The spooky and dangerous side of black licorice

Although black licorice might look and taste innocent, this candy is actually quite dark. It was revealed that black licorice played a role in the murder of a Massachusetts man aged 54 years old on September 23, 2020. How can this happen? It sounds more like a story than a fact.
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My interest in the effects of chemicals in food and our environment on our bodies and minds has been a constant one. We are reminded by the famous Proclamation of Paracelsus, the Father Of Toxicology, that all things are poisonous and no thing is without poison. It is the dose alone that makes it poisonous.

Professor in the department of toxicology and pharmacology, I am also the author of Pleased to Meet me: Genes and Germs and the Curious Forces that Make Us Who We Are.

The root cause of the problem

He is not the only one who fell prey to excessive black liquorice consumption. Medical journals contain a few similar cases in which patients suffer from hypertension, muscle breakdown, or even death. People over 40 are more likely to experience adverse reactions than those who eat far more black liquorice than the average person. They also tend to consume the product for longer periods of time. The Massachusetts man was eating three weeks worth of black licorice daily for the past three weeks.

Glycyrrhiza Glabra is a species that is native to Eurasia, North Africa and from which most confectionery-licorice is made. Franz Eugen Khler, Khler's Medizinal-Pflanzen via Wikimedia Commons

Licorice, a flowering plant that is native to Europe and Asia, is called Glycyrrhiza. Glycyrrhiza is its scientific name. It derives its name from the Greek words glykos, which means sweet, and rhiza, which means root. Its sweet, aromatic root extract has been used for centuries as a herbal remedy for many health conditions. These include heartburn, stomach problems, sore throats, and cough. There is not enough evidence to prove that licorice can be used to treat any medical condition.

Glycyrrhizin, also known as glycyrrhizic Acid, is the chemical found in black licorice. It gives the candy its distinctive flavor but can also cause toxic side effects.

Glycyrrhizin is a mimic of the hormone aldosterone. This hormone is produced by the adrenal glands when the body requires sodium and potassium. As a type of cell battery, sodium and potassium are interconnected and drive communication between nerves as well as the contraction of muscle. Glycyrrhizin can cause a disruption in the electrolytes' balance, leading to high blood pressure and disruption of the heart rhythm. Additional symptoms of excessive licorice consumption include muscle pain, swelling, numbness, and headaches. The man who died due to excessive licorice consumption had dangerously low potassium levels, consistent with glycyrrhizin toxicemia.

You should know that many licorice-based foods don't contain real licorice. Instead, they use anise oil as a flavoring agent, which doesn't pose the same dangers. Red licorice, despite its name may not contain licorice extract. Red licorice instead contains chemicals that give it its strawberry or cherry flavor.

Licorice extract and glycyrrhizic acids are often listed as ingredients in products that contain real licorice. Some products, like black jelly beans and Good & Plenty are mixtures of various candies that include both anise oil as well as licorice extract.

Red licorice can be dangerously sweet, but it is safe to eat. Darren Boucher/Getty Images

Hidden dangers that can increase your risk

Glycyrrhizin is a sweetener that has a distinct licorice taste. It can be used in soft drinks, chocolate, Belgian beers and throat lozenges, as well as other products. It can be difficult to track how much glycyrrhizin you have consumed. Additionally, combining these products may cause adverse reactions.

People who take dietary supplements or health supplements already containing licorice may be at greater risk for toxic effects from eating blacklicorice candy. Hydrochlorothiazide, a diuretic that causes increased urine production, can cause lower potassium levels. Glycyrrhizin can also cause potassium to drop, which can lead to muscle cramps or irregular heart beats.

Preexisting conditions can make it more difficult for people to overdose on black licorice.

Patients with low potassium levels (hypokalemia), high bloodpressure, or heart arrhythmia will be more sensitive to excessive licorice. Glycyrrhizin will be retained in the bloodstream of patients with kidney or liver disease for longer periods, increasing the risk of suffering from its negative effects.

What should you do?

Black licorice is fine to keep in your home, even if you aren't a big fan. Licorice is safe to eat in small amounts from time to time and poses no danger to children or adults otherwise healthy. It is important to be careful about how much you consume.

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As Halloween approaches, remind your children that candy is sometimes a food, particularly black licorice. FDA warns people not to eat more than 2 ounces of black liquorice per day for more than two weeks. If you experience irregular heart beat or muscle weakness after eating large amounts of black licorice, contact your doctor immediately.

Scientists have also cautioned against routine consumption of licorice as a dietary supplement or tea due to its health benefits. This includes the treatment of COVID-19-related cough and other respiratory infections. An article in 2012 reviewed the benefits of licorice and the negative consequences of long-term consumption.

Updated article to address concerns regarding the use of licorice in COVID-19 treatments.

This article was republished by The Conversation, a non-profit news site that shares ideas from academic experts. It was written and edited by Bill Sullivan, Indiana University.

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Bill Sullivan is not affiliated with any company or organization that Bill Sullivan consults, owns shares in, or receives funding from.