Food and Medication Interactions: The Dark Side of Healthy Foods

Eating healthy and clean has become a large part of our pop culture since the organic movement decades ago. Articles are published every day about what the new superfood is and what we should eat to fill our bodies with vitamins and antioxidants. Most superfoods do provide heaps of nutrients, yet there is a dark side to these superfoods for some people with chronic diseases.

Certain foods can interact with medications, vitamins, herbal supplements, and dietary supplements, potentially leading to adverse effects. For instance, grapefruit can interfere with the metabolism of various drugs, while leafy greens high in Vitamin K can affect blood thinners. It’s crucial to be aware of these drug food interactions to avoid compromising the efficacy and safety of your medications. Always inform your healthcare provider about all the supplements and foods you consume to ensure safe and effective treatment.

Understanding Food-Drug Interactions

Food-drug interactions occur when the food we eat affects the way medications work in our bodies. These interactions can be quite significant, impacting the bioavailability, efficacy, and safety of a drug. Factors such as age, weight, sex, medical conditions, the dose of medicine, other medications, vitamins, and herbal supplements can all influence drug interactions.

For instance, some medications work faster, slower, better, or worse on an empty stomach. Food can sometimes prevent medicine from working properly, making medicinal side effects either more pronounced or less effective. In some cases, food can even cause new side effects to emerge. Conversely, drugs can alter the way our bodies use food, affecting our overall nutrition and health. Over-the-counter drugs can also be affected by the presence of food in the digestive system.

Understanding these interactions is crucial for anyone taking prescription drugs or over-the-counter medications. By being aware of how food and medications interact, we can better manage our health and avoid potential complications. Consulting healthcare professionals is essential when taking medication to ensure safe and effective use.

Common Food-Drug Interactions

Food-drug interactions can occur when food affects the way medications work in the body. These interactions can lead to reduced efficacy or increased toxicity of a drug, resulting in adverse drug events or treatment failure. Here are some common food-drug interactions to be aware of:

• Grapefruit juice and statins: Consuming grapefruit or grapefruit juice can inhibit an enzyme necessary for statins to be metabolized, increasing the risk of side effects such as muscle pain.
• Bananas and other potassium-rich foods with ACE inhibitors: Taking blood pressure-lowering ACE inhibitors with potassium-rich foods can lead to high potassium levels in the body, causing potentially dangerous heart arrhythmias.
• High-fiber foods and levothyroxine, digoxin: Consuming high-fiber foods can make levothyroxine (a drug used to treat an underactive thyroid gland) less effective and affect the absorption of digoxin (a drug used to treat heart failure).
• Licorice and blood pressure medications: Black licorice can trigger abnormal heart rhythms and high blood pressure in some people. The compound glycyrrhizin in licorice can interact with medications and supplements, including those prescribed for high blood pressure.

Kale and Blood Thinners: What You Need to Know

One of the most popular superfoods, kale is lauded for its fiber, vitamins and minerals. The leafy green vegetable isn’t just a pretty face. Kale contains roughly 112.8 grams of vitamin K, which can be dangerous to people who take blood thinners, such as warfarin or aspirin. Vitamin K is used by the body to help blood clot, so when it’s taken with a blood thinner, it decreases the medication’s effectiveness and makes the blood more likely to clot. Therefore, it is crucial to consult a healthcare professional when consuming kale alongside any prescription drug.

Grapefruit

It’s the fruit that appears in almost every cereal commercial on TV. Although grapefruit themselves are a rotund fruit, it’s known in health food and diet communities to help trim your waistline. In addition, vitamin C is abundant in grapefruit. However, fruit juice, particularly grapefruit juice, can negatively affect prescribed medications also.

On MayoClinic.org, Katherine Zeratsky, registered and licensed dietician, explains that chemicals in grapefruit interfere with the metabolism of certain medications that:

• Fight infections
• Reduce cholesterol
• Treat high blood pressure
• Treat heart problems
• Prevent organ rejection in transplant recipients

Metabolism is the rate at which your body breaks down food, drink or medication. If your body breaks down medication too fast, it won’t have enough time to take effect. Conversely, if your body breaks it down too slow, the amount of medication in your body may rise to a dangerous level.

Bananas and Potassium Rich Foods

They make on-the-go snacking easy, are full of vitamins and minerals, keep bowels regular and are necessary to slapstick comedy. One of the numerous nutrients in bananas is potassium, which helps with muscle contractions and nerve impulses. 

