Xu Bocheng, Fu Jie, Qiao Yanxiang, Cao Jinping, Deehan Edward C, Li Zhi, Jin Mingliang, Wang Xinxia, Wang Yizhen
College of Animal Sciences, Zhejiang University, Hangzhou, China.
Institute of Metabolic Diseases, the 5th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, China.
Am J Clin Nutr. 2021 Jun 1;113(6):1515-1530. doi: 10.1093/ajcn/nqaa435.
Microbiota-accessible carbohydrates (MACs) are critical substrates for intestinal microbes; the subsequent production of SCFAs may have some potential benefits for patients with type 2 diabetes mellitus (T2DM).
We conducted a meta-analysis of randomized controlled trials (RCTs) to assess the effects of higher compared with lower MAC intakes on cardiovascular risk factors in T2DM patients and performed an umbrella review of RCTs to evaluate the evidence quality concerning existing dietary T2DM interventions.
Publications were identified by searching MEDLINE, EMBASE, and CINAHL. In the meta-analysis, random-effects models were used to calculate pooled estimates, and sensitivity analyses, meta-regression, subgroup analyses, and Egger's test were performed. For the umbrella review, we summarized pooled estimates, 95% CIs, heterogeneity, and publication bias. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) and modified NutriGrade were used to assess the quality of evidence in the meta-analysis and umbrella review, respectively.
Forty-five RCTs with 1995 participants were included in the meta-analysis. High MAC intake significantly reduced glycated hemoglobin (HbA1c) (weighted mean difference [WMD] -0.436% [-0.556, -0.315]), fasting glucose (WMD -0.835 mmol/L [-1.048, -0.622]), total cholesterol (WMD -0.293 mmol/L [-0.397, -0.190]), triglycerides (WMD -0.118 mmol/L [-0.308, -0.058]), BMI (WMD -0.476 [-0.641, -0.312]), and systolic blood pressure (WMD -3.066 mmHg [-5.653, -0.478]), with a moderate-to-high quality of evidence, compared with low intake. Region, dose, and MAC type were key variables. The umbrella review of all dietary interventions for cardiovascular risk factors in patients with T2DM included 26 meta-analyses with 158 pooled estimates. The evidence quality of MACs, dietary fiber, high-protein diet, ω-3 (n-3), viscous fiber, vitamin D, and vitamin E intake was moderate to high.
When compared with lower intake, increased MAC intake improved glycemic control, blood lipid, body weight, and inflammatory markers for people with T2DM. This trial was registered at PROSPERO (https://www.crd.york.ac.uk/PROSPERO/#recordDetails) as CRD42019120531.
可被微生物利用的碳水化合物（MACs）是肠道微生物的关键底物；随后产生的短链脂肪酸可能对2型糖尿病（T2DM）患者有一些潜在益处。
我们进行了一项随机对照试验（RCT）的荟萃分析，以评估较高MAC摄入量与较低MAC摄入量相比对T2DM患者心血管危险因素的影响，并对RCT进行了综合评价，以评估现有饮食T2DM干预措施的证据质量。
通过检索MEDLINE、EMBASE和CINAHL来识别出版物。在荟萃分析中，使用随机效应模型计算合并估计值，并进行敏感性分析、荟萃回归、亚组分析和Egger检验。对于综合评价，我们总结了合并估计值、95%置信区间、异质性和发表偏倚。分别使用推荐分级评估、制定和评价（GRADE）以及改良的营养分级来评估荟萃分析和综合评价中的证据质量。
荟萃分析纳入了45项RCT，共1995名参与者。与低摄入量相比，高MAC摄入量显著降低糖化血红蛋白（HbA1c）（加权平均差[WMD] -0.436% [-0.556, -0.315]）、空腹血糖（WMD -0.835 mmol/L [-1.048, -0.622]）、总胆固醇（WMD -0.293 mmol/L [-0.397, -0.190]）、甘油三酯（WMD -0.118 mmol/L [-0.308, -0.058]）、体重指数（WMD -0.476 [-0.641, -0.312]）和收缩压（WMD -3.066 mmHg [-5.653, -0.478]），证据质量为中到高。地区、剂量和MAC类型是关键变量。对T2DM患者心血管危险因素的所有饮食干预措施的综合评价包括26项荟萃分析和158个合并估计值。MACs、膳食纤维、高蛋白饮食、ω-3（n-3）、粘性纤维、维生素D和维生素E摄入量的证据质量为中到高。
与较低摄入量相比，增加MAC摄入量可改善T2DM患者的血糖控制、血脂、体重和炎症标志物。该试验已在PROSPERO（https://www.crd.york.ac.uk/PROSPERO/#recordDetails）注册，注册号为CRD42019120531。
