The Critical Distinction: Cassia vs. Ceylon
Not all cinnamon is created equal. The risks associated with consuming cinnamon are highly dependent on the type you are taking. The two main varieties are Cassia cinnamon and Ceylon cinnamon.
- Cassia Cinnamon: Also known as Chinese, Indonesian, or Saigon cinnamon, this is the most common and cheapest variety found in grocery stores. It contains high levels of a natural compound called coumarin, which can be toxic to the liver in large doses.
- Ceylon Cinnamon: Often called "true" cinnamon, this type is pricier and comes from Sri Lanka. It contains only trace amounts of coumarin, making it a much safer option for frequent consumption or in larger quantities.
The Risk of Coumarin-Induced Liver Damage
The primary concern with cinnamon consumption, particularly Cassia, is the potential for liver damage from coumarin. The German Federal Institute for Risk Assessment (BfR) and the European Food Safety Authority (EFSA) have established a tolerable daily intake (TDI) of 0.1 mg of coumarin per kilogram of body weight. For a 132-pound (60 kg) adult, this is about 6 mg of coumarin per day. Many Cassia cinnamon powders contain enough coumarin that exceeding this limit is easy, especially for people using supplements or consuming large amounts regularly.
Symptoms of liver injury (hepatotoxicity) can include:
- Jaundice (yellowing of the skin)
- Nausea
- Abdominal pain
- Dark urine
- Itching
While this damage is often reversible upon cessation, individuals with pre-existing liver disease are more vulnerable and should exercise extreme caution with Cassia cinnamon.
Medication Interactions
Cinnamon can interfere with certain medications, either by altering their metabolism or enhancing their effects.
- Diabetes medications: Cinnamon has a mild blood sugar-lowering effect. When combined with prescription diabetes medications like insulin or metformin, it could cause blood sugar levels to drop too low, a condition called hypoglycemia.
- Blood thinners: The coumarin in cinnamon possesses anticoagulant properties and can interfere with blood-thinning medications such as warfarin. This can increase the risk of severe bleeding.
- Hepatotoxic drugs: For individuals taking medications metabolized by the liver, like acetaminophen or statins, high doses of Cassia cinnamon can increase the risk of liver damage due to the additive stress on the liver.
- Other medications: A 2025 study suggested that the compound cinnamaldehyde, which gives cinnamon its flavor, could speed up the metabolism of some drugs, potentially reducing their effectiveness. This can include certain antidepressants and anti-cancer drugs.
Other Adverse Effects
Beyond coumarin and drug interactions, other side effects can occur:
- Allergic Reactions: Some individuals can have allergic reactions to cinnamon, triggered by eating, touching, or inhaling it. Symptoms range from mild skin rashes (contact dermatitis) and mouth irritation (stomatitis) to more severe reactions like hives, swelling, and difficulty breathing.
- Digestive Issues: Excessive consumption of cinnamon can irritate the digestive tract, leading to symptoms like stomach cramps, nausea, heartburn, bloating, and diarrhea.
- Breathing Problems: The "cinnamon challenge," a dangerous stunt involving inhaling dry cinnamon powder, can be life-threatening. The fine powder can irritate the lungs, cause coughing, and lead to aspiration pneumonia, a serious condition where undigested fibers accumulate in the lungs.
- Lead Contamination: An alarming finding from 2024 indicates that some cinnamon products sold in the U.S. may contain dangerously high levels of lead. Chronic exposure to lead can cause kidney and brain damage and is particularly harmful to children and pregnant women. Consumers should check FDA alerts for recalled brands.
Comparison Table: Cassia vs. Ceylon Cinnamon
| Feature | Cassia Cinnamon (Most Common) | Ceylon Cinnamon (True Cinnamon) |
|---|---|---|
| Coumarin Content | High | Trace Amounts |
| Liver Risk | Moderate to High, especially with high intake | Very Low |
| Cost | Inexpensive | More Expensive |
| Flavor Profile | Stronger, more pungent | Milder, sweeter, more delicate |
| Availability | Widely available in supermarkets | Often requires specialty stores or online purchase |
How to Consume Cinnamon Safely
For most people who enjoy cinnamon in moderation, the risks are minimal. The amount used in cooking or sprinkled on oatmeal is typically small enough to be harmless. The dangers arise from excessive intake, prolonged use, and specifically, the high coumarin content of Cassia cinnamon. To mitigate risks:
- Know your cinnamon: When using cinnamon frequently, particularly for health benefits, opt for Ceylon cinnamon to avoid high coumarin levels.
- Use in moderation: A safe guideline is to keep Cassia cinnamon intake to about half a teaspoon or less daily for healthy adults.
- Avoid supplements: Cinnamon supplements contain concentrated amounts and should only be taken under a doctor's supervision, especially for people with liver conditions or those on medication.
- Check for recalls: Stay informed about FDA alerts regarding heavy metal contamination in spices to ensure your products are safe.
Conclusion
Cinnamon is a popular spice with potential health benefits, but it is not without risks, especially when taken in high doses or supplement form. The critical factor is understanding the difference between high-coumarin Cassia and low-coumarin Ceylon cinnamon. Risks like liver damage, hypoglycemia, drug interactions, and allergic reactions become a concern with regular, excessive consumption of the Cassia variety. By choosing Ceylon cinnamon and consuming all types in moderation, most people can enjoy the spice safely while minimizing potential side effects. Always consult a healthcare provider before using cinnamon supplements, especially if you have underlying health conditions or take other medications.
More Information
For further details on cinnamon safety, you can consult resources like the National Center for Complementary and Integrative Health.
Authoritative Reference
National Center for Complementary and Integrative Health (NCCIH). "Cinnamon."
