By Reed Mangels, PhD, RD

It’s simple, right? We all think we know which foods are good for us and which foods are less likely to be health promoting. But when medications enter the mix, it may get more complicated. Some foods that many of us think of as healthy, can interfere with the actions of some medicines, making the medicine less effective or even dangerous.

For example, there are long lists of medications that grapefruit or grapefruit juice can interact with. These include some drugs to lower cholesterol (some statins), some drugs used to treat high blood pressure, some anti-anxiety drugs, some corticosteroids, and some antihistamines. Seville oranges (often used to make orange marmalade), pomelos, tangelos, pomegranates, and pomegranate juice are sometimes identified as having effects similar to those of grapefruit and grapefruit juice (1).

People taking some types of anticoagulants (medicines to reduce the risk of blood clots) are warned to eat a consistent amount of green leafy vegetables and other food sources of vitamin K rather than eating a lot of kale, say, one day and no green vegetables the next (2).

A type of antidepressant called an MAO inhibitor can have dangerous interaction with foods high in tyramine or histamine. These include aged cheeses, pickled or fermented food (sauerkraut, pickles, kimchi), fermented soy sauce, tempeh, and yeast extract.

Your health care provider or pharmacist can help you determine if you need to avoid or limit certain foods because of medications that you are using.

In addition to foods, other products including dietary supplements, herbs, non-prescription medications, and other prescriptions medications all have the potential to interfere with a prescribed medication. It’s a lot to keep straight.

Johns Hopkins Medicine website (3) has these sensible recommendations:

• Ask your pharmacist or healthcare provider if there are foods, beverages, vitamins, or supplements you should avoid with your medicines.
• Read the prescription label on the container. If you do not understand something, or think you need more information, ask your healthcare provider or pharmacist.
• Read directions, warnings, and interaction precautions printed on all medicine labels and instructions. Even over-the-counter medicines can interact with foods, beverages, or supplements.
• Check with your pharmacist or healthcare provider before taking vitamin pills at the same time you take medicine—vitamins and minerals can interact with some medicines.
• Be sure to tell your healthcare provider and pharmacist about all medicines you are taking, both prescription and nonprescription.

References

1. FDA. Grapefruit juice and some drugs don’t mix. https://www.fda.gov/consumers/consumer-updates/grapefruit-juice-and-some-drugs-dont-mix. 2021.
2. National Jewish Health. Anticoagulants and some drug-food interactions. https://www.nationaljewish.org/conditions/medications/cardiology/anticoagulant-and-drug-food-interactions?modal=1. 2013.
3. Johns Hopkins Medicine. Food-drug interactions. https://www.hopkinsmedicine.org/health/conditions-and-diseases/fooddrug-interactions

The contents of this posting, our website, and our other publications, including Vegetarian Journal and Vegan Journal, are not intended to provide personal medical advice. Medical advice should be obtained from a qualified health professional. We often depend on product and ingredient information from company statements. It is impossible to be 100% sure about a statement, info can change, people have different views, and mistakes can be made. Please use your best judgment about whether a product is suitable for you. To be sure, do further research or confirmation on your own.