While the Khan study looked promising, supplementary studies have failed to consistently show beneficial effects. Vanschoonbeek gave 1.5g of cinnamon or placebo to postmenopausal women over 6 weeks. There was no effect reported on blood sugar or blood lipid levels. Baker’s 2008 meta-analysis identified 5 trials including the Khan and Vanschoonbeek studies and concluded the following:
Normally, blood glucose levels are tightly controlled by insulin, a hormone produced by the pancreas. Insulin lowers the blood glucose level. When the blood glucose elevates (for example, after eating food), insulin is released from the pancreas. This release of insulin promotes the uptake of glucose into body cells. In patients with diabetes, the absence of insufficient production of or lack of response to insulin causes hyperglycemia. Diabetes is a chronic medical condition, meaning that although it can be controlled, it lasts a lifetime.