The Science Behind Licorice Limits: Glycyrrhizin
The primary active compound in licorice root (Glycyrrhiza glabra) is glycyrrhizin, which is responsible for the distinct sweet flavor but also carries potential health risks when consumed in excess. Glycyrrhizin has mineralocorticoid-like effects, meaning it can cause the body to retain sodium and water while simultaneously losing potassium. This effect can significantly raise blood pressure and disrupt the body's electrolyte balance.
The Glycyrrhizin-Aldosterone Connection
The mechanism for this is the inhibition of the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2) by glycyrrhizic acid. This enzyme typically deactivates cortisol, preventing it from binding to mineralocorticoid receptors in the kidneys. When glycyrrhizin inhibits this enzyme, active cortisol levels increase, mimicking the effect of excessive aldosterone. This can lead to a condition known as pseudohyperaldosteronism, characterized by high blood pressure and low potassium levels. For individuals with pre-existing conditions like hypertension, this effect can be particularly dangerous, and cases of cardiac arrest have been linked to excessive licorice consumption.
Recommended Daily Intake and Variations
Determining a precise "safe" daily limit for licorice is challenging because the glycyrrhizin content can differ dramatically between products. Factors such as the species of licorice, growing conditions, and processing techniques all influence the concentration of the active compound.
Nonetheless, international health authorities have provided some guidance:
- World Health Organization (WHO): Recommends an upper limit of 100 mg of glycyrrhizic acid per day for most healthy adults.
- U.S. Food and Drug Administration (FDA): Warns that for people age 40 and older, consuming 2 ounces (57 grams) or more of black licorice daily for at least two weeks could lead to heart rhythm issues and potential hospitalization.
Comparing Licorice and Licorice-Flavored Products
To help navigate the risks, it is crucial to understand the different types of products on the market.
| Feature | Black Licorice (Real) | Red Licorice (Fake) | Deglycyrrhizinated Licorice (DGL) |
|---|---|---|---|
| Contains Glycyrrhizin? | Yes, derived from the licorice root. | No, typically flavored with anise oil or other artificial flavors. | No, glycyrrhizin has been removed. |
| Effect on Blood Pressure | Can significantly raise blood pressure with excessive intake. | No effect on blood pressure from the flavoring. | No effect on blood pressure. |
| Potential Risks | High blood pressure, hypokalemia, cardiac issues, edema. | Very low risk, apart from high sugar content. | Considered much safer; side effects are rare. |
| Intended Use | Confectionery, herbal preparations, flavoring. | Confectionery (candy) only. | Sometimes used for digestive issues like ulcers, without the glycyrrhizin risks. |
Who Should Be Cautious or Avoid Licorice?
Certain individuals are more sensitive to the effects of glycyrrhizin and should either avoid licorice products entirely or exercise extreme caution. These groups include:
- Pregnant and breastfeeding women: Licorice consumption during pregnancy has been linked to increased risk of early delivery and potential health problems for the child.
- Individuals with pre-existing heart conditions: Licorice can worsen heart failure and increase the risk of irregular heartbeats.
- People with high blood pressure: Because licorice raises blood pressure, it can counteract the effects of antihypertensive medications and worsen the condition.
- Those with kidney or liver disease: Large amounts of licorice can exacerbate these conditions.
- People with low potassium levels (hypokalemia): Licorice can further deplete potassium, making this condition dangerous.
- Individuals on certain medications: Licorice can interact with diuretics, blood thinners (like warfarin), corticosteroids, and digoxin, potentially causing dangerous side effects.
Understanding Different Licorice Products
Licorice comes in many forms, and not all are created equal in terms of health risks. Real licorice root can be found in herbal teas, dietary supplements, and certain candies, often labeled as containing "licorice extract" or "glycyrrhizic acid". Herbal supplements can contain significantly higher concentrations of glycyrrhizin than confectionery and should be used with extra caution. In contrast, many candies labeled as "licorice" in the United States, especially the red varieties, are flavored with anise oil and contain no real licorice. Deglycyrrhizinated licorice (DGL) products are specifically processed to remove the risky compound and are often marketed for digestive health benefits. Always check the ingredients list to know what you are consuming.
Monitoring for Side Effects
Even if you are not in a high-risk group, it is wise to be aware of the signs of licorice overconsumption. Symptoms can include headaches, swelling (edema), muscle weakness, lethargy, or an irregular heartbeat. If you experience these symptoms, especially after a period of consistent licorice intake, stop consuming it immediately and consult a healthcare provider. The effects are typically reversible upon cessation of consumption, but severe cases may require medical intervention.
Conclusion: Enjoying Licorice Responsibly
While licorice can be a safe and enjoyable treat for many in moderation, its active compound, glycyrrhizin, can have serious consequences when consumed in excess. A general rule of thumb is to stay well within the 100 mg daily glycyrrhizic acid limit recommended by the WHO, which is the equivalent of 60–70 grams of candy, but to be even more cautious due to varying product concentrations. Individuals over 40 and those with existing health conditions, particularly hypertension or heart issues, should be especially vigilant or avoid it altogether. The key to safe enjoyment is awareness of both the product's ingredients and your own health status. When in doubt, opt for products without real licorice or consult a healthcare professional for personalized guidance.
: https://www.medsafe.govt.nz/profs/PUArticles/December2019/Liquorice-side-effects-interactions.htm "Liquorice – All sorts of side effects and interactions - Medsafe"
