Cinnamon Improves Insulin Sensitivity in Type 2 Diabetes Mellitus Subjects

by | Apr 16, 2024 | 2024, Blood Sugar, Botanicals, Cinnamon, Diabetes, Recent Articles

Written by Taylor Woosley, Science Writer. Findings of a meta-analysis including 24 RCTs featuring 1815 participants (case=922; control=893) show that cinnamon administration significantly improved FBS (p < 0.001), HbA1c levels (p = 0.011), and HOMA-IR levels (p < 0.001) in subjects with T2DM. 

botanicals - cinnamonDiabetes mellitus is a metabolic disorder characterized by high levels of blood glucose or hyperglycemia1. The prevalence and incidence of Type 2 Diabetes mellitus (T2DM), representing >90% of all cases of diabetes, are increasing rapidly throughout the world, with the number of people with T2DM expected to rise to 629 million in 20452. Dysfunctions of islet beta cells and insulin resistance predispose to the subsequent stage of disease progression such as cardiovascular disease, neuropathy, and nephropathy3.

Cinnamon, a popular spice, has been shown to exert a potential effect on T2DM management4. Two major components of cinnamon, cinnamaldehyde and trans-cinnamaldehyde, have been found to possess anti-hyperglycemic effects5. Furthermore, in vitro, and in vivo studies suggest that bioactive compounds found in cinnamon improve insulin sensitivity, glycemic control, and lipid levels by multiple mechanisms, such as activating the insulin receptor by increased auto-phosphorylation, inhibition of pancreatic and intestinal amylase and glucosidase, and increased glycogen synthesis in the liver6.

Moridpour et al. conducted a meta-analysis to assess the effects of cinnamon supplementation on glycemic control, including fasting blood sugar (FBS), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), insulin, and HbA1c in subjects with T2DM. Study inclusion consisted of randomized controlled trials with adult subjects aged >18 years old with diagnosed T2DM, including a cinnamon supplementation intervention and a placebo control, with sufficient data regarding serum FBS, serum insulin, HbA1c or HOMA-IR.

The Cochran’s Q test was used to quantify between-study heterogeneity and was evaluated using an I-square (I2) statistic. Subgroup analysis was performed to investigate the parameters that induced heterogeneity, based on mean age, baseline BMI, the dosage of cinnamon, sample size, duration, type of cinnamon, and study quality.

24 studies were included in the final meta-analysis, featuring 1815 participants (case=922; control=893), with publication dates from 2003 to 2021, and study durations ranging from 6 to 16 weeks. The most frequently used cinnamon was Cinnamomum cassia or Cinnamomum verum, with daily doses of cinnamon ranging from 120 to 6000 mg/day, with a mean of 2100 mg/daily. Significant findings of the meta-analysis are as follows:

  • Results on FBS changes from 23 RCTs with 26 arms and 1673 subjects shows that cinnamon significantly improved FBS (p < 0.001). A substantial reduction in FBS levels was noted in subjects aged <50 years consuming ≥3000 mg/day Cinnamomum cassia for a duration of ≤10 weeks.
  • Results on HbA1c levels in 18 RCTs with 19 arms and 1309 subjects show a significant decrease in HbA1c levels after cinnamon supplementation (p = 0.011). Findings from a subgroup analysis show that Cinnamomum cassia in dosage of <3000 mg/day, in subjects <50 years, with a RCT duration of more than 10 weeks experienced the most notable cinnamon impact on HbA1c levels.
  • 8 RCTs with 773 subjects reported findings on the impact of cinnamon on HOMA-IR. The forest plot’s findings indicate that cinnamon significantly affected HOMA-IR levels (p < 0.001). The most substantial decrease in HOMA-IR was noted when cinnamon supplementation was less than 3000 mg/day, including interventions lasting longer than 10 weeks, with samples larger than 50 subjects.
  • 12 RCTs on 973 participants reported the use of cinnamon on insulin. Larger subject groups including more than 50 subjects, with a dose of around 3000 mg/day of Cinnamomum cassia had a greater reduction in insulin levels (p < 0.05).

Results of the meta-analysis suggest that cinnamon supplementation can improve insulin sensitivity in subjects with T2DM. Further RCTs are necessary to better comprehend the optimal dose, duration, and type of cinnamon on fasting blood sugar and insulin sensitivity. Study limitations include the lack of subgroup analysis based on gender due to the limited number of studies, inclusion of studies not specifying the type of cinnamon used, and the risk of bias in some included studies due to poor study design.

Source: Moridpour, Amir Hossein, Zeynab Kavyani, Somaye Khosravi, Elahe Farmani, Maziar Daneshvar, Vali Musazadeh, and Amir Hossein Faghfouri. “The effect of cinnamon supplementation on glycemic control in patients with type 2 diabetes mellitus: An updated systematic review and dose‐response meta‐analysis of randomized controlled trials.” Phytotherapy Research 38, no. 1 (2024): 117-130.

© 2023 John Wiley & Sons Ltd.

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Posted April 16, 2024.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

  1. Rachdaoui N. Insulin: The Friend and the Foe in the Development of Type 2 Diabetes Mellitus. Int J Mol Sci. Mar 5 2020;21(5)doi:10.3390/ijms21051770
  2. Laakso M. Biomarkers for type 2 diabetes. Mol Metab. Sep 2019;27s(Suppl):S139-s146. doi:10.1016/j.molmet.2019.06.016
  3. Shan Z, Fa WH, Tian CR, Yuan CS, Jie N. Mitophagy and mitochondrial dynamics in type 2 diabetes mellitus treatment. Aging (Albany NY). Mar 24 2022;14(6):2902-2919. doi:10.18632/aging.203969
  4. 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. Jul 5 2022;14(13)doi:10.3390/nu14132773
  5. Yu T, Lu K, Cao X, et al. The Effect of Cinnamon on Glycolipid Metabolism: A Dose-Response Meta-Analysis of Randomized Controlled Trials. Nutrients. Jun 30 2023;15(13)doi:10.3390/nu15132983
  6. Wang J, Wang S, Yang J, et al. Acute Effects of Cinnamon Spice on Post-prandial Glucose and Insulin in Normal Weight and Overweight/Obese Subjects: A Pilot Study. Front Nutr. 2020;7:619782. doi:10.3389/fnut.2020.619782