UK

Will my Christmas dinner interfere with my medication?

12 November 2025
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Christmas season is just around the corner and it can be the best time of the year to indulge in elaborate dinners and feasts. But for those taking prescribed medication, such as statins, warfarin or antidepressants, it’s important to be aware that some seasonal foods and drinks can interfere with medicines, reducing how well they work, or increasing the risks of side effects.

Expert pharmacists and nutritional health experts, Amir Bhogal and Deborah Grayson spoke to The Independent, advising which common foods to be careful of to prevent any health hiccups at Christmas.

Grapefruits

Mr Bhogal explained that “Grapefruit contains compounds that interfere with how your body metabolises certain medications”.

Mr Bhogal explained that “Grapefruit contains compounds that interfere with how your body metabolises certain medications”. (Getty Images)

You might like to start the day with a grapefruit or juice over the festive period. But what may seem like a healthy choice, could be harmful for those taking cholesterol-lowering statins, some blood pressure medicines, certain antidepressants and immunosuppressants, according to nutritional pharmacist, Deborah Grayson.

“Chemicals found in grapefruit affect enzymes in the liver responsible for breaking down many drugs. When this process is blocked, the risk is that medication can build up to unsafe levels in your bloodstream”, she said. Ms Grayson advises steering well clear of grapefruit entirely during treatment.

Mr Bhogal added: “What many patients don’t realise is that both the fresh fruit and juice pose the same risk, and the effect can last up to 24 hours after consumption.”

Leafy Greens

“Leafy greens like spinach, kale, and broccoli are nutritionally excellent, but they contain high levels of vitamin K, which directly antagonises warfarin and other anticoagulant medications”, Mr Bhogal said.

“Leafy greens like spinach, kale, and broccoli are nutritionally excellent, but they contain high levels of vitamin K, which directly antagonises warfarin and other anticoagulant medications”, Mr Bhogal said. ((Alamy/PA))

Vitamin K can be found in a range of leafy green vegetables such as spinach, kale, broccoli and everyone’s festive favourite Brussels sprouts, but Ms Grayson says these nutrients can “play a vital role in blood clotting”.

If you’re one of the million or so people prescribed warfarin, a commonly-used blood thinner, “vitamin K intake needs to be carefully balanced”, Ms Grayson warns.

Mr Bhogan advised that “the key issue isn’t avoiding these foods entirely, as that would be nutritionally counterproductive, but rather maintaining consistent intake.”

Dairy Products

Dairy products, particularly milk and cheese, contain calcium and other minerals thatcan significantly reduce the absorption of certain antibiotics, Mr Bhogal described.

Dairy products, particularly milk and cheese, contain calcium and other minerals thatcan significantly reduce the absorption of certain antibiotics, Mr Bhogal described. ((Alamy/PA))

Dairy products, particularly milk and cheese, contain calcium and other minerals that can significantly reduce the absorption of certain antibiotics, such as those commonly prescribed for chest infections and urinary tract infections.

The calcium binds to these medications in the gut, preventing your body from absorbing the full dose, which can lead to prolonged infections or treatment failure. This substantially reduces the medication’s effectiveness, potentially allowing infections to persist or worsen.

Both pharmacists recommended not cutting out dairy completely, but instead spacing out your medicine and dairy intake by at least two hours to ensure adequate absorption.

Tyramine Rich Foods

Tyramine is an amino acid found in aged cheeses, cured meats, fermented foods, and certain soy products. These can interact “dangerously” with the chemical with the enzymes present in depression and anxiety medications, which can cause a sudden spike in blood pressure.

Tyramine is an amino acid found in aged cheeses, cured meats, fermented foods, and certain soy products. These can interact “dangerously” with the chemical with the enzymes present in depression and anxiety medications, which can cause a sudden spike in blood pressure. (Getty/iStock)

Tyramine is an amino acid found in aged cheeses, cured meats, fermented foods, and certain soy products. These can interact “dangerously” with the enzymes present in depression and anxiety medications, which can cause a sudden spike in blood pressure.

This can cause a “life-threatening” condition known as a hypertensive crisis, Mr Bhogan said.

Ms Grayson advises those prescribed with older antidepressants such as monoamine oxidase inhibitors (MAOIs), to avoid Tyramine-rich foods as they can lead to headaches, a rapid heartbeat or even hypertensive crises.

Alcohol

According to the pharmaceutical expert, alcohol interacts with numerous medication classes in ways that can be “unpredictable and sometimes dangerous”.

According to the pharmaceutical expert, alcohol interacts with numerous medication classes in ways that can be “unpredictable and sometimes dangerous”. (Getty/iStock)

A festive drink or two is common, but according to Mr Bhogan, alcohol interacts with numerous medication classes in ways that can be “unpredictable and sometimes dangerous”. Beyond the obvious concern of increased sedation, alcohol can also impair medication metabolism, increase bleeding risk, cause dangerous blood pressure drops, and trigger severe nausea.

Alcohol “can also place additional stress on your liver,” especially if you’re taking medications that are processed there, Ms Grayson says. For people managing diabetes, alcohol can interfere with blood sugar control, sometimes dangerously lowering levels or masking symptoms of hypoglycaemia.

The effects vary depending on the quantity consumed and the specific medication involved and Mr Bhogal and Ms Grayson always advises patients that “even moderate alcohol consumption warrants a conversation with their pharmacist or doctor to understand their specific medication’s interaction profile”.

Cranberries

Cranberries, whether consumed as juice, supplements, or whole fruit, can interact with some warfarin and other anticoagulant medications, potentially increasing bleeding risk if intake suddenly increases.

Cranberries, whether consumed as juice, supplements, or whole fruit, can interact with some warfarin and other anticoagulant medications, potentially increasing bleeding risk if intake suddenly increases. (Copyright 2024 The Associated Press. All rights reserved)

Cranberry sauce is a favourite Christmas dinner condiment. However, cranberries can also interact with warfarin, by increasing the blood-thinning effect which can “raise the risk of bleeding and bruising”, Ms Grayson says.

Cranberries, whether consumed as juice, supplements, or whole fruit, can potentially increase bleeding risk if intake suddenly increases.

Mr Bhogan said: “Patients who regularly consume cranberry products need to maintain that regular intake, whilst those who don’t typically consume them should be cautious about suddenly introducing large quantities”.