ABSTRACT
CONTEXT: Next to a large body of epidemiological observational studies showing that the Mediterranean diet (MD) is an important lifestyle determinant of cardiovascular risk, there is less relevant evidence from well-conducted randomized controlled trials (RCTs) with hard cardiovascular outcomes. OBJECTIVE: The objective of the study was to identify the most effective dietary intervention for reducing cardiovascular morbidity and mortality. DATA SOURCES: A systematic approach following PRISMA network meta-analyses reporting guidelines was applied to a search of electronic databases (MEDLINE, Cochrane Central Register of Controlled Trials, and Embase) without language restrictions, supplemented by scanning through bibliographies of studies and meetings' abstract material. Inclusion criteria were RCTs conducted in an adult population, investigating the effects of different type of diets or dietary patterns on all-cause mortality and cardiovascular outcomes of interest. DATA EXTRACTION: Data extraction for each study was conducted by 2 independent reviewers. DATA ANALYSIS: A frequentist network meta-analysis using a random-effects model was conducted. Death from any cardiovascular cause was defined as the primary outcome. A total of 17 trials incorporating 83â280 participants were included in the systematic review. Twelve articles (n = 80â550 participants) contributed to the network meta-analysis for the primary outcome. When compared with the control diet, only the MD showed a reduction in cardiovascular deaths (risk ratio = 0.59; 95% confidence interval, 0.42-0.82). Additionally, MD was the sole dietary strategy that decreased the risk of major cardiovascular events, myocardial infarction, angina, and all-cause mortality. CONCLUSIONS: MD may play a protective role against cardiovascular disease and death for primary and also secondary prevention. SYSTEMATIC REVIEW REGISTRATION: Center for Open Science, https://doi.org/10.17605/OSF.IO/5KX83.
ABSTRACT
OBJECTIVES: Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease affecting a significant proportion of the general population. Recently, randomized clinical trials have been conducted examining the efficacy of silymarin in individuals with NAFLD, with conflicting results. The aim of this meta-analysis was to evaluate the efficacy of silymarin in the treatment of NAFLD by examining changes in liver biochemistry, body mass index, and liver histology. METHODS: We searched major electronic databases PubMed/MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials, as well as gray-literature sources, up to June 2020 for randomized clinical trials examining the efficacy of treatment with silymarin in individuals with NAFLD compared to placebo. The primary outcomes were changes in the mean values of transaminases (alanine aminotransferase and aspartate aminotransferase). Secondary outcomes included changes in body mass index and liver histology. Quality analysis was performed with the risk-of-bias tool 2.0. We synthesized results using weighted mean differences for continuous outcomes, along with 95% confidence intervals. RESULTS: In the meta-analysis, eight randomized clinical trials were included. A cutoff level of 0.05 was considered to provide statistically significant results. Silymarin treatment led to a statistically significant greater reduction in the levels of transaminases compared to placebo, irrespective of weight loss. CONCLUSIONS: Silymarin seems to be effective in reducing transaminase levels in individuals with NAFLD. Despite the statistical benefits, we call attention to potential flaws related to the quality of the included studies. Further well-designed studies should be carried out to examine whether this reduction in transaminase levels corresponds to histologic improvement.
