In a recently published study, Dr American Journal of Clinical Nutrition, researchers investigated the glucose-modulating effects of cinnamon spice when added daily to regular meals. Although research on the topic has been conducted in the past, their results are available. The current study used a 12-week randomized, controlled, double-blind, crossover trial and revealed that just 4 grams of cinnamon supplements taken daily for four weeks significantly reduced blood glucose concentrations in obese and overweight prediabetic individuals.
Although the underlying mechanism by which cinnamon regulates glucose metabolism remains the subject of future research, the results of this study suggest a profound role of the gut microbiome in the observed association. Research highlights the benefits of cinnamon and other polyphenol-rich spices in preventing chronic disease and improving public health.
Study: Effect of cinnamon spice on continuously monitored glycemic response in adults with prediabetes: a 4-week randomized controlled crossover trial. Image credit: Virrage Images/Shutterstock
Cinnamon, does it have medical potential?
Cinnamon is a spice that comes from the inner bark of many cinnamon Species of tree species. Although there are more than 250 species belonging to the genus, only four are harvested commercially. Traditionally, cinnamon has been used in several world cultures as an aromatic spice and, less often, as an antiseptic, anti-inflammatory and food-preserving agent.
Clinically, cinnamon has been investigated for its potential benefits due to being a rich source of polyphenols, which are believed to improve glucose metabolism and homeostasis. However, previous studies present widely varying results, with some attesting to its glucose-modulating benefits while others describe no such relationship. Unfortunately, most studies in the field have suboptimal effect sizes (Ess), suggesting the need for an investigation comparing cinnamon and its lack in a clinically controlled setting to explain the spice’s benefits.
About the study
The current study consisted of a randomized, controlled, double-blind crossover trial with a 2-week run-in phase and a four-week intervention (cinnamon supplementation). The study was conducted between March and December 2021 and included adult participants over the age of 18 with a clinically confirmed diagnosis of obesity or overweight.
Study screening involved a comprehensive metabolic screening and baseline readings to assess glycated hemoglobin in participants who had previously consumed a low polyphenol diet. Participants were assigned to case (cinnamon supplement) and control (placebo) groups, after which the run-in phase began. This phase is characterized by polyphenol-retention of less than two weeks The beige diet (Included foods are usually beige in color and rich in simple carbohydrates). Participants should abstain from cinnamon and its products during this time.
After the run-in, the four-week intervention began. Participants were provided four grams of cinnamon (or an equivalent placebo) per day in the form of 32 cinnamon capsules (250 grams per day). Records of daily food intake were maintained, as was dietary compliance. Continuous glucose monitoring (CGM) was performed using an Abbott Diabetes Care Flash system. Any discomfort, particularly digestive or abdominal, was recorded and reported by the patient.
To further uncover the real-world benefits of cinnamon supplementation when the spice is commonly consumed as part of a meal, participants underwent oral glucose tolerance testing (OGTT) via an indwelling catheter inserted into the forearm.
Nineteen participants successfully met the inclusion criteria screening requirements and were enrolled in the study. Of these, one participant failed to complete the study (OGTT procedure-related discomfort) and was removed from analysis. Of the remaining 18 participants, 72% were female (m = 13) with a mean age and weight of 51.1 years and 84.6 kg/m.2, respectively. Computer-assisted assessment of variables across case and control cohorts found no parameters significantly different at baseline.
Continuous glucose monitoring (CGM) enabled a total of 694 participant follow-up days of data recording and 66,624 glucose readings. The results of this experiment revealed that peak glucose values were significantly reduced in the case-cohort (Δ = 9.56 ± 9.1 mg/dL) compared to controls (Δ = 11.73 ± 8.0 mg/dL).
“Differences in glucose trajectories between cinnamon and placebo were robustly significant after controlling for age, gender, and HbA1c at baseline/systolic or diastolic blood pressure at baseline/systolic or diastolic blood pressure at baseline in a multivariable repeated measurement model (P < 0.001)."
The CGM results were validated and extended by the OGTT investigation, which showed that the area under the curve (AUC) values in the cinnamon group were significantly higher by the end of the study compared to baseline readings at the beginning of the study. Baseline AUC values increased from 31,885.1 to 43,592.9 over the four intervention weeks.
Encouragingly, adherence to capsule intake in both cohorts was high and indistinguishable (97.6 in the cinnamon group and 97.9 in the placebo group), validating the statistical weight of these results. No patient reported any worrisome adverse side effects during the study, and digestive symptoms were reported to remain relatively stable between cohorts during each follow-up trial.
In the current study, researchers used a double-blind, crossover trial of 18 obese and overweight American adults to investigate any potential relationship between cinnamon consumption and glucose homeostasis in these individuals. The study results showed that cinnamon significantly reduced fasting blood glucose levels in patients compared to controls (Δ = 9.56 ± 9.1 and Δ = 11.73 ± 8.0 mg/dL, respectively).
Postprandial glucose and insulin concentrations were not significantly different between cases and controls. However, trends in glucose modulation, particularly AUC values, changed faster, more dramatically, and beneficially in the case-cohort. Although the specific bioactive cinnamon-containing compounds responsible for these observations remain elusive, this study suggests that even 4 grams of cinnamon, consumed daily as a garnish or spice with meals, can improve prediabetes and reduce the risk of diabetes in overweight individuals.
- Zelicha, H., Yang, J., Henning, SM, Huang, J., Lee, R., Thames, G., Livingston, EH, Heber, D., & Li, Z. (2024). Effect of cinnamon spice on continuously monitored glycemic response in adults with prediabetes: a 4-week randomized controlled crossover trial. American Journal of Clinical Nutrition, DOI – https://doi.org/10.1016/j.ajcnut.2024.01.008, https://www.sciencedirect.com/science/article/pii/S000291652400008X