Features November 2018 Issue

Read This Before Taking Any Kind of Herbal Supplement

None have been proven effective, and many may be unsafe.

Perhaps you've heard that hawthorn extract lowers blood pressure, garlic pills reduce systemic inflammation and lower the risk of heart disease and green tea extract is an effective antioxidant and can help you lose weight.

Do these supplements and others derived from plants and foods provide the benefits they claim? No one knows. "Their benefits have never been proven," says Cleveland Clinic preventive cardiologist Leslie Cho,MD.

That's because natural products are not tested in large, randomized clinical trials or approved by the U.S. Food & Drug Administration. This means manufacturers can claim any health benefits they wish.

"Due to the way U.S. law is written, I could mow my grass and sell it as an antioxidant, and I wouldn't be breaking the law," says Dr. Cho.

Consumer Beware


© Elenathewise | Getty Images

Don't assume an herbal product is safe, just because it's natural. Digitalis is derived from foxglove (the purple flower above), and it's a very potent heart medication.

It's not that you might be wasting money that concerns Dr. Cho and other physicians nationwide. Rather, it's that herbal supplements can interact with prescription medications by increasing or decreasing their potency. When this happens, the result may be serious, or even fatal.

"One of my patients, who was on dual anti-platelet therapy after stenting, decided to take large doses of garlic. He ended up in the emergency department with dangerous internal bleeding," Dr. Cho recalls. "Another patient took hawthorn, and it increased the potency of her digitalis. This caused her ejection fraction and kidney function to plummet."

Moreover, when side effects or organ damage does occur, the problem may not be fixable, since no antidotes for these medications exist.

Besides, herbal products do not always contain what you think they do. Some supplements are made from an alternative to the plant listed on the label or are contaminated with a conventional medication. Others list active ingredients that are unproven, included at ineffectively low levels or in amounts that vary from bottle to bottle.

herbs that interact with heart meds

Herbs that interact with heart medications should be limited or avoided.

More Is Not Better

You would expect supplements derived from garlic, turmeric, soy, grape seed, green tea and other foods to be safe. The foods themselves are considered healthy when consumed as part of a normal diet. However, supplements contain huge concentrations that Dr. Cho calls "super human doses."

Green tea is good example. "It's a healthy drink, but green tea extract contains a significant amount of vitamin K and can interact with heart medications," she says.

Honesty Is the Best Policy

According to a 2017 article in the Journal of the American College of Cardiology, 70 percent of patients who take an herbal supplement do not tell their physicians. That baffles Dr. Cho.

"Why would you try to hide this information? These herbs are essentially drugs. People who take prescription medications should never take an over-the-counter medication without consulting their physician," she says.

"I understand you may think that using a natural substance is giving you an advantage," she continues. "But if we don't know what you are taking, we can't advise you properly. And if you are convinced that a natural substance is better than a prescription drug and stop taking your medication, in effect, you may not be receiving the protection you need. This decision could have a significantly negative impact on your heart," she says.

Dr. Cho suggests you have an open, honest discussion with your doctor about the supplements you wish to take. "If you don't, you could end up in the hospital with internal bleeding, arrhythmia or other serious complication," she says.

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