Cinnamon—it’s not just for perking up the flavor of pies and applesauce anymore. A teaspoonful of the spice can have medicinal properties, at least for most people with diabetes, several trials have indicated. However, the latest study identifies one population that cinnamon doesn’t seem to benefit: individuals suffering from what was once referred to as juvenile diabetes.
“Ours is just one study,” cautions team leader Kevin M. Curtis of Dartmouth-Hitchcock Medical Center in Lebanon, N.H. It was also a small study. Just 57 teens completed the 3-month trial. However, Curtis notes emphatically, “we saw no benefit” in blood sugar control. If anything, he says, there were hints that people who were not getting the cinnamon might have fared better than those who did.
Insulin is a powerful hormone that the body needs to get energy—in the form of blood sugar, or glucose—into cells. Earlier studies tested cinnamon’s potential to stabilize blood sugar in people with type 2 diabetes, the form of the disease in which the body makes ample insulin but cells don’t respond adequately. Called insulin resistance, this condition typically occurs in people who are overweight and older than 40. However, with a rise in juvenile obesity in recent decades, a childhood epidemic of this type of diabetes is now under way.
Type 1 diabetes is a radically different disease. An autoimmune condition, it develops when the body mistakes insulin-secreting, or beta, cells for invaders and inappropriately attacks them. When enough beta cells die, the body can no longer make enough insulin to keep blood sugar in check. Its victims must regularly inject themselves with the hormone to survive.
The new 90-day study recruited adolescents 13 to 19 years old with type 1 disease and asked them to take a daily capsule that might contain cinnamon. Randomly assigned, half the volunteers got 1 gram of cinnamon a day, and the others instead received lactose, a complex sugar found in milk. All capsules looked the same and came packaged in identical pill bottles. During the trial, neither the teens nor the physicians administering the capsules learned who was consuming cinnamon.
Curtis’ team selected adolescents for the study because their growth spurts and other body changes associated with puberty make tight control of blood sugar especially difficult. A lack of blood sugar control can result in serious complications, from heart disease to kidney failure, blindness, and even limb amputations.
The Dartmouth team looked primarily for changes in measures of hemoglobin A1C among the teens. A person’s A1C reading indicates the proportion of red blood cells that have glucose stuck onto them. A high A1C reading indicates that the person’s blood sugar has been too high for months. The researchers focused on this measurement, rather than periodic tests of blood sugar itself, because hemoglobin A1C “has clearly been the best predictor of complications in both type 1 and type 2 diabetics,” Curtis told Science News Online.
At the end of the new study, teens taking both cinnamon and lactose had A1C values averaging roughly 8.75, according to a report in the April Diabetes Care.
By chance, the group assigned to receive lactose capsules for 3 months started the study with an average A1C value of 8.75. The teens getting the cinnamon capsules started the study with an average 8.4 A1C reading. Clearly, there was no advantage to getting the cinnamon treatment, Curtis says.
It’s possible that the daily gram of cinnamon administered to the teens was too small to have a measurable effect in people with type 1 diabetes, the researchers say. On the other hand, the scientists note that this quantity was sufficient to improve glucose control in a 2003 study of people with type 2 disease (SN: 5/1/04, p. 282). More likely, Curtis’ group concludes, is that “whatever effect cinnamon has on glucose uptake in type 2 diabetic subjects is not present in those with type 1 diabetes.”
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