More than Nutrition: How Does Food Impact Patients’ Health and Their Medications?

According to the World Health Organization (WHO), in 2017, 3.9 million deaths worldwide were attributed to inadequate fruit and vegetable consumption.¹ 

Consumption of a variety of fruits and vegetables helps to ensure an adequate intake of essential nutrients, vitamins, minerals, and dietary fiber.² When included as part of a healthy diet, this can help to protect against the development of preventable chronic diseases – such as type 2 diabetes, heart disease, certain cancers, and obesity.^{2, 3} 

Yet, the United States Department of Health and Human Services indicates that about 129 million people in the United States have at least one of the these major chronic conditions.⁴ While these conditions can be hereditary, an estimated 85% of Americans do not consume enough fruit or vegetables in their daily diets, which is a potential explanation for why the prevalence of chronic conditions among Americans continue to rise.^{4, 5} 

Consequently, September observes Fruits and Vegetable Matter More month, with aims of raising awareness of the importance of consuming the FDA recommended amount of fruits and vegetables in order to prevent chronic diseases.² Compelling research indicates that adhering to the recommended 2 cup equivalents of fruit and 2.5 cup equivalents of vegetables each day, correlates with a significant reduction in risk and complications.³ 

Yet, for those managing rather than attempting to prevent chronic diseases, are fruits and vegetables always a good thing?

Food-Drug Interactions

American society consistently reinforces the importance of a “healthy” diet. While a series of fad diets exist, the majority of sustainable diets include adequate consumption of fruits and vegetables.⁶ However, for those with a chronic condition that requires medication for effective management, consuming particular foods can lead to food-drug interactions, altering the drug’s efficacy and safety.⁷ Notably, the timing of food relative to drug uptake, in addition to the content and composition of macro and micronutrients in an individual’s food, can significantly influence an individual’s metabolism, and consequently, the bioavailability and safety of their medication.⁷

Food Consumption 

Breakfast is often referred to as the most important meal of the day, with research suggesting a healthy breakfast may increase weight control and cognition, while reducing cardio-metabolic risk factors.⁸ But, when medications enter the picture, consuming breakfast can play a much more complicated role.

Many medications instruct patients to take them first-thing in the morning, which is often right around breakfast time. While eating in the morning can produce certain benefits, food consumption or eating particular foods can increase or decrease certain drug’s absorption in the body.⁹ In some cases, co-administering medications and food can increase a drug’s bioavailability, enhancing the efficacy of the drug.⁷ However, when this occurs, it can also increase the risk of an individual experiencing unpleasant, adverse, or even dangerous side effects.⁹ On the flip side, consumption of food near one’s dosing time can also decrease the absorption of other drugs, reducing their bioavailability, and consequently, minimizing the full benefits of the medication.⁹ As a result, adhering to guidance on whether a medication should be taken with or without food, is not merely a suggestion, but essential for ensuring the effectiveness and safety of treatment.

• Examples of medications that must be taken with food to prevent adverse side effects or changes in absorption include:¹⁰
  • Sulfonylureas (for Type 2 diabetes) & fact acting insulin (for diabetes)
  • Certain antibiotics (ex: amoxicillin, cefpodoxime, nitrofurantoin, rifabutin)
  • Nonsteroidal anti-inflammatory drugs (ex: advil, motrin, mobic, aleve, naprosyn)
  • Antacids (for heartburn)
  • Chloroquine (for treating and preventing malaria) 
• Examples of medications that must be taken without food to prevent adverse side effects or changes in absorption include:¹¹
  • Certain antibiotics (ex: ampicillin, isoniazid) 
  • Thyroid medications (ex: levothyroxine) 
  • Bisphosphonates (treatment for osteoporosis)  
  • Sucralfate (treatment for intestinal ulcers) 
  • Viagra (treatment for erectile dysfunction) 
  • Semaglutide (treatment for type 2 diabetes and obesity)
  • Captopril (treatment for high blood pressure, heart disease, and kidney issues for people with type 1 diabetes) 

Influence of Macro-Nutrients on Food-Drug Interactions: 

While some medications are influenced by the timing of food consumption, others are specifically impacted by particular meal types and specific foods.⁹

