Health Care Professional Information

Scientific Name
Cinnamomum zeylanicum, Cinnamomum aromaticum, Cinnamomum loureiroi, Cinnamomum burmannii
Common Name

Cassia

Clinical Summary

Cinnamon refers to several plants that belong to the genus Cinnamomum, native to Southeast Asia. The bark, rich in essential oil, is used as a flavoring agent and as a spice. Medicinal uses include appetite stimulation, treatment of arthritis, inflammation, and dyspepsia. In traditional Chinese medicine, cinnamon is used with other herbs in decoctions for cold. In vitro studies have demonstrated that cinnamon has antioxidant (1) (2), anti-inflammatory (3), immunomodulatory (4) (5), antimicrobial (6) and antitumor (7) properties. It has been studied in clinical trials for type 2 diabetes but results are conflicting (8) (9) (10) (11). However, conclusions from a meta-analysis suggest benefits of cinnamon and cinnamon extract in improving fasting blood glucose in patients with type 2 diabetes (12).

Use of cinnamon flavored products has been associated with oral adverse effects (13) (14) (15) (16). Certain cinnamon products are high in coumarin (18) (17) content that can cause hepatotoxicity (19) and can also interact with other drugs (20).

Food Sources

Cinnamon spice

Purported Uses
  • Diabetes
  • Stomach ulcers
  • Inflammation
  • Arthritis
Constituents
  • Volatile oils: Cinnamaldehyde, Eugenol, Trans-cinnamic acid
  • Phenolic Compounds: Tannins, Catechins, Proanthocyanidins
  • Monoterpenes and Sesquiterpenes
    (21)
Mechanism of Action

Cinnamon extract inhibits NFkappaB and AP1 leading to apoptosis (7). It also has antiangiogenic activity by inhibiting vascular endothelial growth factor (VEGF) (22). Compounds isolated from Cinnamon mimicked the action of insulin by activating the insulin receptors (23). Cinnamon has been demonstrated to inhibit hepatic HMG-CoA reductase activity (24) and reduce levels of blood lipids in animals and humans (10). Hydroxycinnamaldehyde, a compound present in cinnamon, exhibits anti-inflammatory activity by inhibiting nitric oxide production via inhibition of NF-kappaB (3). Cinnamon extract binds to estrogen-receptor beta and has a direct stimulatory effect on bone formation (25). The n-hexane extract of cinnamon has antiestrogenic activity (26).

Contraindications
  • Patients taking blood glucose lowering or blood-thinning medications should use cinnamon extract with caution.
  • Cinnamon was shown to have both estrogenic and antiestrogenic activities in vitro (24) (25). Patients with hormone sensitive disease should use caution.
Adverse Reactions
  • Plasma cell gingivitis (PCG) and stomatitis were shown to be associated with the use of oral cinnamon products including toothpaste and chewing gum (13) (15) (16) (27).
  • Occupation allergy has been reported with use of cinnamon (28).
  • Use of vaginal suppositories containing cinnamon oil resulted in allergic contact dermatitis in an 18-year-old woman (29)
Herb-Drug Interactions
  • Cinnamon inhibits cytochrome P450 2C9 and 3A4 activities and may increase the blood levels of substrate drugs (31).
  • Cinnamon extract may have an additive effect with blood glucose-lowering medications.
  • In theory, cinnamon may interact with blood-thinning medications due to the presence of coumarin.
Herb Lab Interactions
  • Cinnamon may lower blood glucose and cholesterol levels but the evidence in support of this is mixed (8) (10).
  • Theoretically, cinnamon may increase prothrombin time (30).
Literature Summary and Critique

Mang B, Wolter M, Schmitt B, et al. Effects of a cinnamon extract on plasma glucose, HbA, and serum lipids in diabetes mellitus type 2. Eur J Clin Invest 2006;36(5):340-4.In this double-blind, placebo-controlled trial, 79 type 2 diabetic patients were randomized to either receive either one gram aqueous cinnamon extract or a placebo capsule three times a day for four months. Only patients being treated with diet or oral antidiabetic medications were recruited. Sixty-five patients completed the study. A significantly higher reduction in fasting plasma glucose was demonstrated in the cinnamon group (10.3%) versus the placebo group (3.4%). But no significant differences were noted in HbA1C, LDL, HDL, total cholesterol or triglyceride levels. There was a significant correlation between the reduction of plasma glucose and baseline concentrations suggesting that patients with higher initial plasma glucose levels benefitted more from the cinnamon extract. No adverse effects were reported. The authors conclude that cinnamon extract may be of moderate benefit in reducing plasma glucose in type 2 diabetics with poor glycemic control.

