Dietary Zinc Intake and Inflammatory Bowel Disease in the French NutriNet-Santé Cohort

Role of diet in prevention versus treatment of Crohn's disease and ulcerative colitis

Diet is a modifiable risk factor for disease course and data over the past decade have emerged to indicate its role in Crohn's disease (CD) and ulcerative colitis (UC). However, literature is riddled with misinterpretation of data, often leading to unexpected or conflicting results. The key understanding is that causative factors in disease development do not always proceed to an opportunity to change disease course, once established. Here, we discuss the data on dietary influences in three distinct disease states for CD and UC-predisease, active disease and quiescent disease. We appraise the literature for how our dietary recommendations should be shaped to prevent disease development and if or how that differs for CD and UC induction therapy and maintenance therapy. In UC, principles of healthy eating are likely to play a role in all states of disease. Conversely, data linking dietary factors to CD prevention and treatment are paradoxical with the highest quality evidence for CD treatment being exclusive enteral nutrition, a lactose, gluten and fibre-free diet comprising solely of ultraprocessed food-all dietary factors that are not associated or inversely associated with CD prevention. High-quality evidence from dietary trials is much awaited to expand our understanding and ultimately lead our dietary recommendations for targeted patient populations.

Potential effects of nutrition-induced alteration of gut microbiota on inflammatory bowel disease: A review

Inflammatory bowel disease (IBD), mainly comprising ulcerative colitis and Crohn's disease, is a group of gradually progressive diseases bringing significant mental anguish and imposes serious economic burdens. Interplay of genetic, environmental, and immunological factors have been implicated in its pathogenesis. Nutrients, as crucial environmental determinants, mainly encompassing carbohydrates, fats, proteins, and micronutrients, are closely related to the pathogenesis and development of IBD. Nutrition is essential for maintaining the dynamic balance of intestinal eco-environments to ensure intestinal barrier and immune homeostasis, while this balance can be disrupted easily by maladjusted nutrition. Research has firmly established that nutrition has the potential to shape the composition and function of gut microbiota to affect the disease course. Unhealthy diet and eating disorders lead to gut microbiota dysbiosis and further destroy the function of intestinal barrier such as the disruption of membrane integrity and increased permeability, thereby triggering intestinal inflammation. Notably, appropriate nutritional interventions, such as the Mediterranean diet, can positively modulate intestinal microecology, which may provide a promising strategy for future IBD prevention. In this review, we provide insights into the interplay between nutrition and gut microbiota and its effects on IBD and present some previously overlooked lines of evidence regarding the role of derived metabolites in IBD processes, such as trimethylamine N-oxide and imidazole propionate. Furthermore, we provide some insights into reducing the risk of onset and exacerbation of IBD by modifying nutrition and discuss several outstanding challenges and opportunities for future study.

Adjunctive therapeutic effects of micronutrient supplementation in inflammatory bowel disease

Growing evidence suggests that micronutrient status may have some impact on the course of inflammatory bowel disease (IBD). However, micronutrient deficiencies are easily overlooked during the treatment of IBD patients. There have been many studies on micronutrient supplementation, in which several clinical trials have been conducted targeting vitamin D and iron, but the current research is still preliminary for other vitamins and minerals. This review provides an overview of the adjunctive therapeutic effects of micronutrient supplementation in IBD, to summarize the available evidence, draw the attention of clinicians to micronutrient monitoring and supplementation in patients with IBD, and also provide some perspectives for future research directions.

Antioxidants, minerals and vitamins in relation to Crohn's disease and ulcerative colitis: A Mendelian randomization study

BACKGROUND

Evidence for antioxidants, minerals and vitamins in relation to the risk of Crohn's disease (CD) and ulcerative colitis (UC) is limited and inconsistent. This mendelian randomization (MR) study aimed to examine the causal associations of circulating levels of antioxidants, minerals and vitamins with CD and UC.

METHODS

Single-nucleotide polymorphisms associated with antioxidants (beta-carotene, lycopene and uric acid), minerals (copper, calcium, iron, magnesium, phosphorus, zinc and selenium), and vitamins (folate, vitamins A, B6, B12, C, D, E and K1) were employed as instrumental variables. Genetic associations with CD and UC were extracted from the UK Biobank, the FinnGen study and the International Inflammatory Bowel Disease Genetics Consortium. The inverse variance weighted method and sensitivity analyses were performed.

