Nonnutritive sweeteners and cardiometabolic health: a systematic review and meta-analysis of randomized controlled trials and prospective cohort studies.
CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne. 2017;189(28):E929-E939
Plain language summary
Obesity is a major public health challenge that contributes to type 2 diabetes and cardiovascular disease. Evidence that sugar consumption is fuelling this epidemic has stimulated the increasing popularity of non-nutritive sweeteners including aspartame, sucralose and stevioside. The aim of this study was to synthesize evidence of whether routine consumption of non-nutritive sweeteners by adults and adolescents is associated with adverse long-term cardiometabolic effects. This study is a systemic review and meta-analysis of randomised controlled trials and prospective cohort studies. It includes 37 studies involving a total of 406910 individuals. The study shows that small RCTs with short follow-up (median 6 months) suggest that consumption of non-nutritive sweeteners is not consistently associated with decreases in body weight, BMI or waist circumference. However, in larger prospective cohort studies with longer follow-up periods (median 10 years), intake of non-nutritive sweeteners is significantly associated with modest long-term increases in each of these measures. Authors conclude that caution in the use of non-nutritive sweeteners is warranted until the long-term risks and benefits of these products are fully characterised.
BACKGROUND Nonnutritive sweeteners, such as aspartame, sucralose and stevioside, are widely consumed, yet their long-term health impact is uncertain. We synthesized evidence from prospective studies to determine whether routine consumption of non-nutritive sweeteners was associated with long-term adverse cardiometabolic effects. METHODS We searched MEDLINE, Embase and Cochrane Library (inception to January 2016) for randomized controlled trials (RCTs) that evaluated interventions for nonnutritive sweeteners and prospective cohort studies that reported on consumption of non-nutritive sweeteners among adults and adolescents. The primary outcome was body mass index (BMI). Secondary outcomes included weight, obesity and other cardiometabolic end points. RESULTS From 11 774 citations, we included 7 trials (1003 participants; median follow-up 6 mo) and 30 cohort studies (405 907 participants; median follow-up 10 yr). In the included RCTs, nonnutritive sweeteners had no significant effect on BMI (mean difference -0.37 kg/m ; 95% confidence interval [CI] -1.10 to 0.36; 9%; 242 participants). In the included cohort studies, consumption of nonnutritive sweeteners was associated with a modest increase in BMI (mean correlation 0.05, 95% CI 0.03 to 0.06; 0%; 21 256 participants). Data from RCTs showed no consistent effects of nonnutritive sweeteners on other measures of body composition and reported no further secondary outcomes. In the cohort studies, consumption of nonnutritive sweeteners was associated with increases in weight and waist circumference, and higher incidence of obesity, hypertension, metabolic syndrome, type 2 diabetes and cardiovascular events. Publication bias was indicated for studies with diabetes as an outcome. INTERPRETATION Evidence from RCTs does not clearly support the intended benefits of nonnutritive sweeteners for weight management, and observational data suggest that routine intake of nonnutritive sweeteners may be associated with increased BMI and cardiometabolic risk. Further research is needed to fully characterize the long-term risks and benefits of nonnutritive sweeteners. PROSPERO-CRD42015019749.
Effects of weight loss interventions for adults who are obese on mortality, cardiovascular disease, and cancer: systematic review and meta-analysis.
BMJ (Clinical research ed.). 2017;359:j4849
Plain language summary
Obesity is known to increase the risk of many diseases including cardiovascular disease, various cancers and type 2 diabetes. Interestingly, there is evidence suggesting weight loss in obese adults may be harmful, particularly in older people with cardiovascular disease. The aim of this systematic review was to assess the effect of weight loss interventions for adults with obesity on mortality, cardiovascular disease, cancer and body weight. Based on the 30,000 participants identified, current evidence shows that weight loss interventions significantly decrease all cause mortality. There was also evidence to suggest weight loss is associated with developing new cardiovascular events, though fewer trials reported these outcomes so uncertainty remains around these results. Based on the current literature and this review, the authors conclude weight-reducing diets may reduce all cause mortality in adults with obesity and support public health measures to prevent weight gain and facilitate weight loss.
