Read the prequel to this post here!
As discussed in a previous blog post, there is research to support the use of cinnamon in type two diabetes and polycystic ovarian syndrome.(1) But, in terms of practical inclusion of this dietary prescription, it’s very important to note that not all “cinnamons” are considered equal. The first principle of Naturopathic Medicine is do no harm. We want to reap the benefits of this dietary supplement, but not at the expense of another organ, especially one as critical as the liver!
Cinnamomum…and True cinnamon.
The genus Cinnamomum (where “True cinnamon comes from) comprises about 300 species, of which 4 are used for “cinnamon”.(2)
“True cinnamon” is known as Ceylon cinnamon, and it includes Cinnamomum verum or Cinnamomum zyelanicum (same plant).(3,4) However, the majority of cinnamon products in North America are of the less expensive cassia variety.(4) Not to be mistaken for the Cassia genus, the cassia cinnamons are considered to include the following species: Cinnamomum cassia, Cinnamomum aromaticum, Cinnamomum loureiroi, and Cinnamomum burmanni.(4) The cassia species, likely due to its widespread availability within North America, is also the variety most often studied in the research.
Coumarins
The issue with cassia cinnamon has to do with its coumarin content. Coumarins are a class of naturally occurring plant compound, and most of the compounds are not harmful to humans in the amounts present in edible plants.(4) However, coumarin as an additive has been banned from food in the United States due to its potential adverse effects; as, coumarins have strong anticoagulant, carcinogenic and hepato-toxic properties. (2,4) Susceptible individuals seem to be at a greater risk for coumarin-induced liver damage; in U.S. and Irish clinical trials, some of the participants receiving coumarin, even at lower doses, developed signs of drug-induced hepatotoxicity (liver toxicity). (4)
Cassia cinnamon and coumarin.
Studies done in Germany, prior to 2008, found that cinnamon-flavoured products and capsules containing cassia cinnamon, instead of “true” cinnamon, exceeded the allowable coumarin limits set by the Council of the European Communities in 1988. (4) They even found that, children who consumed cinnamon-flavoured food and people taking cinnamon capsules could exceed the tolerable daily intake, as set by the European Food Safety Authority. (4) An Italian study stated that 70% of cinnamon-flavoured foods analyzed exceeded the coumarin limit set by the Council of the European Communities. (4)
The study entitled, Cassia Cinnamon as a Source of Coumarin in Cinnamon-Flavored Food and Food Supplements in the United States, tested various Cinnamomum species’ coumarin content. From their investigation, they found that coumarin was detected in all locally bought cinnamon, cinnamon food supplements, and cinnamon-flavoured foods.(4) And, of the species tested, C. verum bark (Ceylon cinnamon) contained only traces of coumarin, whereas barks from cassia species contained substantial amounts of coumarin, especially C. burmannii, and C. loureiroi.(4) Also, to note, according to a 2013 study, the less expensive C. burmannii has replaced the more expensive true cinnamon in Europe, the US, and Canada, with C. burmannii making up more than 90% of the “cinnamon” imported into the U.S. in recent years.(4)
The Condensed Chart.
But you say, that most of the research to support cinnamon and blood sugar regulation was done with Cassia cinnamon….yes, my young Jedi, you are correct!
Read about what the research specifically has to say about Ceylon cinnamon in my blog post here.
References
1. https://www.ncbi.nlm.nih.gov/pubmed/29250843
2. http://onlinelibrary.wiley.com/doi/10.1111/j.1464-5491.2012.03718.x/epdf
3. https://www.nhpassist.com/herbals/cinnamon
4. https://www.cinnamonvogue.com/DOWNLOADS/Cinnamon_and_coumarin.pdf