More than 15 million Americans are using herbal supplements to prevent or treat chronic illnesses. However, a medical review released on February 1st in the Journal of the American College of Cardiology reminds us that all over-the-counter herbal and nutritional products should be discussed with your health care provider before taking.

Most people do not disclose the use of alternative and complementary therapies to their physicians because they view them as “natural” and therefore safe. They may also fear that a Western physician may be more conservative about such treatments and dismiss them as being ineffective scams. However, everyone taking such treatments should be aware of the potential harm of self-treatment.

The recent report focuses on the potential interaction between popular herbal remedies such as ginkgo biloba and St. John’s wort and medications for heart disease. Some herbs may increase the potency of the prescription drug or may reduce its effectiveness. The interaction may also be more serious, such as causing a serious heart rhythm problem and bleeding. Older adults should be particularly aware of the consequences, as they are more likely to have heart problems and may be taking more than one medication.

St. John’s Wort, for example, affects how the body absorbs many medications, and may diminish the effects of statin medications, used to lower cholesterol, and beta blockers, which treat high blood pressure and heart-rhythm disorders.

Dr. Elsa-Grace Giardina, a cardiologist at Columbia University, says to stay away from the four G’s: garlic, ginkgo, ginseng, and ginger, as these all affect bleeding time. Green tea also affects bleeding — it contains vitamin K, which can clot the blood and reduce the effectiveness of blood thinners such as aspirin and Coumadin. Saw palmetto, often used as a treatment for BPH, can also affect bleeding.

U.S. News and World Report lists 9 herbal supplements to avoid when taking heart medications and alternatives to try instead.

Some groups have felt that the report bashes alternative therapies. The Council for Responsible Nutrition, for example, said that the article represents a biased, poorly written and contrived attack on herbal supplements.

Dr. Arshad Jahangir, a cardiologist at the Mayo Clinic in Arizona responds by saying, “These herbs have been used for centuries — well before today's cardiovascular medications — and while they may have beneficial effects, these need to be studied scientifically to better define their usefulness and, more importantly, identify their potential for harm when taken with medications that have proven benefit for patients with cardiovascular diseases.”

All parties agree that the bottom line for Americans is to discuss all therapies with their physician to receive the greatest benefit without causing harm.