Food and Drug Interactions by Tina de los Reyes

Tina 1Have you ever sliced open a beautiful, ripe grapefruit and thought, “This grapefruit is very unhealthy for me!”?

Probably not. However, you may be on certain medications that are negatively affected by something as innocuous as a grapefruit. Before the era of big pharmaceuticals, there were roots to nibble on, elixers to drink, salads to eat, all sorts of different foods to ingest in order to naturally cure ailments. There was some truth to those ideas. Foods sometimes contain chemicals or molecules that can have an effect on the body. Here’s a brief summary of some common food-drug interactions:


Monoamine oxidase inhibitors (MAOIs) anti-depressants can interact negatively with foods containing high levels of tyramine. Aged cheeses, chocolates, cured meats, and wine pair together nicely, but they don’t pair well with MAOI inhibitors.

Selective serotonin reuptake inhibitors, such as Prozac, can have enhanced effects by St. John’s Wort, causing an increase in serotonin. You may feel jittery and anxious.

Black Licorice

I don’t know many people that like black licorice, but the ones that do LOVE it. Make sure that you aren’t taking a steroid, steroid inhaler, blood pressure medication, or a diuretic. Black licorice can increase the effects of these medications, causing lower blood pressure, increased urine excretion, increased peripheral swelling, and many other side effects, depending on the medication you are on.


The news tends to glamorize the beneficial effects of red wine on your heart. However, alcohol itself can negatively affect blood pressure medications, diabetes medications, and antibiotics. Also, any medication that passes through the liver in combination with alcohol can damage the liver itself. Something as simple as Tylenol and a few beers can have negative consequences. Alcohol with aspirin or a non-steroidal anti-inflammatory drug (NSAID) can increase the incidence of ulcers.

Alcohol should never be mixed with opioids and benzodiazepines. This can cause slowing of the respiratory rate, even as severe as respiratory depression.

Fast Fact- a few gummy bears before you drink alcohol can actually decrease the incidence of stomach ulcers by up to 45%!


Soy products can reduce sperm count if consumed in large quantities. In addition to this, soy products can slow down thyroid functions, causing an interference with thyroid medications for hyper or hypothyroidism.


Dairy products inhibit the absorption of antibiotics, blood pressure, and other medications because the stomach must work so hard to digest the lactose. In order to keep these foods from interfering with your medications, keep a one hour window before and after your medication intake dairy-free!

Dark, Leafy Greens

Popeye got strong eating spinach, so what could possibly be wrong with it? If you are on anti-coagulants such as warfarin, the high amounts of vitamin K in dark, leafy greens can be counterproductive to the anti-clot effects of the medication.

Diets and Doses

The bottom line- discuss any medications with your physician to ensure that your daily lifestyle doesn’t affect or get affected by any new pills. For example, if you enjoy grapefruit daily, your physician can adjust the dose of your blood pressure or heart medication to factor the effects of grapefruit.

The information provided is for general interest only and should not be misconstrued as a diagnosis, prognosis or treatment recommendation. This information does not in any way constitute the practice of medicine, or any other health care profession. Readers are directed to consult their health care provider regarding their specific health situation. Marque Medical is not liable for any action taken by a reader based upon this information.





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