Experts Warn Excessive Cinnamon Consumption May Harm Liver

While cinnamon is a popular spice, particularly during the fall season, consuming too much of certain varieties may pose a risk to liver health, according to nutrition experts. The concern centers on coumarin, a natural plant compound found in significant concentrations in Cassia cinnamon, the most common type found in supermarkets. While small amounts of coumarin are generally harmless for most people, regular exposure to higher doses can negatively impact liver function in susceptible individuals.

Cassia cinnamon, predominantly grown in Indonesia, China, and Vietnam, has a strong flavor and a dark reddish-brown color. Dr. Heewon Gray, an associate professor at the University of South Florida's College of Public Health, explained that Cassia cinnamon's high coumarin content can cause liver damage with excessive or prolonged use.

In contrast, Ceylon cinnamon, often referred to as 'true cinnamon,' originates mainly from Sri Lanka. It is lighter, milder, and sweeter, with virtually no coumarin. Gray noted that Ceylon cinnamon contains only trace amounts of coumarin, making it a safer option for daily consumption or larger quantities.

Visually, Ceylon cinnamon sticks have thin, papery layers rolled like a cigar, while Cassia sticks are thick and tough. Ground cinnamon can look similar, so checking labels for the scientific name or country of origin is advised.

The exact amount of cinnamon considered dangerous varies, but a 2022 Food Safety risk assessment indicated that for a 132-pound adult, the daily coumarin limit is 6mg. Cassia cinnamon contains approximately 3mg of coumarin per gram, meaning just two grams (less than a teaspoon) could reach this limit. A study in the Clinical Nutrition Review also highlighted that higher doses or long-term use increase the risk.

When the liver consumes too much coumarin, it can struggle to break it down, potentially leading to the buildup of harmful byproducts. While coumarin-induced liver damage is rare, particularly from typical food consumption, symptoms can be subtle. These may include persistent nausea, poor appetite, fatigue, or a dull ache in the upper right abdomen. More severe signs include yellowing of the skin or eyes, dark urine, pale stools, or persistent vomiting.

Individuals with pre-existing liver conditions, such as fatty liver disease, hepatitis, or cirrhosis, are at a higher risk and should exercise caution. The coumarin content is not only a concern in ground spices but also in cinnamon supplements, often marketed for blood sugar or weight management, which can contain much higher doses. It can also be found in protein bars, chai mixes, pastries, and cereals.

Experts suggest that occasional use of Cassia cinnamon is generally safe for healthy individuals. However, for those who consume cinnamon daily, switching to Ceylon cinnamon is recommended. Gray also stated that there is no need for a special 'detox' to eliminate coumarin, as the liver naturally metabolizes and eliminates substances.

The key takeaway is to be aware of the type of cinnamon consumed. While cinnamon can remain a flavorful part of one's diet, understanding the difference between Cassia and Ceylon varieties can help manage coumarin intake and protect liver health.