Understanding Monoamine Oxidase and Tyramine
First, let's clarify a common misconception. Foods do not contain monoamine oxidase (MAO). Instead, MAO is an enzyme naturally present in the body that breaks down substances like tyramine. The issue arises for individuals taking Monoamine Oxidase Inhibitors (MAOIs), a class of medication used to treat conditions such as depression and Parkinson's disease. MAOIs block the function of the MAO enzyme. When this enzyme is inhibited, the body cannot break down excess dietary tyramine, causing it to build up to dangerously high levels. This leads to a sudden and severe increase in blood pressure, known as a hypertensive crisis, which can result in a stroke or other serious health complications. Therefore, the dietary concern is not about foods that are high in monoamine oxidase but rather foods that are high in tyramine.
The Aging and Fermentation Process
Tyramine levels in food naturally increase with fermentation, aging, and spoilage. This is why fresh foods are generally safe, while their processed counterparts are not. When preparing food, it is important to follow proper food safety guidelines, refrigerating and consuming meals promptly, and avoiding leftovers that are more than a couple of days old. Spoilage can dramatically increase tyramine content and should be avoided entirely.
High-Tyramine Foods to Avoid
The following list details common food categories that contain high levels of tyramine and should be avoided by individuals on MAOIs:
- Aged Cheeses: All aged, mature, or fermented cheeses are high in tyramine. This includes cheddar, stilton, blue cheese, gorgonzola, camembert, brie, feta, parmesan, and gruyere. Fresh, non-aged cheeses like cottage cheese, ricotta, and cream cheese are typically safe.
- Cured, Smoked, and Processed Meats: Tyramine builds up during the curing and smoking process. Avoid sausages, salami, pepperoni, bologna, dry-cured meats, and smoked fish. All meat should be as fresh as possible and consumed immediately after cooking.
- Fermented Soy Products: Fermented foods are a major source of tyramine. This category includes soy sauce, tamari, miso, tempeh, and fermented tofu.
- Certain Fruits and Vegetables: Tyramine can increase as produce becomes overripe or spoils. Specifically, avoid fava beans, broad beans, snow peas, sauerkraut, kimchi, and extremely ripe bananas (especially the peel).
- Yeast Extracts: Concentrated yeast products such as Marmite, Vegemite, and brewer's yeast are high in tyramine and should be avoided.
- Alcoholic Beverages: Different types of alcohol vary in tyramine content, but many contain significant amounts. Tap and home-brewed beers, red wines, and sherry should be avoided. Certain spirits and pasteurized bottled beers may be safer in moderation, but caution is advised.
Moderate-Tyramine Foods
Some foods have moderate levels of tyramine and may be consumed with caution and in limited amounts by those on a low-tyramine diet, depending on individual tolerance and doctor's advice.
- Certain Dairy: Yogurt, sour cream, and some un-aged cheeses like havarti and brie. Intake should be limited.
- Avocados: Tyramine levels can increase as they ripen. Consumption should be limited.
- Chocolate: The amount of tyramine in chocolate varies, but it is considered a moderate-level food.
- Nuts and Seeds: Some nuts, seeds, and nut butters contain moderate tyramine.
High vs. Low Tyramine Food Comparison
| Food Category | High Tyramine (Avoid) | Low Tyramine (Safe) |
|---|---|---|
| Dairy | Aged cheeses (cheddar, blue, parmesan), processed cheese, sour cream | Fresh cheeses (cottage, ricotta, cream), milk, plain yogurt (in moderation) |
| Meat & Poultry | Cured meats (salami, pepperoni), smoked fish, aged game, meat extracts | Fresh or frozen meat, poultry, fish, eggs |
| Soy & Legumes | Fermented soy (miso, soy sauce, tempeh), fava beans, broad beans | Fresh tofu, soy milk, fresh beans and lentils |
| Beverages | Tap beer, red wine, sherry, vermouth, yeast-containing drinks | Pasteurized bottled beer (limited), most spirits (limited), coffee, tea, soft drinks |
| Condiments | Fermented sauces (fish sauce, soy sauce), yeast spreads (Marmite) | Ketchup, most commercially made salad dressings, vinegar |
| Fruits & Veggies | Sauerkraut, kimchi, overripe bananas, dried fruit, overripe avocados | Fresh, frozen, or canned fruits and vegetables |
How to Manage a Low-Tyramine Diet
Managing a low-tyramine diet requires careful attention to food selection, preparation, and storage. The most important rule is to prioritize freshness. Always check expiration dates and avoid any food that appears to be spoiling or past its peak. When eating out, it can be difficult to know the freshness and preparation methods of ingredients, so exercise caution. It is always recommended to consult with a healthcare professional or registered dietitian for personalized dietary advice, especially when on medication.
By being vigilant and knowledgeable about the foods high in tyramine, individuals taking MAOIs can significantly reduce their risk of a dangerous hypertensive crisis. This empowers them to manage their health safely and effectively. Healthline's Guide to Low Tyramine Diet
Conclusion
The perception that certain foods are high in monoamine oxidase is inaccurate. The real risk lies in the high tyramine content of aged, fermented, and spoiled foods, which can cause severe reactions in those taking MAOI medication. By understanding the distinction between the enzyme and the substance, and adhering to a low-tyramine diet, patients can safely manage their condition. Prioritizing fresh ingredients, carefully reading labels, and being cautious with leftovers are the cornerstones of this dietary management strategy. Always consult a healthcare provider for the most accurate and personalized guidance.
