1.
The Effects of Resveratrol Supplementation in Overweight and Obese Humans: A Systematic Review of Randomized Trials.
Christenson, J, Whitby, SJ, Mellor, D, Thomas, J, McKune, A, Roach, PD, Naumovski, N
Metabolic syndrome and related disorders. 2016;(7):323-33
Abstract
BACKGROUND Obesity and metabolic syndrome are significant global health issues, with current public health messages predominately focused on altering dietary and physical activity behaviors. Resveratrol is a polyphenol (stilbenoid) commonly found in grapes, and human trials to date have shown conflicting and limited beneficial effects with respect to health. The aim of this study was to determine the effect of resveratrol supplementation on reducing body weight and modifying associated inflammatory markers. METHODS A systematic review was undertaken following the PRISMA guidelines and using five indexed databases (OVID MEDLINE, Cochrane Library, Web of Science, SCOPUS, and CINAHL). A search strategy was formulated to select randomized, double-blind, placebo-controlled human trials investigating the effects of resveratrol supplementation on obesity or overweight, including body weight, metabolic and inflammatory markers. RESULTS Five thousand five hundred sixty-nine studies published from 1990 to November 2015 were identified, with only nine papers meeting the inclusion criteria. The studies involved 208 participants (aged 49.2 ± 8.3 years) and utilized a substantial range of resveratrol doses (75-3000 mg/day). Study durations were a minimum of 2 weeks (14-90 days). Seven studies indicated no significant change in body mass index or body weight (P > 0.05), and three studies showed no improvements in fat mass, fat volume, or abdominal fat distribution (P > 0.05). Four studies included measurements of inflammatory markers, with three of these finding resveratrol supplementation to have a significant positive effect (P > 0.05). CONCLUSION Based on the included studies, there is currently insufficient evidence to support the recommendation of resveratrol supplements in management of obesity. However, there were significant but not entirely consistent anti-inflammatory effects after resveratrol supplementation in overweight and obese individuals.
2.
Mediterranean diet and weight loss: meta-analysis of randomized controlled trials.
Esposito, K, Kastorini, CM, Panagiotakos, DB, Giugliano, D
Metabolic syndrome and related disorders. 2011;(1):1-12
Abstract
BACKGROUND The epidemiological evidence supporting a causal link between Mediterranean diets and body weight is contrasting. We evaluated the effect of Mediterranean diets on body weight in randomized controlled trials (RCTs) using a meta-analysis. METHODS We searched English and non-English publications in PubMed, Embase, Scopus, and the Cochrane Central Register of Controlled Trials from inception to January, 2010. Two evaluators independently selected and reviewed eligible studies. Sixteen randomized controlled trials, with 19 arms and 3,436 participants (1,848 assigned to a Mediterranean diet and 1,588 assigned to a control diet) were included. RESULTS In a random-effects meta-analysis of all 19 arms, the Mediterranean diet group had a significant effect on weight [mean difference between Mediterranean diet and control diet, -1.75 kg; 95% confidence interval (CI), -2.86 to -0.64 kg] and body mass index (mean difference, -0.57 kg/m², -0.93 to -0.21 kg/m²). The effect of Mediterranean diet on body weight was greater in association with energy restriction (mean difference, -3.88 kg, -6.54 to -1.21 kg), increased physical activity (-4.01 kg, -5.79 to -2.23 kg), and follow up longer than 6 months (-2.69 kg, -3.99 to -1.38 kg). No study reported significant weight gain with a Mediterranean diet. CONCLUSIONS Mediterranean diet may be a useful tool to reduce body weight, especially when the Mediterranean diet is energy-restricted, associated with physical activity, and more than 6 months in length. Mediterranean diet does not cause weight gain, which removes the objection to its relatively high fat content. These results may be useful for helping people to lose weight.