Dietary intake of fish, n-3 polyunsaturated fatty acids, and risk of inflammatory bowel disease: a systematic review and meta-analysis of observational studies

Synergistic effect and mechanism of monoacylglycerol lipase inhibitor and Icaritin in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic, relapsing nonspecific intestinal inflammatory disease. It is difficult for a single drug to treat UC effectively and maintain long-term efficacy. There is an urgent need to find new drugs and treatment strategies. MAGL11 is a new kind of single acylglycerol lipase (MAGL) inhibitor. Icaritin (Y003) is the major metabolite of icariin in vivo. Several studies have confirmed the role of MAGL inhibitors and icariin in anti-inflammatory and regulation of intestinal stability. Therefore, this study adopted a new strategy of combining MAGL inhibitor with Icaritin to further explore the role and mechanism of drugs in the treatment of UC. Enzyme-linked immunosorbent assay (ELISA), hematoxylin-eosin staining (HE), immunohistochemical (IHC) and Western blot were used to detect the synergistic protective effects of MAGL11 and Y003 on intestinal pathological injury, intestinal mucosal permeability and inflammation in UC mice. 16S rDNA sequencing was used to detect the synergistic effect of MAGL11 and Y003 on gut microbiota. The effects of MAGL11 and Y003 combined therapy on serum and fecal metabolism of UC mice were analyzed by untargeted metabolomics. Proteomics method was applied to investigate the molecular mechanisms underlying MAGL11 and Y003 synergy in the treatment of UC. The results showed that MAGL11 and Y003 could synergistically improve the clinical symptoms, reduce intestinal inflammation and pathological damage, and improve intestinal mucosal permeability in UC mice. The mechanism study found that MAGL11 and Y003 could synergistically inhibit Toll-like receptors 4 (TLR4) / Myeloid differentiation primary response gene (Myd88)/Nuclear factor kappa-B (NF-κB) pathway and further regulate gut microbiota imbalance and metabolic disorders to treat UC.

Association between Omega-3 fatty acids and autoimmune disease: Evidence from the umbrella review and Mendelian randomization analysis

BACKGROUND

Autoimmune diseases are a group of disorders characterized by abnormal immune responses that mistakenly target and attack healthy cells, tissues, and organs, resulting in inflammation and tissue damage. Omega-3 fatty acids possess anti-inflammatory activities and may decrease abnormal immune activity. However, the role of omega-3 fatty acids in various autoimmune diseases is still unclear. This umbrella review and Mendelian randomization (MR) study aims to summarize the highest available evidence on omega-3 fatty acids and autoimmune disease.

METHODS

We conducted an umbrella review by searching electronic databases to identify systematic reviews and meta-analyses. The selection criteria included systematic reviews with or without meta-analysis, which evaluated omega-3 fatty acids as the exposure and autoimmune disease as the outcome variable. Two authors independently assessed the overlapping and quality of the reviews using the AMSTAR-2 tool. We also performed MR studies to investigate the potential causal effect of fatty acids on the risk of various autoimmune diseases, utilizing data from the meta-analysis of the UKB-TOPMed and FinnGen cohorts.

RESULT

The umbrella review identified 21 studies (8 systematic reviews and 13 meta-analyses) on 9 autoimmune diseases and 30 diseases in the MR study. AMSTAR 2 categorized the quality of evidence in six studies as critically low, six studies as low, eight studies as moderate, and one as high-quality evidence. The consistent result between the review and the MR study demonstrated the benefit of omega-3 fatty acids on rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Additionally, in our summary review, omega-3 fatty acids can improve disease activity and inflammation biomarkers; however, MR studies provided no consistent evidence for the causal effects of omega-3 fatty acids on psoriasis, multiple sclerosis (MS), type 1 diabetes (T1D), IgA nephropathy (IgAN), juvenile idiopathic arthritis (JIA), Crohn's disease (CD), and ulcerative colitis (UC).

CONCLUSION

The current study presented solid evidence highlighting the advantageous impact of omega-3 fatty acids on SLE and RA. This was achieved through the reduction of disease risk, the decrease of disease activity, and the mitigation of inflammatory biomarkers. To stratify another autoimmune illness, it is necessary to carry out rigorous evaluations to surpass the existing findings and enhance understanding in this domain.

