Written by Selin Eda Sagnak
Illustrated by Jasmine Fu
When we think about drugs and diet, most of us think about instructions given by our physicians like “take after a meal” or “take in the morning with an empty stomach”. Some of us might also remember the warnings of “do not smoke” or “do not drink alcohol” while being on the prescription. This might be an expected instruction as we hear people warning about taking painkillers like Tylenol, which include the active molecule acetaminophen, when dealing with hangover symptoms.1 But how about foods we consume? How much does our daily diet affect the way drugs work in our bodies?
Did you ever wonder why people say don’t take painkillers after drinking alcohol? It is because acetaminophen, which is a medication commonly also known with the brand name Tylenol, can interact with the alcohol in the person’s system.1 How does this happen? Well, in our body we have liver as our major organ that helps us metabolize drugs and this is done by enzymes, protein workers in our body helping us with many functions, such as the cytochrome p450 (CYP) family.2 It is known that a specific CYP named CYP2E1 is responsible of processing acetaminophen but this enzyme is also sensitive to alcohol presence in the body.2 When alcohol is present, the number of this enzyme in our liver goes up, allowing it to breakdown more ethanol compared to the little amount it normally does.2 It was seen that this breakdown resulted in more toxic molecules being released into the body that can essentially damage our DNA and cause other medical issues.2 Along with this potential toxicity arising from alcohol, CYP2E1 also has a role in acetaminophen processing which produces a molecule toxic for our liver and hence increased presence of this drug puts us at higher risk.3 This example illustrates how stuff we consume can interact with drugs we take. While alcohol is a known factor, even foods we consume daily can impact drug effectiveness. Let’s get into more examples that we find in our everyday diet.
Grapefruit… Yes, as surprising as it may sound, grapefruit is actually one of the foods that show the most drastic effects on prescriptions. This is because of Grapefruit is able to interact with the CYP3A4 enzyme which is known for its ability to inactivate the effect of many different drugs.4 The molecules called “furanocoumarins” in grapefruit inhibit CYP3A4, slowing down drug breakdown and potentially leading to overdose.4 If a person is prescribed anything such as “anticancer agents”, “immunosuppressants”, “cardiovascular agents” or “urinary tract agents”, they are at risk for these interactions.4 Alongside grapefruit, another everyday food that can cause reactions with prescriptions is milk.5 The calcium in milk can react with the antibiotics like tetracycline and bind to them, causing the efficiency of the treatment to go down.5,6 This is because it reduces the entry of this drug into the bloodstream.5 Another example can be Vitamin K providing green vegetables, like broccoli and spinach, that will interfere with the activity of the drug named Warfarin, used to prevent blood clotting.6
Finally, emerging research by Poli et al. (2024) suggests that even the way our foods have been processed, including simple cooking referred to as “thermal processing”, can alter the interactions seen with prescriptions.7 This highlights the complexity of interactions between drugs and our diet.7
It is important to share these information as “[o]ver half of Canadian adults aged 18 to 79 have used at least one prescription medication in the past month” according to Statistics Canada’s 2016 to 2019 records.8 For more information on food-drug interactions, please consult a healthcare provider or reliable health resources. We leave you with a link to explore these potential interactions for your interest: https://go.drugbank.com/food-interaction-checker.9
Sources:
- 7 ways to cure your hangover. Harvard Health Publishing Harvard Medical School. 2023 May 22. https://www.health.harvard.edu/staying-healthy/7-steps-to-cure-your-hangover
- Song BJ, Cederbaum AI. Ethanol‐Inducible Cytochrome P450 (CYP2E1): Biochemistry, Molecular Biology and Clinical Relevance: 1996 Update. Alcoholism: Clinical and Experimental Research. 1996 [accessed 2024 Nov 8];20(s8). https://onlinelibrary.wiley.com/doi/10.1111/j.1530-0277.1996.tb01764.x. https://doi.org/10.1111/j.1530-0277.1996.tb01764.x
- Alcohol-Medication Interactions: Potentially Dangerous Mixes. NIH National Institute on Alcohol Abuse and Alcoholism. https://www.niaaa.nih.gov/health-professionals-communities/core-resource-on-alcohol/alcohol-medication-interactions-potentially-dangerous-mixes
- Bailey DG, Dresser G, Arnold JMO. Grapefruit–medication interactions: Forbidden fruit or avoidable consequences? Canadian Medical Association Journal. 2013;185(4):309–316. https://doi.org/10.1503/cmaj.120951
- Some Drug-Food Interactions. MERCK MANUAL Consumer Version. https://www.merckmanuals.com/en-ca/home/multimedia/table/some-drug-food-interactions
- Bushra R, Aslam N, Khan AY. Food-Drug Interactions. Oman Medical Journal. 2011;26(2):77–83. https://doi.org/10.5001/omj.2011.21
- Poli G, Bologna E, Saguy IS. Possible interactions between selected food processing and medications. Frontiers in Nutrition. 2024;11:1380010. https://doi.org/10.3389/fnut.2024.1380010
- Prescription medication use among Canadian adults, 2016 to 2019. Statistics Canada. https://www150.statcan.gc.ca/n1/daily-quotidien/210628/dq210628e-eng.htm
- Food Interaction Checker. DRUGBANK Online. https://go.drugbank.com/food-interaction-checker