The most studied attribute of cinnamon is its anti-diabetic property. In animal models of type II diabetes administration of cinnamon extract was found to reduce blood glucose levels in a dose-dependent manner. Further, it also corrected dyslipidemia, increasing HDL cholesterol with a simultaneous reduction in triglyceride, LDL cholesterol and total cholesterol levels. In high fructose-fed rats, cinnamon extract administration prevented the development of insulin resistance, possibly via enhanced insulin signaling. One study attributed the anti-diabetic activity of cinnamon to water-soluble, polyphenol oligomers of catechins and/or epicatechins. In a study of 49 herb, spice and plant extracts to evaluate possible effects on insulin function, cinnamon was found to be the most active. In another study, cinnamon extract was found to potentiate insulin activity, as measured by glucose oxidation in the rat epididymal fat cell assay. Cinnamon regulated insulin signaling by modulating insulin receptor kinase, and affected protein phosphorylation-dephosphorylation reactions in intact adipocytes. By the same mechanism, cinnamon was also found to have antiproliferative activity and alter cell cycle distribution pattern in tumor cell lines.
In a clinical study conducted in Pakistan, involving 60 type II diabetic patients, powdered cinnamon at doses of 1, 3 or 6 g/day for 40 days, was found to decrease mean fasting blood glucose levels by 18-20%, triglycerides by 23-30%, LDL-cholesterol by 7-27%, and total cholesterol by 12-26%. Changes in HDL-cholesterol were moderate and insignificant. The results indicate that dietary cinnamon may reduce risk factors associated with diabetes and cardiovascular diseases.