The Influence of Consuming High-Fat Meals Near Dosing Windows

While foods that are higher in fat content are often demonized by the media, they are an essential energy source, allowing for the development of cell membranes, nerve ending, and adequate hormone production.¹² Yet, consuming foods high in fat contents close to one’s dosing window can have detrimental effects. For instance, if an individual were to consume a high-fat meal close to or within their dosing window, this would decrease the efficacy of hydrophilic medications (drugs that readily dissolve or mix with water), but increase the effectiveness of hydrophobic medications (drugs that repel water, dissolving less easily).⁹ This suggests that a high-fat diet may amplify adverse side effects for “fat-loving,” hydrophobic drugs and blunt the effectiveness of water-loving, hydrophilic drugs.^{9, 7} 

• Example One: Taking adderall after a high-fat meal can significantly decrease its absorption compared to when it is taken on an empty stomach.¹³
• Example Two: Taking Contrave with a meal high in fat may increase drug levels in the body, increasing the risk of seizures.¹⁴ 

How Eating High-Protein Meals can Influence Drug Absorption 

Adequate protein consumption is essential for the production and repairing of cells.¹⁵ Given the high-satiety of protein-dense foods, many diets prioritize protein over other macronutrients, however, high protein meals also play a role in drug absorption.¹⁵  Protein-rich meals can potentially lead to increased blood flow in the GI track, enhancing absorption rates.⁹ For instance, a high-protein/low-carb diet has been shown to speed up the clearance of propranolol by 74% and theophylline by 32%, whereas the opposite diet (high-carb/low-protein) decreases the clearance of theophylline.⁹ Clinical research indicates the higher clearance of theophylline when one consumes high protein foods has been found to impact the efficacy of the treatment.⁹ 

• Example: Eating a high protein meal close to taking levodopa, a medication for Parkinson’s disease, can reduce its absorption and efficacy.¹⁶

Examining the Influence of Specific Properties on Food-Drug Interactions:

While in some cases drug absorption can be influenced by the consumption of entire food groups, such as lipids, carbohydrates, and proteins, the unique properties of certain foods often play a more crucial role in determining how medications behave in the body.⁹ These properties can alter drug metabolism, absorption, or clearance, significantly impacting the efficacy and safety of treatment.⁹

1. Polyphenals →  Often found in cocoa, green tea, berries, and onions.⁹
   1. Increased consumption of polyphenols is often associated with decreased insulin resistance, which can increase the efficacy of treatments aimed at preventing the development of diabetes.⁹
2. Bioflavonoids → Found in grapefruit.⁹
   1. Bioflavonoids can inhibit CYP3A4 – an enzyme involved in the metabolism of many drugs – resulting in an increased bioavailability of calcium channel blockers (used for hypertension, angina, and arrhythmias), benzodiazepines (used for anxiety, insomnia, and seizures), and lipid-lowering statins (used for managing cholesterol).⁹
      1. This can lead to an increased risk of experiencing severe adverse effects.⁹  
3. Isoflavones → Common in soya products.⁹
   1. Consumption of isoflavones can inhibit CYP enzymes, causing a decrease in CYP1A2 & CYP2A6, both of which play key roles in drug metabolism.⁹ Over time, this decrease in drug metabolism can translate to elevated drug levels in the body, increasing the likelihood of an individual experiencing serious adverse effects.⁹
4. Calcium-Containing Food  → Common in yogurt, cheese, and milk.⁹
   1. The most common reason for mineral-drug interactions occurs when an individual consumes dairy products, due to them containing calcium.⁹ Calcium can reduce the absorption of tetracycline-class antibiotics and methotrexate (an anti-inflammatory medicine), compromising the medication’s ability to effectively treat one’s infection or pain.¹⁷
5. Foods High in Vitamin K → Often found in broccoli, cabbage, kale, spinach, swiss chard, and other leafy greens.¹⁷
   1. Consumption of leafy greens, which are rich in Vitamin K, can reduce the effectiveness of Warfarin, a medication used for blood-clot prevention.¹⁷ For those with chronic conditions necessitating Warfarin, such as various heart conditions, a heart healthy diet is often recommended – including adequate servings of fruits, whole grains, and vegetables.¹⁸ Without adequate warnings and guidance from providers, individuals may begin consuming higher doses of vegetables with the intention of following the recommended heart healthy diet. However, if these vegetables contain high amounts of vitamin K, they may unknowingly reduce the efficacy of their treatment.
6. Tyramine-Containing Food → Commonly found in cured meats, aged cheeses, pickled or fermented foods, red wine, some draft beer, and very ripe bananas.¹⁷
   1. Although monoamine oxidase inhibitors (MAOIs) are no longer commonly used to treat depression, they are still utilized on occasion for Parkinson’s disease.¹⁷ If an individual takes their MAOI close to when they consume tyramine-rich foods, their tyramine levels will increase, which can trigger a rapid, dangerous increase in blood pressure.¹⁷
7. Foods with High Levels of Potassium → This includes bananas, avocados, tomatoes, and dried apricots.¹⁷
   1. For individuals taking blood pressure-lowering ACE inhibitors, if taken alongside of potassium rich foods, potassium levels can skyrocket, leading to potentially dangerous heart arrhythmias.¹⁷
8. Glycyrrhizin → Found in black licorice.¹⁷
   1. Consumption of foods containing the compound glycyrrhizin have been known to trigger abnormal heart rhythms and high blood pressure in some people.¹⁷
      1. The FDA has warned that eating 2+ ounces of black licorice a day for at least two weeks could result in irregular heart rhythms or arrhythmia for those over the age of 40.¹⁷
9. Fortified Foods → Many everyday foods have added vitamins and minerals that can interact with medications.¹⁷
   1. Chelating agents → Found in sodas, canned fruits and vegetables, non-nutrious sweeteners, condiments, salad dressings, etc.¹⁷
      1. Common examples include EDTA and citric acid, which are often added to extend shelf life, improve appearance, and prevent oxidation. ^{18, 19}
         1. Certain drugs may exhibit decreased absorption when taken with foods containing chelating agents, which can lead to treatment failure.²⁰
   2. Iron → Common iron-fortified foods include bread, milk, and breakfast cereals.¹⁷
      1. Consuming iron-fortified food products can reduce the efficacy of tetracycline antibiotics, levothyroxine (hypothyroidism medication), and captopril (blood pressure medication).²¹

