Diet and gut microbial associations in irritable bowel syndrome according to disease subtype

Dietary Interventions in Irritable Bowel Syndrome: A Systematic Review of Clinical Outcomes, Microbiota Changes, and Inflammatory Markers

This systematic review synthesizes findings from 12 studies to evaluate the effectiveness of dietary interventions in managing irritable bowel syndrome (IBS), with a focus on low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diets, probiotics, and prebiotics. The review rigorously follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and includes studies selected through comprehensive database searches. In adults diagnosed with IBS, this review assesses how effective dietary interventions, specifically low-FODMAP diets, probiotics, and prebiotics, are compared to standard management or placebo in improving clinical outcomes, modifying gut microbiota composition, and reducing inflammatory markers. Our analysis reveals that low-FODMAP diets consistently alleviate IBS symptoms and improve quality of life. However, the effectiveness of probiotics and prebiotics varies, with outcomes dependent on specific strains and individual patient microbiota profiles. The studies demonstrate significant improvements in gastrointestinal symptoms and microbiota composition, highlighting the potential of dietary strategies to beneficially modify gut health. However, the research points to the necessity of personalizing dietary approaches based on individual responses and microbiota profiles to optimize treatment efficacy. The risk of bias was assessed using the Cochrane risk-of-bias 2 tool for randomized controlled trials (RCTs) and the AMSTAR 2 tool for systematic reviews, with varying degrees of bias across the studies. This review identifies gaps in the long-term efficacy of these interventions and calls for more extensive trials to explore their sustained impacts. Our findings suggest that dietary management should be integrated into routine IBS treatment protocols and emphasize the need for further research to establish standardized dietary recommendations tailored to patient-specific characteristics.

Investigating the Impacts of Diet, Supplementation, Microbiota, Gut-Brain Axis on Schizophrenia: A Narrative Review

Schizophrenia is a disease with a complex etiology that significantly impairs the functioning of patients. In recent years, there has been increasing focus on the importance of the gut microbiota in the context of the gut-brain axis. In our study, we analyzed data on the gut-brain axis in relation to schizophrenia, as well as the impacts of eating habits, the use of various supplements, and diets on schizophrenia. Additionally, the study investigated the impact of antipsychotics on the development of metabolic disorders, such as diabetes, dyslipidemia, and obesity. There may be significant clinical benefits to be gained from therapies supported by supplements such as omega-3 fatty acids, B vitamins, and probiotics. The results suggest the need for a holistic approach to the treatment of schizophrenia, incorporating both drug therapy and dietary interventions.

Prevalence of and factors associated with symptoms consistent with a diagnosis of irritable bowel syndrome among resident physicians in standardised training in China: a cross-sectional study

OBJECTIVES

This study aims to investigate the incidence of and factors associated with irritable bowel syndrome (IBS) among resident physicians in standardised training at eight traditional Chinese medicine (TCM) hospitals in China.

DESIGN

A cross-sectional survey was administered to resident physicians in their first to third years of standardised training at eight TCM hospitals.

PARTICIPANTS AND SETTING

A total of 514 resident physicians in standardised training were included.

MEASURES

The questionnaire consisted of two sections, namely: section A collected basic information, and section B included the four-item Perceived Stress Scale (PSS-4), the Patient Health Questionnaire-4 (PHQ-4), the Pittsburgh Sleep Quality Index (PSQI) and the Rome IV criteria for IBS. Univariate and multivariate logistic regression models were constructed to assess the associations of age, sex, body mass index, stress, depression, anxiety, sleep quality and IBS.

RESULTS

Of the included resident doctors, 77.2% were female, 20.4% were obese or underweight and 8.6% had symptoms consistent with a diagnosis of IBS. There were no statistically significant differences in lifestyle factors (night shift work, overtime work or working efficiency during the COVID-19 pandemic) between patients with IBS and participants without IBS (hereafter, non-IBS participants) (p=0.429, p=0.572 or p=0.464, respectively). Notably, compared with non-IBS participants, patients with IBS had significantly higher mean scores on the PSS-4 and PHQ-4 (p=0.028 and p=0.012, respectively); however, there was not a significant difference in PSQI scores between these two groups (p=0.079). Depression symptoms were significantly associated with IBS (unadjusted OR 0.498, 95% CI 0.265 to 0.935, p=0.030).

CONCLUSION

These findings suggest that IBS is common among resident physicians in standardised training. Future studies should investigate emotional distress, especially stress and depression, in the development of prevention or treatment of IBS.

The Gut-Brain Axis in Schizophrenia: The Implications of the Gut Microbiome and SCFA Production

Schizophrenia, a severe mental illness affecting about 1% of the population, manifests during young adulthood, leading to abnormal mental function and behavior. Its multifactorial etiology involves genetic factors, experiences of adversity, infection, and gene-environment interactions. Emerging research indicates that maternal infection or stress during pregnancy may also increase schizophrenia risk in offspring. Recent research on the gut-brain axis highlights the gut microbiome's potential influence on central nervous system (CNS) function and mental health, including schizophrenia. The gut microbiota, located in the digestive system, has a significant role to play in human physiology, affecting immune system development, vitamin synthesis, and protection against pathogenic bacteria. Disruptions to the gut microbiota, caused by diet, medication use, environmental pollutants, and stress, may lead to imbalances with far-reaching effects on CNS function and mental health. Of interest are short-chain fatty acids (SCFAs), metabolic byproducts produced by gut microbes during fermentation. SCFAs can cross the blood-brain barrier, influencing CNS activity, including microglia and cytokine modulation. The dysregulation of neurotransmitters produced by gut microbes may contribute to CNS disorders, including schizophrenia. This review explores the potential relationship between SCFAs, the gut microbiome, and schizophrenia. Our aim is to deepen the understanding of the gut-brain axis in schizophrenia and to elucidate its implications for future research and therapeutic approaches.