Dosage (Inside MSKCC Only)
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References
  1. Kim SH, Hyun SH, Choung SY. Antioxidative effects of Cinnamomi cassiae and Rhodiola rosea extracts in liver of diabetic mice. Biofactors. 2006;26(3):209-219.
  2. Lin CC, Wu SJ, Chang CH, et al. Antioxidant activity of Cinnamomum cassia. Phytother Res. Aug 2003;17(7):726-730.
  3. Lee SH, Lee SY, Son DJ, et al. Inhibitory effect of 2'-hydroxycinnamaldehyde on nitric oxide production through inhibition of NF-kappa B activation in RAW 264.7 cells. Biochem Pharmacol. Mar 1 2005;69(5):791-799.
  4. Reddy AM, Seo JH, Ryu SY, et al. Cinnamaldehyde and 2-methoxycinnamaldehyde as NF-kappaB inhibitors from Cinnamomum cassia. Planta Med. Sep 2004;70(9):823-827.
  5. Koh WS, Yoon SY, Kwon BM, et al. Cinnamaldehyde inhibits lymphocyte proliferation and modulates T-cell differentiation. Int J Immunopharmacol. Nov 1998;20(11):643-660.
  6. Shahverdi AR, Monsef-Esfahani HR, Tavasoli F, et al. Trans-cinnamaldehyde from Cinnamomum zeylanicum bark essential oil reduces the clindamycin resistance of Clostridium difficile in vitro. J Food Sci. Jan 2007;72(1):S055-058.
  7. Kwon HK, Hwang JS, So JS, et al. Cinnamon extract induces tumor cell death through inhibition of NFkappaB and AP1. BMC Cancer. 2010;10:392.
  8. 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. Sep 2007;30(9):2236-2237.
  9. Khan A, Safdar M, Ali Khan MM, et al. Cinnamon improves glucose and lipids of people with type 2 diabetes. Diabetes Care. Dec 2003;26(12):3215-3218.
  10. Mang B, Wolters M, Schmitt B, et al. Effects of a cinnamon extract on plasma glucose, HbA, and serum lipids in diabetes mellitus type 2. Eur J Clin Invest. May 2006;36(5):340-344.
  11. Vanschoonbeek K, Thomassen BJ, Senden JM, et al. Cinnamon supplementation does not improve glycemic control in postmenopausal type 2 diabetes patients. J Nutr. Apr 2006;136(4):977-980.
  12. Davis PA, Yokoyama W. Cinnamon intake lowers fasting blood glucose: meta-analysis. J Med Food. Sep 2011;14(9):884-889.
  13. Anil S. Plasma cell gingivitis among herbal toothpaste users: a report of three cases. J Contemp Dent Pract. 2007;8(4):60-66.
  14. Endo H, Rees TD. Clinical features of cinnamon-induced contact stomatitis. Compend Contin Educ Dent. Jul 2006;27(7):403-409; quiz 410, 421.
  15. Endo H, Rees TD. Cinnamon products as a possible etiologic factor in orofacial granulomatosis. Med Oral Patol Oral Cir Bucal. Oct 2007;12(6):E440-444.
  16. Kind F, Scherer K, Bircher AJ. Allergic contact stomatitis to cinnamon in chewing gum mistaken as facial angioedema. Allergy. Feb 2010;65(2):276-277.
  17. Lungarini S, Aureli F, Coni E. Coumarin and cinnamaldehyde in cinnamon marketed in Italy: a natural chemical hazard? Food Addit Contam Part A Chem Anal Control Expo Risk Assess. Nov 2008;25(11):1297-1305.
  18. Woehrlin F, Fry H, Abraham K, et al. Quantification of flavoring constituents in cinnamon: high variation of coumarin in cassia bark from the German retail market and in authentic samples from indonesia. J Agric Food Chem. Oct 13 2010;58(19):10568-10575.
  19. Abraham K, Wohrlin F, Lindtner O, et al. Toxicology and risk assessment of coumarin: focus on human data. Mol Nutr Food Res. Feb 2010;54(2):228-239.
  20. Federal Institute for Risk Assessment. Selected Questions about coumarin in cinnamon and other foods. http://www.bfr.bund.de/cd/8487. Accessed February 18, 2008.
  21. Dugoua JJ, Seely D, Perri D, et al. From type 2 diabetes to antioxidant activity: a systematic review of the safety and efficacy of common and cassia cinnamon bark. Can J Physiol Pharmacol. Sep 2007;85(9):837-847.
  22. Lu J, Zhang K, Nam S, et al. Novel angiogenesis inhibitory activity in cinnamon extract blocks VEGFR2 kinase and downstream signaling. Carcinogenesis. Mar 2010;31(3):481-488.
  23. Jarvill-Taylor KJ, Anderson RA, Graves DJ. A hydroxychalcone derived from cinnamon functions as a mimetic for insulin in 3T3-L1 adipocytes. J Am Coll Nutr. Aug 2001;20(4):327-336.
  24. Lee JS, Jeon SM, Park EM, et al. Cinnamate supplementation enhances hepatic lipid metabolism and antioxidant defense systems in high cholesterol-fed rats. J Med Food. Fall 2003;6(3):183-191.
  25. Lee KH, Choi EM. Stimulatory effects of extract prepared from the bark of Cinnamomum cassia blume on the function of osteoblastic MC3T3-E1 cells. Phytother Res. Nov 2006;20(11):952-960.
  26. Kim IG, Kang SC, Kim KC, et al. Screening of estrogenic and antiestrogenic activities from medicinal plants. Environ Toxicol Pharmacol. Jan 2008;25(1):75-82.
  27. Siqueira AS, Santos CC, Cristino MR, et al. Intraoral contact mucositis induced by cinnamon-flavored chewing gum—a case report. Quintessence Int. Oct 2009;40(9):719-721.
  28. Guarneri F. Occupational allergy to cinnamal in a baker. Contact Dermatitis. Nov 2010;63(5):294.
  29. Lauriola MM, De Bitonto A, Sena P. Allergic contact dermatitis due to cinnamon oil in galenic vaginal suppositories. Acta Derm Venereol. Mar 2010;90(2):187-188.
  30. Chase CK, McQueen CE. Cinnamon in diabetes mellitus. Am J Health Syst Pharm. May 15 2007;64(10):1033-1035.
  31. Kimura Y, Ito H, Hatano T. Effects of mace and nutmeg on human cytochrome P450 3A4 and 2C9 activity. Biol Pharm Bull. 2010;33(12):1977-82.

