Cinnamon adds zest to more than just food. The spice contains substances that, in test tube studies, wake up body cells to the hormone insulin. Because insulin regulates glucose metabolism and thus controls the level of glucose in the blood, the substances may have the potential to delay or prevent adult-onset, or type 2, diabetes. Only time and more research will tell. But the Agricultural research service has filed a patent application on the active substances. The most active--methylhydroxy chalcone polymer (MHCP)---increased glucose metabolism roughly 20-fold in the test tube assay of fat cells.