The do's and don'ts of taking medications can be confusing, but there are good reasons for your doctor's orders. If you're taking a monoamine oxidase inhibitor (MAOI) to help treat depression or Parkinson's disease, it's important to know that the drug can interact with an amino acid called tyramine.
Below, we break down the basics of tyramine and MAOIs, including how both work in the body and which foods are highest in the amino acid.
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What Is Tyramine and How Does It Work in the Body?
Tyramine is an amino acid that's naturally produced in the body and also occurs in certain foods, per the Mayo Clinic.
The amino acid is involved in blood pressure regulation in the body — it can raise blood pressure levels, but the body has a built-in system for breaking down and excreting excess tyramine thanks to an enzyme called monoamine oxidase.
In addition to breaking down tyramine, monoamine oxidase also removes neurotransmitters like dopamine, serotonin and norepinephrine from the body, according to the Mayo Clinic. This can be problematic when these brain chemicals aren't functioning properly, which is the case in conditions like depression and Parkinson's disease. That's where MAOIs come in.
What Are MAOIs?
MAOIs are a class of drugs, which includes meds like Marplan, Nardil and Emsam, that inhibit the actions of the monoamine oxidase enzyme. While this can be helpful for maintaining healthy dopamine and serotonin levels in depression, it also means that tyramine may build up in the bloodstream.
Combining an MAOI prescription with a high-tyramine diet can lead to dangerously high blood pressure levels, as well as symptoms like severe headaches, nausea, vomiting, sweating, elevated heart rate, chest pain, shortness of breath and confusion, according to the Mayo Clinic.
It's important to note that MAOIs are not commonly prescribed anymore due to the risks associated with this class of drugs. These meds are typically used only if other types of antidepressants have not been effective, per the Mayo Clinic.
So, how much tyramine is too much tyramine? The answer is, it depends. Some reports suggest that more than 5 milligrams of tyramine may trigger adverse reactions, including increased blood pressure, nausea and a fast heartbeat, while 25 or more milligrams of tyramine can be life-threatening for people on MAOIs.
Some people are more sensitive to tyramine than others, regardless of whether they’re taking an MAOI. Because tyramine constricts and dilates blood vessels, it may cause headaches for some people, per Penn Medicine. People who get frequent headaches and migraines may want to try eating fewer tyramine-rich foods to see if it helps reduce the severity or frequency of their headaches.
High-Tyramine Foods List
Tyramine naturally occurs in small amounts in some foods, including:
- Chicken liver
But the compound is also formed as a result of fermenting, pickling and aging foods and drinks.
That is, as proteins break down in aged food products, tyramine production increases, according to widely cited January 2005 research in the Journal of the American Dietetic Association. That's why aged cheeses, cured meats and pickled fish are considered some of the most tyramine-rich foods.
For people taking MAOIs, it's essential to significantly minimize or avoid foods and drinks high in tyramine. Here are 10 foods to avoid if you're taking an MAOI and following a tyramine-free diet.
1. Strong and Aged Cheeses
Cheese is one of the richest sources of tyramine in the diet. In fact, adverse reactions to excessive tyramine have been deemed "the cheese effect," per the January 2005 study in the Journal of the American Dietetic Association.
Aged cheeses like cheddar, Swiss, Parmesan, blue cheese and camembert are the highest in tyramine thanks to the way they're processed.
2. Cured, Smoked and Processed Meats
We should all limit the amount of processed meat in our diets, but people taking MAOIs should be extra cautious when it comes to these animal proteins.
Processed and cured meat products like salami, sausage, pepperoni and hot dogs are all rich in tyramine, according to the Mayo Clinic. Opt for fresh proteins like wild salmon, grass-fed lean beef or organic chicken breast instead.
3. Pickled and Fermented Foods
Fermented foods are an essential component of a gut-healthy diet, but pickled and fermented products like herring in brine, sauerkraut and kimchi are high in tyramine.
If you're taking an MAOI, consider showing your gut some love with a probiotic supplement and high-fiber foods like legumes instead. Doing so will help support your good gut bugs — without the tyramine troubles.
We love a tasty sauce, but some flavor enhancers are high in tyramine. Take soy sauce, for example. The ingredient is traditionally made from fermented soybeans. As we know, that fermentation process produces more tyramine.
Other high-tyramine sauces include fish sauce and teriyaki sauce, according to the Mayo Clinic.
If you're following a low-tyramine diet for headache relief, you should know that some soy sauces also contain monosodium glutamate, or MSG, a compound that might trigger headaches in some people, per Penn Medicine. For a similar flavor, try coconut aminos.
5. Soy Products
Soy products like miso, tofu and tempeh are all made from fermented soybeans that also deliver more tyramine due to the way they're produced.
6. Yeast Extracts
Though not commonly eaten in the U.S., savory spreads like Vegemite and Marmite made from yeast extracts are also high in tyramine.
Don't hate us, but booze is also on the no-no list for those taking MAOIs. Alcoholic beverages like tap and homemade beers, red wine, sherry and liqueurs are among the highest in tyramine, per the Mayo Clinic.
8. Less-Than-Fresh Animal Proteins
Meat, poultry or fish that has been stored in the fridge for more than 3 to 4 days is higher in tyramine than fresh options, so be sure to cook fresh proteins ASAP to keep their tyramine content in check.
9. Sourdough Bread
When we think of fermented foods, our minds usually skip to products like kimchi and kombucha. But sourdough bread is a product of yeast fermentation, which means it contains tyramine as well.
Choose non-fermented breads like a seedy whole-wheat for a high-fiber replacement.
10. Caffeinated Drinks
If you're wondering whether coffee contains tyramine, we get it... It's an important question. Unfortunately, caffeinated drinks like coffee, tea and colas should be enjoyed with caution if you're taking an MAOI, per the Mayo Clinic.
Talk to your doctor about how much caffeine is safe to drink daily.
High-tyramine foods should be avoided/limited while taking MAOIs and for a few weeks after stopping them, per the Mayo Clinic.
There are plenty of low-tyramine foods and beverages you can enjoy regularly. Some examples include:
- Dairy products like yogurt, milk, ice cream and cheeses made from pasteurized milk, like cottage cheese, ricotta and cream cheese, per the Mayo Clinic
- Fresh proteins like meat, poultry, fish and eggs. Eat these foods within 2 to 3 days of purchase or store them in the freezer to prevent spoilage.
- Beans and peas, except for fava and broad beans, which are naturally higher in tyramine, according to the review in the Journal of the American Dietetic Association.
- All fresh, frozen or canned fruits and vegetables, except those listed above. Be sure to eat frozen or canned foods immediately after opening or cooking them, as the tyramine content increases the longer they sit around.
- Condiments like ketchup, barbecue sauce, mustard and salad dressings, per Queensland Health.
If you have any doubt about whether or not a food contains too much tyramine, leave it on the plate and check with your doctor first. And if you don't know whether a food is expired or still safe to eat, avoid taking unnecessary risks and toss it.
- UW Health: "Low Tyramine Diet"
- Mayo Clinic: "Monoamine Oxidase Inhibitors (MAOIs)
- Penn Medicine: "Foods That Can Trigger Headaches"
- Queensland Health: "Low Tyramine Diet"
- Journal of the American Dietetic Association: "What is the Bottom Line for Dietary Guidelines When Taking Monoamine Oxidase Inhibitors?"