The effect of cinnamon supplementation on lipid profiles in patients with type 2 diabetes: A systematic review and meta-analysis of clinical trials

Effects of cinnamon supplementation on metabolic biomarkers in individuals with type 2 diabetes: a systematic review and meta-analysis

CONTEXT

The global prevalence of type 2 diabetes mellitus (DM2) has been rising significantly over the years. Recent studies have shown beneficial effects of cinnamon on metabolic biomarkers.

OBJECTIVE

The objective of this review was to assess the effect of cinnamon supplementation on metabolic biomarkers in patients with DM2.

DATA SOURCES

The Pubmed/MEDLINE, Cochrane CENTRAL, and Embase databases were searched up to November 10, 2022.

DATA EXTRACTION

A systematic search was performed for randomized controlled trials (RCTs) evaluating the effect of cinnamon supplementation on metabolic biomarkers, in adults and the elderly with DM2, and comparing the data for a cinnamon intervention group with that for a placebo group or a control group. The main exclusion criteria were studies (1) with other types of diabetes (ie, gestational diabetes or type 1 diabetes), (2) without cinnamon consumption, (3) that did not evaluate metabolic biomarkers, or (4) in vitro and animal studies. Two researchers independently screened 924 records, evaluated full-text studies, extracted data, and appraised their quality. A third researcher was consulted to resolve any discrepancies. The data were pooled using random-effects models and expressed as the weighted mean difference (WMD) with 95% CI. Heterogeneity was assessed using Cochran's Q test and quantified using I2 statistics. Risk of bias was assessed using the Joanna Briggs Institute (JBI) instrument. Sensitivity analysis and the GRADE system were used to assess the robustness and certainty of the findings.

DATA ANALYSIS

In total, 28 RCTs with a duration ranging from 30 to 120 days and a total enrollment of 3054 patients with DM2 were included. Participants consuming cinnamon showed a significant reduction in fasting blood glucose (FBG) (WMD: -15.26 mg/dL; 95% CI: -22.23 to -8.30; I2 = 88%), postprandial glucose (WMD: -39.22 mg/dL; 95% CI: -63.90 to -14.55; I2 = 100%), HbA1c (WMD: -0.56 mg/dL; 95% CI: -0.99 to -0.13; I2 = 94%), and HOMA-IR (WMD = -0.76, 95% CI: -1.13 to -0.39; I2 = 22%) compared with the control group. An intervention of cinnamon in capsule form reduced FBG (WMD:-18.43 mg/dL, 95% CI: -26.32 to -10.53; I2 = 89%), postprandial glucose (WMD: -44.83 mg/dL, 95% CI: -70.67 to -18.99; I2 = 100%), HbA1c (WMD: -0.56 mg/dL, 95% CI: -1.02 to -0.09; I2 = 94%), total cholesterol (WMD: -13.39 mg/dL; 95% CI: -24.71 to -2.07; I2 = 96%), LDL-C (WMD: -6.49 mg/dL, 95% CI: -12.69 to -0.29; I2 = 92%), and triglycerides (WND: -19.75 mg/dL; 95% CI, -33.71 to -5.80; I2 = 88%). Both doses (≤2 g/day and >2 g/day) reduced FBG and postprandial glucose. Only cinnamon doses of ≤2 g/day reduced HbA1c (WMD: -0.68 mg/dL, 95% CI: -1.16 to -0.1; I2 = 92%), HOMA-IR (WMD: -0.94 mg/dL; 95% CI: -1.21 to -0.67; I2 = 0%), and BMI (WMD: -1.18 kg/m2; 95% CI: -1.97 to -0.39; I2 = 0%).

CONCLUSION

The data suggest that cinnamon improves the glycemic and lipid profile and reduces the BMI, particularly in DM2 patients who receive cinnamon supplementation in capsule form and at a dose of ≤2 g/day.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022370332.

Effect of cinnamon supplementation on blood pressure, oxidative stress, and inflammatory biomarkers in adults: An umbrella review of the meta-analyses of randomized controlled trials

AIMS

Cinnamon has positive effects on markers of cardiometabolic health, including blood pressure (BP), oxidative stress, and inflammation. Despite the evidence accumulated from meta-analysis studies on the effects of cinnamon on these markers, the reported findings are still controversial. This umbrella review was conducted to evaluate the evidence and provide a definitive clarification.