Plant-based seafood alternatives: Current insights on the nutrition, protein-flavour interactions, and the processing of these foods

Fish are an important food source; however, the sustainability of current seafood supplies is a major concern for key stakeholders. The development of plant-based seafood alternatives may be suitable products to alleviate some of the pressures on aquatic ecosystems and help support environmental sustainability. However, the wide-spread adoption of these products weighs heavily on the ingredients used in the formulations which should not only satisfy nutritional and sustainability targets but must also meet consumer approval and functionality. In this review, we highlight recent advances in our understanding of the nutritional quality and sensory challenges in particular flavour (which includes taste and aroma), that have so far proven difficult to overcome in the development of plant-based seafood alternatives. Protein interactions that contribute to flavour development in plant-based seafood alternatives and the factors that impact these interactions are also discussed. We also review the recent advances in the innovative technologies used to improve the texture of products in this emerging food category. Finally, we highlight key areas for targeted research to advance the development of this growing segment of food products.

The Role of the Gut Microbiome in Inflammatory Bowel Disease: The Middle East Perspective

The gut microbiome is of paramount importance in preserving internal balance in the gastrointestinal tract; therefore, disruptions in its regulation have been linked to the development of inflammatory bowel disease (IBD). This article explores the intricate details of the gastrointestinal microbiome as it pertains to inflammatory bowel disease (IBD), with an emphasis on the Middle East. The study reviews the typical gut microbiome, modifications in inflammatory bowel disease (IBD), determinants impacting the gut microbiome of the Middle East, and prospective therapeutic interventions.

Diet, Food, and Nutritional Exposures and Inflammatory Bowel Disease or Progression of Disease: an Umbrella Review

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), contributes to substantial morbidity. Understanding the intricate interplay between dietary factors and the incidence and progression of IBD is essential for developing effective preventative and therapeutic strategies. This umbrella review comprehensively synthesizes evidence from systematic reviews and meta-analyses to evaluate these complex associations. Dietary factors associated with an increased incidence and/or progression of IBD include a high intake of red and processed meat, other processed foods, and refined sugars, together with a low intake of vegetables, fruits, and fiber. For most other food groups, the results are mixed or indicate no clear associations with IBD, CD, and UC. Some differences seem to exist between UC and CD and their risk factors, with increased intake of dietary fiber being inversely associated with CD incidence but not clearly associated with UC. Dietary fiber may contribute to maintaining the gut epithelial barrier and reduce inflammation, often through interactions with the gut microbiota. This seems to play an important role in inflammatory mechanisms in the gut and in IBD incidence and progression. Diets low in fermentable saccharides and polyols can alleviate symptom burden, but there are concerns regarding their impact on the gut microbiota and their nutritional adequacy. Mediterranean diets, vegetarian diets, and a diet low in grains, sugars, and lactose (specific carbohydrate diet) are also associated with lower incidence and/or progression of IBD. The associations of dietary patterns are mirrored by inflammatory biomarkers. IBD is typically treated pharmaceutically; however, many patients have a suboptimal response to medical treatments. The findings from this umbrella review could provide evidence for nutritional counseling and be a valuable addition to traditional treatment plans for IBD. This systematic review was registered at PROSPERO as CRD440252.

Krill Oil and Its Bioactive Components as a Potential Therapy for Inflammatory Bowel Disease: Insights from In Vivo and In Vitro Studies

Krill oil is extracted from krill, a small crustacean in the Antarctic Ocean. It has received growing attention because of krill oil's unique properties and diverse health benefits. Recent experimental and clinical studies suggest that it has potential therapeutic benefits in preventing the development of a range of chronic conditions, including inflammatory bowel disease (IBD). Krill oil is enriched with long-chain n-3 polyunsaturated fatty acids, especially eicosapentaenoic and docosahexaenoic acids, and the potent antioxidant astaxanthin, contributing to its therapeutic properties. The possible underlying mechanisms of krill oil's health benefits include anti-inflammatory and antioxidant actions, maintaining intestinal barrier functions, and modulating gut microbiota. This review aims to provide an overview of the beneficial effects of krill oil and its bioactive components on intestinal inflammation and to discuss the findings on the molecular mechanisms associated with the role of krill oil in IBD prevention and treatment.

Early-life diet and risk of inflammatory bowel disease: a pooled study in two Scandinavian birth cohorts

OBJECTIVE

We assessed whether early-life diet quality and food intake frequencies were associated with subsequent IBD.