The Importance of Understanding Food-Drug Interactions and Adhering to Recommendations

Making healthy food choices can be critical for preventing or managing chronic conditions. However, despite best intentions, some of these foods can impact how medications work within the body. The consumption of food, macro and micro nutrients, enzymes, and compounds can all strengthen or weaken the effects of particular medications.⁹ In some cases, these interactions may be clinically insignificant, but in others, the impact may be severe – leading to increased adverse side effects, treatment failure, frequent dosing changes, antibiotic resistance, or even morbidity and mortality.^{9, 13, 19} 

For people managing chronic conditions, these interactions are particularly important. Many of the foods that are considered part of a “healthy” diet – such as certain fruits, vegetables, dairy products, and carbohydrates – can interfere with common medications for diabetes, infections, mental health conditions, heart disease, hypertension, and neurological conditions.^{9, 13} Even fortified foods or additives, which are often not explicitly stated on medication labels as potential food-drug interactions, can alter how a drug is absorbed or its efficacy.^{13, 18, 19}

As a result, understanding food-drug interactions and adhering to medical guidance is essential for remaining healthy and ensuring treatments work as intended to prevent further complications. Patients should …

1. Follow healthcare providers’ recommendations about diet, medication timing, etc. 
2. Ask pharmacists or clinicians about potential interactions with specific foods. 
3. Be consistent with both diet and medication schedules to avoid rapid changes that could impact treatment. 

Adherence is not solely about taking the right dose of medication, it includes following all recommended dosing guidelines, including avoiding foods with known interactions with treatment. Despite best intentions to make healthy food choices, some of these foods may pose serious safety concerns or reduce the efficacy of medications. Increasing patients’ awareness of potential food-drug interactions and the importance of adhering to their prescribed dosing window is essential to ensure they can make choices that not only support their overall health, but enable their medications to work as intended.²² 

Some Common Symptoms and Side Effects That May Signal an Interaction:²³ 

1. Nervous System → Drowsiness, dizziness, confusion, or anxious/depressive symptoms.
2. Heart → Unusual increase or decrease in heart rate or blood pressure. 
3. Stomach → Stomach pain, nausea, vomiting, diarrhea. 
4. Reduced effectiveness of medication 

**If you are experiencing unusual symptoms not listed as common side effects, contact your doctor, or in severe cases, 911.**²³

How Can AdhereTech Support Patients and Providers?

