Cinnamon, due to its exotic flavor and aroma, is a key ingredient in the kitchen of every household. From the beginning of its use in 2800 BC by our ancestors for various purposes such as anointment, embalming and various ailments. The ancient Greeks and Romans also valued cinnamon for its medicinal properties, using it to treat ailments such as coughs, colds, and indigestion. In medieval Europe, cinnamon was used as a status symbol by the wealthy, who used it to flavor their food and perfumes. It was highly prized by ancient civilizations, who traded it across long distances and used it for a variety of purposes. Today, cinnamon is widely used in cuisines around the world and is valued for its flavor and health benefits. In addition to its use in cooking, cinnamon is also used in traditional medicine to treat a variety of conditions, including diabetes, high cholesterol, and inflammation.
Type of Cinnamon
There are four types of cinnamon: Ceylon cinnamon (Cinnamomum verum), Cassia cinnamon (Cinnamomum cassia), Vietnamese cinnamon (Cinnamomum loureiroi), and Indonesian cinnamon (Cinnamomum burmanni). While all three are related and have similar properties, they differ in taste, aroma, and chemical composition. The cinnamon we discussed above is all cassia cinnamon.
- True cinnamon or Ceylon cinnamon or Mexican cinnamon (Cinnamomum zeylanicum)
- Indonesian cinnamon (Cinnamomum burmanni)
- Vietnamese cinnamon (Cinnamomum loureiroi)
- Cassia cinnamon or Chinese cinnamon (Cinnamomum aromaticum)
Ceylon cinnamon, also known as "true" cinnamon, is native to Sri Lanka and is often considered to be of higher quality than the other types. It has a delicate, sweet flavor and aroma and is often used in desserts and sweet dishes. Cassia cinnamon is more commonly used in savory dishes. This cinnamon is lighter and more tan in color. It has a sweeter taste and rich aroma in contrast to Cassia. Ceylon cinnamon bark is compiled of thinner, rolled layers.
Cassia cinnamon, also known as Chinese cinnamon, is one of the most commonly used types of cinnamon in the world. It is native to China and is also grown in other parts of Asia. When compared to other cinnamon, Cassia has a strong, intense aroma and spicier taste. It is darker and more red in color and cannot be easily broken. Cassia cinnamon stick bark is often a single thicker layer that is curled.
Cassia Cinnamon in TCM
In China, cinnamon has been used as a medicinal herb in various formulas. The cinnamon decoction was the first formula recorded in the Shang Han Lun, the oldest medicine book in Chinese history. All cinnamon used in TCM are cassia cinnamon. There are different types of cinnamon in TCM, with Gui Zhi (桂枝) and Rou Gui (肉桂) being the most commonly used. They have different properties, actions, and are used to treat different health conditions.
Guì Zhī, Cinnamon twig is categorized as a warm herb with acrid and sweet flavors. Cinnamon twig enters Heart, Lung, and Bladder channels. Cinnamon twig has several actions on the body. It is known to release the exterior and disperse cold, which means it helps the body overcome the initial stages of a cold or flu. It has a warming effect that can help dispel the coldness that often accompanies fever, headache and sweating. It is also believed to warm and unblock the channels, which can alleviate pain and stiffness in the body. Additionally, cinnamon twig is thought to assist the Heart yang and warm the middle Jiao, which can help regulate the function of the heart and digestive system. In terms of dosage, cinnamon twig is typically prescribed in a range of 3-9 grams in TCM. It can be taken alone or combined with other herbs to enhance its therapeutic effects.
Rou Gui, or Cinnamomi Cortex, is the cinnamon bark. It has a hot, acrid, and sweet taste and is used to treat conditions associated with the Kidney, Spleen, Heart, and Liver channels. Rou Gui is primarily used to warm the fire and assist yang, disperse cold and relieve pain, and warm and unblock the channels and vessels. It is typically taken in doses of 1.5-4.5 grams when decocted and 1-2 grams when powdered, and is added near the end of decoction for about 5-10 minutes.
While Gui Zhi is primarily used to treat conditions associated with the exterior and channels, Rou Gui is used to treat conditions associated with the internal organs coldness. However, both herbs have a warm nature and can be used to alleviate pain, disperse cold, and warm the body.
