The clinical effectiveness of cinnamon (Cinnamomum spp.) at improving glycaemic control in adults with diabetes mellitus

Abstract

Review Objectives: The objective of this systematic review is to evaluate the clinical effectiveness of cinnamon (Cinnamomum spp.) in adults with diabetes mellitus. Review questions: − How effective is cinnamon in adults with type 1 or type 2 diabetes mellitus at reducing total fasting blood glucose, postprandial glucose or glycosylated haemoglobin A1c? − How effective is cinnamon in adults with type 1 or type 2 diabetes mellitus at improving insulin sensitivity? Criteria for considering studies for this review: Types of participants: Participants will be limited to adults over eighteen years of age with either type 1 or type 2 diabetes mellitus. A diagnosis of diabetes mellitus will need to be confirmed using the World Health Organization (WHO) diagnostic criteria for diabetes mellitus (WHO 1999), including a fasting blood glucose ≥7 mmol and/or a 2-hour post-prandial glucose ≥11.1 mmol. Participants under eighteen years of age, or with normal fasting blood glucose or postprandial glucose levels will be excluded. Types of interventions: Interventions will include any orally administered mono-preparation of cinnamon (Cinnamomum spp.) of any dose and form. Combination preparations of cinnamon will be excluded, although the simultaneous administration of cinnamon with insulin and/or oral hypoglycaemic agents will be included. The comparator group may include the use of placebo, no treatment or active medication, such as insulin, oral hypoglycaemic agents, or other herbal/nutritional preparations. Types of outcome measures: Outcomes of interest will include, but are not confined to: • Fasting blood glucose level (FBGL) • Post-prandial glucose (PPG) • Glycosylated haemoglobin A1c (HbA1c) • Serum insulin • Insulin sensitivity (homeostasis model assessment of insulin resistance (HOMA-IR))