The Impact of Dietary Interventions on the Microbiota in Inflammatory Bowel Disease: A Systematic Review

Gut-lung Axis mediates asthma pathogenesis: Roles of dietary patterns and their impact on the gut microbiota

The gut-lung axis, a vital signaling network linking the gastrointestinal and pulmonary systems, regulates immune responses and the progression of respiratory diseases. Nutritional components can modulate the gut microbiome and regulate the synthesis of critical intestinal microbial metabolites, which are essential for maintaining immune homeostasis and supporting respiratory health. Conversely, poor dietary habits exacerbate asthma and other respiratory conditions through the modulation of systemic inflammation and immune responses. Dietary interventions, such as the Mediterranean diet, are reported to restore microbial balance and improve respiratory health by increasing the production of anti-inflammatory metabolites, potentiating immune responses, and preserving epithelial barrier integrity. In contrast, Western dietary patterns, which are characterized by high fat and low fiber intake, disrupt microbial diversity, resulting in increased levels of pro-inflammatory metabolites that aggravate airway inflammation and asthma severity. This review aimed to elucidate the mechanisms underlying the regulatory effects of gut microbes and their metabolites on asthma. Additionally, previous findings related to the gut-lung axis have been summarized, providing insights into potential therapeutic strategies for asthma management.

Exploring the connection between erythrocyte membrane fatty acid composition and oxidative stress in patients undergoing the Crohn's disease Therapeutic Diet Intervention (CD-TDI)

Background

Dietary fatty acids (FA) are crucial to the pathophysiology of inflammatory bowel disease (IBD), influencing systemic and gut inflammatory responses. Dietary FA intake influences the fatty acid profiles of vital cell membranes, which might be a source of inflammatory mediators. Despite their significance, research on dietary FA subtypes and their effects on inflammation and oxidative stress in IBD is limited.

Objective

We investigated the association between dietary FA intake, the erythrocyte membrane FA composition (EMFA), and inflammation and oxidative stress markers in patients with mild-moderate luminal Crohn's Disease (CD) participating in the CD Therapeutic Dietary Intervention (CD-TDI).

Design

A cross-sectional analysis was performed on 24 participants (13 CD-TDI, 11 habitual diet controls) from a 13-week randomized controlled trial assessing the efficacy of CD-TDI in inducing clinical and biomarker remission in CD.

Methods

EMFA was analyzed using direct-injection gas chromatography, and dietary FA intake was assessed using the ASA 24-h Dietary Assessment Tool®.

Results

The CD-TDI group showed a significant increase in dietary n-3 polyunsaturated fatty acids (PUFA) at Week 13 (p = 0.04) compared to no changes in the control group. Participants on the CD-TDI also demonstrated a significant reduction in total fat, saturated fat, and arachidonic acid (AA) (p < 0.01). EMFA analysis revealed lower percentages of AA (p = 0.03) in the CD-TDI group. Positive correlations were observed between C-reactive protein, fecal calprotectin, and dietary stearic acid (p < 0.05). Inverse correlations were found between malondialdehyde (MDA) and the Mediterranean Diet Score (r = -0.67) as well as MDA and the intake of whole fruit, legumes, and nuts/seeds (r > -0.50).

Conclusion

The CD-TDI significantly increased dietary n-3 PUFA intake, reduced pro-inflammatory n-6 PUFA (AA), and improved markers of oxidative stress, supporting its potential in CD management. The cell membrane fatty acid profile might be a therapeutic target in CD.

Trial registration

NCT04596566.

From Evidence to Practice: A Narrative Framework for Integrating the Mediterranean Diet into Inflammatory Bowel Disease Management

Emerging evidence underscores the pivotal role of diet in preventing and managing inflammatory bowel disease (IBD). As our comprehension of the microbiome's role in IBD expands, dietary modifications are increasingly recognized as potential adjuncts or primary therapeutic strategies. Key components of the Mediterranean diet (MD)-including microbiota-accessible carbohydrates, omega-3 fatty acids, polyphenols, and antioxidants-have demonstrated promise in enhancing gut microbiota diversity and reducing intestinal inflammation, making it a practical approach for managing IBD. Moreover, the MD offers additional benefits considering the rising prevalence of comorbid chronic inflammatory conditions such as diabetes, cardiovascular disease, and obesity in IBD patients. The purpose of this narrative review was to provide an overview of the feasibility and clinical outcomes of the MD and offer evidence-based guidance for researchers and practitioners on how to adapt the MD to patients with IBD. According to several cross-sectional and interventional studies, the MD is feasible for patients with IBD and confers several benefits, such as reduced inflammation, improved disease activity, and enhanced quality of life, with a strong adherence rate and minimal adverse effects. To facilitate knowledge translation, we provide a practical framework for integrating the MD as a nutritional therapy for IBD, including specific recommendations and messaging that researchers, practitioners, and patients can use. By synthesizing current evidence and offering actionable insights, the aim is to facilitate the integration of the MD into IBD management, with the potential to improve patient outcomes.

