The Culprit Behind the Sweetness: Glycyrrhizin
While liquorice root has been used for its medicinal properties for centuries, the danger lies in a compound called glycyrrhizin. Glycyrrhizin is the natural sweetener found in real liquorice root and is substantially sweeter than table sugar. When consumed in excess, this compound can have serious and potentially life-threatening effects on the body's delicate balance of electrolytes and hormones.
How Glycyrrhizin Disrupts Body Chemistry
Glycyrrhizin's primary mechanism of action is its ability to inhibit an enzyme in the body called 11-beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2). This enzyme is responsible for converting the stress hormone cortisol into its inactive form, cortisone. When 11β-HSD2 is inhibited, active cortisol levels increase in the kidneys. This elevated cortisol then overstimulates the body's mineralocorticoid receptors, which are normally regulated by aldosterone, a hormone that controls blood pressure and electrolyte balance. This process leads to a condition known as pseudohyperaldosteronism, which mimics the effects of high aldosterone levels in the body.
Major Cardiovascular and Electrolyte Risks
The consequences of this hormonal disruption are primarily seen in the cardiovascular system and are often the most severe side effects of eating too much liquorice.
The Link to Hypertension and Fluid Retention
As a result of pseudohyperaldosteronism, the body retains sodium and water while excreting potassium. This fluid retention can lead to a significant increase in blood pressure. Studies, including one published in The American Journal of Clinical Nutrition, have shown that even relatively low, consistent doses of liquorice can elevate blood pressure in healthy individuals. The resulting hypertension can increase the risk of cardiovascular disease, especially in individuals over 40 or those with pre-existing heart conditions.
The Danger of Hypokalemia
As the body retains sodium, it simultaneously loses potassium, leading to a dangerously low level of potassium in the blood, a condition called hypokalemia. Potassium is a vital electrolyte essential for proper nerve and muscle function, particularly for the heart. Severe hypokalemia can cause:
- Irregular heart rhythms (arrhythmia)
- Congestive heart failure
- Muscle weakness and cramping
- In extreme cases, cardiac arrest
Neurological and Muscular Symptoms
Beyond heart-related issues, severe hypokalemia can cause a range of neurological and muscular problems. Individuals may experience:
- General muscle weakness
- Muscle pain
- Numbness
- Lethargy and fatigue
- Rarely, paralysis
Impact on Kidneys and Other Systems
Chronic excessive liquorice consumption can also place a significant burden on the kidneys, which are responsible for regulating electrolytes and fluid balance. In severe cases, this can lead to kidney failure, especially in those with pre-existing kidney conditions. There are also reported cases of increased blood protein levels in the heart, indicating increased workload. Some studies have also suggested hormonal disruptions affecting testosterone levels and potential risks during pregnancy.
Is All 'Liquorice' Candy Dangerous?
It's important to distinguish between products containing real liquorice extract and those that are simply liquorice-flavored. Many red, fruit-flavored candies that look like liquorice do not contain any of the harmful glycyrrhizin. They are instead flavored with anise oil, which provides a similar flavor profile without the associated health risks. Always check the ingredient list for 'liquorice extract' or 'glycyrrhizinic acid'.
Comparison Table: Real Liquorice vs. Anise Flavoring
| Feature | Real Liquorice (Glycyrrhiza glabra) | Anise (Pimpinella anisum) |
|---|---|---|
| Source | Root of the Glycyrrhiza glabra plant | Seed of the Pimpinella anisum plant |
| Active Compound | Contains glycyrrhizinic acid | Contains anethole, a distinct compound |
| Blood Pressure Impact | Can cause hypertension when consumed excessively | No adverse effect on blood pressure |
| Electrolyte Impact | Can cause hypokalemia (low potassium) | Does not affect potassium levels |
| Associated Products | Black liquorice candy, herbal teas, supplements, syrups | Most 'red licorice' candy, pastis, some flavored beverages |
Who is at Higher Risk from Excessive Liquorice?
Certain individuals are more susceptible to the adverse effects of liquorice.
- Older Adults (over 40): The FDA notes that people over 40 may be more sensitive to the effects of liquorice.
- Individuals with Pre-existing Conditions: Those with heart disease, high blood pressure, or kidney disease are at a significantly higher risk of serious complications.
- Pregnant Women: Excessive liquorice consumption during pregnancy has been linked to potential negative impacts on fetal development.
- People on Certain Medications: Individuals taking diuretics (which deplete potassium), corticosteroids, or digitalis are especially vulnerable to amplified effects.
What is a Safe Amount?
Health authorities generally advise moderation, as the glycyrrhizin content can vary widely between products. The World Health Organization (WHO) recommends limiting glycyrrhizin intake to no more than 100mg per day for most healthy adults, which corresponds to approximately 60-70g of liquorice confectionery. However, some healthy individuals may experience side effects at lower doses. For at-risk populations, it is best to avoid real liquorice entirely.
Conclusion: Moderation and Awareness are Key
While an occasional piece of real black liquorice is unlikely to cause harm, continuous and excessive consumption can lead to severe health consequences. The active compound, glycyrrhizin, disrupts the body's electrolyte and hormonal balance, resulting in potentially dangerous side effects such as high blood pressure and low potassium. For those with pre-existing heart or kidney conditions, or pregnant women, the risks are even greater. Always read product labels to confirm if real liquorice extract is present and when in doubt, choose anise-flavored alternatives to enjoy the flavor without the risk. For any concerns, it is best to consult a healthcare provider, especially if you experience symptoms like swelling, muscle weakness, or irregular heart rhythms. A useful resource for checking drug interactions is Drugs.com: Licorice Uses, Benefits & Dosage - Drugs.com.
