title: Cinnamon use in type 2 diabetes: an updated systematic review and meta-analysis.
abstract: OBJECTIVE
  Cinnamon has been studied in randomized controlled trials (RCTs) for its glycemic-lowering effects, but studies have been small and show conflicting results. A prior meta-analysis did not show significant results, but several RCTs have been published since then. We conducted an updated systematic review and meta-analysis of RCTs evaluating cinnamon's effect on glycemia and lipid levels.
  
  
  METHODS
  MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched through February 2012. Included RCTs evaluated cinnamon compared with control in patients with type 2 diabetes and reported at least one of the following: glycated hemoglobin (A1c), fasting plasma glucose, total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), or triglycerides. Weighted mean differences (with 95% confidence intervals) for endpoints were calculated using random-effects models.
  
  
  RESULTS
  In a meta-analysis of 10 RCTs (n = 543 patients), cinnamon doses of 120 mg/d to 6 g/d for 4 to 18 weeks reduced levels of fasting plasma glucose (-24.59 mg/dL; 95% CI, -40.52 to -8.67 mg/dL), total cholesterol (-15.60 mg/dL; 95% CI, -29.76 to -1.44 mg/dL), LDL-C (-9.42 mg/dL; 95% CI, -17.21 to -1.63 mg/dL), and triglycerides (-29.59 mg/dL; 95% CI, -48.27 to -10.91 mg/dL). Cinnamon also increased levels of HDL-C (1.66 mg/dL; 95% CI, 1.09 to 2.24 mg/dL). No significant effect on hemoglobin A1c levels (-0.16%; 95%, CI -0.39% to 0.02%) was seen. High degrees of heterogeneity were present for all analyses except HDL-C (I(2) ranging from 66.5% to 94.72%).
  
  
  CONCLUSIONS
  The consumption of cinnamon is associated with a statistically significant decrease in levels of fasting plasma glucose, total cholesterol, LDL-C, and triglyceride levels, and an increase in HDL-C levels; however, no significant effect on hemoglobin A1c was found. The high degree of heterogeneity may limit the ability to apply these results to patient care, because the preferred dose and duration of therapy are unclear.
authors.affiliation: College of Pharmacy, Western University of Health Sciences, Pomona, California.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Allen
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Schwartzman
authors.forename: William L
authors.initials: WL
authors.lastname: Baker
authors.forename: Craig I
authors.initials: CI
authors.lastname: Coleman
authors.forename: Olivia J
authors.initials: OJ
authors.lastname: Phung
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D002935:Cinnamomum zeylanicum; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008517:Phytotherapy; D024301:Plant Bark; D028321:Plant Preparations / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D014280:Triglycerides / Q000097:blood
chemical_list: D001786:Blood Glucose; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D006442:Glycated Hemoglobin; D028321:Plant Preparations; D014280:Triglycerides
keywords: cinnamon; lipids; meta-analysis; review; systematic; type 2 diabetes mellitus
references.citation: Diabet Med. 2010 Oct;27(10):1159-67
references.pmid: 20854384
references.citation: J Diet Suppl. 2011 Dec;8(4):378-454
references.pmid: 22432776
references.citation: Chem Biol Interact. 2010 Jun 7;186(1):72-81
references.pmid: 20363216
references.citation: J Med Food. 2011 Sep;14(9):884-9
references.pmid: 21480806
references.citation: Diabetes Care. 2003 Dec;26(12):3215-8
references.pmid: 14633804
references.citation: Diabetes Care. 2008 Jan;31(1):41-3
references.pmid: 17909085
references.citation: Diabetes Care. 2008 Jan;31 Suppl 1:S61-78
references.pmid: 18165339
references.citation: Circulation. 1998 Apr 21;97(15):1440-5
references.pmid: 9576423
references.citation: BMJ. 2011 Oct 18;343:d5928
references.pmid: 22008217
references.citation: Ann Clin Biochem. 2003 Sep;40(Pt 5):489-507
references.pmid: 14503986
references.citation: J Clin Epidemiol. 1992 Jul;45(7):769-73
references.pmid: 1619456
references.citation: J Med Food. 2011 Dec;14(12):1505-10
references.pmid: 21861719
references.citation: Control Clin Trials. 1986 Sep;7(3):177-88
references.pmid: 3802833
references.citation: Ann Intern Med. 2004 Sep 21;141(6):421-31
references.pmid: 15381515
references.citation: Diabetes Care. 2007 Sep;30(9):2236-7
references.pmid: 17563345
references.citation: N Engl J Med. 1999 Aug 5;341(6):410-8
references.pmid: 10438259
references.citation: PPAR Res. 2008;2008:581348
references.pmid: 19096709
references.citation: N Engl J Med. 1998 Mar 26;338(13):867-72
references.pmid: 9516221
references.citation: Diabetes Care. 2006 Dec;29(12):2632-7
references.pmid: 17130196
references.citation: BMJ. 1997 Sep 13;315(7109):629-34
references.pmid: 9310563
references.citation: J Am Board Fam Med. 2009 Sep-Oct;22(5):507-12
references.pmid: 19734396
references.citation: Eur J Clin Invest. 2006 May;36(5):340-4
references.pmid: 16634838
references.citation: Nutr Res. 2012 Jun;32(6):408-12
references.pmid: 22749176
references.citation: J Nutr. 2006 Apr;136(4):977-80
references.pmid: 16549460
references.citation: J Med Assoc Thai. 2006 Sep;89 Suppl 3:S200-5
references.pmid: 17718288
references.citation: BMJ. 2003 Sep 6;327(7414):557-60
references.pmid: 12958120