8 Healthy Foods That Can Interfere With Medications

A bowl of fruit.

Many of us like to keep to a healthy diet to and good exercise routine to keep on top of our physical well being. The benefits of a healthy diet are numerous for not just our physical health but also our mental one too. Unfortunately, some of us also need to take medication to keep either our body or our minds ticking normally.

Medication, of every kind, always comes with some certain risk attached. That is why it is firstly and foremostly important that you discuss taking medication with your doctor and a pharmacist first. Your diet should also be discussed so that they can advise you if some dietary changes are needed in order for the medication to take full effect and for potential side effects to having their harms reduced by discussing food-drug interactions.

We have written this informational blog post to help you to gain an understanding of which types of common foods, particularly healthy ones, can have a negative interference with the medication you are taking. Many of the foods discussed are rich in nutrients that are great for you and you’re even encouraged to take dietary supplements to get the kind of vitamins that these foods supply. Of course, discuss this with a medical professional after reading our guide because they know best. Also, remember that everyone’s body is different, so there may be foods that are not on the list that also may not react well with your medication. This applies to all sorts of kinds of medications from ones treating long-term chronic illnesses to over-the-counter drugs that treat a headache. 

We’ll walk you through each healthy food and discuss its health benefits so that you can understand why having them as part of your diet is beneficial. After that, we’ll mention what medications it may not interact well with and what the potential risks could be when drug interactions are involved.

Grapefruit and Grapefruit Products

First of all, we shall take a look at how grapefruit and grapefruit juice can have an impact if it is mixed with certain types of medication. The health benefits of grapefruit are numerous. They are rich in both potassium and vitamin C which is not only essential contributors to a healthy and balanced diet, but the body actually needs them to function properly. Take for example sailors of over a century ago. When you were a kid you may have read about pirates who were sick with scurvy, which caused their lips to bleed, teeth to fall out, and their skin to flake. This is because they were on long voyages of months at a time with no access to fresh fruit and vegetables. A month without vitamin C can cause the effects of scurvy and other illnesses to become transparent.

Although it is an essential nutrient to the body, the high doses brought on by grapefruit and grapefruit juice may not interact well with some medications. Many of these medications are ones provided to deal with heart problems and heart disease but there are several more:

  • Drugs that treat abnormal heart rhythms, like Nexterone and Pacerone.
  • A variety of antihistamine medications like Allegra.
  • Cholesterol-lowering drugs such as Zocor and Lipitor.
  • Drugs that treat high blood pressure, such as Procardia and Adalat CC.
  • Organ-transplant rejection drugs, such as Sandimmune and Neoral.
  • Anti-anxiety medication like buspirone.
  • Corticosteroids that treat Crohn’s disease or colitis, such as Entocort EC and Uceris.

Depending on your medication, having too much grapefruit or grapefruit juice can affect you in two separate ways depending on the type of medication you are taking. It can either cause too much of the medication to get into the body or it can cause too little. Statin drugs, which purpose is to lower cholesterol, are broken down by enzymes in order for them to work properly. High levels of grapefruit can cause the enzymes to be blocked which means that the drug doesn’t break down properly and too much of it can go throughout your body which can enhance negative side effects. Grapefruit can also affect allergy drugs such as Allegra. This is because allergy drugs are taken throughout the body through transporters, to take them to cells. High volumes of grapefruit can, however, block these from coming through, meaning that your medication may have little effect.

Too much grapefruit can prevent medications from breaking down properly.


Bananas are always a practical and healthy snack to have on hand. Not only are they delicious but they are also stacked with numerous great health benefits. Bananas are great for helping you to maintain a healthy weight, boosting your nervous system, and for aiding you in avoiding type 2 diabetes. Bananas are filled with fiber, potassium, magnesium vitamin C, and B6. All of these things are great for the body and important in maintaining a strong immune system. They also often find their flavor used in nutritional drinks, which may or may not be healthy.