Consumer Information

How It Works


Bottom Line: There is mixed evidence on cinnamon's ability to lower glucose, cholesterol and triglyceride levels.Cinnamon refers to several plants native to Southeast Asia. The bark, rich in essential oil, is used as a flavoring agent and as a spice. Cinnamon has a long history of use as an herbal medicine. Laboratory studies have shown that cinnamon has antibacterial, anti-inflammatory, and antioxidant properties. It was also shown to lower blood glucose levels in patients with type 2 diabetes but more studies are needed to confirm such effects.

Purported Uses
  • Diabetes
    Evidence is mixed: A few clinical trials have shown that cinnamon is beneficial in lowering blood glucose, lipids, and insulin levels; other studies have demonstrated no such effects.
  • Stomach Ulcer
    In one clinical trial, cinnamon extract proved ineffective in eradicating an H. pylori infection.
  • Inflammation
    Laboratory studies showed that cinnamon can reduce inflammation. Human data is lacking.
  • Arthritis
    Cinnamon is used in traditional medicine for arthritis but there is no scientific evidence to support this.
Research Evidence

Type 2 diabetes
Seventy-nine patients with type 2 diabetes were given either one gram of cinnamon extract or a placebo three times daily. Researchers observed a significant reduction in fasting plasma glucose in patients who took cinnamon compared to those on placebo. There were no differences between the groups in cholesterol or triglyceride levels.

Patient Warnings
  • Some cinnamon products contain high levels of coumarin, a natural constituent that can cause liver damages.
Do Not Take If
  • You are taking antidiabetic or anticoagulant medications (Cinnamon may have additive effects)
  • You have hormone-sensitive cancer (cinnamon was found to have both estrogenic and antiestrogenic activities)
Side Effects
  • Oral lesions were shown to be associated with the use of oral cinnamon products like herbal toothpaste and chewing gum.
  • Occupational allergy has been reported with use of cinnamon.
  • Use of vaginal suppositories containing cinnamon oil resulted in allergic contact dermatitis in an 18-year-old woman.
E-mail your questions and comments to aboutherbs@mskcc.org.