Case study: Death by black licorice

The candy contains a sweetening compound that can cause abnormal heart rhythms, high blood pressure, swelling, lethargy and congestive heart failure.

Dave Yasvinski 4 minute read April 8, 2021
black licorice

It is possible to eat way too much black licorice. Getty

Each week we comb through science journals to explore a baffling medical issue.

A 54-year-old construction worker who bit off more than he could chew now serves as another cautionary tale of the dark side of black licorice.

The Massachusetts man, whose untimely death two years ago was documented in The New England Journal of Medicine, had no history of heart problems and was active at home and work before suddenly collapsing at a McDonald’s and dying in hospital 24 hours later. Doctors soon discovered the man, who was not identified in the report, had been consuming one to two bags of black licorice every day for the previous three weeks.

“We almost didn’t believe it when we figured it out,” said Jacqueline B. Henson, the doctor who treated the man while a resident at the hospital, according to The New York Times. “We were all shocked and surprised.”

Black licorice contains a sweetening compound known as glycyrrhizin that can cause a person’s potassium levels to drop to dangerous levels, according to the U.S. Food and Drug Administration (FDA). This deficit can lead some people to experience a range of problematic symptoms, including abnormal heart rhythms, high blood pressure, swelling, lethargy and congestive heart failure.

Far from sugar-coating the risks, the agency recommends against eating large amounts of the controversial candy, regardless of age, as it can also interact with some medications and dietary supplements. Anyone who experiences muscle weakness or an irregular heartbeat after doing so is advised to put the bag down and seek medical assistance immediately. Just two ounces of the candy per day for two weeks can lead to arrhythmia, a condition where the heart beats too fast, too slow or at an irregular speed. Potassium levels usually return to normal with no lingering health issues once consumption stops.

The patient in this case smoked a pack of cigarettes a day and had a poor diet, but doctors concluded the real problems began when he decided to switch from red to black licorice just three weeks before his death. Tests confirmed his potassium levels were dangerously low, despite the absence of other factors normally responsible for such results.

The “very unusual case” will hopefully serve as a warning to others, said Keith Ferdinand, a cardiologist at Tulane University School of Medicine, who was not involved in treating the patient. “Any substance that’s taken into the body, especially taken in excess, can have true physiological effects,” he said. “It is always hard to find a cause and effect when a person has a sudden catastrophic event.”

In this case, however, Ferdinand said all signs point to black licorice as the factor behind the man’s fatal condition. Similar studies have also pointed the finger at the risks of the concerning confection, including one on licorice abuse from 2012 that called on the FDA to regulate the candy. “The daily consumption of licorice is never justified because its benefits are minor compared to the adverse outcomes of chronic consumption,” the authors of the study wrote in their analysis of a 35-year-old man who drank a litre of licorice-flavoured water prior to losing control of his motor functions temporarily.

“There are numerous licorice-containing products that are readily available in our everyday use and can be unintentionally consumed by the public in liberal amounts, putting them at risk of complications.”

For those not loving the idea of living without black licorice, Henson said the candy isn’t poisonous but should definitely be consumed with caution. “It’s fine taken in sort of small amounts, infrequently,” she said. “But when taken on a regular basis, it can lead to these issues.”

Dave Yasvinski is a writer

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