducing the drug’s effectiveness.
• Examples: Tetracyclines like doxycycline (Vibramycin) and minocycline (Minocin or Minomycin) or quinolones like ciprofloxacin (Cipro) and levofloxacin (Levaquin).
• Advice: Avoid consuming cheese two hours before or after taking these antibiotics. This ensures proper absorption of the medication.

Bisphosphonates (osteoporosis)

Bisphosphonates, like alendronate, treat and prevent osteoporosis by improving bone density. Calcium-rich foods, including cheese, can interfere with these medications.

• Mechanism: Calcium competes with bisphosphonates for absorption in the gut. This reduces the medication’s bioavailability.
• Examples: Common bisphosphonates include alendronate (Fosamax) and risedronate (Actonel).
• Advice: Take bisphosphonates on an empty stomach with water. Avoid cheese and other calcium sources for at least two hours.

Levothyroxine (thyroid hormone replacement)

Levothyroxine treats hypothyroidism by supplementing thyroid hormones. Its absorption can be affected by dietary calcium.

• Mechanism: Calcium in cheese binds to levothyroxine in the gut. This reduces the amount of medication absorbed into the bloodstream.
• Examples: Levothyroxine is available under brand names like Synthroid, Euthyrox, Levothroid and Oroxine.
• Advice: Take levothyroxine on an empty stomach. Wait four hours before eating cheese or other calcium-rich foods.

Lithium (bipolar disorder)

Lithium, commonly used to treat bipolar disorder, does not have a direct interaction with cheese in most cases. However, certain aspects of diet, including sodium and hydration, can influence lithium levels in the blood. Cheese, particularly aged and processed varieties, may indirectly affect lithium therapy due to its sodium content.

Mechanism of interaction

• Sodium Levels: Lithium and sodium are processed similarly in the kidneys. High-sodium foods, including salty cheeses like Parmesan, Roquefort and Feta, can increase sodium levels in the body. When sodium intake rises, the kidneys may excrete more lithium, reducing its therapeutic effect.
• Dehydration: A diet high in sodium, often paired with insufficient water intake, can cause dehydration. Dehydration may lead to a concentration of lithium in the blood, increasing the risk of lithium toxicity.

Potential risks

• Reduced Efficacy: Excess sodium can lower lithium levels, making it less effective for mood stabilization.
• Toxicity: Conversely, rapid changes in sodium levels or dehydration may cause lithium levels to rise dangerously, leading to side effects such as tremors, confusion, or even kidney damage.

Advice for Lithium users

1. Moderate Sodium Intake: Avoid excessive consumption of salty cheeses like blue cheese or processed varieties.
2. Stay Hydrated: Drink plenty of water to maintain proper hydration and stable lithium levels.
3. Consistent Diet: Maintain a stable sodium intake daily, as sudden dietary changes can disrupt lithium balance.
4. Monitor Levels: Regular blood tests are essential to monitor lithium levels and ensure they remain within the therapeutic range.

If you’re on lithium therapy, it’s always best to consult with a healthcare provider about your diet, including cheese consumption.

Iron supplements

Cheese is a significant source of calcium. Consuming it with iron supplements can reduce their absorption.

• Mechanism: Calcium competes with iron for absorption in the intestines. This interaction reduces the effectiveness of iron supplements.
• Examples: Common iron supplements include ferrous sulfate, ferrous gluconate and ferrous fumarate.
• Advice: Space iron supplements from cheese consumption by at least two hours.

Integrase Inhibitors (HIV management)

Integrase strand transfer inhibitors (INSTIs), such as dolutegravir, bictegravir and raltegravir, can interact with calcium.

• Mechanism: Calcium in cheese binds to INSTIs in the gastrointestinal tract, forming insoluble complexes. This reduces drug absorption and efficacy. Hard cheeses like Parmesan and aged Cheddar are particularly high in calcium.
• Advice: Avoid consuming cheese two hours before or after taking INSTIs. If consuming cheese, consider spacing it apart from your medication doses.

