Many people enjoy licorice because of its sweet and unique flavor. It has been eaten for hundreds of years and has also been used in traditional medicine in many parts of the world.
Licorice comes from the root of the Glycyrrhiza plant. Today it is found in candy, herbal teas, drinks, and some natural health products. Because it has been used for such a long time, many people believe that eating a small amount is harmless.
However, a new study from Linköping University suggests that even a moderate amount of licorice may increase blood pressure. The findings were published in the American Journal of Clinical Nutrition and question current advice about what is considered a safe daily amount.
High blood pressure is one of the biggest risk factors for heart disease and stroke. Many people do not know they have high blood pressure because it often causes no clear symptoms.
Over time, however, it can damage the heart, brain, kidneys, and blood vessels. Because of this, even small increases in blood pressure can matter, especially for people who already have heart problems or hypertension.
The sweetness of licorice mainly comes from a natural substance called glycyrrhizic acid. This substance can affect the body’s hormone system. It reduces the body’s ability to control salt and water correctly.
As more fluid stays inside the body, blood pressure can rise. Scientists have known about this effect for years, but many health organizations believed that up to 100 milligrams of glycyrrhizic acid each day was generally safe for most people.
Researchers wanted to test whether this recommendation was truly safe. They recruited 28 healthy volunteers between 18 and 30 years of age. During the study, each person ate either licorice containing 100 milligrams of glycyrrhizic acid or a comparison product that tasted similar because it contained salmiak but did not contain licorice extract.
After a two-week break, the participants switched to the other product. This allowed the scientists to compare the effects in the same people, making the results more reliable.
Participants checked their blood pressure every day at home. The research team also measured hormones that control fluid balance, examined salt levels, and looked for signs that the heart was working harder than normal.
The results surprised the researchers. Even the amount that has long been considered safe caused blood pressure to rise by an average of 3.1 mmHg. The volunteers also showed lower levels of the hormones renin and aldosterone, which normally help control the body’s fluid balance. Some people were more sensitive than others.
These participants kept more fluid in their bodies, gained a small amount of weight, and had higher levels of NT-proBNP, a blood marker that can show extra stress on the heart.
The findings suggest that people do not all react to licorice in the same way. A healthy young person may notice little or no effect, while another person could experience a meaningful increase in blood pressure.
For people who already have high blood pressure, heart disease, kidney disease, or who take medicines that affect blood pressure, even a small increase may become more important.
The study also highlights another problem. Many licorice products do not clearly state how much glycyrrhizic acid they contain. Without this information, shoppers may not realize how much they are eating each day. Someone who enjoys licorice candy, drinks licorice tea, and takes herbal supplements could easily consume more than expected.
This research is another reminder that everyday foods can have a real effect on health. Scientists continue to study how diet changes blood pressure and heart health.
Foods rich in potassium, balanced eating habits, regular exercise, maintaining a healthy weight, limiting excess salt, and avoiding smoking are all known to support healthy blood pressure. At the same time, this new study shows that foods often thought to be harmless may deserve closer attention.
The researchers believe their findings support the need for better food labeling and greater public awareness. More studies involving larger and more diverse groups of people will help confirm the results.
Until then, people who are concerned about blood pressure may wish to be careful with licorice products, whether they are eaten as candy, taken as supplements, or enjoyed in herbal teas. Even moderate amounts may have a stronger effect on the body than many people realize.
If you care about high blood pressure, please read studies about unhealthy habits that may increase high blood pressure risk, and drinking green tea could help lower blood pressure.
For more information about high blood pressure, please see recent studies about what to eat or to avoid for high blood pressure, and 12 foods that lower blood pressure.
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