Food-Drug Interactions: What You Should Know

Print Friendly, PDF & Email

Because of modern medicine, today we are the beneficiaries of numerous improved drugs. These medications have not only prolonged and/or saved lives, these drugs have also improved the quality of our lives. Medicines have existed for thousands of years in the form of herbs and plants. Even thousands of years ago, there was documentation of some herbs interacting with certain foods.

A food-drug interaction occurs when the food one eats affects the ingredient(s) in the medication one is taking and perhaps preventing the medicine from working the way it was intended to. Food-drug interactions are not limited to prescription medication; over-the-counter medications often lead to interactions equal in severity to those from prescribed drugs.

There are three basic types of food-drug interactions:

Drug Effects on Nutritional Status– this type of interaction is when a drug interferes with the absorption, excretion or use in the body of a nutrient or nutrients. Example: abuse of antacids can lead to phosphorus depletion which can eventually cause a Vitamin D deficiency leading to weaken bones.

Food Effects on Drug Absorption– this type of interaction is when certain foods may increase or decrease the absorption of the drug into the body. This is the most common type of food-drug interaction. Example: calcium in dairy products can decrease the absorption of certain antibiotics so dairy products are not to be taken at the same time as certain antibiotics.

Food Effects on Drug Utilization– this type of interaction is when certain foods may alter the chemical actions of a drug so that it loses its therapeutic effect on the body. Example: liver and green leafy vegetables, also known as high Vitamin K foods, can decrease the effectiveness of anticoagulants/ blood thinning medication like Coumadin because of the blood clotting properties of Vitamin K.

Some Key Points To Taking Medications Wisely:

  • Keep an up to date list of all the prescribed and over the counter medications you take on a regular and occasional basis. Always keep a copy in your wallet.
  • Always bring your list of medications to every physician visit.
  • Before your doctor prescribes a medication make sure that he/she reviews your current list of medicines.
  • Read the prescription warning labels on the container prior to taking the medicine. If you need more information, call your doctor or pharmacist.
  • Read directions, warnings, and interaction precautions printed on all medicine inserts including information provided for over the counter medications.
  • Immediately report any changes or ill effects you have after taking a new medication or any unusual symptoms that you notice after eating certain foods.
  • Always take medications with a full glass of WATER (other beverages have the potential of interacting with the medication).
  • Alcohol should be avoided when taking any medication unless it has been discussed with a doctor or pharmacist.
  • Long term use of certain medications can cause vitamin and/or mineral deficiencies. Always talk with your doctor about potential nutrient deficiencies.
  • Take vitamin-mineral supplements and other medications at different times.
  • Keep the pill intact unless instructed by your doctor or pharmacist. Breaking capsules apart may change the way the drug works. Stirring medicine into food or beverages is discouraged.
  • Avoid mixing medicines into hot drinks or drinking hot beverages when taking medica- tions as the heat can decrease the drugs effectiveness.
  • Medications should be taken at different times relative to meals unless noted.


Information from: Food-Drug Interactions, University of Maryland Medical Center; Avoiding Food Drug Interactions, University of Florida; Drug Interactions: What You Should Know, Food and Drug Administration. Nutrition Education for APRIL 2007. Produced by Meals On Wheels, Inc., of Tarrant County by Sherry Simon, R.D./L.D. For questions regarding nutrition education contact: Sherry Simon, R.D./L.D., Director of Nutrition Services for Meals On Wheels, Inc. of Tarrant County at 817-336-0912 or email: Website: 

Posted in Nutritional Education.

Leave a Reply