Cassia Cinnamon (Cinnamomum cassia)
Cassia cinnamon (Cinnamomum cassia) contains cinnamaldehyde and type-A procyanidins as its primary bioactive compounds, which improve insulin sensitivity by activating insulin receptor signaling and inhibiting protein tyrosine phosphatase 1B (PTP1B). These compounds also slow gastric emptying and inhibit intestinal alpha-glucosidase enzymes, reducing postprandial blood glucose spikes.
Origin & History
Cassia cinnamon (Cinnamomum cassia) is the bark of an evergreen tree native to southern China and Southeast Asia, distinguishing it as a cultivar variant from Ceylon cinnamon. The inner bark is dried into quills for use as a spice or supplement, typically involving drying and grinding into powder or encapsulating whole bark powder without advanced solvent extraction.
Historical & Cultural Context
Cassia cinnamon has historical use in traditional Chinese medicine for glucose regulation and metabolic disorders. Modern clinical trials for type 2 diabetes and prediabetes build upon this traditional foundation, though specific duration and system details are not elaborated in current research.
Health Benefits
• Reduces peak blood glucose response by 10-16 mg/dL in obese women during glucose tolerance testing (moderate evidence from crossover trial) • Lowers fasting blood glucose by 10.3-29% in type 2 diabetics (strong evidence from systematic review of 3 RCTs) • Decreases postprandial blood glucose by 7-13 mg/dL in diabetics (moderate evidence from 12-week trial) • May attenuate insulin resistance in sleep loss models (preliminary evidence from review) • Potentially reduces plasma lipids in type 2 diabetics (limited evidence from open trial)
How It Works
Cinnamaldehyde and type-A procyanidins in Cassia cinnamon activate insulin receptor autophosphorylation and inhibit PTP1B, enhancing downstream GLUT4 translocation to cell membranes and increasing peripheral glucose uptake. These compounds also inhibit intestinal alpha-glucosidase and alpha-amylase enzymes, slowing carbohydrate digestion and blunting postprandial glucose excursions. Additionally, cinnamaldehyde activates TRPA1 receptors and may modulate GLP-1 secretion, contributing to improved glycemic control through an incretin-mediated pathway.
Scientific Research
Clinical evidence includes a crossover trial (n=10) showing 5g Cassia reduced peak glucose but not insulin sensitivity (PMID: 26716656), and a systematic review finding 2 of 3 RCTs demonstrated 10.3-29% fasting glucose reduction in type 2 diabetics (PMID: 18066129). However, a 12-week RCT using 12g daily found no insulin sensitivity changes via gold-standard clamp testing (PMID: 25249415).
Clinical Summary
A systematic review of 3 RCTs in type 2 diabetic patients demonstrated that Cassia cinnamon supplementation (1–6 g/day) lowers fasting blood glucose by 10.3–29% compared to placebo. A crossover trial in obese women found that 3 g of Cassia cinnamon reduced peak blood glucose by 10–16 mg/dL during oral glucose tolerance testing. Postprandial glucose reductions of approximately 7–30% have been observed in additional controlled trials, though effect sizes vary with dose, duration, and baseline glycemic status. Evidence is strongest for short-term fasting glucose reduction in type 2 diabetics; long-term cardiovascular and HbA1c outcomes require larger confirmatory trials.
Nutritional Profile
Per 100g dried Cassia Cinnamon powder: Calories ~247 kcal, Carbohydrates ~80.6g (of which dietary fiber ~53.1g, representing dominant macronutrient fraction), Protein ~3.99g, Fat ~1.24g (primarily polyunsaturated and saturated fatty acids in roughly equal fractions). Key minerals: Calcium ~1002mg (high but bioavailability limited by oxalate content), Iron ~8.32mg, Manganese ~17.5mg (exceptionally high, exceeding daily requirements in typical serving sizes), Magnesium ~60mg, Phosphorus ~64mg, Potassium ~431mg, Zinc ~1.83mg. Vitamins present in modest amounts: Vitamin K ~31.2mcg per 100g, Vitamin A ~15 IU, small amounts of B vitamins (B6 ~0.158mg, folate ~6mcg). Primary bioactive compounds: Cinnamaldehyde (60-75% of essential oil fraction, the dominant phenylpropanoid responsible for most pharmacological effects), Coumarin at notably high concentrations of 1,000-12,000mg/kg dry weight (significantly higher than Ceylon cinnamon at <100mg/kg — a critical safety distinction), Cinnamyl acetate (~3% of essential oil), Eugenol (~10% of essential oil), Procyanidin-type polyphenols (primarily type-A procyanidins) estimated at ~8,000mg/kg dry weight, trans-cinnamic acid, and smaller amounts of linalool and camphor. Bioavailability notes: Cinnamaldehyde is rapidly absorbed via gastrointestinal tract but undergoes extensive first-pass metabolism to cinnamic acid and hippuric acid; polyphenol absorption is moderate (~5-10%) and enhanced by fat co-ingestion; coumarin is well-absorbed (near complete oral bioavailability) and accumulates with repeated use, posing hepatotoxicity risk at intakes exceeding 0.1mg/kg body weight/day — a threshold reachable with as little as 1-2 teaspoons daily of Cassia variety specifically. Typical culinary serving (1 teaspoon ≈ 2.6g) provides approximately 26-31mg coumarin, ~1.6-1.95g cinnamaldehyde, and ~208mg polyphenols.
Preparation & Dosage
Clinically studied doses range from 1g/day (capsules) for 9-12 weeks for glucose control, 5g single dose before glucose testing, up to 12g/day (6g twice daily) in impaired glucose tolerance studies. Studies used whole bark powder in capsules, not standardized extracts. Consult a healthcare provider before starting any new supplement.
Synergy & Pairings
Chromium picolinate, alpha-lipoic acid, bitter melon extract, gymnema sylvestre, fenugreek seed
Safety & Interactions
Cassia cinnamon contains coumarin at concentrations of 1–12 mg/g of powder, which poses hepatotoxicity risk at chronic high doses; the European Food Safety Authority set a tolerable daily intake of 0.1 mg/kg body weight for coumarin, limiting safe Cassia intake to roughly 0.5–1 g/day for a 70 kg adult with daily use. Cassia cinnamon can potentiate the blood-glucose-lowering effects of insulin, metformin, sulfonylureas, and other antidiabetic medications, increasing hypoglycemia risk and requiring dose monitoring. It may also interact with hepatotoxic drugs or anticoagulants such as warfarin due to coumarin content affecting CYP2A6 metabolism. Cassia cinnamon is not recommended in pregnancy at supplemental doses due to uterine-stimulating properties of cinnamaldehyde and insufficient safety data.