RESULTS

Genetically predicted higher lycopene (OR = 0.94, 95% CI: 0.91-0.97), vitamins D (OR = 0.65, 95% CI: 0.54-0.79) and K1 (OR = 0.93, 95% CI: 0.90-0.97) levels were inversely associated with CD risk, whereas genetically predicted higher magnesium (OR = 1.53, 95% CI: 1.23-1.90) levels were positively associated with CD risk. Higher levels of genetically predicted lycopene (OR = 0.91, 95% CI: 0.88-0.95), phosphorus (OR = 0.69, 95% CI: 0.58-0.82), selenium (OR = 0.91, 95% CI: 0.85-0.97), zinc (OR = 0.91, 95% CI: 0.89-0.94), folate (OR = 0.71, 95% CI: 0.56-0.92) and vitamin E (OR = 0.78, 95% CI: 0.69-0.88) were associated with reduced UC risk, whereas genetically predicted high levels of calcium (OR = 1.46, 95% CI: 1.22-1.76) and magnesium (OR = 1.24, 95% CI: 1.03-1.49) were associated with increased risk of UC.

CONCLUSIONS

Our study provided evidence that circulating levels of antioxidants, minerals and vitamins might be causally linked to the development of IBD.

Association Between Dietary Zinc Intake and Metabolic Syndrome. A Meta-Analysis of Observational Studies

Background

Epidemiological studies have investigated the association between dietary zinc intake and metabolic syndrome (MetS). However, their results are conflicting. This meta-analysis was therefore employed to investigate the associations further.

Methods

A comprehensive literature search was employed by using the electronic database of PubMed, Web of Science, and Embase up to November 2021. The pooled relative risk (RR) of MetS for the highest vs. lowest dietary zinc intake category, and the weighted mean difference (WMD) of dietary zinc intake for MetS vs. control subjects as well as their corresponding 95% confidence interval (CI) were calculated.

Results

A total of 13 observational studies (18,073 participants) were identified in this meta-analysis. The overall multi-variable adjusted RR demonstrated that the dietary zinc intake was inversely associated with MetS (RR = 0.75, 95%CI: 0.61 to 0.93; P = 0.009). The subgroup analysis confirmed such findings in cross-sectional (RR = 0.70, 95%CI: 0.55 to 0.87; P = 0.002), NCEP-ATP III (RR = 0.64, 95%CI: 0.48 to 0.84; P = 0.002), adult (RR = 0.77, 95%CI: 0.62 to 0.96; P = 0.02), dietary recall method (RR = 0.70, 95%CI: 0.55 to 0.87; P = 0.002), and >500 sample-sized study (RR = 0.79, 95%CI: 0.64 to 0.99; P = 0.002), respectively. On the other hand, the overall combined WMD showed that the dietary zinc intake in MetS was also lower than that in control subjects (WMD = −0.21, 95%CI: −0.42 to 0.00; P = 0.05).

Conclusions

Our results suggest that the dietary zinc intake is negatively associated with MetS. However, due to the limitation of available evidence. More well-designed prospective cohort studies are still needed.

Crohn's Disease: Is the Cold Chain Hypothesis Still Hot?

Crohn's disease [CD] is an inflammatory bowel disease of unknown aetiology. During recent decades, significant technological advances led to development of -omic datasets allowing a detailed description of the disease. Unfortunately these have not, to date, resolved the question of the aetiology of CD. Thus, it may be necessary to [re]consider hypothesis-driven approaches to resolve the aetiology of CD. According to the cold chain hypothesis, the development of industrial and domestic refrigeration has led to frequent exposure of human populations to bacteria capable of growing in the cold. These bacteria, at low levels of exposure, particularly those of the genus Yersinia, are believed to be capable of inducing exacerbated inflammation of the intestine in genetically predisposed subjects. We discuss the consistency of this working hypothesis in light of recent data from epidemiological, clinical, pathological, microbiological, and molecular studies.