Department of Surgery, University of California, Los Angeles, Los Angeles, CA, United States.
Department of Medicine, Center for Human Nutrition, David Geffen School of Medicine, Los Angeles, United States.
Am J Clin Nutr. 2024 Mar;119(3):649-657. doi: 10.1016/j.ajcnut.2024.01.008. Epub 2024 Jan 26.
Previous clinical studies showing that cinnamon spice lowers blood glucose concentrations had inconsistent results.
To determine the effect of daily cinnamon spice supplementation in an amount commonly used for seasoning on glucose concentrations in adults with obesity and prediabetes.
Following a 2-wk run-in period of maintaining a low polyphenol/fiber diet, 18 participants with obesity and prediabetes underwent a 10-wk randomized, controlled, double-blind, crossover trial (mean age 51.1 y; mean fasting plasma glucose 102.9 mg/dL). The participants were randomly assigned to take cinnamon (4 g/d) or placebo for 4-wk, followed by a 2-wk washout period, and then crossed over to the other intervention for an additional 4-wk. Glucose changes were measured with continuous glucose monitoring. Oral glucose tolerance testing immediately following ingestion of cinnamon or placebo was performed at 4-time points to assess their acute effects both at the baseline and end of each intervention phase. Digestive symptom logs were obtained daily.
There were 694 follow-up days with 66,624 glucose observations. When compared with placebo, 24-h glucose concentrations were significantly lower when cinnamon was administered [mixed-models; effect size (ES) = 0.96; 95 % confidence interval (CI): -2.9, -1.5; P < 0.001]. Similarly, the mean net-area-under-the-curve (netAUC) for glucose was significantly lower than for placebo when cinnamon was given (over 24 h; ES = -0.66; 95 % CI: 2501.7, 5412.1, P = 0.01). Cinnamon supplementation resulted in lower glucose peaks compared with placebo (Δpeak 9.56 ± 9.1 mg/dL compared with 11.73 ± 8.0 mg/dL; ES = -0.57; 95 % CI: 0.8, 3.7, P = 0.027). Glucose-dependent-insulinotropic-polypeptide concentrations increased during oral glucose tolerance testing + cinnamon testing (mixed-models; ES = 0.51; 95 % CI: 1.56, 100.1, P = 0.04), whereas triglyceride concentrations decreased (mixed-models; ES = 0.55; 95 % CI: -16.0, -1.6, P = 0.02). Treatment adherence was excellent in both groups (cinnamon: 97.6 ± 3.4 % compared with placebo: 97.9 ± 3.7 %; ES = -0.15; 95 % CI: -1.8, 0.2, P = 0.5). No differences were found in digestive symptoms (abdominal pain, borborygmi, bloating, excess flatus, and stools/day) between cinnamon and placebo groups.
Cinnamon, a widely available and low-cost supplement, may contribute to better glucose control when added to the diet in people who have obesity-related prediabetes. This trial was registered at clinicaltrials.gov as NCT04342624.
之前的临床研究表明，肉桂香料可以降低血糖浓度，但结果并不一致。
确定在习惯性调味用量下，肉桂香料补充剂对肥胖和糖尿病前期成年人血糖浓度的影响。
在为期 2 周的低多酚/纤维饮食维持期后，18 名肥胖和糖尿病前期患者进行了为期 10 周的随机、对照、双盲、交叉试验（平均年龄 51.1 岁；平均空腹血糖 102.9 mg/dL）。参与者被随机分配服用肉桂（4 g/d）或安慰剂 4 周，然后进行 2 周洗脱期，然后再交叉接受另一种干预措施 4 周。使用连续血糖监测仪测量血糖变化。在摄入肉桂或安慰剂后立即进行口服葡萄糖耐量测试，在每个干预阶段的基线和结束时评估其急性作用，共进行 4 次测试。每天记录消化症状日志。
共有 694 天的随访，共进行了 66624 次血糖观察。与安慰剂相比，服用肉桂时 24 小时血糖浓度显著降低[混合模型；效应大小（ES）=0.96；95%置信区间（CI）：-2.9，-1.5；P<0.001]。同样，当给予肉桂时，葡萄糖的平均净曲线下面积（netAUC）也显著低于安慰剂（24 小时内；ES=-0.66；95%CI：2501.7，5412.1，P=0.01）。与安慰剂相比，肉桂补充剂可降低血糖峰值[峰值降低 9.56±9.1 mg/dL 与 11.73±8.0 mg/dL；ES=-0.57；95%CI：0.8，3.7，P=0.027]。口服葡萄糖耐量测试+肉桂测试期间，葡萄糖依赖性胰岛素释放肽浓度升高（混合模型；ES=0.51；95%CI：1.56，100.1，P=0.04），而甘油三酯浓度降低（混合模型；ES=0.55；95%CI：-16.0，-1.6，P=0.02）。两组的治疗依从性均非常好（肉桂组：97.6±3.4%，安慰剂组：97.9±3.7%；ES=-0.15；95%CI：-1.8，0.2，P=0.5）。肉桂组和安慰剂组在腹痛、肠鸣、腹胀、过度排气和每日排便次数等消化症状方面无差异。
肉桂作为一种广泛应用且成本低廉的补充剂，在肥胖相关糖尿病前期人群的饮食中添加肉桂可能有助于更好地控制血糖。本试验在 clinicaltrials.gov 注册为 NCT04342624。