Biomarkers of Intestinal Permeability Are Influenced by Diet in Patients with Ulcerative Colitis-An Exploratory Study

Background and Objectives: The disruption of the intestinal epithelial barrier leads to increased intestinal permeability (IP), allowing endotoxins and pathogens to enter the bloodstream contributing to chronic inflammation. Western diets are associated with increased IP, while diets rich in polyphenols, fiber, and omega-3 fats are linked to decreased IP. The relationship between diet, disease activity, and IP in ulcerative colitis (UC) is poorly understood. We evaluated the effects of serum zonulin and lipopolysaccharide-binding protein (LBP) and their relationship to dietary factors in UC. Methods: A cross-sectional analysis was conducted on 37 UC participants who had baseline measures of dietary intake, disease activity and serum. Serum LBP and zonulin levels were measured by ELISA. Spearman's rank correlations explored relationships between baseline IP, diet, and disease activity. Results: The median age was 35 years (29-47 years), 54% were male, and 76% were in clinical remission or had mild disease activity (partial Mayo score ≤ 4). LBP was significantly correlated (p < 0.05) with disease activity (partial Mayo score (r = 0.31), and positively correlated with total fat (r = 0.42) and refined grains (r = 0.35), but negatively correlated with fruit consumption (r = -0.50) and diet quality (r = -0.33). Zonulin was negatively correlated with protein (r = -0.39), niacin (r = -0.52) and vitamin B12 (r = -0.45) with a trend for significance (p = 0.06) with body mass index (r = 0.32). Conclusions: Baseline LBP levels were correlated with disease activity markers and dietary factors, suggesting that it could be a useful biomarker for assessing disease activity and diet quality in UC. Further trials are needed to confirm these findings.

Healing from Within: How Gut Microbiota Predicts IBD Treatment Success-A Systematic Review

Recent research indicates that the microbiome has a significant impact on the progression of inflammatory bowel disease (IBD) and that creating therapies that change its composition could positively impact the outcomes of IBD treatment. This review summarizes the results of extensive studies that examined IBD patients undergoing several therapies, including anti-TNF medication, vedolizumab, ustekinumab, probiotics, and fecal microbiota transplantation (FMT), and the alterations in their gut microbiota's composition and function. The objective was to investigate the variety and effectiveness of microbial species in order to discover new biomarkers or therapeutic targets that could improve the outcome of treatment for these patients. This research aimed to offer useful insights into personalized medicine techniques for managing IBD. Beneficial bacteria such as Faecalibacterium prausnitzii and Roseburia have been consistently linked to favorable clinical outcomes, whereas pathogenic bacteria such as Escherichia coli and Clostridioides difficile are associated with worsening disease conditions. Although many studies have examined the role of gut microbiota in IBD, there is still a need for more targeted research on the connection between specific microbial communities and treatment outcomes. This study sought to address this gap by exploring the intricate relationship between the gut microbiota composition and the effectiveness of IBD medications.

How the Western Diet Thwarts the Epigenetic Efforts of Gut Microbes in Ulcerative Colitis and Its Association with Colorectal Cancer

Ulcerative colitis (UC) is an autoimmune disease in which the immune system attacks the colon, leading to ulcer development, loss of colon function, and bloody diarrhea. The human gut ecosystem consists of almost 2000 different species of bacteria, forming a bioreactor fueled by dietary micronutrients to produce bioreactive compounds, which are absorbed by our body and signal to distant organs. Studies have shown that the Western diet, with fewer short-chain fatty acids (SCFAs), can alter the gut microbiome composition and cause the host's epigenetic reprogramming. Additionally, overproduction of H2S from the gut microbiome due to changes in diet patterns can further activate pro-inflammatory signaling pathways in UC. This review discusses how the Western diet affects the microbiome's function and alters the host's physiological homeostasis and susceptibility to UC. This article also covers the epidemiology, prognosis, pathophysiology, and current treatment strategies for UC, and how they are linked to colorectal cancer.

Mannose enhances intestinal immune barrier function and dextran sulfate sodium salt-induced colitis in mice by regulating intestinal microbiota

Background

Inflammatory bowel disease (IBD) greatly affects human quality of life. Mannose has been reported to be used to treat IBD, but the mechanism is currently unknown.

Methods

C57/BL mice were used as research subjects, and the mouse acute colitis model was induced using dextran sulfate sodium salt (DSS). After oral administration of mannose, the body weights and disease activity index (DAI) scores of the mice were observed. The colon lengths, histopathological sections, fecal content microbial sequencing, colon epithelial inflammatory genes, and tight junction protein Occludin-1 expression levels were measured. We further used the feces of mice that had been orally administered mannose to perform fecal bacterial transplantation on the mice with DSS-induced colitis and detected the colitis-related indicators.

Results

Oral administration of mannose increased body weights and colon lengths and reduced DAI scores in mice with DSS-induced colitis. In addition, it reduced the expression of colon inflammatory genes and the levels of serum inflammatory factors (TNF-α, IL-6, and IL-1β), further enhancing the expression level of the colonic Occludin-1 protein and alleviating the toxic response of DSS to the intestinal epithelium of the mice. In addition, gut microbial sequencing revealed that mannose increased the abundance and diversity of intestinal flora. Additionally, after using the feces of the mannose-treated mice to perform fecal bacterial transplantation on the mice with DSS-induced colitis, they showed the same phenotype as the mannose-treated mice, and both of them alleviated the intestinal toxic reaction induced by the DSS. It also reduced the expression of intestinal inflammatory genes (TNF-α, IL-6, and IL-1β) and enhanced the expression level of the colonic Occludin-1 protein.

Conclusion

Mannose can treat DSS-induced colitis in mice, possibly by regulating intestinal microorganisms to enhance the intestinal immune barrier function and reduce the intestinal inflammatory response.