Sotalol (heart)

Sotalol is a beta-blocker commonly prescribed to treat irregular heart rhythms (arrhythmias) such as atrial fibrillation. While there is no direct interaction between cheese and sotalol, certain components in cheese, like calcium and sodium, can indirectly affect how the medication works.

Calcium in cheese and sotalol absorption

Calcium-rich cheeses, such as Parmesan, Cheddar and Swiss, can interfere with sotalol absorption if consumed around the same time as the medication.

• Mechanism: Calcium binds to sotalol in the gut, forming insoluble complexes. This reduces the amount of sotalol absorbed into the bloodstream, potentially decreasing its effectiveness in managing arrhythmias.
• Advice: Avoid consuming calcium-rich cheeses within two hours of taking sotalol. If cheese is part of your diet, schedule it away from your medication times.

General tips for patients on sotalol

1. Time Cheese Consumption: Avoid eating cheese, particularly calcium-rich varieties, close to your medication time.
2. Choose Low-Sodium Options: Stick to cheeses with less sodium to support cardiovascular health.
3. Monitor Electrolytes: Sotalol can affect potassium and magnesium levels, so balance your diet accordingly.
4. Stay Consistent: Maintain a regular diet and medication schedule to ensure stable sotalol levels in the blood.

Always consult your healthcare provider for specific advice on your diet and medication. By understanding potential interactions, you can enjoy cheese while effectively managing your heart health.

Deferasirox (iron overload treatment)

Deferasirox is an oral iron chelator used to treat iron overload in conditions like thalassemia or sickle cell disease. It works by binding excess iron in the body, which is then excreted via the stool.

Interaction with dairy and supplements

Deferasirox requires special consideration because calcium in dairy products and other minerals can interfere with its effectiveness.

• Mechanism: Deferasirox binds to calcium and other minerals, reducing its ability to chelate iron effectively. The presence of calcium, magnesium, or aluminium in the stomach can lower the drug’s bioavailability.
• Advice: Avoid dairy products, antacids, and mineral supplements two hours before and after taking deferasirox. Take deferasirox on an empty stomach with water or a small non-dairy snack for better absorption.
• Common Dairy Products to Avoid: Milk, cheese, yoghurt and cream. Calcium-fortified plant-based milks (check labels for added calcium).

By following these guidelines, patients can ensure optimal iron chelation and avoid reducing the drug’s efficacy. Always consult your doctor or pharmacist for personalised advice.

Ursodeoxycholic acid (gallstones)

Ursodeoxycholic acid (UDCA) is used to treat gallstones and liver conditions such as primary biliary cholangitis.

Interaction with dairy and supplements

• Mechanism: UDCA’s absorption relies on bile salts. High-fat meals, including some cheeses, can enhance bile secretion and improve UDCA absorption. However, antacids containing aluminium hydroxide or calcium carbonate can bind to UDCA in the gut, reducing its effectiveness.
• Advice: While dairy (including cheese) doesn’t directly interfere with UDCA, antacids and calcium supplements should not be taken at the same time. If taking antacids or calcium supplements, space them out by at least two hours from UDCA to ensure proper absorption.
• Practical Tips for Patients: UDCA is usually taken with food to enhance bile secretion and absorption. If prescribed antacids or supplements, discuss timing with your doctor or pharmacist.

While cheese and dairy products are generally safe with UDCA, careful scheduling of other medications can help optimise treatment outcomes.

Conclusion

Cheese is a delicious and nutritious food, but it can interact with various medications and supplements. The calcium, sodium, and other compounds in cheese are the main culprits. To avoid complications, understand how cheese interacts with your medications.

Consult your healthcare provider for tailored advice. By planning your diet wisely, you can enjoy cheese safely while maintaining your health.