DESIGN

Prospectively recorded 1-year and 3-year questionnaires in children from the All Babies in Southeast Sweden and The Norwegian Mother, Father and Child Cohort Study were used to assess diet quality using a Healthy Eating Index and intake frequency of food groups. IBD was defined as >2 diagnoses in national patient registers. Cox regression yielded HRs adjusted (aHRs) for child's sex, parental IBD, origin, education level and maternal comorbidities. Cohort-specific results were pooled using a random-effects model.

RESULTS

During 1 304 433 person-years of follow-up, we followed 81 280 participants from birth through childhood and adolescence, whereof 307 were diagnosed with IBD. Compared with low diet quality, medium and high diet quality at 1 year of age were associated with a reduced risk of IBD (pooled aHR 0.75 (95% CI=0.58 to 0.98) and 0.75 (95% CI=0.56 to 1.00)). The pooled aHR per increase of category was 0.86 (0.74 to 0.99). Pooled aHR for children 1 year old with high versus low fish intake was 0.70 (95% CI=0.49 to 1.00) for IBD, and showed association with reduced risk of UC (pooled aHR=0.46; 95% CI=0.21, 0.99). Higher vegetable intake at 1 year was associated with a risk reduction in IBD. Intake of sugar-sweetened beverages was associated with an increased risk of IBD. Diet quality at 3 years was not associated with IBD.

CONCLUSION

In this Scandinavian birth cohort, high diet quality and fish intake in early life were associated with a reduced risk of IBD.

GPR120/FFAR4: A Potential New Therapeutic Target for Inflammatory Bowel Disease

Inflammatory bowel disease, whose major forms are Crohn's disease and ulcerative colitis, is characterized by chronic inflammation of the gut due to the loss of tolerance toward antigens normally contained in the gut lumen. G protein-coupled receptor (GPR) 120 has gained considerable attention as a potential therapeutic target for metabolic disorders due to its implication in the production of the incretin hormone glucagon-like peptide 1 and the secretion of cholecystokinin. Recent studies have also highlighted the role of GPR120 in regulating immune system activity and inflammation. GPR120, expressed by intestinal epithelial cells, proinflammatory macrophages, enteroendocrine L cells, and CD4+ T cells, suppresses proinflammatory and enhances anti-inflammatory cytokine production, suggesting that GPR120 might have a pivotal role in intestinal inflammation and represent a possible therapeutic target in inflammatory bowel disease. This narrative review aims at summarizing the role of GPR120 in the maintenance of intestinal homeostasis through the analysis of the most recent studies.

PUFAs add fuel to Crohn's disease-associated AIEC-induced enteritis by exacerbating intestinal epithelial lipid peroxidation

Polyunsaturated fatty acids (PUFAs) have been shown to exacerbate Crohn's disease (CD) by promoting lipid peroxidation (LPO) of intestinal epithelial cells (IECs). Dysbiosis of the gut microbiota may play a crucial role in this process. CD patients often exhibit an increased abundance of Escherichia coli (E. coli) in the gut, and the colonization of adherent-invasive E. coli (AIEC) is implicated in the initiation of intestinal inflammation in CD. However, the impact of AIEC on LPO remains unclear. In this study, we observed that AIEC colonization in the terminal ileum of CD patients was associated with decreased levels of glutathione peroxidase 4 (GPX4) and ferritin heavy chain (FTH) in the intestinal epithelium, along with elevated levels of 4-Hydroxynonenal (4-HNE). In vitro experiments demonstrated that AIEC infection reduced the levels of GPX4 and FTH, increased LPO, and induced ferroptosis in IECs. Furthermore, arachidonic acid (AA) and docosahexaenoic acid (DHA) supplementation in AIEC-infected IECs significantly aggravated LPO and ferroptosis. However, overexpression of GPX4 rescued AIEC-induced LPO and ferroptosis in IECs. Our results further confirmed that AIEC with AA supplementation, associated with excessive LPO and cell death in IECs, worsened colitis in the DSS mouse model and induced enteritis in the antibiotic cocktail pre-treatment mouse model in vivo. Moreover, treatment with ferrostatin-1, a ferroptosis inhibitor, alleviated AIEC with AA supplementation-induced enteritis in mice, accompanied by reduced LPO and cell death in IECs. Our findings suggest that AIEC, in combination with PUFA supplementation, can induce and exacerbate intestinal inflammation, primarily through increased LPO and ferroptosis in IECs.

