Food Additive Emulsifiers and Their Impact on Gut Microbiome, Permeability, and Inflammation: Mechanistic Insights in Inflammatory Bowel Disease.

The global burden of inflammatory bowel disease [IBD] has increased over the 21st century. Despite multiple studies investigating the pathogenesis of IBD, the causative mechanisms pertaining to its increased prevalence remain unclear. There is growing evidence that aspects of a 'Western diet' increase the risk of developing IBD. More recently, evidence implicating dietary emulsifiers has accumulated, with ecological studies showing a positive correlation between inflammatory bowel disease and emulsifier consumption. Further to these, cell and animal studies have demonstrated plausible mechanisms by which dietary emulsifiers may contribute to IBD pathogenesis through mechanisms including: promotion of pro-inflammatory intestinal microbiota; disruption of mucus architecture; increased intestinal permeability; activation of inflammatory pathways; and disruption of the cell cycle. This review critically analyses the current evidence for these mechanisms that may be of pathological relevance to IBD, evaluates recent dietary trials, acknowledges the challenges of dietary intervention studies, and gives an overview of ongoing and future clinical trials in this important area.

Emulsifiers Impact Colonic Length in Mice and Emulsifier Restriction is Feasible in People with Crohn's Disease.

There is an association between food additive emulsifiers and the prevalence of Crohn's disease. This study aimed to investigate: (i) the effect of different classes of emulsifiers on markers of intestinal inflammation in mice and (ii) the feasibility, nutritional adequacy and symptom impact of restricting all emulsifier classes in Crohn's disease. Mice were exposed to different classes of emulsifiers (carboxymethycellose, polysorbate-80, soy lecithin, gum arabic) in drinking water for 12-weeks, after which markers of inflammation and metabolism were measured. A low emulsifier diet was developed to restrict all classes of emulsifiers and its feasibility measured over 14-days in 20 participants with stable Crohn's disease. Crohn's disease-related symptoms, disease control, body weight and composition, nutrient intake and food-related quality of life (QoL) were measured. All emulsifiers resulted in lower murine colonic length compared with control (mean 9.5 cm (SEM 0.20)), but this only reached significance for polysorbate-80 (8.2 cm (0.34), p = 0.024) and carboxymethylcellulose (8.0 cm (0.35), p = 0.013). All 20 participants completed the feasibility study. The frequency of consuming emulsifier-containing foods decreased by 94.6% (SD 10.3%). Food-related QoL improved between habitual (median 81.5 (IQR 25.0)) and low emulsifier diet (90.0 (24.0), p = 0.028). Crohn's disease-related symptoms reduced (median 3.0 (IQR 5.3) vs. 1.4 (3.9), p = 0.006), and disease control scores improved (13.5 (IQR 6.0) vs. 15.5 (IQR 3.0), p = 0.026). A range of emulsifiers may influence intestinal inflammation in mice, and dietary restriction of emulsifiers is feasible. Trials investigating the efficacy of a low emulsifier diet in Crohn's disease are warranted.

Nutrition Assessment in Crohn's Disease using Anthropometric, Biochemical, and Dietary Indexes: A Narrative Review.

Malnutrition is common in patients with Crohn's disease and negatively influences immunity and quality of life. The optimal tools for nutrition assessment in patients with Crohn's disease are not clearly defined and lead to variations in practice. With this review, we aimed to appraise the existing evidence for nutrition assessment of patients with Crohn's disease compared with healthy controls and provide a comprehensive guide with relevant measures applicable to clinical practice. A literature search using Medline, Embase, and Scopus from inception to October 1, 2018, was conducted. Forty-one articles that assessed body composition, muscle strength, micronutrient status and/or dietary intake in adults with Crohn's disease compared with an age- and sex-matched healthy individuals were included. There were heterogeneous findings on nutritional status in patients with Crohn's disease compared with healthy controls. Only one article reported a clinically significant difference for body mass index; however, significant deficits in fat mass, fat-free mass, and muscle strength were observed in patients with Crohn's disease compared with healthy controls, with more pronounced differences with increasing disease activity and length of diagnosis. Most research reported significantly lower serum micronutrients in patients with Crohn's disease compared with healthy controls. Half of studies measuring micronutrient intake reported lower intakes in patients with Crohn's disease compared with healthy controls. Fruit and vegetable intake was also lower in patients with Crohn's disease. Difficulties characterizing the type and prevalence of malnutrition exist due to the heterogeneous nature of Crohn's disease and warrants continued investigation. As a result of this review, we advocate that a nutrition assessment should include more parameters than weight and body mass index.