At AdhereTech, we recognize that adherence is far more complicated than simply remembering to take medication. Factors like food-drug interactions add an additional layer of complexity for patients, adding to patient burden by requiring fasting, checking ingredient and medication labels, or requiring dietary restrictions. Our smart adherence devices, which provide adherence data in real time, can help patients and providers work towards successfully navigating these challenges. 

1. Reminder System → AdhereTech’s devices follow a reminder escalation protocol — gentle glow one hour before dose time, chimes every 15 minutes during one’s dosing window, and text messages for missed doses. Patients can customize their dosing windows, ensuring that taking their medication integrates seamlessly into their schedule.
   1. How this works: Patient 1 needs to eat breakfast before heading into work at 8am, since they cannot eat anything within two hours of taking their medication, their scheduled dosing time is set to 6am. Patient 2 is on the same medication, but leads a completely different lifestyle. They sleep till mid-day and do not eat their first meal until 4pm, therefore they choose their dosing time as 2pm. 
2. Education and Alerts → One key feature of AdhereTech’s Aidia system is its capability to share important reminders or messages, with the ability to connect patients to additional support when necessary. The system’s text-based or phone call reminders could enable patients to receive direct communication about whether to take their food with medication and what foods to avoid, serving as a reinforcement to guidance on food-drug interactions provided by healthcare providers.
   1. By utilizing “pre-set” reminders outlining food restrictions and guidance, patients’ safety and health remains a top priority, while provider burden is diminished. 
3. Invaluable Insights for Speciality Pharmacies → AdhereTech can provide specialty pharmacies and clinical trial sites with immediate real-time adherence data. If treatment seems to be ineffective, or posing serious safety risks, providers can look into each individual patient’s adherence behaviors, determining whether non-adherence, or other factors such as food-drug interactions may be preventing or exacerbating the effectiveness of treatment. 

By combining adherence technology with increased recognition of potential food-drug interactions, we can empower patients to not only take their medication, but follow all recommended guidance – ensuring treatments are as safe and effective as possible. 

The Importance of Accounting for Food-Drug Interactions 

Food is more than nutrition – it can act as a facilitator or barrier in managing one’s health condition, particularly for patients with chronic conditions that require daily dosing. Although fruits, vegetables, and additional nutrient-rich foods are critical for preventing and managing certain chronic diseases, they can also interfere with treatment effectiveness if food-drug interactions are overlooked. 

Here at AdhereTech, our definition of adherence expands beyond just taking a pill, it also includes following guidance from healthcare providers about how and when medications should be taken. By combining increased education and awareness of food-drug interactions with smart adherence solutions, patients and providers can work towards minimizing unnecessary risks, optimizing treatment outcomes, and ensuring that all treatments work as intended. 

In honor of Fruits and Veggies Matter More Month, we are reminded that healthy eating plays a powerful role in preventing disease and supporting effective treatment. But society’s definition of “healthy” is not always so straightforward — what provides nutritional benefits and protective factors to one individual may interfere with another’s medication. At AdhereTech, we’re committed to empowering patients with the tools and knowledge they need to make safe, informed food choices—so fruits, vegetables, and other nutrient-dense foods can serve their true purpose, helping patients live longer, healthier lives.

To learn if your medication has any food-drug interactions, you can … 

1. Review your medication label.
2. Contact your healthcare provider.
3. Utilize free, food-drug interaction resources.
   1. https://www.drugs.com/drug_interactions.html²³ 
   2. https://www.webmd.com/interaction-checker/default.htm²⁴ 
4. Conduct a simple google search: “Food-drug interactions for [insert name of medication].”

References 

¹ World Health Organization. (2023, August 9). Increasing fruit and vegetable consumption to reduce the risk of noncommunicable diseases. https://www.who.int/tools/elena/interventions/fruit-vegetables-ncds

² Centers for Disease Control and Prevention. (2018, May 1). State indicator report on fruits and vegetables, 2018. U.S. Department of Health and Human Services. https://www.cdc.gov/nutrition/php/data-research/fruits-vegetables.html

³ Fjeldberg, G. (2022, June 21). Plant power: Using diet to lower cancer risk. Mayo Clinic Health System. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/plant-power-to-lower-cancer-risk

