Cinnamon

Cinnamon comes in four main varities; most common: Ceylon “true” cinnamon and Cassia cinnamon. Ceylon is more expensive, lower coumarin levels, usually sold only in specialty stores. Cassia is cheaper, higher coumarin levels, sold in supermarkets in North America. Coumarin can cause damage to liver; tolerable daily intake (TDI) is 0.1 mg coumarin per kg body weight. (BfR) (About)

Research indicates safety up to 1g of Cassia cinnamon per day (instructables). Fortunately, as little as just 1/2 teaspoon of Cinnamon per day can lower LDL cholesterol. (cinnamon-extract)

My advice: Add 1 teaspoon of Ceylon “true” cinnamon to your morning shake. Note: pregnant women should avoid excessive amounts of cinnamon and shouldn’t take it as a supplement primarily due to effects of coumarin and cinnamaldehyde levels in cinnamon powder capsules.