http://holfordwatch.wordpress.com/h...scientific-support-for-chromium-and-cinnamon/
There are more recent studies that Holford does not cite. These studies report that cinnamon does not have a beneficial effect on the blood glucose or cholesterol levels of people with Diabetes Type I or II; this result holds true even for sub-groups.
You will always find studies for and against in pretty much anything ..... especially anything to do with diet. A drug company can do 10 studies/trials on something, and if only 2 give positive results, they are allowed to market the drug as being proven to do whatever it's supposed to do. Rather like the great cholesterol myth .. Ancel Keys skewed the results of studies done in many countries on cholesterol levels and diet ... he conveniently did not include all the countries so that his theory could be proven. If he had included all the countries studied he wouldn't have had a leg to stand on.
I think the answer to this and many other diet related questions is, whatever works for you. Why don't you try the cinnamon and see what happens? Nothing ventured gained
Tried cinnamon, note there are two main types of cassis and Ceylon, both had no effect on me . I had better results just by eating a plant based diet mainly with no processed foods and a simple multivitamin as an insurance policy.