Department of Medicine, Division of Health Sciences, University of Otago Wellington, School of Medicine and Health Sciences Building, Wellington, New Zealand.
Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
Diabetes Obes Metab. 2022 Dec;24(12):2431-2442. doi: 10.1111/dom.14837. Epub 2022 Sep 5.
Very low carbohydrate/ketogenic diets (VLC/KDs) are popular but their role in managing pre-diabetes and type 2 diabetes (T2D) is uncertain. This study uses a systematic review and meta-analysis of randomized controlled trials to estimate the effect of these diets in this population.
A systematic review identified randomized controlled trials of at least 6 months duration comparing efficacy and safety of VLC/KDs (≤50 g carbohydrate or ≤10% total energy from carbohydrate per day) with a control diet (carbohydrate above the VLC/KD threshold) in adults with pre-diabetes or T2D. The primary outcome variable was glycated haemoglobin (HbA1c) after 12 months. The meta-analysis method was inverse variance weighting of mean values for continuous variables.
Key word searches identified 2290 studies; 2221 were not in scope. A full text review of 69 studies identified eight meeting inclusion criteria; in total, it involved 606 participants. Six studies reported HbA1c (%) at 12 months; four as change from baseline with a fixed effects estimate (95% confidence interval): VLC/KD minus control of 0.01% (-0.22 to 0.25), p = .91; and two as change from baseline: -0.65% (-0.99; -0.31) [-7.1 mmol/mol (-10.8; -3.4)], p < .001. Serum triglycerides were lower with VLC/KD versus control: -0.28 mmol/L (-0.44 to -0.11), p < .001. High-density lipoprotein was higher with an estimate of 0.04 mmol/L (0.01 to 0.08), p = .03, in the five studies reporting 12-month summary data.
A VLC/KD may cause reductions in HbA1c and triglycerides in those with pre-diabetes or T2D but evidence of an advantage over other strategies is limited. More well-designed studies are required to provide certain evidence.
极低碳水化合物/生酮饮食（VLC/KD）很受欢迎，但它们在管理糖尿病前期和 2 型糖尿病（T2D）中的作用尚不确定。本研究通过系统评价和随机对照试验的荟萃分析来评估这些饮食在该人群中的效果。
系统评价确定了至少持续 6 个月的随机对照试验，比较了 VLC/KD（≤50g 碳水化合物或每天总能量的≤10%来自碳水化合物）与糖尿病前期或 T2D 成人的对照饮食（碳水化合物高于 VLC/KD 阈值）的疗效和安全性。主要结局变量为 12 个月后的糖化血红蛋白（HbA1c）。荟萃分析方法是对连续变量的平均值进行逆方差加权。
关键词搜索确定了 2290 项研究；2221 项不在范围内。对 69 项研究的全文审查确定了符合纳入标准的 8 项研究；共涉及 606 名参与者。6 项研究报告了 12 个月时的 HbA1c（%）；4 项为从基线变化的固定效应估计值（95%置信区间）：VLC/KD 减去对照为 0.01%（-0.22 至 0.25），p=0.91；2 项为从基线变化：-0.65%（-0.99；-0.31）[-7.1mmol/mol（-10.8；-3.4）]，p<0.001。与对照组相比，VLC/KD 可降低血清甘油三酯：-0.28mmol/L（-0.44 至 -0.11），p<0.001。五项报告 12 个月汇总数据的研究中，高密度脂蛋白升高，估计值为 0.04mmol/L（0.01 至 0.08），p=0.03。
VLC/KD 可能降低糖尿病前期或 T2D 患者的 HbA1c 和甘油三酯，但与其他策略相比具有优势的证据有限。需要更多精心设计的研究来提供明确的证据。
