Many people enjoy licorice for its unusual sweet and salty taste. It is a popular candy in several countries and is also used in teas, herbal remedies, and flavored drinks. For years, many people believed that eating small amounts of licorice was harmless.
However, a new study from researchers at Linköping University in Sweden suggests that even moderate amounts may raise blood pressure and put extra stress on the heart.
The study was published in the American Journal of Clinical Nutrition and challenges current beliefs about what amount of licorice is considered safe.
Licorice comes from the root of the Glycyrrhiza plant. It has been used for hundreds of years in traditional medicine because people believed it could help with stomach problems, coughs, sore throats, and inflammation.
Today, licorice is still commonly used around the world as a flavoring in candy, chewing gum, drinks, herbal teas, and even some medicines.
The main ingredient responsible for licorice’s strong sweetness is a natural substance called glycyrrhizic acid. This compound is much sweeter than regular sugar and gives licorice its distinctive taste. But scientists have known for some time that glycyrrhizic acid can also affect the body in ways that may not be healthy.
The substance interferes with hormones that help control salt and water balance in the body. When these hormone systems are disrupted, the body may hold onto extra salt and fluid. This can increase blood pressure and place extra strain on the heart and blood vessels.
High blood pressure is a major health concern because it raises the risk of heart attacks, strokes, kidney disease, and heart failure. Often called the “silent killer,” high blood pressure may not cause noticeable symptoms for many years while slowly damaging the body.
Health authorities such as the European Union and the World Health Organization currently state that consuming up to 100 milligrams of glycyrrhizic acid per day should generally be safe for most people.
However, researchers in Sweden noticed that many people regularly consume more than this amount, especially those who frequently eat licorice candy.
To better understand the possible risks, researchers at Linköping University carried out a carefully controlled study involving 28 healthy young adults between the ages of 18 and 30.
The participants were divided into two groups. One group ate licorice products containing 100 milligrams of glycyrrhizic acid each day, which matches the currently accepted “safe” limit. The other group ate salmiak-flavored products. Salmiak gives licorice its salty taste but does not contain real licorice extract or glycyrrhizic acid.
After two weeks, the groups switched products so the researchers could compare how the same people reacted to both treatments. This type of study design helped improve the accuracy of the results.
During the study, participants checked their blood pressure at home every day. Researchers also monitored hormone levels, body fluid balance, salt levels, body weight, and signs that the heart might be under stress.
The results surprised the scientists. Even at the supposedly safe dose, licorice caused an average increase in blood pressure of 3.1 mmHg. While this rise may sound small, experts say even modest increases in blood pressure can raise the risk of heart disease over time, especially in people who already have health problems.
The study also found that participants had lower levels of two important hormones called renin and aldosterone. These hormones normally help the body regulate salt, water, and blood pressure. Lower levels suggested that the body’s normal balance system had been disturbed by the licorice.
Some participants appeared more sensitive to these changes than others. People who showed stronger hormone changes also retained more fluid, gained a small amount of weight, and had higher levels of a substance called NT-proBNP. Doctors use NT-proBNP as a marker to detect stress on the heart.
The findings suggest that even moderate amounts of licorice could be risky for certain people, especially those who already have high blood pressure, heart disease, kidney problems, or other cardiovascular conditions.
Another issue raised by the researchers is the lack of clear labeling on many licorice products. Most products do not clearly show how much glycyrrhizic acid they contain.
This makes it difficult for consumers to know how much they are actually eating. Someone who regularly eats licorice candy, drinks licorice tea, or takes herbal supplements may easily consume more than the recommended limit without realizing it.
The study highlights how foods and natural products can sometimes have powerful effects on the body. Many people assume that foods labeled as “natural” are automatically safe, but scientists say natural substances can still affect hormones, blood pressure, and organ function.
Researchers are continuing to study how different foods influence heart health. For example, scientists have also investigated how potassium-rich vegetables, salt intake, and common foods such as potatoes may affect blood pressure and circulation.
The Linköping University study adds to growing evidence that diet plays a major role in long-term health. The researchers hope their findings will encourage better product labeling and greater public awareness about licorice consumption.
For people concerned about heart health or blood pressure, experts suggest being cautious with licorice products. Whether consumed as candy, tea, supplements, or herbal remedies, even relatively small amounts may affect the body more than many people realize.
If you care about high blood pressure, please read studies about breakfast for better blood pressure management, and the gut feeling that lowers blood pressure.
For more health information, please see recent studies about how the dash diet helps lower blood pressure, and how to eat your way to healthy blood pressure.
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