Leach Matthew J, Kumar Saravana
School of Nursing & Midwifery, University of South Australia, Adelaide, South Australia.
Cochrane Database Syst Rev. 2012 Sep 12;2012(9):CD007170. doi: 10.1002/14651858.CD007170.pub2.
Diabetes mellitus is a chronic metabolic disorder that is associated with an increased risk of cardiovascular disease, retinopathy, nephropathy, neuropathy, sexual dysfunction and periodontal disease. Improvements in glycaemic control may help to reduce the risk of these complications. Several animal studies show that cinnamon may be effective in improving glycaemic control. While these effects have been explored in humans also, findings from these studies have not yet been systematically reviewed.
To evaluate the effects of cinnamon in patients with diabetes mellitus.
Pertinent randomised controlled trials were identified through AARP Ageline, AMED, AMI, BioMed Central gateway, CAM on PubMed, CINAHL, Dissertations Abstracts International, EMBASE, Health Source Nursing/Academic edition, International Pharmaceutical Abstracts, MEDLINE, Natural medicines comprehensive database, The Cochrane Library and TRIP database. Clinical trial registers and the reference lists of included trials were searched also (all up to January 2012). Content experts and manufacturers of cinnamon extracts were also contacted.
All randomised controlled trials comparing the effects of orally administered monopreparations of cinnamon (Cinnamomum spp.) to placebo, active medication or no treatment in persons with either type 1 or type 2 diabetes mellitus.
Two review authors independently selected trials, assessed risk of bias and trial quality, and extracted data. We contacted study authors for missing information.
Ten prospective, parallel-group design, randomised controlled trials, involving a total of 577 participants with type 1 and type 2 diabetes mellitus, were identified. Risk of bias was high or unclear in all but two trials, which were assessed as having moderate risk of bias. Risk of bias in some domains was high in 50% of trials. Oral monopreparations of cinnamon (predominantly Cinnamomum cassia) were administered at a mean dose of 2 g daily, for a period ranging from 4 to 16 weeks. The effect of cinnamon on fasting blood glucose level was inconclusive. No statistically significant difference in glycosylated haemoglobin A1c (HbA1c), serum insulin or postprandial glucose was found between cinnamon and control groups. There were insufficient data to pool results for insulin sensitivity. No trials reported health-related quality of life, morbidity, mortality or costs. Adverse reactions to oral cinnamon were infrequent and generally mild in nature.
AUTHORS' CONCLUSIONS: There is insufficient evidence to support the use of cinnamon for type 1 or type 2 diabetes mellitus. Further trials, which address the issues of allocation concealment and blinding, are now required. The inclusion of other important endpoints, such as health-related quality of life, diabetes complications and costs, is also needed.
糖尿病是一种慢性代谢紊乱疾病，与心血管疾病、视网膜病变、肾病、神经病变、性功能障碍及牙周疾病风险增加相关。改善血糖控制可能有助于降低这些并发症的风险。多项动物研究表明，肉桂可能对改善血糖控制有效。虽然在人类中也对这些作用进行了探索，但这些研究的结果尚未得到系统评价。
评估肉桂对糖尿病患者的影响。
通过美国退休人员协会老年信息库（AARP Ageline）、联合和补充医学数据库（AMED）、澳大利亚和新西兰重症监护学会（AMI）、生物医学中心网关（BioMed Central gateway）、PubMed上的补充和替代医学（CAM）、护理及健康照护领域数据库（CINAHL）、国际学位论文摘要数据库（Dissertations Abstracts International）、荷兰医学文摘数据库（EMBASE）、健康源护理/学术版（Health Source Nursing/Academic edition）、国际药学文摘数据库（International Pharmaceutical Abstracts）、医学索引数据库（MEDLINE）、天然药物综合数据库（Natural medicines comprehensive database）、考克兰图书馆（The Cochrane Library）和循证医学高级检索平台（TRIP database）检索相关随机对照试验。还检索了临床试验注册库及纳入试验的参考文献列表（截至2012年1月）。还联系了肉桂提取物的内容专家和制造商。
所有比较口服肉桂单制剂（樟属植物）与安慰剂、活性药物或不治疗对1型或2型糖尿病患者影响的随机对照试验。
两名综述作者独立选择试验、评估偏倚风险和试验质量并提取数据。我们联系研究作者获取缺失信息。
共识别出10项前瞻性、平行组设计的随机对照试验，涉及577例1型和2型糖尿病患者。除两项试验被评估为具有中度偏倚风险外，其余所有试验的偏倚风险均为高或不明确。50%的试验在某些领域的偏倚风险较高。肉桂口服单制剂（主要为桂皮）的平均日剂量为2 g，服用时间为4至16周。肉桂对空腹血糖水平的影响尚无定论。肉桂组与对照组之间在糖化血红蛋白A1c（HbA1c）、血清胰岛素或餐后血糖方面未发现统计学显著差异。没有足够的数据汇总胰岛素敏感性的结果。没有试验报告与健康相关的生活质量、发病率、死亡率或成本。口服肉桂的不良反应很少见，且一般性质轻微。
没有足够的证据支持将肉桂用于1型或2型糖尿病。现在需要进一步的试验，解决分配隐藏和盲法问题。还需要纳入其他重要终点，如与健康相关的生活质量、糖尿病并发症和成本。