References

1. Gül, N. (2020). “Drug-food interactions: A focus on calcium-rich foods.” Journal of Clinical Pharmacy and Therapeutics. DOI: 10.1111/jcpt.13204
2. Kellie, D., & Lambert, S. (2018). “Understanding tyramine and its effects with MAOIs.” Journal of Mental Health Practice. Retrieved from mentalhealth.org
3. Dorrington, C., et al. (2017). “The impact of dietary calcium on antibiotic efficacy.” Pharmacological Reviews, 69(2), 154–163.
4. American Thyroid Association. (2023). “Levothyroxine and dietary considerations.” Retrieved from thyroid.org
5. National Heart, Lung, and Blood Institute (NHLBI). (2022). “Managing cholesterol with statins and diet.” Retrieved from nhlbi.nih.gov
6. Young, L. J. (2019). “Calcium-zinc competition: Implications for supplementation.” Nutrition Insights, 34(6), 124–130.

Consult these sources or your healthcare provider for further details about drug-cheese interactions and safe dietary practices.

Jonah Kincaid

Cheese lover. Scientist. Created a website and a Youtube channel about cheese science because he could not find answers to his questions online. 

cheesescientist.com

The post Medications That Interact With Cheese (Including Supplements) appeared first on Cheese Scientist.

SEE ALSO: The types of medications and supplements that can interact with cheese →

The role of dietary calcium in cheese

Cheese, a beloved food for its flavour and texture, is also a rich source of calcium, a vital mineral for strong bones and teeth. Calcium also supports muscle function and nerve signalling. However, when it comes to absorbing iron, calcium can become problematic. The calcium in cheese competes with iron during digestion, particularly in the intestines.

This competition limits the amount of iron that gets absorbed into the bloodstream. It is especially relevant for non-haem iron. Non-haem iron comes from plant-based sources and supplements. It’s less readily absorbed compared to haem iron from meat.

Why iron is essential

Iron is a critical mineral for the human body. It helps create haemoglobin, the protein in red blood cells that carries oxygen. Without enough iron, you can develop iron deficiency anaemia. Symptoms include fatigue, pale skin and shortness of breath.

Your body’s ability to absorb iron varies depending on the type of iron and what you eat with it. Haem iron, found in animal products, is easily absorbed. On the other hand, non-haem iron, present in plants and supplements, needs a boost to be absorbed well.

How calcium in cheese affects iron absorption

The interaction between calcium and iron occurs primarily in the intestines during digestion. Calcium can inhibit the absorption of both haem and non-haem iron by competing for the same transport pathways. This competition is more significant for non-haem iron, which is already less bioavailable than haem iron.

When calcium binds to iron in the gut, it forms insoluble complexes that the body cannot absorb. This reduces the amount of iron entering the bloodstream. The effect is dose-dependent, meaning higher calcium intakes result in greater interference. For instance, consuming a calcium-rich food like cheese or milk alongside an iron supplement can substantially decrease the supplement’s effectiveness.

Calcium’s impact on iron absorption has been studied extensively. Research shows that calcium can block both haem and non-haem iron absorption. However, non-haem iron is more affected because it is less bioavailable.

When you consume calcium-rich foods like cheese along with iron supplements, absorption drops significantly. Even small amounts of calcium can reduce iron uptake. For example, drinking a glass of milk with your supplement has a similar effect.

Timing is everything

If you need both calcium and iron, timing matters. Don’t take them together. Space them out by at least two hours. This allows your body to process each nutrient separately, ensuring better absorption.

For instance, take your iron supplement first thing in the morning. Later, indulge in calcium-rich foods like cheese or yoghurt. This simple habit can make a big difference.

Enhancing iron absorption

Certain foods and nutrients can improve iron absorption. Vitamin C is the most well-known. It converts non-haem iron into a more absorbable form. Pairing iron supplements with orange juice or eating citrus fruits can help.

