Common Food & Drug Interactions

Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

Variety is nice when it comes to your diet. But if you take medication, you need to be aware of foods that interact with drugs. Learn how grapefruit juice, licorice, chocolate, aged cheese, leafy vegetables and other foods can interact with drugs.

Food & Drug Interactions

Eating a variety of foods makes your daily diet enjoyable. It's fun to add colorful fruits and vegetables, like grapefruit and green leafy vegetables, to your meals. It's even more fun to snack on flavorful licorice, chocolate and cheese. But did you know that these foods can alter the way your body handles certain medications? Foods contain compounds that can enhance or reduce the effectiveness of common medications. If you're not careful, these interactions can cause dangerous side effects. In this lesson we will take a look at common food and drug combinations to avoid.

Grapefruit Juice

statins + grapefruit juice = side effects
Statins and grapefruit juice do not mix

Grapefruit juice contains a lot of healthy vitamins. But if you are taking statins, which are popular cholesterol-lowering drugs, then you should avoid this drink. Grapefruit juice contains a class of compounds called furanocoumarins that can alter the way statin drugs are absorbed or metabolized. This causes levels of the medication to increase within the body. While taking statins you need to give up grapefruit, but you might not need to give up all citrus juices. Other juices, like orange juice, do not contain the interfering compounds and should be fine to drink - but check with your doctor to be sure.

Grapefruit juice may also interfere with the metabolism of other drugs, including medication for blood pressure, anxiety, malaria, and thyroid function. With so many potential drug interactions, it's a good idea to read drug warning labels and talk with your doctor about your food intake anytime you start a new prescription or over-the-counter medication.

Natural Black Licorice

Natural black licorice has a very distinct taste that some people love. However, if you are taking digoxin, which is a drug used to treat congestive heart failure and heart rhythm problems, then you need to avoid this snack. Natural licorice contains glycyrrhiza, which is a substance that can deplete potassium within the body. The lowered potassium intensifies the drug and its side effects. Natural black licorice can also negatively impact the effectiveness of blood pressure medication and certain diuretics. However, if you are on any of these medications and you get a craving for licorice, your body should tolerate artificially flavored black licorice because it does not contain glycyrrhiza.

Choose artificial black licorice over natural if you are on digoxin
black licorice

Chocolate and Aged Cheese

Aged cheese and chocolate make wonderful snacks, especially when you are feeling a bit blue. However, they need to be limited if you are taking Monoamine Oxidase Inhibitors (MAOIs) for the treatment of depression. The reason these foods are a problem is because they contain tyramine, which is an amino acid that helps with blood pressure regulation. It's natural to have some tyramine in the body, but taking MAOIs and eating too many tyramine-rich foods can increase your blood pressure to unsafe levels. This dangerous increase happens because the medication blocks the enzyme that breaks down excess tyramine, allowing it to accumulate in the body. Tyramine is also found in some processed meats, such as hot dogs, bologna, pepperoni and lunch meats, as well as some fermented foods. Therefore, if your doctor prescribes MAOIs he or she may also recommend a low-tyramine diet that consists of mostly fresh foods.

Green Leafy Vegetables


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