DATA SYNTHESIS

We conducted a systematic search in four scientific databases, including PubMed, Scopus, Web of Science, and Embase electronic databases, up to March 2024 to identify systematic reviews and meta-analyses of randomized clinical trials investigating the impact of cinnamon on blood pressure, oxidative stress, and inflammation. The findings revealed that cinnamon might exert favorable effects on systolic blood pressure (SBP) (ES = -2.36 mmHg; 95% CI: 3.86, -1.40), diastolic blood pressure (DBP) (ES = -1.65 mmHg; 95% CI: 2.41, -0.90), total antioxidant capacity (TAC) (WMD = 0.34; 95% CI: 0.04, 0.64), and interleukin-6 (IL-6) (WMD = -1.48; 95% CI: 2.96, -0.01). However, the results did not show any significant effect of cinnamon on malondialdehyde (MDA) (WMD = -0.47; 95% CI: 0.99, 0.05), C-reactive protein (CRP) (WMD = -1.33; 95% CI: 2.66, 0.00), and intercellular adhesion molecule 1 (ICAM-1) (WMD= 1.53, 95% CI: 12.03, 15.10).

CONCLUSIONS

The results of the studies included in this umbrella review support the usefulness of cinnamon consumption in modulating BP as well as improving TAC and IL-6 in metabolic disorders. Due to the limited number of studies, clinical diversity, and other limitations, more high-quality studies must be conducted to provide more precise and comprehensive recommendations.

REGISTRATION NUMBER

PROSPERO, CRD42023487350.

Effect of cinnamon as a Chinese herbal medicine on markers of cardiovascular risk in women with polycystic ovary syndrome: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Polycystic Ovary Syndrome (PCOS) is a hormonal disorder in women associated with increased cardiovascular risk. Cinnamon, a Chinese herbal medicine, is known for its anti-inflammatory and insulin-sensitizing properties, making it a potential therapeutic agent for PCOS-related cardiovascular complications. This systematic review and meta-analysis aimed to assess the impact of cinnamon supplementation on cardiovascular risk markers in women diagnosed with PCOS.

METHODS

Twelve randomized controlled trials (RCTs) were included in the analysis. The primary outcomes assessed were body weight, insulin resistance measured by Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), and fasting blood sugar (FBS).

RESULTS

The meta-analysis revealed a statistically significant effect of cinnamon on reducing weight. Under the random-effects model, the pooled weighted mean difference (WMD) was -0.47 kg (95 % CI: -0.80 to -0.15, p < 0.001; I2 = 0.0 %). There was also a beneficial impact on insulin resistance, with reduced HOMA-IR scores following cinnamon supplementation (SMD=0.5015, 95 % CI: 0.2496 to 0.7533, p < 0.0001). Additionally, there was a significant improvement in FBS levels (pooled WMD: -7.72 mg/dL, 95 % CI: -12.33 to -3.12, p < 0.001; I2 = 91.3 %). The meta-analysis indicated a tendency towards reduced total cholesterol (WMD: -11.12 mg/dL, 95 % CI: -19.06 to -3.18, p = 0.01; I2 = 0.0 %) and LDL levels (WMD: -11.11 mg/dL, 95 % CI: -18.22 to -4.00, p < 0.01; I2 = 0.0 %) following cinnamon intervention. Substantial heterogeneity was observed among the studies, indicating the need for further research with larger sample sizes and standardized methodologies.

CONCLUSION

Cinnamon supplementation demonstrates promising effects on body weight, blood sugar, total cholesterol, LDL, and insulin resistance in women with PCOS, indicating its potential in mitigating cardiovascular risk factors associated with this condition.

Development and Evaluation of a Framework for Identifying and Addressing Spin for Harms in Systematic Reviews of Interventions

"Spin" refers to misleading reporting, interpretation, and extrapolation of findings in primary and secondary research (such as in systematic reviews). The study of spin primarily focuses on beneficial outcomes. The objectives of this research were threefold: first, to develop a framework for identifying spin associated with harms in systematic reviews of interventions; second, to apply the framework to a set of reviews, thereby pinpointing instances where spin may be present; and finally, to revise the spin examples, offering guidance on how spin can be rectified.

