Licorice, a perennial native to Europe and Asia, has been used in traditional medicine to treat a wide variety of ailments. Licorice's medicinal effects, some of which have been substantiated by scientific studies, extend to certain aspects of heart function. Consult your doctor or qualified health professional before including licorice in your diet or using licorice to treat a health condition.
Risks and Contraindications
Licorice, even at low doses, can cause high blood pressure that may cause complications in people with coronary artery disease, according to biologist Kenneth M. Klemow of Wilkes University. You should avoid using licorice if you have been diagnosed with hypertension or another chronic heart condition. Other adverse effects of licorice may include low potassium levels, fluid retention, muscle spasm and blood clotting. Do not use licorice if you have a chronic liver or kidney condition.
Compounds in licorice may have direct effects on heart function, according to a study published in the January 2012 issue of the "Journal of Nutritional Biochemistry." In the tissue culture study, glycyrrhizin and a derivative molecule known as glycyrrhetinic acid significantly increased heart rate. However, the two molecules have opposite effects on contraction of the heart muscle, with one increasing the strength of contraction and one decreasing it. Researchers noted that this study was the first to demonstrate direct effects of these licorice components on heart function. Further studies are needed to confirm these preliminary results and to more fully explain the significance of licorice's opposing actions on the heart.
Licorice may help the heart by reducing the damaging effects of stress and making the adrenal glands stronger and more resilient to stress. In herbalists' terms, licorice is an adrenal tonic with adaptogen qualities, meaning that it helps the body respond to stress. Stress impairs heart function by influencing activity of the parts of the nervous system that control heart rate and blood pressure, according to the University of Maryland Medical Center.
Adverse side effects of excessive licorice consumption include headache, lethargy, water retention, muscle pain, high blood pressure and irregular heart rate or rhythm. It is generally safe for a healthy person to consume up to 10 milligrams of glycyrrhizin, the amount found in 5 grams of real licorice candy, per day, according to pharmacist Heather Boon, author of "The Complete Natural Medicine Guide to the 50 Most Common Medicinal Herbs." To avoid potential heart problems while still receiving its other potential health benefits you can take a form of licorice called deglycyrrhizinated licorice, or DGL. This form of licorice has had about 97 percent of the glycyrrhizin removed. However, if you have an existing heart, kidney or liver conditio, consult your doctor before using licorice and only use licorice under your doctor's supervision.
Glycyrrhizic acid, one of the active ingredients in licorice, is also what gives licorice its characteristic flavor. This compound, present in the roots of the plant, has similar effects in the body to aldosterone, a kidney hormone that regulates your blood pressure by controlling your body's levels of salt and water. Both aldosterone and glycyrrhizic acid cause the kidneys to retain sodium and water and release potassium, resulting in increased blood pressure. A study published in the April 2011 issue of the journal "Deutsche Medizinische Wocenschrift" illustrates the drastic effects licorice can have on blood pressure. The study reported on a case of a 28-year-old woman with high blood pressure and low potassium levels from consuming 300 milligrams of licorice per day. Discontinuing licorice consumption along with medication and partial kidney removal were required to bring the patient's blood pressure and kidney function to normal levels.
- Dr. Melissa Palmer's Guide to Hepatitis & Liver Disease; Melissa Palmer
- Deutsche Medizinische Wocenschrift; [Hypertension and Hypokalemia - a Reninoma as the Cause of Suspected Liquorice-induced Arterial Hypertension]
- Journal of Nutritional Biochemistry: Glycyrrhizin and Glycyrrhetinic Acid Directly Modulate Rat Cardiac Performance
- Nature's Medicines: From Asthma to Weight Gain, from Colds to High Cholesterol, the Most Powerful All-Natural Cures; Gale Maleskey
- The Vegetarian Diet for Kidney Disease: Preserving Kidney Function With Plant-Based Eating; Joan Brookhyser Hogan
- University of Maryland Medical Center: Stress - Complications
- University of Maryland Medical Center: Licorice
- Wilkes University Biology Department: Medical Attributes of Glycyrrhiza Glabra – Licorice
- Oregon State University: Adaptogen
Tracey Roizman, DC is a writer and speaker on natural and preventive health care and a practicing chiropractor. She also holds a B.S. in nutritional biochemistry.