Safety & Individual Considerations
Functional food safety: grapefruit and medicines, warfarin and vitamin K, MAOI antidepressants and tyramine, pregnancy, allergy, fish and mercury, and when to ask a professional.
Content last updated . This page has not been medically reviewed.
Food is not automatically safe for everyone. The cautions below come from the sources named; they are not a full list.
Food and medicine
| Medicine or situation | Foods | What the source says |
|---|---|---|
| Some statins, blood pressure drugs, transplant drugs | Grapefruit, grapefruit juice | FDA: grapefruit can affect how some medicines work; severity depends on drug, person and amount; ask a pharmacist [1] |
| Warfarin | Leafy greens, Brussels sprouts, natto | Keep vitamin K intake consistent; tell your anticoagulation clinic before big changes [2] |
| MAOI antidepressants | Aged, fermented or pickled foods: sauerkraut, kimchi, fermented sauces and miso, aged cheese | Mayo Clinic: tyramine; cooking does not lower it; your clinician can give a list [3] |
| Potassium-restricted kidney disease | Beans, avocado and others | Ask a clinician; we did not find a source to quote |
Pregnancy and breastfeeding
- Choose pasteurized milk and cheese; avoid raw sprouts. [4]
- Fish: FDA and EPA advise 2 to 3 servings a week from the Best Choices list for pregnant or breastfeeding people, and avoiding the Choices to Avoid list. [5]
- Coffee: the BMJ review excludes pregnancy from its safety conclusion; ask your clinician. [6]
Allergy
Milk (yogurt, kefir), soy (miso, tempeh, natto, tofu), tree nuts (walnuts, almonds, pistachios), fish and seeds can cause allergy. For swelling or trouble breathing, call 911.Weak immune systems
Ask a clinician before live-culture foods. Proper evidence of infection risk from specific fermented foods was not found in the sources we read.Histamine and food intolerance
Proper evidence was not found in the sources we read for guidance on histamine and fermented foods; ask a clinician or dietitian.Do not
- Stop a prescribed medicine to try a food.
- Treat a symptom with food alone when it is severe, new or persistent.
If something goes wrong
In the US, Poison Control is 1-800-222-1222; call 911 for collapse, seizure or trouble breathing. [7]Frequently asked questions
Can I eat grapefruit with my medicine?
Ask a pharmacist; some medicines warn against it. [1]
References
- U.S. Food and Drug Administration. Grapefruit Juice and Some Drugs Don't Mix.
- Cedars-Sinai. For Warfarin: Eating a Consistent Vitamin K Diet. Patient education page; ask your anticoagulation clinic for your own plan.
- Mayo Clinic. MAOIs and diet: Is it necessary to restrict tyramine?.
- Clemson Cooperative Extension. Food Safety for Pregnant Women and Their Babies. Extension fact sheet.
- U.S. Food and Drug Administration and U.S. Environmental Protection Agency. Advice About Eating Fish.
- Poole R et al. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ 2017. PMID 29167102.
- Poison Control (America's Poison Centers). poison.org. Help line 1-800-222-1222; call 911 for collapse, seizure, trouble breathing or inability to wake.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.