The authors developed their framework through an iterative process that engaged an international group of researchers specializing in spin and reporting bias. The framework comprises 12 specific types of spin for harms, grouped by 7 categories across the 3 domains (reporting, interpretation, and extrapolation). The authors subsequently gathered instances of spin from a random sample of 100 systematic reviews of interventions. Of the 58 reviews that assessed harm and the 42 that did not, they found that 28 (48%) and 6 (14%), respectively, had at least 1 of the 12 types of spin for harms. Inappropriate extrapolation of the results and conclusions for harms to populations, interventions, outcomes, or settings not assessed in a review was the most common category of spin in 17 of 100 reviews.

The authors revised the examples to remove spin, taking into consideration the context (for example, medical discipline, source population), findings for harms, and methodological limitations of the original reviews. They provide guidance for authors, peer reviewers, and editors in recognizing and rectifying or (preferably) avoiding spin, ultimately enhancing the clarity and accuracy of harms reporting in systematic review publications.

Advances in pharmacological effects and mechanism of action of cinnamaldehyde

Cinnamaldehyde is extracted from Cinnamomum cassia and other species, providing diverse sources for varying chemical properties and therapeutic effects. Besides natural extraction, synthetic production and biotechnological methods like microbial fermentation offer scalable and sustainable alternatives. Cinnamaldehyd demonstrates a broad pharmacological range, impacting various diseases through detailed mechanisms. This review aims to encapsulate the diverse therapeutic effects of cinnamaldehyde, its molecular interactions, and its potential in clinical applications. Drawing on recent scientific studies and databases like Web of Science, PubMed, and ScienceDirect, this review outlines cinnamaldehyde's efficacy in treating inflammatory conditions, bacterial infections, cancer, diabetes, and cardiovascular and kidney diseases. It primarily operates by inhibiting the NF-κB pathway and modulating pro-inflammatory mediators, alongside disrupting bacterial cells and inducing apoptosis in cancer cells. The compound enhances metabolic health by improving glucose uptake and insulin sensitivity and offers cardiovascular protection through its anti-inflammatory and lipid-lowering effects. Additionally, it promotes autophagy in kidney disease management. Preclinical and clinical research supports its therapeutic potential, underscoring the need for further investigation into its mechanisms and safety to develop new drugs based on cinnamaldehyde.

The Impact of Curcumin, Resveratrol, and Cinnamon on Modulating Oxidative Stress and Antioxidant Activity in Type 2 Diabetes: Moving beyond an Anti-Hyperglycaemic Evaluation

Research indicates that up to half of the population resorts to dietary supplements for managing diseases such as type 2 diabetes rather than changing their nutritional habits. These supplements not only aim to have an anti-hyperglycaemic effect but also seek to reduce oxidative stress to prevent diabetes complications. This systematic literature systematic review aims to evaluate the efficacy of curcumin, resveratrol, and cinnamon in modulating oxidative stress and antioxidant activity in individuals with type 2 diabetes. Data were collected from PubMed, Web of Sciences, and Scopus databases regarding the impact of curcumin, resveratrol, and cinnamon on total antioxidant capacity (TAC), malondialdehyde (MDA), tumour necrosis factor α (TNF-α), interleukin 6 (IL-6), and high-sensitivity C-reactive protein (hs-CRP) levels for this review. Effect sizes for each study were calculated using Cohen's or Hedges's d coefficient. Parameters of oxidative stress and inflammatory status, such as TAC, MDA, TNF-α, IL-6, and hs-CRP, improved following phytochemicals. Additionally, curcumin, resveratrol, and cinnamon exhibited regulatory effects on carbohydrate metabolism by reducing glucose, insulin, and glycated haemoglobin concentrations and lipid metabolism by lowering total cholesterol (TC), low-density lipoprotein (LDL), and triglycerides (TG) and increasing high-density lipoprotein (HDL). Incorporating curcumin, resveratrol, and cinnamon into diets may be beneficial for maintaining organism homeostasis and improving metabolic control in individuals with type 2 diabetes. However, the conflicting results reported in the literature highlight the need for further detailed investigations into the effectiveness of phytochemical use for type 2 diabetes.