People who are taking angiotensin-converting enzyme (ACE) inhibitors should avoid bananas, however. This medication lowers your blood pressure and helps the heart to pump more blood. Potassium does not interact with this too well though. This is because high levels of potassium can contribute to having an irregular heartbeat and cause heart palpitations which can lead to heart failure. Potassium only affects your blood levels when it is taken in high amounts but make sure that you speak to your doctor first if you are taking ACEs. 

Leafy Greens 

Foods that are rich in vitamin K are simply wonderful for the body. They include green leafy vegetables such as broccoli, cabbage, kale, brussels sprouts, and spinach. These have high levels of fiber and have a low-calorie count meaning that they are excellent for maintaining healthy body weight and diet. Vitamin K is vital to help keep your blood flow healthy as it helps to thin the blood and let it flow better. Low term absence of vitamin K can cause your bones to weaken and may cause osteoporosis in older people as well as calcification (calcium channel blockers) in arteries. 

The effect of leafy green vegetables and vitamin K can have an adverse effect if the patient is taking Warfarin (also known as Coumadin). Warfarin is an anticoagulant, which is a blood thinner and helps circulation move as normal. This medication tends to be prescribed to you if you have had a blood clot in the past or if you are at risk of one in the future. Users of Warfarin must always be cautious about the side effects as some of them can be extremely harmful, and even cause death

Vitamin K can cause your blood to clot which is why you must be cautious with leafy vegetables if you are taking Warfarin. This is not to say that eating some cabbage soup will cause you adverse side effects but rather that you shouldn’t base your diet on it. If you are prescribed Warfarin speak to your doctor first to find out if you can safely reintroduce leafy greens into your diet. 

Cranberry Juice

Cranberry juice and cranberries are considered by many nutritional experts to be a ‘superfood’. This is because of their high levels of nutrients and antioxidants. They are well known to help stop urinary tract infections, lowering the risk of heart problems, and slowing the spread of some cancers. Despite all of these great benefits, cranberries can be counterproductive if you are taking heart medication such as Digoxin, Warfarin, or Lovastatin. This is because similarly to leafy greens, cranberries also thin the blood. Although this is good if you are healthy, if you are on some heart medications, drinking too much cranberry juice can have an adverse effect. 

Dairy Products

Dairy products such as milk, yogurt, cheese, and aged cheeses are full of health benefits for everyone, particularly children and adolescents. This is because they are full of calcium which helps to promote bone growth. As well as this there are many other healthy nutrients be found in dairy products such as phosphorus, vitamin A, vitamin D (in products fortified with vitamin D), riboflavin, vitamin B12, protein, potassium, zinc, and magnesium. As well as this many dairy products such as yogurt are great for digestive health as they help to regulate the bacteria in your gut.

The gut is where calcium can become problematic when medication is involved. Antibiotics such as the Quinolone (Cipro, Levofloxacin Ciprofloxacin, and Avelox) and tetracyclines (Vibramycin and Minocin), varieties, do not interact well with dairy products. These antibiotics need to interact with gut bacteria in order to work effectively but due to the dairy products already mixing with these bacterias in a positive manner the effectiveness is reduced. This is because the bacteria in the gut struggles to absorb the antibiotics properly because of the way the dairy products are interacting with them.

Due to the antibiotics possibly not being able to work effectively it means that the infection that you were trying to treat may rebound in an even stronger manner. This can lead to the possibility of becoming very sick or in the best-case scenario, having to retake an extended dosage of the antibiotics. That is not to say that dairy products are to be outright forbidden if you are on these types of antibiotics as most of the time it is ok to have a glass of milk or yogurt at least two hours after taking a dosage. Like always, double-check this with a doctor or pharmacist first. 

High Fiber Foods

Fiber is a very important part of any balanced diet and can mainly be found in rich foods such as fruit, vegetables, and grains. They are fantastic for overall health and particularly good at reducing the chances of diabetes and heart disease. One of the great benefits of fiber is that the body cannot digest it. The reason that this is great is that it passes through our digestive tract and feeds the bacteria that live there. 

