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, antiinflammatory, 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.
Warnings
This product is regulated by the F.D.A. as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
Cinnamon may have a additive effect when taken with antidiabetic medications.
Theoretically, cinnamon may interact with anticoagulant medications.
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 estrogenic activity and may be harmful)
Side Effects
Oral lesions were shown to be associated with the use of oral cinnamon products like herbal toothpaste and chewing gum.
Certain cinnamon products are high in coumarin content that may cause liver damage and may also interact with other drugs.
Scientific Name
Cinnamomum zeylanicum, Cinnamomum aromaticum, Cinnamomum loureiroi, Cinnamomum burmannii
Common Name
Cassia
Clinical Summary
Cinnamon refers to several plants that belong to the genius 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
(2) (3), anti-inflammatory
(4), immunomodulatory
(5) (6), and antimicrobial
(7) (8) properties. It has been studied in clinical trials for type 2 diabetes but results are conflicting
(9) (10) (11) (12). Well-designed clinical trials are needed to determine efficacy.
Use of cinnamon flavored products has been associated with oral adverse effects
(13) (14) (15). Certain cinnamon products are high in coumarin content that can cause liver damage and can also interact with other drugs
(16).
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
(1)
Mechanism of Action
Compounds isolated from Cinnamon mimicked the action of insulin by activating the insulin receptors
(17). Cinnamon has been demonstrated to inhibit hepatic HMG-CoA reductase activity and reduce levels of blood lipids in animals and humans; however evidence is conflicting as it has also been shown to raise cholesterol levels in rats
(11). Hydroxycinnamaldehyde, a compound present in cinnamon, exhibits anti-inflammatory activity by inhibiting nitric oxide production via inhibition of NF-kappaB
(4).
Contraindications
Patients taking blood glucose lowering or blood-thinning medications should use cinnamon extract with caution (4).
Cinnamon was shown to have estrogenic activity in vitro (19). 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) (14).
Herb-Drug Interactions
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 (18).
Lab Interactions
Cinnamon may lower blood glucose and cholesterol levels but the evidence in support of this is mixed (9) (11).
Theoretically, cinnamon may increase prothrombin time (18).
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.
References
1. 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.
2. 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.
3. Lin CC, Wu SJ, Chang CH, Ng LT. Antioxidant activity of Cinnamomum cassia. Phytother Res. Aug 2003;17(7):726-730.
4. 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.
5. Reddy AM, Seo JH, Ryu SY, Kim YS, Min KR, Kim Y. Cinnamaldehyde and 2-methoxycinnamaldehyde as NF-kappaB inhibitors from Cinnamomum cassia.Planta Med. Sep 2004;70(9):823-827.
6. Koh WS, Yoon SY, Kwon BM, Jeong TC, Nam KS, Han MY.Cinnamaldehyde inhibits lymphocyte proliferation and modulates T-cell differentiation. Int J Immunopharmacol. Nov 1998;20(11):643-660.
7. Shahverdi AR, Monsef-Esfahani HR, Tavasoli F, Zaheri A, Mirjani R. 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.
8. Martin KW, Ernst E. Herbal medicines for treatment of bacterial infections: a review of controlled clinical trials.J Antimicrob Chemother. Feb 2003;51(2):241-246.
9. Blevins SM, Leyva MJ, Brown J, Wright J, Scofield RH, Aston CE. Effect of cinnamon on glucose and lipid levels in non insulin-dependent type 2 diabetes.Diabetes Care. Sep 2007;30(9):2236-2237.
10. Khan A, Safdar M, Ali Khan MM, Khattak KN, Anderson RA. Cinnamon improves glucose and lipids of people with type 2 diabetes. Diabetes Care. Dec 2003;26(12):3215-3218.
11. 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.
12. Vanschoonbeek K, Thomassen BJ, Senden JM, Wodzig WK, van Loon LJ. Cinnamon supplementation does not improve glycemic control in postmenopausal type 2 diabetes patients.J Nutr. Apr 2006;136(4):977-980.
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. 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.
17. 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.
18. Chase CK, McQueen CE. Cinnamon in diabetes mellitus. Am J Health Syst Pharm. May 15 2007;64(10):1033-1035.
19. 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.