The official medicinal use of cinnamon varies across different countries.
- In Korea, Gui Pi (桂皮) is listed in the 8th revised edition of the Korean Pharmacopoeia (대한약전외한약(생약)규격집(생규, 2002년판)). And, Rou Gui(肉桂), Gui Zin (桂心), and Gui Zhi (桂枝) are listed in the Korean Pharmacopoeia and Specifications for Non-Korean Medicines(대한약전외한약(생약)규격집(생규, 2002년판) totaling four kinds.
- In China and Taiwan, Rou Gui and Gui Zhi are officially recognized as distinct herbs.
- North Korea includes both Gui Pi and Gui Zhi in its official regulation.
- However, in Japan, only Gui Pi is listed in official regulations for medicinal use.
Differentiation of cinnamon had been always controversial and confusing through the history. The first official differentiation of cinnamon was published in the books "Yi Zong Jin Jian(醫宗金鑑)", and "Bencao Qiu Zhen(本草求眞)" during the Qing dynasty. For 1700 years, since the Shang Han Lun, Gui (cinnamon) was considered as a single entity. Although the term Gui Zhi (cinnamon twig) appeared in the book(本草別說, 陳承) during the Song dynasty, it was introduced as an alias of Gui (cinnamon) rather than a distinct type of cinnamon.
In the medical book "Yi Zong Jin Jian" (1742), it is stated that "Cinnamon twig is pungent and sweet in taste, and all of its medicinal properties are found in the bark. If the bark is removed, it becomes just a dead tree and loses its ability to induce sweating and dispel superficial muscles."
In the herbal book "Bencao Qiu Zhen" (1769), it is acknowledged for the first time in the field of herbal medicine that Gui Zhi (桂枝) refers to the twigs of Cassia cinnamon.
Coumarin and Cassia Cinnamon(Gui Zhi or Rou Gui)
Cassia cinnamon(Gui Zhi or Rou Gui) contains a higher amount of coumarin (1%) compared to Ceylon cinnamon (0.004%). Coumarin can inhibit blood coagulation. Interestingly, Cassia cinnamon has been used as an anticoagulant for 2,000 years. Anticoagulation is not commoly listed action of Gui Zhi, but they are used in one of the most famous formula, Gui Zhi Fu Ling Wan. It is made from a combination of five different herbs, including Gui Zhi (cinnamon twig), Fu Ling (poria), Mu Dan Pi (tree peony bark), Tao Ren (peach kernel), and Chi Shao (red peony root). Gui Zhi Fu Ling Wan is often used to address gynecological issues such as irregular menstruation, painful periods, and infertility. It is also believed to help promote blood circulation and reduce inflammation in the body. Gui Zhi Fu Ling Wan is believed in traditional Chinese medicine to warm the interior and transform blood stasis, a concept that is equivalent to preventing blood coagulation.
There was a randomized controlled trial with dysmenorrhea. The participants were divided into two groups: the Gui Zhi Fu Ling Wan group and the placebo group. The experiment group was given Gui Zhi Fu Ling Wan for three menstrual cycles, while the placebo group was given a placebo for the same duration. The results showed that Gui Zhi Fu Ling Wan significantly alleviated the severity of menstrual pain in primary dysmenorrhea patients with the heat-burning blood-stasis syndrome without significant adverse effects. (Luo Y, Mao P, Chen P, Li C, Fu X, Zhuang M. Effect of Guizhi Fuling Wan in primary dysmenorrhea: A randomized controlled trial. J Ethnopharmacol. 2023;307:116247. doi:10.1016/j.jep.2023.116247)
But, coumarin inside Gui Zhi can interact with anti-coagulant potentially. If taken with drugs such as warfarin, a daily intake of more than 0.1 mg/kg body weight can have a significant impact on the blood coagulation profile. (Kawatra P, Rajagopalan R. Cinnamon: Mystic powers of a minute ingredient. Pharmacognosy Res. 2015;7(Suppl 1):S1-S6. doi:10.4103/0974-8490.157990)
In a reported case, an 80-year-old male patient who presented to the emergency department with symptoms of gastrointestinal bleeding and hemorrhagic shock came to ER. The patient had been taking oral anticoagulants. The patient also reported consuming a boiled mixture of ginger and cinnamon for three days without physician counseling. The patient's condition worsened and he eventually developed severe vomiting of blood, which required mechanical ventilation and packed red blood cell transfusion.