There are ten times as many bacteria in our body than there are cells. It helps to regulate our body’s functions and is important to every aspect of our health such as blood sugar levels, the immune system, and even brain function. The majority of the bacteria in our bodies live in our digestive tract so it is vital that it is fed and kept healthy. If it is not conditions such as colitis and inflammatory bowel disease can occur. Thus, a good range of fiber in the body is a great thing. 

However, due to the way that fiber interacts with the gut it may be a good idea to try and reduce your intake when you are on some types of medication. It causes the same effect that some antibiotics do when they are mixed with dairy products. You don’t want the effects of your antibiotics to be subsided when taking them so its best to reduce your intake and to speak to a doctor or pharmacist about changing the fiber in your diet when you receive a drug prescription. 

That morning coffee might be interfering with your medication more than you think.


Some of us simply need our coffee and cannot bear the thought of rolling out of bed without the knowledge that a steaming cafe late shall soon be resting on the kitchen counter. Similarly, that commute to work can also be unbearable if you know that you won’t be able to swing by your favorite coffee shop before walking through the office door. Although it may not be considered a healthy food like our article states. For many of you, it is a vice that has positive effects on your mental health. 

This is the type of medication that coffee can affect. If you have been prescribed an antipsychotic drug such as Clozapine or MAOIs, it is best to avoid caffeinated drinks. Caffeine can contribute to increasing the number of antipsychotics in your blood and thus put you at a greater risk of adverse side effects. 


Again, alcohol is not a healthy food but it does have some benefits for us. If it is drunk in moderation and with good company, it can be a catalyst towards good times. Also, a smooth red wine at the end of a long, hard day can take the edge off things and bring you some relaxation. With some of the positive mental health benefits to the side, alcohol can also interfere in very bad ways if you are on some types of medication.

There is a long list of prescription drugs, and over the counter medications that alcohol simply does not go with. Alcohol does not mix with many painkillers such as paracetamol, codeine, morphine, antihistamines, antibiotics, diabetes drugs, and medication for HIV/AIDS. If you are on a larger combination of medications then you should certainly be wary of consuming alcohol.

The side effects of your medication can be multiplied if alcohol is consumed while you are taking them. Even after just one drink.  The bad side effects that you can receive include symptoms such as vomiting, stomach problems, drowsiness, dizziness, nausea, memory problems, brain functions, changes to blood pressure, fainting, and a heightened risk of accidents. As well as these unwanted symptoms alcohol can also increase the damage that you may be taking medication for. This is apparent with liver damage, heart issues, and many mental health problems.

Alcohol can also decrease the effectiveness of the medication that you are taking, perhaps even making it obsolete. It can even make some medications toxic for your body. If you drink alcohol always make sure to check with your doctor about the risks of drinking it alongside your new medication as you can never know what the risks may be. 


It is important to have a varied and balanced diet that is filled with nutrients. By doing this you help to contribute to the overall health of your body, helping to minimize the risks of you having health issues in the future. This applies to both your physical and mental health. Nobody wants to be in a position where they need to take medication, particularly if it is long term or chronic. By eating healthy foods you can help to perhaps mitigate this risk. 

If at some point in your life, you must take medication you need to check the risks of every kind of food or substance and how that can interact with it. This even applies to healthy, common food. Many of the foods that we discussed such as leafy green vegetables, grapefruit, cranberry juice, high fiber foods, and dairy products are essential parts of having a well-rounded diet. 

However, when taking alongside many medications, there is a risk of side effects. This tends to be when you consume high amounts of these foods but every person’s body interacts differently. Even a small amount of these kinds of foods can bring out negative side effects depending on the medication. The bottom line is though like it has been throughout this article, is to always check with your doctor first about the risks that some types of food, even healthy ones, may have on your medication.

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