Randomized controlled trial of hydrolyzed fish diets in dogs with chronic enteropathy

BACKGROUND

The role of diet in the pathogenesis and treatment of chronic enteropathies (CE) in dogs is unresolved.

OBJECTIVES

To compare the ability of diets composed of hydrolyzed fish, rice starch, and fish oil without (HF) or with prebiotics, turmeric, and high cobalamin (HF+) against a limited ingredient diet containing mixed nonhydrolyzed antigens and oils (control) to resolve clinical signs and maintain serum cobalamin and folate concentrations in dogs with nonprotein losing CE (non-PLE). To determine the ability of hydrolyzed fish diets to support recovery and remission in dogs with PLE.

ANIMALS

Thirty-one client-owned dogs with CE: 23 non-PLE, 8 PLE.

METHODS

Randomized, blinded, controlled trial. Diets were fed for 2 weeks; responders continued for 12 weeks. Nonresponders were crossed over to another diet for 12 weeks. Response was determined by standardized clinical evaluation with long-term follow-up at 26 weeks. Concurrent medications were allowed in PLE.

RESULTS

Nineteen of 23 (83%; 95% confidence interval [CI], 60%-94%) non-PLE CE responded clinically to their initial diet, with no difference between diets (P > .05). Four nonresponders responded to another diet, with sustained remission of 18/18 (100%; 95%CI, 78%-100%) at 26 weeks. Serum cobalamin concentration was increased (P < .05) and maintained by diet. Serum folate concentration decreased posttreatment (P < .05) but was restored by dietary supplementation. Hydrolyzed fish diets supported weight gain, serum albumin concentration, and recovery (P < .05) in dogs with PLE.

CONCLUSIONS AND CLINICAL IMPORTANCE

Changing diet, independent of antigen restriction or supplemental ingredients, induced long-term remission in dogs with non-PLE CE. Serum cobalamin and folate concentrations were maintained by diet. Hydrolyzed fish diets supported clinical recovery and remission in PLE.

Fatty acids and lipid mediators in inflammatory bowel disease: from mechanism to treatment

Inflammatory Bowel Disease (IBD) is a chronic, relapsing inflammatory disorder of the gastrointestinal tract. Though the pathogenesis of IBD remains unclear, diet is increasingly recognized as a pivotal factor influencing its onset and progression. Fatty acids, essential components of dietary lipids, play diverse roles in IBD, ranging from anti-inflammatory and immune-regulatory functions to gut-microbiota modulation and barrier maintenance. Short-chain fatty acids (SCFAs), products of indigestible dietary fiber fermentation by gut microbiota, have strong anti-inflammatory properties and are seen as key protective factors against IBD. Among long-chain fatty acids, saturated fatty acids, trans fatty acids, and ω-6 polyunsaturated fatty acids exhibit pro-inflammatory effects, while oleic acid and ω-3 polyunsaturated fatty acids display anti-inflammatory actions. Lipid mediators derived from polyunsaturated fatty acids serve as bioactive molecules, influencing immune cell functions and offering both pro-inflammatory and anti-inflammatory benefits. Recent research has also highlighted the potential of medium- and very long-chain fatty acids in modulating inflammation, mucosal barriers, and gut microbiota in IBD. Given these insights, dietary intervention and supplementation with short-chain fatty acids are emerging as potential therapeutic strategies for IBD. This review elucidates the impact of various fatty acids and lipid mediators on IBD and delves into potential therapeutic avenues stemming from these compounds.

Evaluating the Effects of Omega-3 Polyunsaturated Fatty Acids on Inflammatory Bowel Disease via Circulating Metabolites: A Mediation Mendelian Randomization Study

Epidemiological evidence regarding the effect of omega-3 polyunsaturated fatty acid (PUFA) supplementation on inflammatory bowel disease (IBD) is conflicting. Additionally, little evidence exists regarding the effects of specific omega-3 components on IBD risk. We applied two-sample Mendelian randomization (MR) to disentangle the effects of omega-3 PUFAs (including total omega-3, α-linolenic acid, eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA)) on the risk of IBD, Crohn's disease (CD) and ulcerative colitis (UC). Our findings indicated that genetically predicted increased EPA concentrations were associated with decreased risk of IBD (odds ratio 0.78 (95% CI 0.63-0.98)). This effect was found to be mediated through lower levels of linoleic acid and histidine metabolites. However, we found limited evidence to support the effects of total omega-3, α-linolenic acid, and DHA on the risks of IBD. In the fatty acid desaturase 2 (FADS2) region, robust colocalization evidence was observed, suggesting the primary role of the FADS2 gene in mediating the effects of omega-3 PUFAs on IBD. Therefore, the present MR study highlights EPA as the predominant active component of omega-3 fatty acids in relation to decreased risk of IBD, potentially via its interaction with linoleic acid and histidine metabolites. Additionally, the FADS2 gene likely mediates the effects of omega-3 PUFAs on IBD risk.

