Five surprising foods that could affect your medication – from licorice to CHEESE

Some of your favorite foods can interfere with the effectiveness of your medication — and many medications don’t list the warning on their labels.

Medicines for heart disease, high blood pressure, depression — and even antibiotics — can all be blunted by chemicals in cheese, tea, fruit juices, and even some sweets.

While the negative effects will be minor for many, in rare cases they can cause serious problems and even be fatal.

Below are the five surprising foods and nutritional supplements that doctors warn you should avoid while taking certain medications:

Grapefruit juice

Grapefruit juice is often cited as an immune system booster or cholesterol-lowering drink.

But the acidic drink could actually make statins taken by millions of patients at risk for heart disease less effective or even toxic.

Statins are normally broken down in the gut by an enzyme – scientifically called CYP3A – so less of them enter the bloodstream.

But if someone drinks grapefruit juice before taking the drug, a compound in the drink — called furanocoumarins — binds to the enzymes and stops them from working.

This means that patients receive a much stronger dose of statins than expected, putting them at risk of liver damage, dizziness and muscle pain, among other things.

Doctors at Harvard University in Massachusetts say only a few 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 may also interfere with calcium channel blocking drugs used by blood pressure patients.

These medicines work by relaxing muscles in the walls of arteries to help lower blood pressure.

But the Food and Drug Administration (FDA) warns that compounds in grapefruit juice can block these channels, stopping the drug from working.

Drop

Love it or hate it, candy, licorice, can interact with blood pressure medications and cause them to stop working.

These drugs work by blocking the activity of an enzyme called ACE that helps to constrict blood vessels and help lower blood pressure.

But licorice contains glycyrrhizin, a plant compound that can stimulate the release of the stress hormone cortisol, which raises blood pressure.

Other drugs that may stop working properly include corticosteroids – often prescribed for asthmatics.

Licorice works on this by blocking enzymes that break down and remove the medication from the system, leading to higher levels and the effects they cause.

This increases the risk of side effects, including acne, muscle weakness, and thin skin that bruises easily.

In fact, in response to the risk of licorice in the early 2010s, medical authorities began warning that eating too many sweets could be bad for you.

The British NHS said at the time that eating more than 2 oz (57 grams) of black licorice a day for two weeks could raise blood pressure and cause an irregular heart rhythm.

They added, “It doesn’t matter how old you are, you should avoid eating large amounts of black licorice in a short period of time.”

Some herbal supplements

St. John’s wort can be taken in addition to teas and tablets and there is some evidence that it can treat depression and symptoms of menopause.

But experts warn that if taken with the wrong medication, it could cause a potentially life-threatening complication.

St. John’s wort is sometimes used by people with mild to moderate depression to ease their feelings.

But doctors say that when taken with antidepressants, it can cause too many feel-good hormones like serotonin to be released in the nervous system.

This can overstimulate the system, they said, and in severe cases can lead to seizures, agitation, confusion and muscle stiffness.

Medics also suggest it could lead to the potentially fatal complication of serotonin syndrome, although this is rarely recorded.

People can also take herbal supplements such as ginkgo biloba leaf extract as an oral tablet, capsule or in tea.

Research shows that it contains flavonoids, known to have powerful antioxidant effects, and terpenoids, which can help improve circulation. There are also suggestions that it can improve one’s memory, although these have yet to be backed up by rigorous studies.

But doctors warn that if this supplement is used with blood-thinning medications, it may also cause a higher risk of bleeding.

Blood-thinning medications such as warfarin (Coumadin or Jantoven) work by making it harder for the blood to clot.

But when someone also takes the supplement ginkgo biloba, compounds in it called ginkgolides can also cause blood thinning.

This increases the risk of someone taking the medication suffering from bleeding, medics say.

It is also known to act on enzymes in the liver that break down serotonin, which can also lead to the potentially fatal complication of serotonin syndrome.

Strong cheeses

Blue cheese, Swiss, and Parmesan might be a favorite to sprinkle on spaghetti carbonara or enjoy with crackers.

But doctors warn that people taking a less common form of antidepressant — called monoamine oxidase inhibitors (MAOIs) — should avoid them entirely.

Antidepressants work by blocking an enzyme — called monoamine oxidase — that breaks down the feel-good hormones serotonin, dopamine, and the stress hormone norepinephrine, raising their levels in the brain.

But aged cheese contains a compound called tyramine, which scientists say may 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 for the life-threatening ‘serotonin syndrome’.

These antidepressants are rarely prescribed in the US, but make up 15 to 20 percent of prescriptions for patients with major depression in other countries.

Aged cheese is also known to interact with Parkinson’s disease medications and antibiotics.

Green tea

Green tea is often touted for purported health benefits, such as better brain function, a lower risk of diabetes and even longer life.

But patients taking medications for heart disease and high blood pressure should think twice before consuming the drink.

The blood-thinning medication 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 a continuing risk of a blood clot.

There is also some evidence in the medical literature that patients who drink green tea while on warfarin are at greater risk of bleeding.

Likewise, those taking blood pressure lowering propranolol (Inderal) and metoprolol (Lopressor) should avoid drinking green tea.

This is because the drink contains caffeine, which can stimulate an increase in heart rate and increase blood pressure, rendering the drug ineffective.