Whether in apple pie or various candies, cinnamon has long been a favorite flavor and common kitchen spice. Its aromatic scent and warm, exotic taste are recognized around the world.

Cinnamon, documented in ancient Chinese literature as far back as 2000 bc, was an integral part of the spice trade that blossomed in the 18th and 19th centuries and is still a major export from Sri Lanka and southern India.1

Background

Cinnamon grows as a tree 10-15 meters in height with large oblong leaves. The light-green flowers occur in clusters and have a paradoxically unpleasant odor. These flowers give way to a small marble-sized purple fruit with a single seed. The spice, however, has nothing to do with the flowering or seed functions of the tree. The bark of the mature tree (at least two years old, but preferably more) and its numerous sapling shoots are the source of the spice.2

The thin bark is stripped from the tree and pounded into a fibrous sheet, which curls at the edges as it dries. The bark is then macerated in seawater and dried, turning a golden amber color.1 As the dried, powdery bark ages, the color deepens.

The two primary types of commercially available spice are cinnamon cassia and plain cinnamon. The subtle differences are found in the strength of the volatile oil concentration, the area of production, and the degree of “heat.” The higher the essential oil content, the more valuable the cinnamon product. Cinnamon connoisseurs identify different variations by area of origin, taste, and aroma.

Cinnamon cassia is more intense and has a greater concentration of volatile oils. The flavor and aroma of cinnamon result from the content of those essential oils rich in cinnamic aldehyde, which comprise 0.5%-1% of the bark. In addition, cinnamon essential oil contains ethyl cinnamate, eugenol, beta-caryophyllene, linalool, and methyl chavicol.2

Scientific data

Cinnamon has been credited with significant antioxidant activity, antimicrobial action, gastric-calming activity, and insulin- activity enhancement in type 2 diabetes. In addition to these uses, a noted antiplatelet action has been identified and is credited to the action of the cinnaldehyde. This compound is thought to inhibit the release of arachidonic acid (a pro-inflammatory fatty acid) from platelet membranes, which reduces the activation of thromboxane A2.3

In a study of 100 patients with type 2 diabetes, daily cinnamon doses of 1, 3, or 6 g were administered. At the conclusion of the trial, glucose and LDL levels were each reduced by a statistically significant amount.4 However, a similar study involving postmenopausal type 2 diabetics given 1.5 g of cinnamon per day showed no statistically significant difference in blood glucose levels.5 One possible explanation for the difference in outcomes of these studies is the divergent dose ranges.

Cinnamon is also credited with an antitriglyceridemic effect.3 Whether chemical or mechanical, the action for this is not clear. However, as a high-fiber substance, consumption would aid antilipemic effect (Table 1).3 Reports of triglyceride reductions maintained for 60 days after cessation of cinnamon therapy are weak and supported by few studies.

The most recent purported health benefit attributed to cinnamon is the boosting of cognitive function. Chewing cinnamon-flavored gum or even merely smelling cinnamon appears to have led to higher test scores on several performance levels in a group of healthy volunteers.3 This test was repeated using four-way control of no odor, cinnamon, and a randomization of two other odors.

Cinnamon once again outranked the other choices.3 No hypothesis has been offered as to the possible mechanism of this finding, but research is being conducted to further evaluate this potential.

Safety, dosage, side effects, and drug interactions

There are no known drug interactions.6 While no deaths have been reported from “cinnamon overdose,” excessive use can produce gastric discomfort in the form of heartburn, diarrhea, increased heart rate, flushing, and shortness of breath.6 As always, assess for hypersensitivity before advising the use of cinnamon.Cinnamon is available in a variety of forms for medicinal use. Capsules of ground powder (similar to kitchen-grade cinnamon) should be used in a 2-4 g/day dosage, while a cinnamon tincture is dosed at 1-3 mL daily.6 Multiple teas, essential oils, and other concoctions are widely available.

Cinnamon essential oils and powders should be stored in areas of low heat and low humidity to prevent caking of the powder and dissipation of the essential oils.

Cost

Cinnamon is inexpensive. Whether as a kitchen- spice formulation or pharmacologic-grade preparation, less than $20 purchases a month’s supply of most any form.

Summary

While cinnamon is inexpensive and readily available, the data supporting its efficacy in diabetic management are weak at best. Though cinnamon is not harmful and has no documented drug-drug interaction, its merit as an antidiabetic is relatively nonexistent, according to available data. Any recommendation should be tempered with the understanding that cinnamon alone will not be sufficient to combat true hyperglycemia.

References

1. Wikipedia. Cinnamon. Available at en.wikipedia.org/wiki/cinnamon. Accessed April 12, 2007.

2. Fetrow CW, Avila JR. The Professional’s Handbook of Complementary & Alternative Medicines. Springhouse, Pa.: Springhouse; 1999:171.

3. The World’s Healthiest Foods. Cinnamon, ground. Available at www.whfoods.com. Accessed April 12, 2007.

4. Khan A, Safdar M, Ali Khan MM, et al. Cinnamon improves glucose and lipids of people with type 2 diabetes. Diabetes Care. 2003;26:3215-3218.

5. Vanschoonbeek K, Thomassen BJ, Senden JM, et al. Cinnamon supplementation does not improve glycemic control in postmenopausal type 2 diabetes patients. J Nutr. 2006;136:977-980.

6. Skidmore-Roth L. Mosby’s Handbook of Herbs & Natural Supplements. 3rd ed. St. Louis, Mo.: Elsevier Mosby; 2006:304.