⁴ Niederberger, E., & Parnham, M. J. (2021). The Impact of Diet and Exercise on Drug Responses. International journal of molecular sciences, 22(14), 7692. https://doi.org/10.3390/ijms22147692

⁵ Stewart, H., Hyman, J., & Young, S. (2024, September 9). Satisfying fruit and vegetable recommendations possible for under $3 a day, data analysis shows. U.S. Department of Agriculture, Economic Research Service. https://www.ers.usda.gov/amber-waves/2024/september/satisfying-fruit-and-vegetable-recommendations-possible-for-under-3-a-day-data-analysis-shows

⁶ Tahreem, A., Rakha, A., Rabail, R., Nazir, A., Socol, C. T., Maerescu, C. M., & Aadil, R. M. (2022). Fad Diets: Facts and Fiction. Frontiers in nutrition, 9, 960922. https://doi.org/10.3389/fnut.2022.960922

⁷ Bushra, R., Aslam, N., & Khan, A. Y. (2011). Food-drug interactions. Oman medical journal, 26(2), 77–83. https://doi.org/10.5001/omj.2011.21

⁸ Gibney, M. J., Barr, S. I., Bellisle, F., Drewnowski, A., Fagt, S., Livingstone, B., Masset, G., Varela Moreiras, G., Moreno, L. A., Smith, J., Vieux, F., Thielecke, F., & Hopkins, S. (2018). Breakfast in Human Nutrition: The International Breakfast Research Initiative. Nutrients, 10(5), 559. https://doi.org/10.3390/nu10050559

⁹ Niederberger, E., & Parnham, M. J. (2021). The Impact of Diet and Exercise on Drug Responses. International journal of molecular sciences, 22(14), 7692. https://doi.org/10.3390/ijms22147692 

¹⁰ Hannemann, K., & Ulrich, A. (2024, April 15). 11 medications that should be taken on an empty stomach. GoodRx. https://www.goodrx.com/drugs/medication-basics/taking-medication-empty-stomachGoodRx

¹¹ Hannemann, K., & Murdock, J. (2022, November 28). Why some medications should always be taken with food. GoodRx. https://www.goodrx.com/drugs/side-effects/taking-medication-with-foodG

¹² Nemours KidsHealth. (2022, May). Fats. https://kidshealth.org/en/parents/fat.html

¹³ Rosack, J. (2002). High-Fat Diet May Affect Absorption Of Once-Daily ADHD Medications. Psychiatric News, 37(15), 19-19.

¹⁴  Drugs.com. (2025, April 24). Contrave for weight loss: Dosage, side effects, warnings. https://www.drugs.com/contrave.html

¹⁵ Carbone, J. W., & Pasiakos, S. M. (2019). Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit. Nutrients, 11(5), 1136. https://doi.org/10.3390/nu11051136 

¹⁶ Advance ER. (2023, September 29). Foods to avoid if you take these common medications. https://www.advanceer.com/resources/blog/2023/september/foods-to-avoid-if-you-take-these-common-medicati/

¹⁷ Colino, S. (2022, March). 8 foods that don’t mix with prescription drugs. AARP. https://www.aarp.org/health/drugs-supplements/food-medication-interaction/ 

¹⁸ ScienceDirect. (n.d.). Chelating agent. In ScienceDirect Topics. https://www.sciencedirect.com/topics/neuroscience/chelating-agent

¹⁹ WebMD. (2024, April 24). EDTA: Uses and risks. https://www.webmd.com/vitamins-and-supplements/edta-uses-and-risks

²⁰ Schmidt, L. E., & Dalhoff, K. (2002). Food-drug interactions. Drugs, 62(10), 1481–1502. https://doi.org/10.2165/00003495-200262100-00005 

²¹ Ulrich, A., & Murdock, J. (2024, May 7). Iron supplement interactions to know: Medications, foods, and drinks. GoodRx. https://www.goodrx.com/classes/iron-supplements/interactions

²² Wallace, A. W., & Amsden, G. W. (2002). Is it really OK to take this with food? Old interactions with a new twist. Journal of clinical pharmacology, 42(4), 437–443..

²³ Drugs.com. (n.d.). Drug interaction checker. https://www.drugs.com/drug_interactions.html 

²⁴ Starkman, E. & Conrad, J. (2025, August). Drug Interaction Checker: Commonly asked drug interaction questions. WebMD. https://www.webmd.com/interaction-checker/default.htm