However, you can have too much of a good thing. Excess potassium can cause an irregular heartbeat and heart palpitations, according to the U.S. Food and Drug Administration. Potassium doesn’t play nicely with some medications. For instance, it can negatively interact with ACE inhibitors (used to treat heart failure and high blood pressure) because they increase the levels of potassium in the body.

Do you or a loved one have high blood pressure? Download our quick and easy blood pressure log to help you monitor your levels.

Oatmeal

Oatmeal is the DIY of breakfast foods. Fruits, seeds, nuts and spices form endless combinations and flavors to make oatmeal tasty and interesting. 

Oatmeal is well-known for its high fiber levels, which can regulate the digestive tract, bowel movements and blood sugar levels by slowing absorption; along with the add-ins that come with their own health (or non-health) benefits. 

Oatmeal itself is very healthy, but if your add-ins are sugar, cream or lots of dried fruit, you might as well have a sundae. Sugar and cream are obvious villains. However, dried fruit can be dangerous too because some have added sugar. High levels of sugar can have numerous adverse effects on your health, such as an increased risk of depression.

Medications Affected by Food Interactions

Certain medications are more prone to food-drug interactions than others. Being aware of these can help you manage your health more effectively:

• Blood thinners (e.g., warfarin): Vitamin K-rich foods, such as green leafy vegetables, can counteract the effects of blood thinners.
• Statins (e.g., atorvastatin): Grapefruit juice can increase the risk of side effects such as muscle pain.
• Blood pressure medications (e.g., lisinopril): Potassium-rich foods, such as bananas and avocados, can lead to high potassium levels in the body.
• Diabetes medications (e.g., metformin): Certain foods, such as those high in fiber, can affect the absorption of diabetes medications.

Dietary Supplements and Medication Interactions

Dietary supplements can also interact with medications, leading to adverse effects. Here are some common interactions to keep in mind:

• Vitamin K and blood thinners: Vitamin K can counteract the effects of blood thinners, increasing the risk of blood clots.
• Omega-3 fatty acids and blood thinners: Omega-3 fatty acids can increase the risk of bleeding when taken with blood thinners.
• St. John’s Wort and prescription drugs: St. John’s Wort can interact with a variety of prescription drugs, including antidepressants, blood thinners, and cancer medications.

It is essential to consult with a pharmacist or healthcare provider before taking any dietary supplements, especially if you are already taking prescription medications. They can help you identify potential interactions and recommend safe alternatives.

Managing Medication Interactions

Managing medication interactions starts with being well-informed about the common medications you take and their potential food interactions. Your doctor and pharmacist are invaluable resources for answering questions about medication use and food interactions. Keeping a food diary to track your nutrient intake and any medication interactions can also be incredibly helpful.

It’s essential to consult with a healthcare provider or registered dietitian before starting any new medications. They can provide personalized advice on how to avoid food-drug interactions. For example, some medications should be taken on an empty stomach, while others need to be taken with food to prevent stomach upset.

Grapefruit juice is a well-known culprit in food-drug interactions. It can interfere with the metabolism of certain medications, such as statins, increasing the risk of side effects. Similarly, potassium-rich foods like bananas and avocados can interact with blood pressure medications, potentially causing dangerous heart arrhythmias.

To avoid these interactions, consider the following tips:

• Always consult with a healthcare provider or registered dietitian before taking new medications.
• Keep a food diary to monitor your nutrient intake and any potential medication interactions.
• Avoid consuming grapefruit or grapefruit juice while taking certain medications.
• Opt for a balanced diet rich in whole foods and limit excessive caffeine intake. 
• Follow the instructions provided by your doctor or pharmacist regarding food and medication use.

By understanding food-drug interactions and managing medication interactions effectively, you can minimize the risk of adverse effects and ensure the safe and effective use of your medications.

When the next superfood emerges to rescue us from dastardly cupcakes or soft drinks, it could be a villain in disguise. Always read the nutrition facts on the packaging and talk to your physician or dietician about a tailored diet plan for you.

If you need assistance preparing healthy meals, ComForCare Home Care can help. Caregivers can accompany you to the grocery store and help you cook foods that follow your doctor’s orders. Call 800-886-4044 or find a location near you to learn more about our meal preparation services.

Editor’s note: This article was originally published August 10, 2016. It has been revamped and updated for accuracy and comprehensiveness.