Effects of the ketogenic diet on performance and body composition in athletes and trained adults: a systematic review and Bayesian multivariate multilevel meta-analysis and meta-regression.

This systematic review with meta-analysis aimed to determine the effects of the ketogenic diet (KD) against carbohydrate (CHO)-rich diets on physical performance and body composition in trained individuals. The MEDLINE, EMBASE, CINAHL, SPORTDiscus, and The Cochrane Library were searched. Randomized and non-randomized controlled trials in athletes/trained adults were included. Meta-analytic models were carried out using Bayesian multilevel models. Eighteen studies were included providing estimates on cyclic exercise modes and strength one-maximum repetition (1-RM) performances and for total, fat, and free-fat masses. There were more favorable effects for CHO-rich than KD on time-trial performance (mode [95% credible interval]; -3.3% [-8.5%, 1.7%]), 1-RM (-5.7% [-14.9%, 2.6%]), and free-fat mass (-0.8 [-3.4, 1.9] kg); effects were more favorable to KD on total (-2.4 [-6.2, 1.8] kg) and fat mass losses (-2.4 [-5.4, 0.2] kg). Likely modifying effects on cyclic performance were the subject's sex and VO2max, intervention and performance durations, and mode of exercise. The intervention duration and subjects' sex were likely to modify effects on total body mass. KD can be a useful strategy for total and fat body losses, but a small negative effect on free-fat mass was observed. KD was not suitable for enhancing strength 1-RM or high-intensity cyclic performances.

Effect of oral nutritional supplements with or without nutritional counselling on mortality, treatment tolerance and quality of life in head-and-neck cancer patients receiving (chemo)radiotherapy: a systematic review and meta-analysis.

Oral nutritional supplements are widely recommended to head-and-neck cancer patients undergoing anti-cancer treatment; however, their effects on the outcomes of most importance to patients are unclear. This study aimed to systematically review the evidence of effect of oral nutritional supplements on mortality, treatment tolerance, quality of life, functional status, body weight and adverse effects. We searched PubMed, Embase, CENTRAL, LILACS, Web of Science, CINAHL, two trial registry platforms, three sources of grey literature and reference lists of included studies. We assessed the risk of bias using the revised Cochrane risk-of-bias tool (RoB 2), and certainty of evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. We used random-effects models with Hartung-Knapp correction for the meta-analyses. We included fifteen trials, of which five were ongoing or unpublished, providing evidence in four comparisons. We found very low to low certainty evidence for the effect of oral nutritional supplements on mortality, treatment tolerance, quality of life, functional status and adverse effects. When compared with nutritional counselling alone, nutritional counselling plus oral nutritional supplements probably increased body weight slightly. We also found adverse events relating to supplements use such as nausea, vomiting and feeling of fullness. Possible increases in mortality, treatment tolerance and quality of life besides a possible decrease in functional status are worthy of further investigation. Future research could attempt to address the clinical importance of a probable increase in body weight. Possible adverse effects of the use of oral nutritional supplements should not be overlooked.

Polymeric implants with drug-releasing capabilities: a mapping review of laboratory research.

PURPOSE: To provide a systematic map of the nature and extent of preclinical research concerning drug-releasing polymeric implants. SIGNIFICANCE: By summarizing available data, this mapping review can guide the development of new drug-delivery devices. METHODS: In-vitro studies assessing drug-delivery implants were reviewed. A study protocol was registered at Open Science Framework. The association of polymers with prominent drugs, manufacturing processes, geometries, treatments, and anatomical locations was assessed using the VOSviewer software. The release periods were also evaluated. RESULTS: A total of 423 articles, published between 1975 and 2020, were included and grouped into a framework with nine main categories. More than half of studies were published between 2010 and 2020. Among 201 individual polymers or combinations, the most investigated were PLGA, PCL, PLA, Silicone (SIL), EVA, and PU. Similarly, from 232 individual drugs or combinations, the most prominent were dexamethasone (DEX; anti-inflammatory), paclitaxel (PTX; anticancer), fluoruracil (anticancer), ciprofloxacin (CFX) hydrochloride (antibiotic), and gentamicin (GS; antibiotic). A total of 51 manufacturing processes were encountered, of which the most reported were solvent evaporation, compression molding (CM), extrusion (EX), electrospinning (ELS), and melt molding (MM). Among 38 implant geometries, cylinder (CIL) was the most prominent, followed by disk, square film, circular film (FCIR), and undefined film. Release times varied greatly, although the majority of articles ranged between 5 and 300 d. CONCLUSIONS: Drug-delivery implants were highly heterogeneous due to its applicability for multiple health conditions. Most implants were made of PLGA and most drugs assessed presented anti-inflammatory, antibiotic, or anticancer effects. Solvent evaporation and CIL were the most prominent manufacturing process and geometry, respectively.

