Licorice, derived from the root of the Glycyrrhiza glabra plant, is a common flavoring in foods, beverages, candies, and herbal teas. It also has a long history of traditional medicinal use. However, consuming certain forms of licorice can affect blood pressure, a significant consideration for individuals sensitive to such changes.
How Licorice Affects Blood Pressure
The primary compound in licorice responsible for its effect on blood pressure is glycyrrhizin, also known as glycyrrhizic acid. Glycyrrhizin interferes with an enzyme called 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). This enzyme inactivates cortisol, a natural steroid hormone, by converting it into cortisone, a less active form.
When glycyrrhizin inhibits 11β-HSD2, less cortisol is converted to cortisone, leading to increased cortisol levels, especially in cells with mineralocorticoid receptors. Cortisol can then bind to and activate these receptors, similar to aldosterone, a hormone that regulates blood pressure. This activation mimics aldosterone’s effects, even when aldosterone levels are normal.
The stimulation of mineralocorticoid receptors by excess cortisol causes the kidneys to retain more sodium and water and increase potassium excretion. This leads to increased blood volume and elevated blood pressure. The resulting loss of potassium, known as hypokalemia, can contribute to muscle weakness and heart rhythm abnormalities.
Identifying Problematic Licorice Products
Not all licorice products pose the same risk to blood pressure. The concern primarily lies with products containing significant amounts of glycyrrhizin. Natural licorice root, found in some herbal teas and traditional remedies, contains varying concentrations of glycyrrhizin.
Licorice candies, especially black licorice, and supplements containing whole licorice extract are common sources of glycyrrhizin. Consuming more than 57 grams (approximately 2 ounces) of black licorice daily for at least two weeks can lead to increased blood pressure. The exact amount of glycyrrhizin in these products can vary, making it difficult to precisely calculate a safe limit.
A notable exception is deglycyrrhizinated licorice (DGL), a processed form of licorice where most of the glycyrrhizin has been removed. DGL is often used in supplements because it retains other beneficial compounds like flavonoids without the blood pressure-raising effects of glycyrrhizin. When choosing licorice products, read labels carefully to identify whether glycyrrhizin is present or if it is a DGL formulation.
What to Do If Blood Pressure Rises
If you consume licorice and experience symptoms suggesting elevated blood pressure, stop consuming the product immediately. Signs of elevated blood pressure due to licorice can include headaches, swelling (edema), fatigue, muscle weakness, muscle pain, and heart palpitations. These symptoms often arise alongside low potassium levels.
The effects of licorice on blood pressure are generally reversible once consumption ceases. After discontinuing licorice, blood pressure, sodium, and potassium levels usually return to normal. However, consult a healthcare professional for diagnosis and management, especially if symptoms are severe or if you have pre-existing conditions like hypertension or heart disease. Your doctor can determine if licorice was the cause and guide appropriate steps, including monitoring blood pressure and addressing any electrolyte imbalances.