Other strategies include avoiding inhibitors like tannins and polyphenols. These are found in tea, coffee and red wine. High-fibre foods and phytates, present in whole grains and legumes, also interfere with iron absorption. Avoid these close to taking your iron supplements.

Who needs to be cautious?

Some groups need to pay extra attention to their iron levels. Pregnant women, for example, have higher iron requirements. Children and teenagers going through growth spurts also need more iron. Vegetarians and vegans may struggle to get enough iron from their diet alone.

People with conditions like coeliac disease or Crohn’s disease might have impaired iron absorption. Regular blood donors and those with heavy menstrual periods can also experience iron deficiency. If you fall into one of these categories, consult your doctor for personalised advice.

Signs of iron deficiency

Recognising iron deficiency early can prevent complications. Common symptoms include tiredness, weakness, and difficulty concentrating. You might notice brittle nails or hair loss. In severe cases, you could experience dizziness or a rapid heartbeat.

If you suspect you’re deficient, get your iron levels checked. A blood test can confirm if you need supplements or dietary adjustments.

What type of foods are rich in iron

Incorporating iron-rich foods into your diet is key. For haem iron, include red meat, poultry and fish. For non-haem iron, focus on lentils, beans, tofu and spinach. Fortified cereals and bread can also be good sources.

Combining these foods with vitamin C sources can enhance absorption. Try adding bell peppers, tomatoes or strawberries to your meals. Avoid pairing these with dairy products to maximise their benefits.

Comparing calcium content in cheese and dairy products

Cheese and other dairy products vary in their calcium content, which can influence iron absorption differently. For instance:

• Hard cheeses like Parmesan have high calcium levels, with about 948 milligrams per 100-gram serving.
• Cheddar contains approximately 707 milligrams of calcium per 100-gram slice.
• Soft cheeses like Brie have lower calcium content, around 460 milligrams per 100-gram portion.
• Cow’s milk provides roughly 120 milligrams of calcium per 100 millilitres.

The higher the calcium content, the greater its potential to inhibit iron absorption when consumed alongside iron supplements. For example, eating a serving of Parmesan with an iron supplement could significantly reduce absorption compared to having a softer cheese like Brie.

Understanding these differences allows you to plan your meals effectively. If you’re consuming a high-calcium cheese, space it further from your iron intake to minimise interaction.

Balancing cheese & iron

Both calcium and iron are essential nutrients. The key is finding a balance that works for you. Plan your meals and supplements thoughtfully. If you’re taking both nutrients, stagger them to avoid interference.

For example, enjoy a cheese sandwich for lunch. Then, take your iron supplement in the evening with a vitamin C-rich snack to boost absorption. This ensures you get the best of both worlds.

Some other considerations

Some medications and health conditions can also affect nutrient absorption. Antacids, for instance, can reduce iron absorption. If you’re on medication, check with your doctor about possible interactions.

Additionally, over-supplementing with calcium or iron can lead to side effects. Too much calcium can cause constipation or kidney stones. Excess iron can lead to toxicity, causing nausea or organ damage. Stick to recommended doses and consult your doctor if unsure.

Conclusion

Pairing cheese with iron supplements at the same time isn’t ideal for maintaining nutrient balance. Calcium in cheese interferes with iron absorption, particularly non-haem iron. To maximise iron uptake, space out your calcium and iron intake by at least two hours.

Enhance your iron absorption with vitamin C-rich foods. Avoid inhibitors like tea, coffee, and high-fibre foods when taking your supplement. Balance your diet carefully to meet your nutrient needs without compromising absorption.

If you suspect an iron deficiency, consult your doctor. A blood test can help determine if supplements are necessary. With thoughtful planning, you can enjoy cheese and maintain healthy iron levels.

Jonah Kincaid

Cheese lover. Scientist. Created a website and a Youtube channel about cheese science because he could not find answers to his questions online. 

cheesescientist.com

The post Why You Shouldn’t Eat Cheese & Iron Supplements Together appeared first on Cheese Scientist.