For Patients & Caregivers
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.
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.
Laboratory studies showed that cinnamon can reduce inflammation. Human data is lacking.
Cinnamon is used in traditional medicine for arthritis but there is no scientific evidence to support this.
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.
For Healthcare Professionals
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).
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).
- 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)
- 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.
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.