A new study from Linköping University has revealed that even small amounts of licorice can increase blood pressure, challenging previous assumptions about its safety. While many enjoy licorice for its unique taste, this research suggests that its effects on the body might not be as harmless as once thought.
Licorice comes from the root of the Glycyrrhiza plant and has been used for centuries in both traditional medicine and as a popular flavoring.
However, its sweetness is largely due to a compound called glycyrrhizic acid, which can interfere with the body’s ability to regulate fluid levels. This disruption can lead to higher blood pressure, a key risk factor for heart disease.
Health authorities such as the European Union and the World Health Organization have suggested that consuming up to 100 mg of glycyrrhizic acid per day is generally safe. Yet, studies show that about 5% of Swedes regularly consume more than this amount, raising concerns about potential health risks.
The study, published in the American Journal of Clinical Nutrition, set out to test whether the current safety guidelines for licorice consumption hold up under closer scrutiny. Researchers recruited 28 healthy adults between the ages of 18 and 30 and divided them into two groups.
Participants consumed either licorice containing 100 mg of glycyrrhizic acid or a control product with salmiak (which gives licorice its salty taste) but no licorice extract. After a two-week break, they switched products, allowing scientists to compare the effects within the same individuals.
Throughout the study, participants measured their blood pressure daily at home. Researchers also examined their hormone levels, salt balance, and signs of heart strain.
The results were striking. Even at the so-called “safe” dose of 100 mg, licorice caused an average blood pressure increase of 3.1 mmHg. Researchers also observed lower levels of renin and aldosterone—hormones that help control fluid balance.
Those who were more sensitive to these hormonal changes also showed signs of fluid retention, slight weight gain, and increased levels of NT-proBNP, a marker that signals extra stress on the heart.
These findings suggest that licorice, even in moderate amounts, may pose health risks—especially for people who are more sensitive to its effects. While a small increase in blood pressure may not be a concern for everyone, it could be more serious for individuals already dealing with high blood pressure or heart issues.
The study raises an important issue: many licorice products do not list their glycyrrhizic acid content on the packaging. This makes it difficult for consumers to track how much they’re consuming, potentially leading to unintentional overconsumption.
This research adds to the growing evidence that diet plays a crucial role in heart health. While licorice is just one example, other foods and nutrients can either raise or lower blood pressure. Scientists continue to explore how diet influences hypertension, including the impact of potassium-rich foods, vitamins, and common staples like potatoes.
As researchers push for clearer food labeling and increased awareness, individuals who are concerned about their blood pressure should be mindful of their licorice intake. Whether as a candy, tea, or supplement, even moderate amounts of licorice could have an effect on heart health.
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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