Abstract

INTRODUCTION Orthorexia nervosa (ON), characterized by a pathological preoccupation with "extreme dietary purity," is increasingly observed as a mental health condition among young adults and the general population. However, its diagnosis is not formally recognized and has remained contentious. OBJECTIVE In this systematic review, we attempt to overview previous reviews on ON, focusing on the methodological and conceptual issues with ON. This would serve both as a summary and a way to highlight gaps in earlier research. METHODS This systematic review took reference from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines, and using combinations of the search terms ("orthorexia" OR "orthorexia nervosa" OR "ON") AND ("review" OR "systematic review" OR "meta-analysis"), a literature search was performed on EMBASE, Medline and PsycINFO databases from inception up to October 31, 2023. Articles were included if (1) they were written or translated into English and (2) contained information pertaining to the diagnostic stability or validity of ON, or instruments used to measure ON symptoms and behaviors. Only review articles with a systematic literature search approach were included. RESULTS A total of 22 reviews were qualitatively reviewed. Several studies have reported variable prevalence of ON and highlighted the lack of thoroughly evaluated measures of ON with clear psychometric properties, with no reliable estimates. ORTO-15 and its variations such as ORTO-11, ORTO-12 are popularly used, although their use is discouraged. Existing instruments lack specificity for pathology and several disagreements on the conceptualization and hence diagnostic criteria of ON exist. DISCUSSION Previous reviews have consistently highlighted the highly variable (and contradictory) prevalence rates with different instruments to measure ON, lack of stable factor structure and psychometrics across ON measures, paucity of data on ON in clinical samples, and a need for a modern re-conceptualization of ON. The diagnosis of ON is challenging as it likely spans a spectrum from "normal" to "abnormal," and "functional" to "dysfunctional." "Non-pathological" orthorexia is not related to psychopathological constructs in the same way that ON is.

Abstract

Irritable bowel syndrome (IBS) is a highly prevalent disorder of brain-gut interaction with a significant impact on quality of life. Coffee is a widely consumed beverage with numerous bioactive compounds that have potential effects on human health and disease states. Current studies on the effect of regular coffee consumption on the risk of developing IBS symptoms have yielded conflicting results. This systematic review and meta-analysis aimed to determine whether coffee intake is associated with developing IBS. A systematic literature search was performed in three electronic databases, namely PubMed, EMBASE, and The Cochrane Library, from inception until 31 March 2023. All original studies reporting associations between coffee intake and IBS were considered for inclusion. Odds ratios (ORs) were calculated for each study, and estimates were pooled, and where appropriate, 95% confidence intervals (95% CI) and p-values were calculated. Eight studies comprising 432,022 patients were included in the final meta-analysis. Using a fixed-effects model, coffee drinkers (any intake) had a reduced likelihood of developing IBS compared to controls, with a pooled OR of 0.84 (95% CI: 0.80 to 0.84). Sensitivity analysis confirmed the stability of the estimates. Future research should prioritise prospective cohort studies that are robust and closely track the development of incident IBS in previously healthy individuals.

Abstract

Irritable bowel syndrome is a prototypical disorder of the brain-gut-microbiome axis, although the underlying pathogenesis and mechanisms remain incompletely understood. With the recent advances in 'omics' technologies, studies have attempted to uncover IBS-specific variations in the host-microbiome profile and function. However, no biomarker has been identified to date. Given the high inter-individual and day-to-day variability of the gut microbiota, and a lack of agreement across the large number of microbiome studies, this review focused on omics studies that had sampling at more than one time point. A systematic literature search was performed using various combinations of the search terms "Irritable Bowel Syndrome" and "Omics" in the Medline, EMBASE, and Cochrane Library up to 1 December 2022. A total of 16 original studies were reviewed. These multi-omics studies have implicated Bacteroides, Faecalibacterium prausnitzii, Ruminococcus spp., and Bifidobacteria in IBS and treatment response, found altered metabolite profiles in serum, faecal, or urinary samples taken from IBS patients compared to the healthy controls, and revealed enrichment in the immune and inflammation-related pathways. They also demonstrated the possible therapeutic mechanisms of diet interventions, for example, synbiotics and low fermentable oligosaccharides, disaccharides, monosaccharides, and polyol (FODMAP) diets on microbial metabolites. However, there was significant heterogeneity among the studies and no uniform characteristics of IBS-related gut microbiota. There is a need to further study these putative mechanisms and also ensure that they can be translated to therapeutic benefits for patients with IBS.

Abstract

OBJECTIVE Metabolic bariatric procedures are potentially efficacious treatment options in patients with type 2 diabetes mellitus (T2DM). Previous meta-analyses focused on individual operative approaches rather than the mechanistic pathways behind different bariatric procedures. This updated network meta-analysis aimed to synthesize new evidence and comparatively evaluate the efficacy of metabolic surgery against restrictive procedures and standard first-line treatment for patients with T2DM. METHODS Embase, MEDLINE, and trial registries were searched for randomized controlled trials on bariatric surgeries in patients with T2DM on September 3, 2021. A Bayesian network meta-analysis was conducted. The primary outcome was T2DM remission. Secondary outcomes included changes in BMI, lipoprotein levels, and blood pressure. RESULTS Thirty-two articles were included. Metabolic surgery was statistically superior to restrictive procedures (risk ratio [RR]: 2.57, 95% credibility intervals [CrI]: 1.36-5.43), medical therapy (RR: 35.29, 95% Crl: 10.56-183.23), and lifestyle intervention (RR: 40.51, 95% Crl: 5.32-402.59) in T2DM remission. Metabolic surgery significantly lowered BMI and blood pressure compared with other interventions. Restrictive procedures significantly increased high-density lipoprotein compared with metabolic surgery. Lifestyle intervention and metabolic surgery were statistically superior to restrictive procedures in reducing low-density lipoprotein. CONCLUSIONS The superiority in diabetes remission and favorable metabolic profile support the choice of metabolic surgery over restrictive bariatric procedures.