Department of Dermatology, Leiden University Medical Center, Leiden, Netherlands.
DynaMed Plus, EBSCO Health, Ipswich, MA.
Am J Clin Nutr. 2018 Aug 1;108(2):300-331. doi: 10.1093/ajcn/nqy096.
It remains uncertain which diet is best for people with type 2 diabetes (T2D).
We compared the effects of dietary carbohydrate restriction with fat restriction on markers of metabolic syndrome and quality of life in people with T2D.
This systematic review of randomized controlled trials (RCTs) and controlled clinical trials (CCTs) compares the effects of a low-carbohydrate [≤40% of energy (%)] diet with those of a low-fat (≤30%) diet over a period of ≥4 wk in patients with T2D. Two investigators independently selected studies, extracted data, and assessed risk of bias. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach was used to assess the certainty of evidence. Pooled mean differences (MDs) and 95% CIs were calculated with the use of a random-effects model.
Thirty-three RCTs and 3 CCTs (n = 2161) were included. Glycated hemoglobin declined more in people who consumed low-carbohydrate food than in those who consumed low-fat food in the short term (MD: -1.38%; 95% CI: -2.64%, -0.11%; very-low-certainty evidence). At 1 y, the MD was reduced to -0.36% (95% CI: -0.58%, -0.14%; low-certainty evidence); at 2 y, the difference had disappeared. There is low to high (majority moderate) certainty for small improvements of unclear clinical importance in plasma glucose, triglycerides, and HDL concentrations favoring low-carbohydrate food at half of the prespecified time points. There was little to no difference in LDL concentration or any of the secondary outcomes (body weight, waist circumference, blood pressure, quality of life) in response to either of the diets (very-low- to high-certainty evidence).
Currently available data provide low- to moderate-certainty evidence that dietary carbohydrate restriction to a maximum of 40% yields slightly better metabolic control of uncertain clinical importance than reduction in fat to a maximum of 30% in people with T2D. This systematic review is registered at http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42017052467 as CRD42017052467.
目前仍不确定哪种饮食方式对 2 型糖尿病（T2D）患者最有益。
我们比较了低碳水化合物（碳水化合物供能比≤40%）饮食和低脂肪（脂肪供能比≤30%）饮食对 T2D 患者代谢综合征标志物和生活质量的影响。
本系统评价纳入了比较低碳水化合物饮食与低脂肪饮食对 T2D 患者影响的随机对照试验（RCT）和对照临床试验（CCT），观察时间均≥4 周。两名研究者独立筛选研究、提取数据和评估偏倚风险。采用 GRADE（推荐分级的评估、制定与评价）方法评估证据质量。采用随机效应模型计算合并均数差值（MD）和 95%置信区间（CI）。
共纳入 33 项 RCT 和 3 项 CCT（n=2161）。短期来看，低碳水化合物饮食组患者的糖化血红蛋白（HbA1c）下降幅度大于低脂肪饮食组（MD：-1.38%；95%CI：-2.64%，-0.11%；极低质量证据）。1 年时，MD 降低至-0.36%（95%CI：-0.58%，-0.14%；低质量证据）；2 年时，差异消失。在部分预设时间点，血糖、三酰甘油和高密度脂蛋白浓度的改善具有较小但临床意义不明确的优势，倾向于低碳水化合物饮食，其证据质量为低到高（主要为中等）。两种饮食对 LDL 浓度或任何其他次要结局（体重、腰围、血压、生活质量）均无差异（极低到高质量证据）。
目前的证据质量为低到中等，提示对于 T2D 患者，碳水化合物摄入量限制在 40%以内可能比脂肪摄入量限制在 30%以内在代谢控制方面略有优势，但这种优势具有较小的、不确定的临床意义。本系统评价已在 http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42017052467 注册，注册号为 CRD42017052467。
