A pilot study (Phase I - first study on a small number of patients to basically prove a theory and use as a basis of a larger study - Phase II)

Wang JG, Anderson RA, Graham GM 3rd, Chu MC, Sauer MV, Guarnaccia MM, Lobo RA.
Department of Obstetrics & Gynecology, Division of Reproductive Endocrinology, College of Physicians & Surgeons, Columbia University, New York, New York.
Cinnamon extract has been shown to reduce insulin resistance in in vitro and in vivo studies by increasing phosphatidylinositol 3-kinase activity in the insulin signaling pathway and thus potentiating insulin action.

Fifteen women with polycystic ovary syndrome (PCOS) were randomized to daily oral cinnamon and placebo for 8 weeks. Comparisons of post-treatment to baseline insulin sensitivity indices using fasting and 2-hour oral glucose tolerance tests showed significant reductions in insulin resistance in the cinnamon group but not in the placebo group.

A larger trial is needed to confirm the findings of this pilot study and to evaluate the effect of cinnamon extract on menstrual cyclicity.

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.

NOT SO HOT. Many teens with type 1 diabetes need help maintaining tight control of their blood sugar. Cinnamon isn’t the answer, a new study finds, even though the spice appears to help moderate blood sugar in persons with type 2 diabetes.
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.”

Previous research has shown that cinnamon appears to help fat cells recognize and respond to insulin. In test tube experiments and in animal studies, the spice led to a noteworthy increase in the processing of glucose.

Moreover, in a previous study of people with type 2, or non-insulin dependent, diabetes, those who incorporated a small amount of cinnamon each day for 40 days into their normal diets experienced a healthy drop in blood sugar levels.

Against this backdrop, Dr. Kevin M. Curtis from Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire and colleagues had 72 adolescents with type 1 diabetes take 1 gram of cinnamon per day or a matching placebo while they continued with their existing medication, diet and exercise routines.

They chose adolescents for the study, the investigators explain in the journal Diabetes Care, because this age-group is particularly at risk for uncontrolled blood sugar and had the most to gain from the intervention.

However, after 90 days, Curtis and colleagues failed to see any marked differences in blood sugar control, changes in blood sugar levels, total daily insulin requirement, or number of low blood-sugar episodes between cinnamon takers and placebo takers.

In fact, “In essentially all outcomes…the trend favored the placebo group, although did not achieve statistical significance,” the researchers report.

The current study “introduces significant doubt regarding the efficacy of cinnamon in diabetic subjects,” Curtis and colleagues conclude.

SOURCE: Diabetes Care, April 2007.

The trial is designed to run from March 2007 to August 2007 for 140 patients with type 2 diabetes between 18 - 90 years of age.

From the official study:

As the worldwide incidence of diabetes increases, the search for dietary adjuncts to treat this life-altering disease becomes far ranging. Cinnamon is purported to be a natural insulin sensitizer without any known adverse effects. Both in vitro and in vivo animal studies have shown that cinnamon is an insulin sensitizer1. Several compounds within cinnamon have been identified as possible sources of this sensitization process.

To-date, three small randomized trials studying cinnamon in human diabetics have been published. Khan et al. reported that fasting serum glucose could be reduced by 18-29% after 40 days of supplementation with 1, 3, or 6 g of cinnamon (Cinnamomum cassia) in type 2 diabetics. 2 This study had several limitations that included failure to measure hemoglobin A1C, all patients were Pakistani, and no power analysis was documented. Vanschoonbeek, et al.3 report a small RCT of postmenopausal women with well-controlled type 2 diabetes which showed no change in HbA1C or fasting glucose. Once again no power analysis is reported. Mang et al. 4 conducted a RCT of type 2 diabetics treated with aqueous extract of cinnamon for 4 months. They report a 15% decrease in fasting glucose and no change in HbA1C over the duration of this trial. Subjects had HbA1C less than 7% and again no power analysis was included in this study.

This study will address whether cinnamon at the dose of 1g daily in addition to usual care lowers hemoglobin A1c compared to usual care. Power analysis indicates that 63 per group are needed and we will recruit 70 patients.