Some of your favorite foods can interfere with the effectiveness of your medications — and many medications don’t mention a warning on their labels.
Medications for heart disease, high blood pressure, and depression—and even antibiotics—can be diluted by chemicals found in cheese, tea, fruit juices, and even some candy.
While the negative effects will be minor for many, in rare cases they can cause serious problems and even lead to death.
Here are the five surprising foods and supplements doctors warn not to eat while on certain medications:
The chart above shows five surprising foods that doctors warn you should avoid while taking certain medications
Doctors warn that grapefruit juice can interact with statins
grapefruit juice
Grapefruit juice is often cited as a drink to boost the immune system or as a drink to lower cholesterol.
But acidic drinks can make statins — which are taken by millions of patients at risk of heart disease — less effective or even toxic.
Statins are usually broken down in the intestines by an enzyme – scientifically called CYP3A – which reduces the amount that enters the bloodstream.
But if someone drinks grapefruit juice before taking the drug, a compound in the drink — called furanocoumarins — binds to the enzymes and prevents them from working.
This means that patients receive a much stronger dose of statins than expected, which puts them at risk of liver damage, dizziness, and muscle pain, among other effects.
doctors in Harvard university In Massachusetts he says some statins are affected by grapefruit juice, including atorvastatin (sold under the brand name Lipitor), lovastatin (Mevacor) and simvastatin (Zocor).
But others — such as fluvastatin (Lescol) and pitavastatin (Livalo) — aren’t affected because they’re broken down by a different enzyme.
Grapefruit juice can also interfere with calcium channel blocking medications used by patients with high blood pressure.
These medications work by relaxing the muscles in the artery walls to help lower blood pressure.
But the Food and Drug Administration (FDA) warns that compounds in grapefruit juice can block these ducts, which stops the medication from working.
Licorice may affect blood pressure medications
Licorice
Love or hate the sweet, licorice, can interact with blood pressure medications and stop them from working.
These drugs work by blocking the activity of an enzyme — called ACE — that helps narrow blood vessels, which helps lower blood pressure.
But licorice contains glycyrrhizin, a plant compound that can stimulate the release of the stress hormone cortisol, which leads to high blood pressure.
Other medications that can stop it working properly include corticosteroids – which are commonly prescribed to patients with asthma.
Licorice works on these by blocking enzymes that would otherwise break down and remove the drug from the system, resulting in higher levels and increasing the effects it causes.
This increases the risk of suffering from side effects, including acne, muscle weakness, and thin skin that bruises easily.
In fact, in response to the licorice danger in the early 2010s, medical authorities began warning that eating too much of the candy could be bad for you.
The NHS said at the time that eating more than 2 ounces (57 grams) of black licorice per day for two weeks could raise blood pressure and lead to an irregular heartbeat.
They added, “No matter your age, you should avoid consuming large amounts of black licorice over a short period of time.”
Herbal supplements can affect antidepressants, leading to a fatal condition, and blood thinners
Some herbal supplements
St. John’s wort is taken as a dietary supplement in teas and tablets, and there is some evidence that it can treat depression and symptoms of menopause.
But experts warn that if the wrong medication is taken, it can lead to potentially life-threatening complications.
St. John’s wort is sometimes used by people with mild to moderate depression to help ease their feelings.
But doctors say that when taken with antidepressant medication, it can cause too many feel-good hormones like serotonin to be released into the nervous system.
This can overstimulate the system, they said, and in serious cases may lead to seizures, agitation, confusion, and muscle stiffness.
Medics also suggest that it can lead to a fatal complication of serotonin syndrome, although this is rarely recorded.
People can also take herbal supplements such as ginkgo biloba Leaf extract taken by mouth, capsule, or in tea.
Research shows that it contains flavonoids, which are known to have powerful antioxidant effects, and terpenoids, which may help improve circulation. There are also suggestions that it could enhance someone’s memory, although these have not been backed up by rigorous studies.
But doctors warn that if this supplement is used in combination with blood-thinning medications, it may also lead to an increased risk of bleeding.
Blood thinners such as warfarin (Coumadin or Jantoven) make it more difficult for your blood to clot.
But when someone also uses ginkgo biloba supplements, which are called ginkgolides, they can also cause blood thinning.
Medics say this increases the risk of someone taking the drug bleeding.
It is also known to act on enzymes in the liver that break down serotonin, which can also lead to the potentially fatal complications of serotonin syndrome.
Doctors have warned that aged cheese can also affect antidepressants
strong cheeses
Blue cheese, Swiss cheese, and Parmesan might be a favorite to sprinkle on spaghetti carbonara or enjoy with crackers.
But doctors warn that people who take a less common type of antidepressant — called monoamine oxidase inhibitors (MAOIs) — should avoid them altogether.
Antidepressants work by blocking an enzyme — called monoamine oxidase — that breaks down feel-good hormones like serotonin and dopamine, as well as the stress hormone norepinephrine, raising their levels in the brain.
But aged cheese contains a compound called tyramine, which scientists say can stimulate the release of more of these hormones.
This leads to very high levels in the brain and, as with St. John’s wort, can put people at risk of a life-threatening “serotonin syndrome.”
These antidepressants are rarely prescribed in the United States, but make up 15 to 20 percent of prescriptions for severely depressed patients in other countries.
Aged cheese is also known to interact with medications to combat Parkinson’s disease and antibiotics.
Green tea can affect medications used to thin the blood
Green tea
Green tea is often touted for its purported health benefits such as improved brain function, reduced risk of diabetes, and even a longer life.
But patients who take medications for heart disease and high blood pressure should think twice before consuming the drink.
The blood-thinning drug warfarin (Coudamin) works by decreasing the production of blood-clotting factors in the liver.
But when someone drinks green tea, the vitamin K in the drink can have the opposite effect putting patients at constant risk of a blood clot.
There is also some evidence in the medical literature that patients who drink green tea while taking warfarin have a higher risk of bleeding.
Likewise, those taking the blood pressure-lowering propranolol (Inderal) and metoprolol (Lopressor) should avoid drinking green tea.
This is because the drink contains caffeine, which can stimulate an elevated heart rate and increased blood pressure, rendering the drug ineffective.
