Ceylon Cinnamon Reduces Blood Pressure and Lowers Cholesterol in Healthy Adults
Cinnamon (Cinnamomum verum syn. C. zeylanicum, Lauraceae; CV), a well-known spice derived from the inner bark of the tree, is indigenous to Sri Lanka and parts of India. Cinnamon is used in Ayurvedic medicine and marketed as a treatment for various ailments, including metabolic syndrome, insulin resistance, type 2 diabetes mellitus, hyperlipidemia, and arthritis. Compared to cassia cinnamon (C. aromaticum syn. C. cassia), CV has a different phytochemical profile and lower levels of coumarin. CV could possibly be used in higher doses for treating metabolic syndrome without the potential toxic liver effects associated with cassia cinnamon. These authors conducted a phase I clinical trial to evaluate the pharmacodynamic properties and safety of CV in healthy adults.
The trial was conducted at the Department of Pharmacology at the University of Colombo Faculty of Medicine in Sri Lanka. Thirty healthy adults between ages 18 years and 60 years were recruited for the three-month study. Their health was assessed by a medical history and physical examination at baseline, one and two months into the study, and at the end of the study This included systolic blood pressure (SBP) and diastolic blood pressure (DBP) and biochemical parameters, including full blood count, fasting blood glucose (FBG), serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), very-low-density lipoprotein (VLDL), serum triglycerides (TG), serum creatinine, urine full report, liver enzymes aspartate transaminase (AST) and alanine transaminase (ALT), serum bilirubin, the coagulation tests prothrombin time (PT) and international normalized ratio (INR), and electrocardiogram.
To prepare the CV capsules, the authors purchased grade H2 CV quills from a private estate in Kalupe in southern Sri Lanka. At the Industrial Technology Institute in Colombo, Sri Lanka, dried CV powder was extracted from stem barks with distilled water and followed by freeze-drying to obtain crude water extract for the capsules. The manufacturing yield of cinnamon was about 8% to 9%.
The participants were instructed to take one 85 mg CV capsule daily the first month, one 250 mg capsule daily during the second month, and two 250 mg CV capsules daily during the third month. The participants were not taking any medications, nutritional supplements, or herbal medicines. Of the 30 enrolled participants, two moved to another country, and two discontinued the intervention because of dyspeptic symptoms that gradually worsened and did not respond to lifestyle modifications. The remaining 26 participants were included in the final analysis.
The mean age of the participants was 38.8 ± 10.4 years, with an equal number of males and females. At baseline, the mean body mass index (BMI) was 24.8 ± 3.6 kg/m2, waist circumference was 86.6 ± 10.6 cm, and hip circumference was 97.8 ± 9.0 cm. The mean TC was 226.4 ± 38.7 mg/dL, mean LDL-C was 152.8 ± 37.1 mg/dL, mean HDL-C was 52.7 ± 14.2 mg/dL, VLDL-C was 24.6 ± 15.2 mg/dL, and TG was 112.1 ± 49.9 mg/dL. SBP, DBP, pulse rate, serum creatinine, AST, ALT, serum bilirubin, and PT/INR were within normal limits at baseline and remained so during the study.
During the three-month study, no significant changes were seen in weight, BMI, waist circumference, or waist-to-hip ratio. Hip circumference significantly decreased after one month (P<0.05) and from baseline to the end of the study (P<0.05). Pulse rates significantly increased between months two and three (P<0.05). SBP decreased significantly after month one (P<0.001) and after month three compared with baseline (P<0.01). DBP also decreased significantly after the first month (P<0.05) and after month three compared with baseline (P<0.01). Results of urine analysis were normal throughout the study. FBG, HDL-C, VLDL-C, and TG did not change significantly during the study; however, a significant reduction was observed in TC (P<0.05) and LDL-C (P<0.001) at the end of the study compared with baseline.
No serious adverse effects were reported, and liver and kidney function tests were normal throughout the study. Four participants reported dyspeptic symptoms, including upper abdominal discomfort, nausea, heartburn, and bloating. In two of those participants, mild symptoms lasted only during the first week of CV intake, disappearing with diet and lifestyle changes. Mean compliance rates were 90.2 ± 11.6% during month one, 89.9 ± 11.5% during month two, and 88.7 ± 9.7% during month three.
The authors suggest CV reduces arterial blood pressure in hypertensive patients by reducing peripheral vascular resistance through its vasodilatation properties and its effects on arterial wall compliance. The mechanism responsible for the cholesterol-lowering effect of CV may be the inhibition of lipid absorption or increase in expression of the LDL receptor gene. “Since studies have contradictory findings this effect needs to be explored further via clinical trials in humans before drawing conclusions with regards to the anti-hyperlipidemic activity of CV,” write the authors.
Limitations of the study include the small sample size, the short duration, the lack of a control group, and the absence of a quantification of the active compounds in CV.
“Our results demonstrate no significant side effects and toxicity of CV, including hepatotoxicity and anti-coagulation properties. CV demonstrated beneficial anti-hyperlipidaemic and blood pressure lowering effects among healthy adults,” conclude the authors.
The authors report no conflicts of interest.
Ranasinghe P, Jayawardena R, Pigera S, et al. Evaluation of pharmacodynamic properties and safety of Cinnamomum zeylanicum (Ceylon cinnamon) in healthy adults: a phase I clinical trial. BMC Complement Altern Med. December 2017;17(1):550. doi: 10.1186/s12906-017-2067-7.