Scientists from the University of Rochester have reported that eating too much black licorice can lead to dangerously high blood pressure and serious disturbances in the body’s electrolyte balance.
Licorice is a plant that grows in parts of Europe and Asia, and its root contains a compound called glycyrrhizin.
When consumed in large amounts, glycyrrhizin can have powerful effects on the body that go far beyond its sweet taste.
Recent research shows that glycyrrhizin can mimic the hormone aldosterone, which is produced by the adrenal glands to help regulate sodium and potassium levels in the body.
When aldosterone levels are too high, the body retains more sodium and water while excreting potassium.
This imbalance can raise blood pressure and interfere with the normal electrical activity of the heart. Other symptoms of excessive licorice intake may include swelling, muscle pain, numbness, headaches, and heart rhythm disturbances.
In a recent case study, the research team described the experience of a 50-year-old woman who had consumed large amounts of black licorice over several weeks. She arrived at the hospital after four days of muscle aches and dark-coloured urine.
At the time, she was taking a diuretic, or “water pill,” which increases the amount of urine the body produces. She later reported eating one and a half bags of black licorice bites per day, containing about two percent natural licorice, during the previous three weeks.
Medical examinations showed that she had high blood pressure and significant abnormalities in her blood chemistry.
Tests revealed severe muscle injury, along with low levels of potassium, calcium, and phosphorus. Potassium is essential for maintaining normal nerve and muscle function, especially for the heart.
Calcium plays a key role in nerve signalling and muscle contraction. Low phosphorus levels can also cause serious complications, including muscle weakness, breathing difficulties, heart failure, seizures, or coma.
Further analysis revealed that glycyrrhizic acid, the active compound in licorice, inhibits an enzyme that normally converts the hormone cortisol into its less active form, cortisone. As a result, cortisol levels remain abnormally high in the body.
This excess cortisol can mimic a rare genetic disorder known as apparent mineralocorticoid excess (AME), a condition characterised by high blood pressure and dangerous drops in key minerals such as potassium and phosphorus.
In this patient, the licorice-induced drop in potassium triggered a life-threatening condition called rhabdomyolysis, which occurs when muscle tissue breaks down and releases harmful substances into the bloodstream. This condition, combined with severe electrolyte imbalances, led to further complications and increased the risk of organ damage.
The researchers, led by Megha Shah and published in Clinical Nephrology, emphasised that black licorice is not a harmless snack when consumed in large amounts over a sustained period.
They warn that excessive intake can carry serious health risks, particularly for people who already have heart or kidney problems or who are taking medications that affect fluid and electrolyte balance.
Moderation, they concluded, is critical when it comes to consuming products made with real licorice root.