A Scoping Review of the Clinical Evidence for the Health Benefits of Culinary Doses of Herbs and Spices for the Prevention and Treatment of Metabolic Syndrome

Metabolic syndrome (MetS) is a growing global health problem. Evidence suggests that diets rich in phytochemical-containing herbs and spices can contribute to reducing the risk of chronic diseases. This review assesses the scope of evidence supporting the use of herbs and spices in the diet for the prevention or treatment of MetS and its associated health conditions. A search of the PubMed, Scopus and Google Scholar databases was carried out to assess the available clinical evidence for culinary doses of commonly used herbs and spices. Trials that were measuring health factors related to metabolic disorders in healthy individuals, or the health of individuals with MetS or associated diseases, were included. Out of a total of 1738 papers identified, there were 142 relevant studies on black pepper, chilli, cardamom, cinnamon, coriander, cumin, fennel, fenugreek, garlic, ginger, nigella seed, rosemary, sage and turmeric. No relevant research was found for cloves, mint, oregano, parsley or thyme. Cinnamon, fenugreek and ginger were the herbs/spices with the most published trials on them and that showed promise for glycaemic control. Cardamom appears to have potential to reduce inflammatory markers, and cinnamon, ginger and turmeric to reduce blood lipids. Patients with type 2 diabetes were the population most likely to be included in studies, but the preventative benefits of herbs/spices in healthy populations were also investigated, particularly for chilli, ginger and cinnamon. There is evidence for the beneficial effect of culinary doses of many common herbs/spices in the prevention and treatment of MetS and associated disorders.

The effect of cinnamon consumption on lipid profile, oxidative stress, and inflammation biomarkers in adults: An umbrella meta-analysis of randomized controlled trials

AIMS

Cinnamon is a polyphenol-rich spice that has beneficial effects on markers of cardio metabolic health such as lipid profile, oxidative stress, and inflammation. Despite the accumulating evidence from meta-analyses on the effects of cinnamon on these markers, their findings are controversial. Thus, this umbrella meta-analysis was performed to evaluate the present evidence and provide a conclusive clarification.

DATA SYNTHESIS

We searched the following international databases from inception to January 2022: PubMed, Scopus, Web of Science and Embase, and Google Scholar. Our findings of eleven meta-analyses showed that cinnamon consumption can significantly improve total cholesterol (TC) (WMD = -1.01 mg/dL; 95% CI: -2.02, -0.00, p = 0.049), low-density lipoprotein-cholesterol (LDL-C) (WMD = -0.82 mg/dL; 95% CI: -1.57, -0.07, p = 0.032), and high-density lipoprotein-cholesterol (HDL-C) (WMD = 0.47 mg/dL; 95% CI: 0.17, 0.77, p = 0.002) levels but not triglyceride (TG) levels (WMD = -0.13 mg/dL; 95% CI: -0.58, 0.32, p = 0.570). Our results did not show any significant effect of cinnamon on malondialdehyde (MDA) levels (WMD = -0.47; 95% CI: -0.99, 0.05, p = 0.078) and C-reactive protein (CRP) levels (WMD = -1.33; 95% CI: -2.66, 0.00, p = 0.051) but there was enhanced total antioxidant capacity (TAC) in patients with type 2 diabetes (T2DM) and polycystic ovary syndrome (PCOS) (WMD = 0.34; 95% CI: 0.04, 0.64, p = 0.026) and increased levels of interleukin-6 (WMD = -1.48; 95% CI: -2.96, -0.01, p = 0.049).

CONCLUSIONS

Our results support the usefulness of cinnamon intake in modulating an imbalanced lipid profile in some metabolic disorders, particularly PCOS, as well as in improving TAC and interleukin-6. The review protocol was registered on PROSPERO as CRD42022358827.

Cinnamon as a Complementary Therapeutic Approach for Dysglycemia and Dyslipidemia Control in Type 2 Diabetes Mellitus and Its Molecular Mechanism of Action: A Review

The scientific evidence that cinnamon may exert beneficial effects on type 2 diabetes mellitus due to the biological activity of its bioactive compounds has been increasing in recent years. This review provides an overview of the effects of cinnamon on clinical parameters of diabetes and summarizes the molecular mechanisms of action of cinnamon on glucose and lipid metabolism. Search criteria include an electronic search using PubMed, Medline, and Cochrane Library databases. English literature references from 2000 up to 2022 were included. Following title and abstract review, full articles that met the inclusion criteria were included. The results from the available evidence revealed that cinnamon improved glycemic and lipidemic indicators. Clinical trials clarified that cinnamon also possesses an anti-inflammatory effect, which may act beneficially in diabetes. Based on in vitro and in vivo studies, cinnamon seems to elicit the regulation of glucose metabolism in tissues by insulin-mimetic effect and enzyme activity improvement. Furthermore, cinnamon seems to decrease cholesterol and fatty acid absorption in the gut. The current literature search showed a considerable number of studies on diabetic subjects. Some limitations in comparing published data should be highlighted, including variability in doses, extracts and species of cinnamon, administration forms, and antidiabetic therapy.

