What is Ceylon Cinnamon?
Most of us are familiar with the slightly sweet, warm, woody flavor of cinnamon—a spice derived from the inner bark of trees from the Cinnamomum genus.
However, not all cinnamon is created equal!
In fact, what we call “cinnamon” can actually refer to one of two very different spices: cassia cinnamon, harvested from Cinnamomum cassia trees, and Ceylon cinnamon, harvested from Cinnamomum verum trees.
Nearly all the cinnamon we encounter in grocery stores and food products is the cassia variety, because it is significantly cheaper than Ceylon cinnamon. However, despite its relative rarity, Ceylon is considered to be “true” cinnamon, and offers some special benefits compared to cassia—making it well worth the effort to find.
So, what makes Ceylon cinnamon so unique?
Ceylon cinnamon has a distinctive flavor profile compared to cassia cinnamon, due to having a lower content of cinnamaldehyde—an essential oil that imparts a very strong, spicy taste and aroma.
Nearly all the oil in cassia cinnamon is cinnamaldehyde (95%), versus only about 50 – 60% of the oil content of Ceylon cinnamon. Ceylon also contains other essential oils like eugenol, which adds sweet clove-like undertones. As a result, cassia cinnamon has a somewhat harsh and spicy flavor, while Ceylon cinnamon has a more delicate, mild, and complex flavor. Many chefs regard Ceylon cinnamon as superior for cooking a variety of dishes and desserts.
Ceylon has an elegant appearance, with a light, delicate color and thin, fragile bark that’s easily rolled into quills. The classic “cinnamon sticks” we see in stores are the thicker, darker cassia bark.
One of the biggest advantages of Ceylon cinnamon involves coumarin, a compound that naturally occurs in cinnamon trees. At high enough doses, coumarin is toxic to the liver, causing damage and injury to liver cells.
Cassia cinnamon has among the highest levels of coumarin out of any food. Analyses of commercially available cinnamon products show cassia cinnamon contains about 7 - 18 mg of coumarin per teaspoon, but can also vary enormously from sample to sample—in some cases, ranging from undetectable to 26 mg per teaspoon. 
Meanwhile, Ceylon cinnamon reliably contains only trace amounts of coumarin, often below detectable limits.
Health organizations generally set the tolerable daily intake (TDI) for coumarin at 0.1 mg per kg of body weight—approximately 6.8 mg for a 150-pound adult. However, these recommendations are based solely on animal toxicology studies; human research shows that certain people are particularly sensitive to the effects of coumarin, sometimes experiencing toxicity at intakes normally deemed safe. In fact, coumarin metabolism can vary 17-fold among different people, likely due to genetic differences in liver enzyme activity.  As a result, intakes that are safe for one person could potentially be harmful for another.
Given the generally high coumarin content of cassia cinnamon and wide variation in individual tolerance, it’s possible to consume harmful levels of coumarin from this type of cinnamon. In fact, surveys show that people can easily reach the safety cutoff for daily coumarin exposure around the winter holidays, when cinnamon-rich desserts and beverages are particularly abundant.
Given these risks, Ceylon cinnamon is a far safer choice for liver health!
All forms of cinnamon have demonstrated impressive health benefits. However, only Ceylon cinnamon delivers these benefits while being fully safe for the liver. And while most of the research on cinnamon has focused on the cassia variety (or looked at “cinnamon” as an undifferentiated group), studies examining Ceylon cinnamon specifically have found the following:
Better blood sugar control. A variety of animal, in vitro, and human studies suggest Ceylon cinnamon has a positive effect on blood sugar control. More specifically, this spice helps reduce the absorption of glucose after meals, increases glucose uptake by cells (in turn helping clear sugar from the bloodstream), stimulates glucose metabolism, and increases insulin sensitivity. 
Improved cardiovascular risk factors. Ceylon cinnamon has been shown to improve a number of risk factors for cardiovascular disease—including reducing LDL cholesterol, increasing HDL (“good”) cholesterol, lowering blood pressure, and protecting against oxidative stress and lipid peroxidation.
Antimicrobial activity. Ceylon cinnamon has antimicrobial activity against a number of human pathogens, including Salmonella, E. coli., methicillin resistant Staphylococcus aureus (MRSA), Candida fungus, Clostridium difficile, multiple Listeria species, and H. pylori (a pathogen responsible for stomach ulcers).   This gives Ceylon cinnamon the potential to help protect against infection from a variety of sources.
Neurological benefits. Although more research is needed in humans, preliminary evidence suggests that Ceylon cinnamon could have protective effects for neurological health. One experiment showed that Ceylon cinnamon extract inhibited filament formation and tau aggregation, two hallmarks of Alzheimer’s disease. A rodent study likewise found that Ceylon cinnamon extract reduced symptoms of depression, due to increasing certain proteins and gene expression in the prefrontal cortex of the animals’ brains.
Anti-inflammatory and antioxidant effects. Ceylon cinnamon, as well as its individual constituents, demonstrate powerful anti-inflammatory and antioxidant effects. Ceylon cinnamon tea, extracts, oils, and powder have all been shown to help scavenge free radicals and decrease the formation of harmful oxidation products. 
In a nutshell
While the more common cassia cinnamon is generally fine in small doses, it’s not without risks. Ceylon cinnamon, on the other hand, is a true luxury spice with a flavor profile and health benefits to match.
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