Cinnamon is a strong stimulator of insulin activity therefore it is potentially helpful for those with adult-onset diabetes. When seasoned with cinnamon, a high-carb food will have less of an impact on blood sugar levels.
In addition, it has been shown to help prevent blood clots. A substance found in cinnamon, called cinnaldehyde, inhibits the release of an inflammatory substance which prevents clumping of blood platelets.
The oil of cinnamon also stops the growth of problematic bacteria, fungi and yeast (candida). In fact, some studies are showing it to be an effective food preservative.
But here's a tidbit many people don't know. This only applies to real cinnamon. But most spices sold as cinnamon are actually a cousin of it called "cassia." To find the real cinnamon, look for Ceylon Cinnamon. It's light brown, the "sticks" are thin, soft, sweet, and filled (like a cigar).
I have found it online at www.ceylon-cinnamon.com and www.penzeys.com