Mechanisms for Improving Hepatic Glucolipid Metabolism by Cinnamic Acid and Cinnamic Aldehyde: An Insight Provided by Multi-Omics

Cinnamic acid (AC) and cinnamic aldehyde (AL) are two chemicals enriched in cinnamon and have been previously proved to improve glucolipid metabolism, thus ameliorating metabolic disorders. In this study, we employed transcriptomes and proteomes on AC and AL treated db/db mice in order to explore the underlying mechanisms for their effects. Db/db mice were divided into three groups: the control group, AC group and AL group. Gender- and age-matched wt/wt mice were used as a normal group. After 4 weeks of treatments, mice were sacrificed, and liver tissues were used for further analyses. Functional enrichment of differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. DEPs were further verified by parallel reaction monitoring (PRM). The results suggested that AC and AL share similar mechanisms, and they may improve glucolipid metabolism by improving mitochondrial functions, decreasing serotonin contents and upregulating autophagy mediated lipid clearance. This study provides an insight into the molecular mechanisms of AC and AL on hepatic transcriptomes and proteomes in disrupted metabolic situations and lays a foundation for future experiments.

Development and Validation of Ultrahigh-Performance Liquid Chromatography Coupled with Triple Quadrupole Mass Spectrometry Method for Quantitative Determination of Ten Active Compounds in Ge-Gen-Jiao-Tai-Wan

A rapid, accurate, and sensitive method for the simultaneous determination of 10 main components, namely puerarin, daidzin, coptisine, epiberberine, jatrorrhizine, berberine, palmatine, coumarin, daidzein, and cinnamic acid in Ge-Gen-Jiao-Tai-Wan, was developed based on ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry. Analysis was performed on an Agilent 1290 Infinity II series UHPLC system, equipped with a Waters ACQUITY UPLC HSS T3 column (100 × 2.1 mm, 1.8 μm) by using (A) 0.1% acetic acid and (B) methanol as mobile phase. The flow rate was 0.3 mL/min, and the injection volume was 1 μL. Mass spectrometry was operated in multiple reaction monitoring mode using an Agilent 6460 triple quadrupole mass spectrometer equipped with an AJS-ESI ion source. Agilent Mass Hunter Work Station Software was employed for data acquisition and processing. All calibration curves showed excellent linear regressions (R ² > 0.9992). The precision, repeatability, and stability of the ten compounds were below 4.56% in terms of relative standard deviation. The average extraction recovery ranged from 96.53% to 102.69% with a relative standard deviation of 1.14-3.78% for all samples. This study potently contributes to the quantitative evaluation of Ge-Gen-Jiao-Tai-Wan, thereby providing a scientific basis for further studies and clinical application of Ge-Gen-Jiao-Tai-Wan.

The effect of cinnamon supplementation on liver enzymes in adults: A systematic review and meta-analysis of randomized controlled trials

AIMS

The aim of this study was to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) to examine the effect of cinnamon supplementation on liver enzymes.

METHODS

A systematic search was performed in electronic databases including PubMed-Medline, Scopus, and ISI Web of Science up to November 2020. We used a random effects model to estimate pooled effect size of alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) levels.

RESULTS

Seven RCTs (9 treatment arms) fulfilled the eligibility criteria of the present meta-analysis. Overall, meta-analysis could not show any beneficial effect of cinnamon supplementation on AST, ALT, and ALP. Subgroup analyses showed that the effect of cinnamon supplementation on ALT was significant at the dosages of <1500 mg/day (Hedges's: -0.61; 95 % CI: -1.11, -0.10; P = 0.002), in trials lasting>12 weeks (Hedges's: -0.83; 95 % CI: -1.36, -0.30; P = 0.01), and in trials conducted of both gender (Hedges's: -0.72; 95 % CI: -1.45, -0.01; P = 0.04).

CONCLUSION

In summary, cinnamon supplementation had no significant effect on liver enzymes in adults. However, the effect of cinnamon on ALT levels was significant at the dosages of <1500 mg/day, in trials lasting>12 weeks, and in trials conducted of both gender. Nevertheless, further studies should be performed to confirm our results.