A pharmacist has shared which foods and drinks can interfere with medication and make certain tablets less effective, and in some cases, increase the risk of side effects
If you’re having a cheeseboard this Christmas, be aware of what could happen if you’re on certain medication(Image: The Good Brigade via Getty Images)
A pharmacist has issued a warning, urging people to be mindful of their diet when taking medication. The caution comes from a specialist who revealed that certain everyday foods and drinks can reduce the effectiveness of medicines and, in some cases, increase the risk of side effects.
Ian Budd, prescribing pharmacist at Chemist4U, shared which common foods and beverages can interfere with medication. He explained that our diet plays a far greater role than we might realise. The expert said: “Even choices we think are healthy, like fruits, vegetables, or supplements, can sometimes affect how your medication works or how well your body absorbs it.
“For example, something as simple as having grapefruit juice with breakfast can interfere with blood pressure medication, antidepressants or cholesterol medication, while foods high in vitamin K can impact how blood thinners work. These are small details, but they can make a real difference in how well your treatment does its job.”
Foods and drinks that can affect medication
1. Dairy products
Your breakfast could cause side effects(Image: David Pardoe via Getty Images)
The expert explained that your cheeseboard could cause issues, and if you love hot chocolate, you will also want to be careful. He shared: “The calcium in dairy products can bind medicines like tetracyclines and fluoroquinolones, that are often used to treat chest or urine infections.
“When that happens, the medicine isn’t absorbed properly, which means your body doesn’t get the full dose and the infection might take longer to clear. If you’re prescribed one of these antibiotics, don’t worry; you don’t need to avoid dairy altogether. Just try to take your dose a couple of hours before or after having milk or dairy foods so it can do its job properly.”
The expert also warned that mature cheeses, cured meats and fermented products contain tyramine, which “can cause a sudden rise in blood pressure”, Ian explained.
This means that “if you’re taking older antidepressants known as MAO inhibitors. This type of reaction can make you feel unwell with headaches, a fast heartbeat, or even very high blood pressure.. These drugs aren’t prescribed as often now, but for anyone taking them, it’s important to know which foods to avoid. Your pharmacist can help your spot tyramine-rich foods and give simple swaps so you can still enjoy your meals safely.”
2. Grapefruit
This brightly coloured fruit presents one of the greatest risks. So, if you usually take your tablets with the fruit or its juice, you may want to think twice. The pharmacist explained: “They contain natural chemicals that block an enzyme in your liver, which helps break down certain medicines. When that happens, your body can’t process the drug as it normally would, so more of it stays in your system. That can make side effects stronger or more likely.
“This is especially important if you’re taking medicines like statins, blood pressure tablets, some antidepressants, or immune-suppressing drugs. Even one glass of grapefruit juice can have an effect that lasts for up to one day, so it’s safest to avoid it completely with these medications.”
3. Leafy greens
Greens may not be great(Image: Kseniya Ovchinnikova via Getty Images)
Many people don’t know that even nutritious vegetables can pose a risk. The expert explained that spinach, kale and broccoli are high in vitamin K. This nutrient is essential for blood clotting. Warfarin works by limiting the effects of vitamin K, which helps to reduce the formation of blood clots.
Ian warned: “So, if you suddenly eat a lot more (or a lot less) vitamin K-rich foods than usual, it can throw off the balance and make warfarin either less effective (if you eat more greens) or too strong (if you suddenly cut them off). This is why pharmacists always recommend keeping your intake consistent rather than avoiding greens altogether.”
4. Cranberry juice
This is another fruit which could affect your medication. This can pose issues if you’re on warfarin. Ian explained that the red berries contain natural compounds that can influence how your body metabolises warfarin, potentially intensifying the drug’s effects.
“That means your blood could become thinner, increasing the risk of bruising or bleeding”, he cautioned, adding: “It’s not an issue for everyone, and an occasional glass is unlikely to cause harm. But drinking cranberry juice regularly or taking cranberry supplements can be risky if you’re on warfarin. It’s always best to check with your pharmacist before making it part of your daily routine.”
5. Alcohol
Your glass of wine could cause issues(Image: Maskot via Getty Images)
Another commonly consumed drink is alcohol, and with Christmas Day around the corner, more people will be keen to have a glass or two. But don’t worry, you don’t need to stop completely.
The expert warned: “Alcohol is one of the most common things that interacts with medications, and the effects can vary depending on what you’re taking. It can make some drugs, like antidepressants, sedatives, and strong painkillers, much more sedating, which can leave you feeling drowsy or unsteady. It can also put extra strain on your liver or interfere with how medicines for diabetes work, making blood sugar harder to control.”
He added: “It doesn’t mean you can never drink, but it’s always worth checking your patient information leaflet or asking your pharmacist what’s safe for you. Knowing how alcohol might affect your medication can help you make more confident, informed choices.”
Ian concluded that understanding what to watch out for can help you take charge of your health and get the best results from your treatment, whilst helping to avoid unwanted side effects. The better you understand how your medication fits into your daily routine, the safer and more effective it will be.