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Expect questions on use of cinnamon from your patients with diabetes
Challenge is to find reliable, clinically relevant studies to provide guidance about dietary supplements usefulness in diabetes management.
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Cinnamon is a spice that has been used in many cultures for centuries. It has traditional medicinal value in relieving stomach pain and gas. The bark of two cinnamon species, Cinnamomum zeylanicum and Cinnamomum cassia, is used to make the spice.
In vitro data have found various spices to be involved in insulin-potentiating activity. The active ingredients of cinnamon include polyphenolic polymers (hydroxychalcone). The active constituent may be related to procyanidine type-A polymers.
Researchers have proposed that cinnamon, including aqueous extracts, can increase cell and tissue glucose uptake and enhance glycogen synthesis based on results in both in vitro and in vivo studies and in animal studies.
How do these results in basic science research translate to results in clinical trials?
The results of recent trials are reviewed in this column.
Clinical trials of cinnamon
The first clinical study of cinnamon was conducted in 2003 with 60 Pakistani participants who had type 2 diabetes and received monotherapy with a sulfonyurea (glibenclamide). Baseline fasting blood glucose was between 140 mg/dL and 400 mg/dL (HbA1c was not measured). The researchers randomly assigned participants to 1 g, 3 g, or 6 g of powdered C. cassia daily or matching placebo as a capsule for 40 days. Patients in all of the cinnamon groups experienced a decrease in fasting plasma glucose levels of 18% to 29%, decreases in serum total glucose of 23% to 30%, decreases in total cholesterol of 13% to 26% and decreases in LDL of 24% in the 6 g cinnamon group.
 June Felice Johnson |
The first U.S. study of cinnamon in type 2 diabetes management was conducted with 57 patients who had a baseline HbA1c greater than 6% and were on a variety of oral diabetes medications. The researchers randomly assigned participants to 500 mg of C. cassia as a capsule or placebo twice daily for three months. They found no differences between treatment and placebo groups in fasting glucose, HbA1c, total cholesterol, triglycerides or insulin levels. The researchers pointed out that the difference in results between this study and the 2003 Pakistan study could be related to differences in diet, BMI, baseline glucose and medication regimens between the two countries.
The most recent study was a meta-analysis conducted at the University of Connecticut. The researchers included five prospective randomized controlled trials that included 282 participants in their analysis. The conclusion from this analysis was that cinnamon does not appear to improve glycemic parameters such as HbA1c or fasting blood glucose levels or lipid parameters in patients with either type 1 or type 2 diabetes.
Discussion
Based on the clinical information, cinnamon, as C. cassia, does not appear to be useful in improving either glycemic or lipid parameters in patients with diabetes.
Patients often ask their prescribers to determine whether or not a dietary supplement can assist in diabetes management. A recent analysis of 2,474 patients with diabetes revealed that 48% used some form of complementary and alternative medicine. The challenge for providers is to find reliable, clinically relevant studies that are powered with adequate sample size to provide guidance when advising patients. Unfortunately, it is common for claims to be made about these unregulated products with few adequate clinical trials to substantiate them. An excellent source of information for both the provider and the consumer can be found at the Natural Standard website.
June Felice Johnson, BS, PharmD, FASHP, CDM-Diabetes, is the Director of Faculty & Site Development and Associate Professor of Pharmacy Practice at Drake University College of Pharmacy & Health Sciences, Des Moines, Iowa.
For more information:
- For more information about integrative medicine, visit Natural Standard at www.naturalstandard.com.
- Baker WL, Gutierrez-Williams G, White CM, et al. Effect of cinnamon on glucose control and lipid parameters. Diabetes Care. 2008;31:41-43.
- Blevins SM, Leyva MJ, Brown J, et al. Effect of cinnamon on glucose and lipid levels in non-insulin-dependent type 2 diabetes. Diabetes Care. 2007;30:2236-2237.
- Garrow D, et al. Association between complementary and alternative medicine use, preventive care practices, and use of conventional medical services among adults with diabetes. Diabetes Care. 2006;29:15-19.
- Khan A, Safdar M, Ali Khan MM, et al. Cinnamon improves glucose and lipids of people with type 2 diabetes. Diabetes Care. 2003;26:3215-3218.