This case report highlights the potential for serious interactions between cinnamon and anticoagulant medications. (Maadarani O, Bitar Z, Mohsen M. Adding Herbal Products to Direct-Acting Oral Anticoagulants Can Be Fatal. Eur J Case Rep Intern Med. 2019;6(8):001190. Published 2019 Jul 19. doi:10.12890/2019_001190)
Cinnamon and Diabetes
After eating a carb-heavy meal, the writer personally consumes 1/3 spoonful of cinnamon powder. There are various studies on the impact of cinnamon on blood glucose levels, and the results are conflicting.
One study found that adding 1.2 teaspoons (6 grams) of cinnamon to a serving of rice pudding led to slower stomach emptying and lower blood sugar elevations than eating rice pudding without cinnamon. (Joanna Hlebowicz, Effect of cinnamon on postprandial blood glucose, gastric emptying, and satiety in healthy subjects, The American Journal of Clinical Nutrition, Volume 85, Issue 6, June 2007, Pages 1552–1556)
Another study suggests that cinnamon may help lower blood sugar and fight diabetes by imitating the effects of insulin and increasing glucose transport into cells. It can also improve insulin sensitivity, making insulin more efficient at moving glucose into cells. (Jarvill-Taylor KJ, A hydroxychalcone derived from cinnamon functions as a mimetic for insulin in 3T3-L1 adipocytes. J Am Coll Nutr. 2001 Aug;20(4):327-36)
A meta-analysis of 543 patients in ten randomized controlled trials has established that taking cinnamon in a dose of 120 mg/day to 6 g/day for approximately four months can significantly decrease fasting plasma glucose levels and improve lipid profile. (Allen RW, Schwartzman E, Baker WL, Coleman CI, Phung OJ. Cinnamon use in type 2 diabetes: An updated systematic review and meta-analysis. Ann Fam Med. 2013;11:452–9.)
Finally, one review study analyzed 14 clinical trials about the effect of cinnamon on blood glucose concentration in diabetes patients. Of those trials, eight studies demonstrated that cinnamon improved fasting blood glucose and postprandial blood glucose. The other six trials revealed that cinnamon administration had no beneficial effect on either fasting or postprandial blood glucose levels. (Silva ML, Bernardo MA, Singh J, de Mesquita MF. Cinnamon as a Complementary Therapeutic Approach for Dysglycemia and Dyslipidemia Control in Type 2 Diabetes Mellitus and Its Molecular Mechanism of Action: A Review. Nutrients. 2022;14(13):2773. Published 2022 Jul 5. doi:10.3390/nu14132773)
Risk and Dosage
Coumarin may have hepatotoxic toxicity. However, due to the lack of awareness regarding the standard limits of cinnamon in these products, it is advisable for patients with hepatic disorders to avoid consuming cinnamon. In rodents, coumarin has been shown to cause damage to the liver, kidneys, and lungs, and it may even cause cancer. While there have been isolated incidents of similar effects in humans, the overall risk to human health from consuming cinnamon is believed to be low when consumed within recommended limits.
In fact, the Tolerable Daily Intake (TDI) of coumarin used to be 0.2 mg/lb (0.5 mg/kg) of body weight. It has now been reduced to 0.05 mg/lb (0.1 mg/kg). It is recommended to limit the daily intake of cinnamon to 3-6 grams (1-2 teaspoons) for a 60 kg adult, and the EU advises a daily intake of no more than 0.1 mg/kg of body weight (https://www.healthline.com/nutrition/ceylon-vs-cassia-cinnamon#TOC_TITLE_HDR_7).
If you are taking cinnamon to manage diabetes, it is important to note that a large dose may not necessarily be needed to see improvements in blood sugar levels. According to a study conducted by Alam Khan and colleagues and published in Diabetes Care in 2003, people taking either 1, 3, or 6 grams of cinnamon daily all experienced the same decrease in blood sugar levels. (Cinnamon Improves Glucose and Lipids of People With Type 2 Diabetes, Diabetes Care 2003 Dec; 26(12): 3215-3218.Alam Khan, MS,)