Variation observed in consensus judgments between pairs of reviewers when assessing the risk of bias due to missing evidence in a sample of published meta-analyses of nutrition research.

OBJECTIVES: To evaluate the risk of bias due to missing evidence in a sample of published meta-analyses of nutrition research using the Risk Of Bias due to Missing Evidence (ROB-ME) tool and determine inter-rater agreement in assessments. STUDY DESIGN AND SETTING: We assembled a random sample of 42 meta-analyses of nutrition research. Eight assessors were randomly assigned to one of four pairs. Each pair assessed 21 randomly assigned meta-analyses, and each meta-analysis was assessed by two pairs. We calculated raw percentage agreement and chance corrected agreement using Gwet's Agreement Coefficient (AC) in consensus judgments between pairs. RESULTS: Across the eight signaling questions in the ROB-ME tool, raw percentage agreement ranged from 52% to 100%, and Gwet's AC ranged from 0.39 to 0.76. For the risk-of-bias judgment, the raw percentage agreement was 76% (95% confidence interval 60% to 92%) and Gwet's AC was 0.47 (95% confidence interval 0.14 to 0.80). In seven (17%) meta-analyses, either one or both pairs judged the risk of bias due to missing evidence as "low risk". CONCLUSION: Our findings indicated substantial variation in assessments in consensus judgments between pairs for the signaling questions and overall risk-of-bias judgments. More tutorials and training are needed to help researchers apply the ROB-ME tool more consistently.

Credibility at stake: only two-thirds of randomized trials of nutrition interventions are registered and lack transparency in outcome and treatment effect definitions.

OBJECTIVES: This study aimed to investigate the adherence of randomized controlled trials of nutrition interventions to transparency practices informing assessments of selective reporting biases, including the availability of a trial registration entry, protocol and statistical analysis plan (SAP). STUDY DESIGN AND SETTING: Retrospective observational study with cross-sectional design. We systematically searched for trials published from 1 July 2019, to 30 June 2020, and included a randomly selected sample of 400 studies. We searched for registry entries, protocols, and SAPs for all included studies. We extracted data to characterize the disclosure of sufficient information in the available materials to inform assessments of selective reporting biases, considering the definition of outcome domain, measure, metric, method of aggregation, time point, analysis population, methods to handle missing data and method of adjustment. RESULTS: Most trials (69%) were registered, but these often lacked sufficient specification of outcomes and intended treatment effects. Protocols and SAPs provided more details but were less often available (14% and 3%, respectively), and even then, almost all studies presented limited information to inform the assessments of risk of bias due to the selection of the reported result. CONCLUSION: Lack of full specification of outcomes and intended treatment effects hinder a full adherence of randomized controlled trials of nutrition interventions to transparency practices and may affect their credibility.

Prebiotics may reduce serum concentrations of C-reactive protein and ghrelin in overweight and obese adults: a systematic review and meta-analysis.

CONTEXT: Biochemical markers correlate positively with the development and severity of obesity, depression, and anxiety, and can be modulated by changes in intestinal microbiota composition. OBJECTIVE: A systematic review and meta-analysis was conducted to determine the effects of prebiotics or synbiotics on blood biomarkers of obesity, depression, and anxiety (including: ACTH [adrenocorticotropic hormone], cortisol, leptin, ghrelin, TSH [thyroid-stimulating hormone], PTH [parathyroid hormone], vitamin D, BDNF [brain-derived neurotrophic factor], and PCR [polymerase chain reaction]) in individuals with overweight or obesity. DATA SOURCES: MEDLINE, Web of Science, Scopus, and CENTRAL databases were searched, along with the reference lists of included articles. Authors were contacted for unpublished data. STUDY SELECTION: RCT in individuals with overweight or obesity, supplemented with prebiotics or synbiotics, assessing any of the outcomes of interest. DATA EXTRACTION: Data were extracted independently by three researchers. RESULTS: Thirteen studies were identified up to March 7, 2018. Regarding outcomes, 1 study assessed leptin, 4 studies assessed ghrelin, and 10 studies assessed CRP (C-reactive protein). Meta-analysis showed reduction in serum concentrations of ghrelin (-37.17 pg/mL; 95%CI = -69.62, -4.73; P = 0.025) and CRP (SMD [standardized mean difference] = -0.31; 95%CI = -0.58, -0.04; P = 0.027) after supplementation of inulin-type fructans. CONCLUSIONS: Prebiotics may help regulate blood concentrations of ghrelin and CRP in overweight or obese individuals.