By Stabilicinn
Short answer: Coumarin is a naturally occurring plant compound with a sweet, hay-like smell. It is a blood thinner and a potential liver toxin under long-term use in high concentration. Cassia cinnamon, the common supermarket kind, can contain high levels of it. Ceylon (“true”) cinnamon contains negligible amounts. If cinnamon is part of your daily routine, the type matters.
What coumarin is
Coumarin occurs naturally in a number of plants, including tonka beans, sweet clover, woodruff and Cassia cinnamon. It gives freshly cut hay part of its scent. It has been used in perfumes and was once used as a food flavoring. Its use as a direct food additive is restricted in the United States and in Europe.
Why food safety authorities pay attention to it
Studies in animals, along with case reports in a small number of sensitive people, led European food safety authorities to set a tolerable daily intake (TDI) for coumarin: an amount considered safe to consume every day over a lifetime. The European Food Safety Authority (EFSA) confirmed this TDI at 0.1 mg of coumarin per kilogram of body weight per day. For a 70 kg (154 lb) adult, that is about 7 mg a day.
Because Cassia cinnamon can contain high levels of coumarin, regulators have pointed out that people who eat a lot of Cassia every day, or children who regularly eat cinnamon-heavy foods, could exceed that TDI. One Norwegian risk assessment, for example, found that children who regularly ate oatmeal porridge with cinnamon could exceed the TDI several times over. See the research library.
Cassia vs. Ceylon: the coumarin gap
Laboratory testing of commercial cinnamon samples has repeatedly found that Cassia contains far more coumarin than Ceylon cinnamon, which contains only trace amounts. Germany’s Federal Institute for Risk Assessment (BfR) reports that Cassia contains about 3,000 mg of coumarin per kilogram on average, and up to about 10,000 mg/kg, while Ceylon cinnamon contains low levels. At 3,000 mg/kg, a single teaspoon of ground Cassia (roughly 2.5 g) holds about 7.5 mg of coumarin, more than the daily TDI for a 70 kg adult. Coumarin levels in Cassia also vary widely from sample to sample, and even within a single tree, so it’s hard to know how much a given jar contains.
What it means for everyday use
- Occasional use: a sprinkle of Cassia on toast or in baking is perfectly safe for most people.
- Daily use: if you consume cinnamon every day, in food or as a supplement, choosing Ceylon cinnamon keeps coumarin intake negligible.
- Read labels: “cinnamon” without a species or origin is almost always Cassia. How to tell the difference.
Stabilicinn is made only from certified Ceylon cinnamon, which is one reason Dr. Jayasena chose it as the basis for a daily product.
As with any supplement, talk with your doctor before starting, particularly if you take any medication.
Sources: EFSA Journal 6(10):793 (2008); BfR, FAQ on coumarin in cinnamon and other foods; Fotland et al., Food and Chemical Toxicology (2012); Wang et al., J. Agric. Food Chem. (2013); Woehrlin et al., J. Agric. Food Chem. (2010).
Related: Glossary: coumarin · Research library: Ceylon vs. Cassia and coumarin safety