Herbal Supplements For Heart Disease Not Supported By Science, May Cause Side Effects: Study

A new study suggests there is no real evidence that herbal supplements actually help treat heart problems, despite their growing popularity. 

Italian researchers have determined that the use of herbal medications to treat heart disease and other coronary ailments is not supported by proven clinical trials. In addition, they warn that the dietary supplements may in fact cause adverse side effects, including conflicts with medications that are proven to work.

The findings were published in the March issue of the Journal of the American College of Cardiology.

Herbal supplements are commonly used in the U.S. and in other countries for various conditions, including cardiovascular problems. Estimates indicate 1 in 5 people in the U.S. have taken an herbal or dietary supplement during their lifetime.

Researchers selected 42 herbal medications used to treat cardiovascular disease from the report of the National Center for Complimentary Medicine of the National Institutes for Health. The herbal remedies were used to treat one or more of these conditions: hypertension, heart failure, coronary artery disease, dyslipidemia, thromboembolic disorders and peripheral artery disease.

Ten of the herbal supplements were chosen to be reviewed for the study, including Asian ginseng, astragalus, flaxseed oil, garlic, ginkgo, grape seeds, green tea, hawthorn, milk thistle, and soy.

Researchers searched PubMed Central from 1966 to June 2016, Cochrane Database of Systemic Reviews from 1996 to June 2016, and the U.S. National Center for Complementary and Integrative Health website for studies related to key herbal supplement terms, latin and common names of the herbs, and their relation to cardiovascular disease.

The study’s findings indicated there was not enough evidence to conclude herbal remedies would improve any of the cardiovascular conditions. In most cases, the herbal supplements lacked sufficient clinical data, focused studies, studies on humans or in-depth information for researchers to draw conclusions as to whether the supplement would improve any of the conditions.

Dietary Supplement Side Effects

Researchers also warn that while there was some evidence in smaller studies or studies that included animal testing, the supplements were often linked to side effects or other complications.

For example, researchers failed to find evidence linking Asian ginseng to improved blood pressure or blood sugar. However, some of the studies indicated the herb can interact with medications, like Warfarin, which is used as a blood thinner.

Some smaller studies indicated flaxseed may help the heart in marginal ways, however the effect was not investigated on humans. Yet, research linked flaxseed to potential side effects, including intestinal problems and diarrhea. It can also interfere with the absorption of other pharmaceutical drugs.

One study linked green tea to reduced risk of cardiovascular death when consumed at high doses. However, clinical studies also linked green tea to reports of liver damage in those taking green tea extract.

In each case, when studies linked the herbal supplements to positive outcomes, the research was conducted on small sample sizes and needed confirmation from larger clinical studies.

Dietary supplements do not require clinical studies before being released on the market. They also do not need to be proven safe or effective to the FDA, like pharmaceutical drugs. The FDA oversees dietary supplements, but only monitors side effects and adverse events, like death.

Researchers say doctors should focus on herbal supplement history with patients and discuss their possible side effects.

“Use of herbal medications for the treatment of cardiovascular diseases is not supported by scientific evidence,” the researchers concluded. “Physicians should improve their knowledge of herbal medications to adequately weigh the clinical implications related to their use, and be able to discuss with patients their possible benefits and side effects, and explain that natural does not always mean safe.”