The Culprit: What is Glycyrrhizin?
For centuries, licorice root (Glycyrrhiza glabra) has been used in traditional medicine and as a flavoring agent. The source of its characteristic sweetness, which is up to 50 times sweeter than sugar, is a compound called glycyrrhizin, or glycyrrhizic acid. While glycyrrhizin can provide some beneficial properties in moderation, such as anti-inflammatory effects, it is the compound responsible for the serious adverse health effects linked to excessive licorice consumption. The concentration of glycyrrhizin can vary significantly among products, making consistent intake levels difficult to monitor without clear labeling. This makes it challenging for consumers to determine a safe daily amount, especially in health supplements where concentrations may be higher.
How Glycyrrhizin Harms the Body
When ingested in large amounts over a prolonged period, glycyrrhizin can disrupt the body's delicate balance of electrolytes. The core mechanism is its ability to inhibit an enzyme called 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). This enzyme is responsible for inactivating cortisol, a stress hormone, in the kidneys. By blocking this process, glycyrrhizin allows cortisol to act on mineralocorticoid receptors, mimicking the effects of the hormone aldosterone.
This overstimulation of mineralocorticoid receptors causes a cascade of physiological issues:
- The kidneys retain more sodium and water, leading to fluid retention and increased blood volume.
- At the same time, the body excretes too much potassium, leading to dangerously low potassium levels (hypokalemia).
- This mineralocorticoid-like effect is known as pseudohyperaldosteronism.
The resulting imbalance between sodium and potassium can profoundly affect nervous system and muscle function, and, most critically, the electrical signaling in the heart.
Who is at Risk?
While most healthy individuals can consume small, occasional amounts of licorice without issue, certain groups are at a much higher risk of experiencing adverse effects from glycyrrhizin exposure.
- Individuals over 40: Research suggests that older adults may be more susceptible to glycyrrhizin's effects. The FDA has specifically warned that individuals over 40 eating more than two ounces of black licorice daily for two weeks may experience irregular heart rhythms.
- People with heart conditions: Those with existing heart disease, high blood pressure (hypertension), or a history of irregular heartbeats are especially vulnerable to the electrolyte imbalances and blood pressure increases caused by glycyrrhizin.
- Kidney disease patients: Because glycyrrhizin affects the kidneys' ability to regulate electrolytes, those with kidney conditions face an increased risk of complications.
- Pregnant and breastfeeding women: Consumption of large amounts of licorice during pregnancy is considered unsafe and has been linked to an increased risk of early delivery. It is also advised against while breastfeeding.
- Those on certain medications: Licorice can have significant interactions with various prescription drugs, including diuretics, corticosteroids, and warfarin.
Not All Licorice is Created Equal
It is important to distinguish between products that contain real licorice root extract and those that are merely licorice-flavored. Many candies, particularly red licorice, do not contain any licorice extract. Instead, they use anise oil, an unrelated flavoring that provides a similar taste but does not contain glycyrrhizin. Always check the ingredient list to determine if a product contains real licorice root extract or glycyrrhizic acid.
Understanding Deglycyrrhizinated Licorice (DGL)
For those who wish to benefit from licorice's health-promoting properties without the risks associated with glycyrrhizin, Deglycyrrhizinated Licorice (DGL) is a safer alternative. DGL has been specially processed to remove most of the glycyrrhizin, making it a viable option for digestive support. DGL is often used to soothe stomach upset, heartburn, and to promote the healing of ulcers. It is available in chewable tablet or capsule form.
Glycyrrhizin Side Effects Explained
When glycyrrhizin is consumed in large or prolonged doses, it can lead to a range of severe symptoms related to high blood pressure and electrolyte imbalance. The potential health consequences can be life-threatening.
- High Blood Pressure (Hypertension): The most common side effect is an increase in blood pressure due to fluid retention and sodium accumulation.
- Low Potassium (Hypokalemia): The disruption of electrolyte balance leads to low levels of potassium, which can cause muscle weakness, fatigue, and paralysis.
- Irregular Heartbeat (Arrhythmia): Severely low potassium can trigger abnormal heart rhythms, which can be fatal in extreme cases, as highlighted by the FDA and medical reports.
- Swelling (Edema): Fluid retention can cause puffiness and swelling, particularly in the ankles and legs.
- Muscle Weakness and Pain: Hypokalemia can lead to significant muscle problems, ranging from soreness to severe muscle weakness and paralysis.
- Headaches: Frequent or severe headaches are another reported symptom linked to glycyrrhizin toxicity.
Comparison Table: Real Licorice vs. Anise-Flavored Candy
| Feature | Real Black Licorice (with Glycyrrhizin) | Anise-Flavored Candy (e.g., Red Licorice) |
|---|---|---|
| Source | Root extract of the Glycyrrhiza glabra plant | Anise oil from the anise plant, or artificial flavorings |
| Flavoring Compound | Glycyrrhizin (up to 50x sweeter than sugar) | Anethole (the compound that gives anise its licorice-like flavor) |
| Potential Health Risks | High blood pressure, hypokalemia, cardiac issues, fluid retention with excessive, prolonged use | Generally safe in moderation, but excess sugar can pose risks |
| Risk Group | Individuals with heart or kidney disease, high blood pressure, and pregnant women | None related to glycyrrhizin; general risks of high sugar intake |
Conclusion
While licorice root has a long history of traditional use and can offer benefits in controlled, moderate doses, the ingredient glycyrrhizin presents real and serious health risks when consumed excessively. This is particularly true for vulnerable populations with pre-existing health conditions or those taking specific medications. Consumers should be mindful of the products they are consuming, distinguish between real and anise-flavored candies, and consider safer, deglycyrrhizinated alternatives if they wish to reap the benefits without the significant cardiovascular risks. Always consult a healthcare professional, especially if you have concerns about existing health conditions or medication interactions. For additional safety information on herbal supplements like licorice, see the National Center for Complementary and Integrative Health.
