Understanding Licorice and the Dangers of Glycyrrhizin
Licorice, derived from the root of the Glycyrrhiza glabra plant, has been used for centuries as both a flavoring agent and an herbal remedy. However, the most active compound in licorice, glycyrrhizin (also known as glycyrrhizic acid), is responsible for its medicinal properties and most of its side effects. It is this substance that dictates how much licorice is safe to eat daily. Glycyrrhizin can affect the body in ways that mimic certain hormones, leading to serious health issues when consumed in large quantities or over a prolonged period.
The Recommended Daily Limit
For the average healthy adult, the World Health Organization (WHO) and other food safety bodies recommend limiting glycyrrhizin intake to no more than 100 mg per day. This amount can be roughly equivalent to 2–2.5 ounces (60–70 grams) of licorice candy, but this is a very general estimate. The concentration of glycyrrhizin varies dramatically between products, with content ranging from less than 1% to over 12%, making it incredibly difficult for consumers to track their intake. For this reason, many health experts advise caution and moderation.
Who Should Avoid Licorice?
Some individuals are far more sensitive to glycyrrhizin's effects and should limit or completely avoid licorice products. These high-risk groups include:
- Individuals over 40: The FDA specifically warns that for those over 40, consuming just two ounces (57 grams) of black licorice daily for two weeks could cause heart problems.
- People with heart disease: Licorice can cause fluid retention, worsening heart failure and increasing the risk of irregular heart rhythms.
- Individuals with high blood pressure: Glycyrrhizin can raise blood pressure, making it dangerous for those already managing hypertension.
- Patients with kidney disease: High intake of licorice can exacerbate kidney problems.
- Pregnant and breastfeeding women: It is unsafe for pregnant women due to the risk of premature birth and potentially negative effects on child development. Data is limited for breastfeeding women, so avoidance is advised.
- Those with low potassium (hypokalemia): Licorice lowers potassium levels, a dangerous combination for those already low in the electrolyte.
- People on certain medications: Licorice can interact with diuretics, blood pressure medications, and blood thinners like Warfarin.
Potential Side Effects of Overconsumption
Regularly consuming too much licorice, particularly for more than a few weeks, can lead to a condition called pseudohyperaldosteronism. The symptoms are often severe and can include:
- Abnormally high blood pressure (hypertension)
- Dangerously low potassium levels (hypokalemia)
- Swelling or edema
- Abnormal heart rhythms (arrhythmias)
- Muscle weakness, cramps, or paralysis
- Lethargy and fatigue
- In severe, rare cases, cardiac arrest
These effects are typically reversible once licorice consumption stops, but prompt medical attention is necessary if symptoms appear.
The Importance of Label Reading
Many licorice-flavored products, particularly in the US, do not contain real licorice root but instead use anise oil for flavor. This distinction is critical, as anise does not contain glycyrrhizin and is safe for consumption. Products with real licorice should list "licorice extract" or "glycyrrhizic acid" in their ingredients. Always check the label, especially for herbal teas, which can also contain licorice root.
Comparison of Licorice Types
To help navigate the choices, here is a comparison table of regular licorice versus deglycyrrhizinated licorice (DGL), which is processed to remove the problematic compound.
| Feature | Regular Licorice | Deglycyrrhizinated Licorice (DGL) |
|---|---|---|
| Glycyrrhizin Content | Present; highly variable concentration | Removed to undetectable levels |
| Cardiovascular Risk | Moderate to High, especially with high intake | Very Low |
| Effect on Blood Pressure | Can significantly raise blood pressure | No significant effect on blood pressure |
| Potassium Levels | Can cause hypokalemia (low potassium) | Does not affect potassium levels |
| Risk of Edema | Can cause fluid retention and swelling | No risk of fluid retention |
| Best For | Occasional indulgence in small amounts | Therapeutic use (e.g., stomach ulcers, GERD) and daily consumption |
Conclusion
While a delicious treat for many, determining precisely how much licorice is safe to eat daily is complicated by varying glycyrrhizin levels across products. For most healthy adults, sticking to the WHO guideline of under 100 mg of glycyrrhizin per day is a safe approach. However, for vulnerable populations such as those over 40 or with pre-existing heart or kidney conditions, avoidance is often the safest strategy. Always check product labels for glycyrrhizin content and, when in doubt, consult a healthcare provider, especially if you take other medications. For those seeking health benefits without the cardiovascular risks, deglycyrrhizinated licorice (DGL) is a much safer alternative. For more information on licorice root and its effects, see this authoritative resource: Licorice Root: Usefulness and Safety.
