Enlarge /. Bulk black liquorice candies.
With 2020 not offering enough extraordinary opportunities to die, the universe grimly reminds us that eating too much licorice can be deadly.
A 54-year-old construction worker recently died in Massachusetts after eating too much black liquorice – which, of course, contains a toxin called glycyrrhizin, also known as glycyrrhizic acid. Doctors published a case study of his poisoning in the New England Journal of Medicine this week.
According to the study, the poor guy was in a fast food restaurant when he suddenly got into cardiac arrest. He "suddenly gasped for air, with full body shaking and unconsciousness," the doctors report. Paramedics arrived within minutes and gave him four shocks and CPR. However, when he was hospitalized about 30 minutes later, doctors found he had multiple organ failure, "profound metabolic disorders," dangerously low blood potassium levels, and cardiac arrest associated with ventricular fibrillation. Heart chambers twitch erratically without pumping blood. All of these conditions are consistent with licorice poisoning.
A thorough medical exam found that he appeared to have no history of heart problems, and doctors stuck to his conditions on the candy. Discussions with his family revealed that he had eaten one or two "large" bags of black liquorice every day for about three weeks before his heart stopped short. Too much damage had already been done by the time he got to the hospital. He and his family died on his bed about 32 hours later.
Medical researchers have long known about the complex and toxic effects of the licorice plant on the human body. Licorice has a storied and twisted history in both eastern and western cultures, dating back to the Babylonian and Egyptian empires. Hippocrates prescribed it in the treatment of asthma and dry cough. Traditional Chinese medicine has used licorice to treat conditions ranging from tuberculosis to gastric ulcers.
However, these uses were not without side effects. In the 1950s, the Dutch doctor F. E. Revers carried out one of the first systematic studies on the effects of licorice extract against ulcers and found that the patients suffered from swelling, "severe headaches", high blood pressure and chest pain and pressure.
In the decades that followed, researchers found that the glycyrrhizin in licorice was absorbed by microbes in the gut and converted to glycyrrhetinic acid (also known as glycyrrhetinic acid). This metabolized version is then absorbed by the body. In the kidneys, glycyrrhetinic acid derivatives interfere with a critical enzyme called 11β-hydroxysteroid dehydrogenase type 2 or 11βHSD2, which converts the steroid hormone cortisol into cortisone. Cortisol has many important functions, including the fact that it is a critical regulator of ion, salt, and water balance. This in turn has a significant impact on blood volume, blood pressure and the overall function of the cardiovascular system.
When 11βHSD2 is blocked by glycyrrhetinic acid, cortisol levels build up in the kidney. This leads to higher sodium levels, water retention, a dip in potassium levels, and a subsequent cascade of life-threatening problems in the body, including kidney failure. The increase in sodium and water retention leads to swelling and high blood pressure. The extreme drop in potassium levels (hypokalaemia) affects the ionic balance, which is vital for the cardiac conduction system. This is a specialized group of heart muscle cells that use electrical signals to contract the heart muscles and pump blood around. Therefore, a drop in potassium levels can lead to fatal irregular heart rhythms such as ventricular fibrillation.
Scary but rare
To make matters worse, glycyrrhetinic acid also disrupts enzymes in the liver that affect aldosterone levels, another critical steroid hormone that worsens all of the toxin's other health effects. The liver also circulates glycyrrhetinic acid, which means that after frequent licorice consumption, high levels can accumulate and remain high for long periods of time. It can take weeks for symptoms of licorice poisoning to go away.
For these reasons, medical researchers and health authorities warn against eating a lot of black liquorice – immediately and / or daily. In fact, the U.S. Food and Drug Administration typically reminds consumers of the life-threatening risk associated with Halloween every year (although sadly it isn't required this year).
In previous warnings, the FDA states, "If you are 40 years or older and eat 2 ounces of black liquorice a day for at least two weeks, you can end up in the hospital with an irregular heartbeat or arrhythmia."
Since black liquorice is not a particularly popular candy and few people indulge in enough toxic amounts, the gummy candies are not a public health threat. (Also, not all “licorice” candies actually contain licorice plant extract, including many red licorice candies such as red twizzler.) Reports of illness are rare, let alone death. Some of the few examples of damage are FDA indications of a "black liquorice lover" who "had a problem" after consuming the candy in 2016. In 1977, researchers reported the case of a 58-year-old woman ate a whopping 1.8 kilograms of black liquorice per week and went into cardiac arrest. But she survived the cardiac arrest and made a full recovery after she stopped eating licorice.
The poor fellow in Massachusetts wasn't so lucky. Although doctors were able to increase his potassium levels with large intravenous doses of potassium chloride, his condition worsened. His blood pressure became unstable, his neurological prognosis was poor, and his kidneys were failing. He was moved to consolation before he died peacefully with his family.