RESUMO
Abstract To review scientific evidence on the effects of a gluten-free diet on body composition and improvement of clinical and biochemical parameters of metabolic syndrome. The Preferred Reporting Items for Systematic Reviews and Meta-Analyzes - PRISMA guidelines were followed. A literature search was performed in the PubMed, ScienceDirect, Trip Database, Bireme and Scielo databases, without language restriction, until March 2021. The terms "gluten-free diet", "obesity", "metabolic syndrome", and "weight loss", and Boolean operators (AND/OR) were used. The clinical hypothesis was structured according to the acronym PICOT. Randomized clinical trials with adult and elderly humans without a diagnosis of celiac disease, consuming a gluten-free diet, evaluating associations of the effects of this diet on weight loss and metabolic syndrome components were considered eligible. To assess the risk of bias, the RoB2 was used. A total of 3,198 articles were identified and, after the screening and evaluation of pre-defined eligibility criteria, four studies were included in the qualitative analysis. Weight loss was not associated with a gluten-free diet. However, individuals under a gluten-free diet had lower mean waist circumference, fat percentage (-2.3%) and serum triglyceride levels. The impact of a gluten-free diet on metabolic syndrome parameters is still controversial. In individuals without gluten sensitivity or celiac disease, the consumption of a gluten-free diet appears to provide no nutritional benefit.
RESUMO
Enterococcus faecium is a lactic acid bacterium with applications in food engineering and nutrigenomics, including as starter cultures in fermented foods. To differentiate the E. faecium probiotic from pathogenic bacteria, physiological analyses are often used but they do not guarantee that a bacterial strain is not pathogenic. We report here new findings and an approach based on comparison of the genetic mobility of (1) probiotic, (2) pathogenic, and (3) nonpathogenic and non-probiotic strains, so as to differentiate probiotics, and inform their safe use. The region of the 16S ribosomal DNA (rDNA) genes of different E. faecium strains native to Pernambuco-Brazil was used with the GenBank query sequence. Complete genomes were selected and divided into three groups as noted above to identify the mobile genetic elements (MGEs) (transposase, integrase, conjugative transposon protein and phage) and antibiotic resistance genes (ARGs), and to undertake pan-genome analysis and multiple genome alignment. Differences in the number of MGEs were found in ARGs, in the presence and absence of the genes that differentiate E. faecium probiotics and pathogenic bacteria genetically. Our data suggest that genetic mobility appears to be informative in differentiating between probiotic and pathogenic strains. While the present findings are not necessarily applicable to all probiotics, they offer novel molecular insights to guide future research in nutrigenomics, clinical medicine, and food engineering on new ways to differentiate pathogenic from probiotic bacteria.
