Cinnamon first came to my attention over a decade ago, when a randomized clinical trial was published suggesting that cinnamon improved blood sugars and cholesterol levels in people with type 2 diabetes.  Another randomized controlled trial confirmed the improvement in blood glucose as well.  However, the quantities used were quite large, up to 6 grams per day – imagine dumping that amount of powder on your cereal in the morning?!  Ick.

It turns out that taking in generous quantities of cinnamon may in fact be harmful – depending on what kind of cinnamon you consume.  The most common type of cinnamon sold is cassia cinnamon, which contains a natural but toxic component called coumarin, which has been associated with possible liver toxicity. This is contrasted with ceylon cinnamon, which is thought to contain little coumarin.

It actually doesn’t take that much cinnamon to exceed the daily tolerable intake of coumarin – as little as a teaspoon (which is just under 3 grams) of cassia cinnamon per day may be too much.

This has lead to an outrage and heartbreak in Denmark, where the cinnamon bun or kanelsnegle (a staple Danish bakery product) has come under attack following the EU’s recent moves to limit cinnamon consumption due to the risks noted above.

So, cinnamon is not a great treatment for patients with diabetes – cassia cinnamon must not be taken in the quantities needed to have an impact on blood sugars due to possible toxicity, and eating that amount of ceylon cinnamon every day just isn’t practical.

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