|Date: 07-29-2016||HC# 071621-549|
Anderson RA, Zhan Z, Luo R, et al. Cinnamon extract lowers glucose, insulin and cholesterol in people with elevated serum glucose. J Tradit Complement Med. 2015; [epub ahead of print]. doi: 10.1016/j.jtcme.2015.03.005.
Cinnamon (Cinnamomum spp., Lauraceae) is used in cooking, as a preservative, and in traditional medicine. A number of studies have shown that cinnamon supplementation may help reduce plasma glucose, triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and total cholesterol. In contrast, other studies showed cinnamon had no effect on these measures. Cinnamon contains high concentrations of procyanidin polyphenols, which are known to have antioxidant and anti-inflammatory properties. In vitro studies have found procyanidin polyphenols may also alter the regulation of glucose metabolism. In this double-blind, randomized, controlled study, the effect of cinnamon extract on fasting glucose, insulin resistance, blood lipids, and blood pressure was measured in patients with hyperglycemia.
The study was conducted at the General Hospital of the 2nd Artillery in Beijing, China; the Beijing Tang-An Clinic in Beijing, China; and the Dalian Dakang Clinic in Dalian, China. Patients with fasting plasma glucose (FPG) > 6.1 mmol/L or 2-hour plasma glucose > 7.8 mmol/L were invited to join the study. Patients were excluded if their FPG was > 20 mmol/L or 2-hour plasma glucose > 25 mmol/L; if their plasma insulin was < 5 IU; or if they had other serious health conditions. Of the selected 173 patients, 89 were placed in the control group and 84 in the treatment group. Seventy-three patients in the control group and 64 patients in the treatment group were included in the final analysis. Patients were excluded from analysis either because they changed medications during the study or missed a blood sample collection.
The treatment group consumed 250 mg of water-extracted cinnamon in capsules (CinSulin®; BJTA Nutrition & Healthcare Prods. Co.; Beijing, China) daily for 2 months. The placebo group took capsules of 250 mg of cooked wheat (Triticum aestivum, Poaceae) flour for the 2-month period. The flour was cooked to a dark brown color to resemble ground cinnamon. At the beginning and end of the study, FPG, 2-hour plasma glucose, LDL-C, total cholesterol, TGs, high-density lipoprotein cholesterol (HDL-C), and fructosamine were measured in the blood samples. Blood pressure, weight, and body mass index (BMI) also were assessed at the beginning and end of the study. Insulin resistance was calculated with the homeostasis model assessment for insulin resistance (HOMA-IR). Data were analyzed with analysis of variance with repeated measures.
The average age of patients was 61.3 ± 0.8 years and average BMI was 25.3 ± 0.3. Of the patients, 56% were overweight and 14% were obese. There was not a significant difference in blood or anthropometric measures between the treatment and control groups at the beginning of the study. Baseline measurements showed obese and overweight patients had significantly greater fasting insulin and HOMA-IR than did patients with a normal weight (P < 0.05 for both). Obese patients also had significantly greater 2-hour postprandial insulin levels and diastolic blood pressure than overweight or normal weight patients (P < 0.05 for both). In addition, normal weight patients had significantly higher HDL-C and lower TG blood concentrations than did overweight or obese patients (P < 0.05 for both). There was a significant increase in TGs and systolic blood pressure in the control group over the course of the study (P < 0.0001 and < 0.05, respectively). In the treatment group, FPG, 2-hour glucose, fasting insulin, and HOMA-IR decreased significantly (P < 0.005, < 0.0001, < 0.05, < 0.005, respectively). In addition, total cholesterol, LDL-C, and HDL-C decreased significantly and TGs increased significantly over the course of the study in the treatment group (P < 0.05, < 0.005, < 0.005, and < 0.05, respectively).
The study demonstrated that 500 mg/day of cinnamon supplementation for 2 months improved glucose control and lipid profiles in patients with hyperglycemia. Previous in vitro and in vivo studies with cinnamon have suggested the underlying mechanisms of action may involve decreased oxidative stress by scavenging free radicals, improved insulin sensitivity by altering insulin regulation, decreased blood glucose by altering glucose utilization, and decreased inflammation. Larger clinical studies would be useful in elucidating the effect of cinnamon on blood glucose regulation in patients with hyperglycemia, metabolic syndrome, or diabetes. Cinnamon may provide an alternative method of prevention and treatment for individuals with elevated blood glucose levels and related conditions.—Cheryl McCutchan, PhD