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大医编dayibian 权威医学报道尽在大医编 背 景 1975年至2018年间,世界范围内肥胖的患病率几乎增加了两倍。对此,有关机构提出了一些饮食建议,以管理体重和降低心血管疾病的风险。饮食计划(一些侧重于减少碳水化合物,另一些侧重于减少脂肪)已经被媒体广泛推广,并引起了关于其相对优点的激烈讨论。数百万人试图通过改变饮食来减肥。 近日,有学者为确定超重或肥胖成年人的饮食中营养元素模式和流行的饮食计划对体重减轻和心血管危险因素改善的相对有效性开展了一项随机试验的系统回顾和网络元分析。 该研究纳入了121项试验包含21942例患者,并报告了14种饮食模式和三种对照饮食。结果显示与通常的饮食相比,低碳水化合物和低脂饮食在六个月内对减肥(4.63 v 4.37 kg,均具有中等确定性)和降低收缩压(5.14毫米汞柱,中等确定性v 5.05毫米汞柱,低确定性)和舒张压(3.21 v 2.85毫米汞柱,均不太确定)有相似的作用。适量的营养素饮食会使体重下降和血压轻微下降。低碳水化合物饮食对降低低密度脂蛋白胆固醇的影响小于低脂饮食和适量营养素饮食(分别为1.01 mg / dL,低确定性v 7.08 mg / dL,中度确定性v 5.22 mg / dL,中度确定性),但高密度脂蛋白胆固醇增加(2.31 mg / dL,低确定性),而低脂(-1.88 mg / dL,中等确定性)和适量营养素(−0.89 mg / dL,中等确定性)则没有。在流行的饮食计划中,与普通饮食相比,对减肥和血压影响最大的是Atkins(体重5.5千克,收缩压5.1毫米汞柱,舒张压3.3毫米汞柱),DASH(3.6千克,4.7毫米汞柱,2.9毫米汞柱)和Zone(4.1千克,3.5毫米汞柱,2.3毫米汞柱)。然而,这些饮食均无法提高高密度脂蛋白或C反应蛋白的水平。到12个月时,所有实验性饮食模式所带来的体重下降的效果都开始减弱(除地中海饮食),它们对心血管的益处也基本消失。 研究者认为大多数饮食模式在6个月内会导致体重一定程度地下降,与此同时还伴随着心血管危险因素的下降,特别是血压得到了显著地改善。然而,12个月后这些饮食模式对体重减轻和心血管危险因素改善的效果基本消失。 原 文 阅 读 Objective To determine the relative effectiveness of dietary macronutrient patterns and popular named diet programmes for weight loss and cardiovascular risk factor improvement among adults who are overweight or obese. Design Systematic review and network meta-analysis of randomised trials. Data sources Medline, Embase, CINAHL, AMED, and CENTRAL from database inception until September 2018, reference lists of eligible trials, and related reviews. Study selection Randomised trials that enrolled adults (≥18 years) who were overweight (body mass index 25-29) or obese (≥30) to a popular named diet or an alternative diet. Outcomes and measures Change in body weight, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, systolic blood pressure, diastolic blood pressure, and C reactive protein at the six and 12 month follow-up. Review methods Two reviewers independently extracted data on study participants, interventions, and outcomes and assessed risk of bias, and the certainty of evidence using the GRADE (grading of recommendations, assessment, development, and evaluation) approach. A bayesian framework informed a series of random effects network meta-analyses to estimate the relative effectiveness of the diets. Results 121 eligible trials with 21 942 patients were included and reported on 14 named diets and three control diets. Compared with usual diet, low carbohydrate and low fat diets had a similar effect at six months on weight loss (4.63 v 4.37 kg, both moderate certainty) and reduction in systolic blood pressure (5.14 mm Hg, moderate certainty v 5.05 mm Hg, low certainty) and diastolic blood pressure (3.21 v 2.85 mm Hg, both low certainty). Moderate macronutrient diets resulted in slightly less weight loss and blood pressure reductions. Low carbohydrate diets had less effect than low fat diets and moderate macronutrient diets on reduction in LDL cholesterol (1.01 mg/dL, low certainty v 7.08 mg/dL, moderate certainty v 5.22 mg/dL, moderate certainty, respectively) but an increase in HDL cholesterol (2.31 mg/dL, low certainty), whereas low fat (−1.88 mg/dL, moderate certainty) and moderate macronutrient (−0.89 mg/dL, moderate certainty) did not. Among popular named diets, those with the largest effect on weight reduction and blood pressure in comparison with usual diet were Atkins (weight 5.5 kg, systolic blood pressure 5.1 mm Hg, diastolic blood pressure 3.3 mm Hg), DASH (3.6 kg, 4.7 mm Hg, 2.9 mm Hg, respectively), and Zone (4.1 kg, 3.5 mm Hg, 2.3 mm Hg, respectively) at six months (all moderate certainty). No diets significantly improved levels of HDL cholesterol or C reactive protein at six months. Overall, weight loss diminished at 12 months among all macronutrient patterns and popular named diets, while the benefits for cardiovascular risk factors of all interventions, except the Mediterranean diet, essentially disappeared. Conclusions Moderate certainty evidence shows that most macronutrient diets, over six months, result in modest weight loss and substantial improvements in cardiovascular risk factors, particularly blood pressure. At 12 months the effects on weight reduction and improvements in cardiovascular risk factors largely disappear. 参 考 文 献 Ge Long, Sadeghirad Behnam, Ball Geoff D C, da Costa Bruno R, Hitchcock Christine L, Svendrovski Anton et al. Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials BMJ 2020; 369 :m696  |
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