美国德克萨斯农工大学Bradley C Johnston团队研究了低碳水化合物和极低碳水化合物饮食对2型糖尿病缓解的疗效和安全性。2021年1月13日，该研究发表在《英国医学杂志》上。
为了确定低碳水化合物饮食（LCD）和极低碳水化合物饮食（VLCD）对2型糖尿病患者的疗效和安全性，研究组对CENTRAL、Medline、Embase等大型数据库中从成立到2020年8月25日的文献进行检索，筛选出评估2型糖尿病成人至少12周LCD和VLCD干预的随机临床试验，并进行系统审查和荟萃分析。主要结局是糖尿病的缓解（HbA1c<6.5％或空腹血糖<7.0 mmol / L，无论是否服用糖尿病药物）、体重减轻、HbA1c、空腹血糖和不良事件。次要结局包括与健康相关的生活质量和生化实验室数据。
Title: Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis of published and unpublished randomized trial data
Author: Joshua Z Goldenberg, Andrew Day, Grant D Brinkworth, Junko Sato, Satoru Yamada, Tommy Jnsson, Jennifer Beardsley, Jeffrey A Johnson, Lehana Thabane, Bradley C Johnston
Objective To determine the efficacy and safety of low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes.
Design Systematic review and meta-analysis.
Data sources Searches of CENTRAL, Medline, Embase, CINAHL, CAB, and grey literature sources from inception to 25 August 2020.
Study selection Randomized clinical trials evaluating LCDs (<130 g/day or <26% of a 2000 kcal/day diet) and VLCDs (<10% calories from carbohydrates) for at least 12 weeks in adults with type 2 diabetes were eligible.
Data extraction Primary outcomes were remission of diabetes (HbA1c <6.5% or fasting glucose <7.0 mmol/L, with or without the use of diabetes medication), weight loss, HbA1c, fasting glucose, and adverse events. Secondary outcomes included health related quality of life and biochemical laboratory data. All articles and outcomes were independently screened, extracted, and assessed for risk of bias and GRADE certainty of evidence at six and 12 month follow-up. Risk estimates and 95% confidence intervals were calculated using random effects meta-analysis. Outcomes were assessed according to a priori determined minimal important differences to determine clinical importance, and heterogeneity was investigated on the basis of risk of bias and seven a priori subgroups. Any subgroup effects with a statistically significant test of interaction were subjected to a five point credibility checklist.
Results Searches identified 14759 citations yielding 23 trials (1357 participants), and 40.6% of outcomes were judged to be at low risk of bias. At six months, compared with control diets, LCDs achieved higher rates of diabetes remission (defined as HbA1c <6.5%) (76/133 (57%) v 41/131 (31%); risk difference 0.32, 95% confidence interval 0.17 to 0.47; 8 studies, n=264, I2=58%). Conversely, smaller, non-significant effect sizes occurred when a remission definition of HbA1c <6.5% without medication was used. Subgroup assessments determined as meeting credibility criteria indicated that remission with LCDs markedly decreased in studies that included patients using insulin. At 12 months, data on remission were sparse, ranging from a small effect to a trivial increased risk of diabetes. Large clinically important improvements were seen in weight loss, triglycerides, and insulin sensitivity at six months, which diminished at 12 months. On the basis of subgroup assessments deemed credible, VLCDs were less effective than less restrictive LCDs for weight loss at six months. However, this effect was explained by diet adherence. That is, among highly adherent patients on VLCDs, a clinically important reduction in weight was seen compared with studies with less adherent patients on VLCDs. Participants experienced no significant difference in quality of life at six months but did experience clinically important, but not statistically significant, worsening of quality of life and low density lipoprotein cholesterol at 12 months. Otherwise, no significant or clinically important between group differences were found in terms of adverse events or blood lipids at six and 12 months.
Conclusions On the basis of moderate to low certainty evidence, patients adhering to an LCD for six months may experience remission of diabetes without adverse consequences. Limitations include continued debate around what constitutes remission of diabetes, as well as the efficacy, safety, and dietary satisfaction of longer term LCDs.