If you’re one of the millions of Americans who take a statin medication such as atorvastatin (Lipitor and generic) or simvastatin (Zocor and generic) to lower cholesterol, you may have been told to avoid grapefruit juice. That’s because the juice can intensify the strength of these common drugs and increase the chance of side effects—notably, muscle pain.

More on Drug Interactions

Dozens of other foods, including some that are part of a healthy diet—such as kale and green leafy vegetables—are also risky to mix with certain medications.

This doesn’t mean you have to avoid such foods completely—just be cautious. In most instances, “leaving at least 2 to 4 hours between the interacting food or juice and the medication is usually recommended,” says Dima Qato, Pharm.D., Ph.D., assistant professor at the University of Illinois at Chicago, who has studied food and drug interactions. Talk with your doctor about your specific medications and your diet.

Below, we list some common foods that could interact with your medications, and offer suggestions on how to safeguard yourself.

Type of Food

Don't Mix With

The Reason

Bananas, green leafy vegetables, oranges, salt substitutes

ACE inhibitors such as captopril (Capoten), enalapril (Vasotec), and lisinopril (Prinivil, Zestril), used to lower blood pressure or treat heart failure. And avoid mixing with some diuretics, such as triamterene (Dyrenium), used to reduce fluid retention and treat high blood pressure.

These foods are all high in potassium, which helps provide electrical signals to heart-muscle cells and other cells. Consuming them with the medications listed to the left could increase the amount of potassium in your body and may lead to an irregular heartbeat or heart palpitations—which could be deadly.

Broccoli, Brussels sprouts, cabbage, kale, spinach

Blood thinners such as warfarin (Coumadin).

Foods that contain a lot of vitamin K, such as the greens noted on the left, can reduce the drugs’ ability to thin the blood. In some people with heart disease, that could trigger a heart attack or a stroke. Once you begin taking warfarin, maintain a consistent diet and don’t suddenly overload on leafy greens.

Real black licorice (or supplements with licorice extract)

Digoxin (Lanoxin), used to treat heart failure and abnormal heart rhythms. It’s also best not to consume with most blood pressure drugs, blood thinners, and birth-control pills.

Real black licorice (and products with licorice extract, as opposed to licorice-flavored candy) contain glycyrrhizin, which can cause an irregular heartbeat, or even death, when combined with digoxin. Glycyrrhizin may reduce the effectiveness of most blood pressure drugs, intensify the side effects of blood thinners, and raise blood pressure and lower potassium levels when consumed with birth-control pills.

Cheese, yogurt, milk, calcium supplements, antacids with calcium

Tetracycline.

The calcium in these foods and products can interfere with the body’s ability to absorb the antibiotic fully. In general, tetracycline works better if taken 1 hour before or 2 hours after eating.

Alcohol, avocados, bananas, chocolate, salami

Drugs such as metronidazole (Flagyl) and linezolid (Zyvox), used to treat bacterial infections.

The foods to the left, along with tap beer, red wine, and sherry, contain tyramine, an amino acid that can cause blood pressure to spike if taken with linezolid. Tyramine is also found in foods that are aged, pickled, fermented, or smoked, such as processed cheeses, anchovies, and dry sausage. Alcohol and metronidazole together could cause nausea, stomach cramping, and vomiting.

Soybean flour, walnuts

Thyroid drugs such as levothyroxine (Levothroid, Levoxyl, Synthroid).

These high-fiber foods can prevent your body from absorbing the medications. If you eat a high-fiber diet, try taking your medications later in the evening. One study found that the drugs were better absorbed when taken at bedtime rather than a half-hour before breakfast, which is what is usu­­ally recommended in the instructions.

Editor’s Note: This article and related materials are made possible by a grant from the state Attorney General Consumer and Prescriber Education Grant Program, which is funded by the multistate settlement of consumer-fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin).

This article also appeared in the December 2017 issue of Consumer Reports on Health