The Danes like liquorice. They are available there as sweets, liqueur, ice cream, in chocolate - or simply from the bag on the candy shelf in the supermarket.

The warning from researchers is now coming from Denmark of all places: too much liquorice is not healthy! Even worse: In some cases it is even life-threatening. The reason for this is glycyrrhizic acid, also known as glycyrrhizin. This is a sweet-tasting glycoside, a chemical compound of alcohol and sugar. It is found in the root of the liquorice plant and is used to make liquorice.

Scientists from the Danish Food Authority and the Food Institute at the Technical University of Denmark tested 219 different liquorice products from Denmark in a new study published in January. According to the Danish science portal videnskab.dk, the study published in January in the specialist magazine "Food Control" is the world's largest study of its kind.

The researchers discovered that a number of liquorice products contain high levels of glycyrrhizic acid, which can be harmful to health in excessive amounts.

"We were surprised that in many products you don't have to eat more than four to five grams of liquorice to get enough glycyrrhizic acid to exceed the EU limit," said Nicolai Zederkopff Ballin, a chemist at the Danish Food Safety Authority and first author of the Study. The limit is 100 milligrams per day.

The scientists also found that ten percent of the tested products did not contain sufficient warnings about the high acid content, as is actually required by law.

Too much liquorice increases blood pressure. "Patients with high blood pressure and cardiovascular diseases in particular need to be careful when consuming liquorice," explains Gunnar Gislason, head of research at the Center for Cardiovascular Diseases at Herlev and Gentofte Hospital, the portal videnskab.dk.

"It can raise blood pressure and have other adverse effects. If you eat licorice in very large amounts, they can be deadly right out of the box." The new study therefore recommends that campaigns be used to draw the public's attention to the dangers of overconsumption of liquorice.

Two examples show that enjoying too much liquorice is not something to be trifled with: In 2021, the Danish “Wochenschrift für Ärzte” reported on a 43-year-old woman who came to the emergency room because of acute extensor paralysis of the fingers on both hands. In the days before, she had increasingly felt sore muscles, tiredness and general muscle weakness and complained of numbness in her feet and lower legs.

When the woman was examined, it was found that she had severe hypokalemia – i.e. too little potassium in the blood. Her blood pressure was elevated and there were changes in the EKG. In the worst cases, hypokalemia can lead to ventricular fibrillation, which stops the heart from pumping – a life-threatening condition.

The cause of the suffering: The woman had been drinking two and a half liters of liquorice tea every day to relieve the dry cough since his whooping cough infection eight weeks earlier.

The second case ended fatally. A 54-year-old man from the state of Massachusetts in the United States had eaten a bag and a half of licorice a day for several weeks. This brought his heart to a standstill, the AP news agency reported in September 2020. The man died of an overdose of liquorice.

As early as 1999, the Federal Institute for Health Protection of Consumers and Veterinary Medicine (BgVV) warned against products with an excessively high glycyrrhizic acid content, as they can trigger high blood pressure. At that time, people with high blood pressure, cardiovascular diseases, diabetes and pregnant women were advised against "constant consumption of large quantities".

The scientists of the new Danish study say that it is okay to enjoy the black treat in smaller quantities. Liquorice rarely causes serious or even fatal illnesses. "People tend to only become seriously ill after eating too much licorice over a period of time," says medical student Mikkel Rodin Deutch, first author of a study that summarizes a long line of studies on licorice and health.

"If you eat too much liquorice one day, that's not bad either. But if you constantly consume too much glycyrrhizic acid, it can have serious consequences, even for young, healthy people," says doctor Gunnar Gislason.

One problem, however, is that the EU limit, which was only set temporarily, can easily be exceeded, according to the study. Less than half a cup of liquorice tea or four to five liquorice dragees would be enough to reach 100 milligrams.

"The EU has set the limit at 100 milligrams of glycyrrhizic acid per day, but various independent scientists have repeatedly suggested that the limit should be lowered to 10-15 milligrams. But the EU will not lower the limit because it lacks the data," explained the scientist Nicolai Zederkopff Ballin.

He hopes the new study will help raise awareness about licorice consumption.

Sources: "Glycyrrhizinic acid in licorice products on the Danish market", videnskab.dk, DocCheck Flexikon, "Ugeskrift for Læger", AP news agency, Federal Institute for Risk Assessment​​​​​​