Licorice is a flavoring derived from the root of the Glycyrrhiza glabra plant, found in candies, herbal teas, and supplements. The consumption of real licorice has been scientifically linked to increases in blood pressure, an effect that depends on the amount consumed and individual sensitivity. This connection is significant enough that health organizations have issued advisories regarding daily intake.
The Compound Behind the Effect
The primary active compound in licorice root responsible for affecting blood pressure is glycyrrhizic acid. When consumed, it interferes with the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (HSD11B2). This enzyme’s function is to deactivate the hormone cortisol within the kidneys.
By inhibiting this enzyme, glycyrrhizic acid allows cortisol to accumulate in the kidneys. While the hormone aldosterone normally manages the body’s sodium and potassium balance, the excess cortisol begins to mimic its action by binding to its receptors.
Responding to these cortisol signals, the kidneys retain sodium and water, which increases the volume of blood in the vessels. Simultaneously, the kidneys excrete potassium, lowering its level in the blood. This combination of increased fluid and sodium retention directly elevates blood pressure.
Identifying and Quantifying Risk
The risk of high blood pressure from licorice depends on the amount of glycyrrhizic acid consumed and individual sensitivity. The U.S. Food and Drug Administration (FDA) notes that consuming two ounces of black licorice daily for two weeks can be problematic, particularly for those over 40 with a history of heart disease or high blood pressure. A study found a daily intake of 100 mg of glycyrrhizic acid was enough to raise blood pressure in healthy young adults.
It is important for consumers to distinguish between products containing real licorice root extract and those that are “licorice-flavored.” Many candies use anise oil, which provides a similar taste but does not contain glycyrrhizic acid and therefore does not pose the same risk to blood pressure. True licorice extract is found in black licorice, certain herbal teas, and some dietary supplements.
For those who use licorice for its herbal properties but are concerned about blood pressure, an alternative exists. Deglycyrrhizinated Licorice (DGL) is a supplement from which the glycyrrhizic acid has been removed. This makes DGL a safer option for individuals who need to manage their blood pressure.
Recognizing the Symptoms
The symptoms of licorice-induced high blood pressure are related to the underlying fluid and electrolyte imbalances. One common sign is fluid retention, known as edema, which presents as swelling in the legs and feet. Headaches are also a frequent symptom, resulting from the increased pressure within the circulatory system, and can be accompanied by a general feeling of lethargy or tiredness.
The loss of potassium, a condition called hypokalemia, can lead to muscle weakness and cramping. In more severe cases, low potassium levels can disrupt the heart’s electrical signals, leading to dangerous irregular heart rhythms, or arrhythmias.
These symptoms are reversible and resolve after an individual stops consuming licorice. Anyone experiencing these symptoms, especially those with pre-existing heart or kidney conditions, should stop eating licorice and consult a healthcare provider.