undefined: To assess whether weight loss interventions for adults with obesity affect all cause, cardiovascular, and cancer mortality, cardiovascular disease, cancer, and body weight. Systematic review and meta-analysis of randomised controlled trials (RCTs) using random effects, estimating risk ratios, and mean differences. Heterogeneity investigated using Cochran's Q and I statistics. Quality of evidence assessed by GRADE criteria. Medline, Embase, the Cochrane Central Register of Controlled Trials, and full texts in our trials' registry for data not evident in databases. Authors were contacted for unpublished data. RCTs of dietary interventions targeting weight loss, with or without exercise advice or programmes, for adults with obesity and follow-up ≥1 year. 54 RCTs with 30 206 participants were identified. All but one trial evaluated low fat, weight reducing diets. For the primary outcome, high quality evidence showed that weight loss interventions decrease all cause mortality (34 trials, 685 events; risk ratio 0.82, 95% confidence interval 0.71 to 0.95), with six fewer deaths per 1000 participants (95% confidence interval two to 10). For other primary outcomes moderate quality evidence showed an effect on cardiovascular mortality (eight trials, 134 events; risk ratio 0.93, 95% confidence interval 0.67 to 1.31), and very low quality evidence showed an effect on cancer mortality (eight trials, 34 events; risk ratio 0.58, 95% confidence interval 0.30 to 1.11). Twenty four trials (15 176 participants) reported high quality evidence on participants developing new cardiovascular events (1043 events; risk ratio 0.93, 95% confidence interval 0.83 to 1.04). Nineteen trials (6330 participants) provided very low quality evidence on participants developing new cancers (103 events; risk ratio 0.92, 95% confidence interval 0.63 to 1.36). Weight reducing diets, usually low in fat and saturated fat, with or without exercise advice or programmes, may reduce premature all cause mortality in adults with obesity. PROSPERO CRD42016033217.
Exercise for overweight or obesity.
The Cochrane database of systematic reviews. 2006;(4):CD003817
Plain language summary
Overweight and obesity are important public health problems and are associated with many serious health conditions. The risk of developing overweight and obesity depends on lifestyle factors such as food intake and physical activity. Treatment for these conditions therefore commonly involves diet and exercise. The aim of this systematic review was to assess the efficacy of exercise as a means of achieving weight loss in overweight or obese people. While the primary measure was weight loss, this review also assessed the effectiveness of exercise on cardiovascular disease (CVD) risk factors. The study included nearly 3,500 participants and participants were followed for at least 3 months. The findings of this review showed that exercise has a positive effect on body weight, as well as improvements on a range of CVD risk factors even when weight loss does not occur. When combined with dietary interventions, the amount of weight loss achieved with exercise increased significantly. Based on this review, the authors’ suggest that exercise is an effective weight loss intervention especially when combined with dietary interventions.
BACKGROUND Clinical trials have shown that exercise in adults with overweight or obesity can reduce bodyweight. There has been no quantitative systematic review of this in The Cochrane Library. OBJECTIVES To assess exercise as a means of achieving weight loss in people with overweight or obesity, using randomised controlled clinical trials. SEARCH STRATEGY Studies were obtained from computerised searches of multiple electronic bibliographic databases. The last search was conducted in January 2006. SELECTION CRITERIA Studies were included if they were randomised controlled trials that examined body weight change using one or more physical activity intervention in adults with overweight or obesity at baseline and loss to follow-up of participants of less than 15%. DATA COLLECTION AND ANALYSIS Two authors independently assessed trial quality and extracted data. MAIN RESULTS The 43 studies included 3476 participants. Although significant heterogeneity in some of the main effects' analyses limited ability to pool effect sizes across some studies, a number of pooled effect sizes were calculated. When compared with no treatment, exercise resulted in small weight losses across studies. Exercise combined with diet resulted in a greater weight reduction than diet alone (WMD -1.1 kg; 95% confidence interval (CI) -1.5 to -0.6). Increasing exercise intensity increased the magnitude of weight loss (WMD -1.5 kg; 95% CI -2.3 to -0.7). There were significant differences in other outcome measures such as serum lipids, blood pressure and fasting plasma glucose. Exercise as a sole weight loss intervention resulted in significant reductions in diastolic blood pressure (WMD -2 mmHg; 95% CI -4 to -1), triglycerides (WMD -0.2 mmol/L; 95% CI -0.3 to -0.1) and fasting glucose (WMD -0.2 mmol/L; 95% CI -0.3 to -0.1). Higher intensity exercise resulted in greater reduction in fasting serum glucose than lower intensity exercise (WMD -0.3 mmol/L; 95% CI -0.5 to -0.2). No data were identified on adverse events, quality of life, morbidity, costs or on mortality. AUTHORS' CONCLUSIONS The results of this review support the use of exercise as a weight loss intervention, particularly when combined with dietary change. Exercise is associated with improved cardiovascular disease risk factors even if no weight is lost.