What You Need to Know Post-Transplant: Common Nutrient and Herbal Interactions

Stacy Crow, Pharm.D

Fruits and vegetables are healthy dietary choices for most people. As common “healthy” staples on many plates, it is easy to forget that certain fruits and vegetables can interact with transplant medications. Some herbal products may also have similar interactions.

Why do certain foods cause interactions?
These interactions are usually due to either the natural ability of the food to activate the body (even in ways that can be similar to medications) or as a result of drug-food interactions with medications. For transplant recipients, the most frequent interactions are those that activate the immune system and those that affect the ability of the drug to enter or exit the blood. As a result, some foods and herbal products are no longer safe to consume after receiving a transplant.

What foods should I avoid after receiving a transplant?
The below fruits and juices may interact with your immunosuppression, causing toxicity. They should be avoided.

• Grapefruit and grapefruit juice (please note that some citrus-flavored drinks have a grapefruit extract in them, so it is important to check ingredient lists.)
• Pomegranate and pomegranate juice
• Seville Oranges (normal oranges are fine in moderation)

Other fruits and vegetables that should be consumed in moderation are grapes, cranberries, tangerines, cauliflower, and broccoli.¹

What supplements or herbal products should I avoid after receiving a transplant?
Many supplements and herbal products have drug interactions with your immunosuppression or may increase the risk of toxicity or rejection. Please talk to your transplant doctor or pharmacist before starting any new supplements or herbal products.
Some of the more popular herbal products that can have adverse interactions include:²

• Vitamin C
• St. John’s Wort
• Herbal teas: green tea, chamomile, peppermint, dandelion
• Echinacea
• Ginseng
• Feverfew

Living with a transplant requires achieving a balance between having enough of a natural defense system to protect from everyday sicknesses such as a cold or the flu and lowering the immune system enough to protect the transplant from being attacked and rejected by the body. Please talk to your doctor or pharmacist if you have any questions about what foods, medications, or herbal supplements are safe to use after transplant.

1. Rodríguez-Fragoso L, et.al. Potential risks resulting from fruit/vegetable-drug interactions: effects on drug-metabolizing enzymes and drug transporters. J Food Sci. 2011 May;76(4):R112-24. doi: 10.1111/j.1750-3841.2011.02155.x. Review. PubMed PMID: 22417366.
2. Moore LW. Food, food components, and botanicals affecting drug metabolism in transplantation. J Ren Nutr. 2013 May;23(3):e71-3. doi: 10.1053/j.jrn.2013.02.002. PubMed PMID: 23611558.