Diet associations in endometriosis: a critical narrative assessment with special reference to gluten

Endometriosis is characterized by the presence of endometrium-like tissue outside the uterus. The etiology remains largely unknown. Despite adequate treatment, patients can still experience symptoms or side effects resulting in therapy incompliance and in self-management strategies such as dietary measures is increasing. A gluten free diet is thought to be contributory in reducing endometriosis-related pain, thereby optimizing quality of life. However, data is conflicting and currently provides no evidence for causality. This narrative review aims to put the effect of dietary self-management strategies on endometriosis in a balanced perspective, especially the effect of gluten and a gluten free diet. Several studies have found a strong overlap in symptoms, metabolic and immune responses associated with endometriosis and those associated with celiac disease, ulcerative colitis, Crohn's disease, irritable bowel syndrome and non-celiac wheat sensitivity. However, it remains unclear whether these diseases and/or disorders are causal to an increased risk of endometriosis. Some studies have found a positive effect on the risk of endometriosis, endometriosis-related symptoms and quality of life (QoL) when women either avoided certain nutrients or foods, or applied a specific nutrient supplementation. This includes the avoidance of red meat, an increasing intake of foods rich in anti-oxidants, omega-3, micronutrients and dietary fibers (e.g., fruit, vegetables) and the appliance of a gluten free diet. However, data from the available studies were generally graded of low quality and it was noted that placebo and/or nocebo effects influenced the reported positive effects. In addition, such effects were no longer seen when adjusting for confounders such as overweight, when a translation was made from in vitro to in vivo, or when the nutrients were not supplemented as isolated sources but as part of a mixed daily diet. Finally, some studies showed that long-term adherence to a gluten free diet is often associated with an impaired diet quality and nutrient intake, leading to negative health outcomes and reduced QoL. Concluding, scientific evidence on the efficacy of dietary interventions on well-defined clinical endpoints of endometriosis is lacking and recommending a gluten free diet to women solely diagnosed with endometriosis should therefore not be advised.

Nutritional aspects of inflammatory bowel disease

INTRODUCTION

The number of people diagnosed with inflammatory bowel disease (IBD) continues to increase in most parts of the world. Although the exact etiology of this chronic intestinal disease is not fully understood, nutritional factors appear to play key roles. Furthermore, individuals with IBD are at increased risk of adverse nutritional impacts, including micronutrient deficiencies.

AREAS COVERED

This review aims to summarize recent reports focusing on nutritional factors relevant to the development of IBD and to also review data on nutritional deficiencies seen in individuals with IBD.

EXPERT OPINION

The typical western diet, characterized by high-fat/high-sugar foods, along with food additives, appears to contribute to the etiopathogenesis of IBD. In contrast, some reports indicate that some foods are likely protective. However, there are inconsistencies in the currently available data, reflecting study design and other confounding factors. Furthermore, some of the conclusions are inferred from animal or in vitro studies. The presence of IBD can compromise the nutrition of individuals with one of these disorders: ongoing monitoring is critical. Nutrition and diet in the setting of IBD remain key areas for further and ongoing study.

Immune regulation of poly unsaturated fatty acids and free fatty acid receptor 4

Fatty acid metabolism contributes to energy supply and plays an important role in regulating immunity. Free fatty acids (FFAs) bind to free fatty acid receptors (FFARs) on the cell surface and mediate effects through the intra-cellular FFAR signaling pathways. FFAR4, also known as G-protein coupled receptor 120 (GPR120), has been identified as the primary receptor of omega-3 polyunsaturated fatty acids (ω-3 PUFAs). FFAR4 is a promising target for treating metabolic and inflammatory disorders due to its immune regulatory functions and the discovery of highly selective and efficient agonists. This review summarizes the reported immune regulatory functions of ω-3 PUFAs and FFAR4 in immune cells and immune-related diseases. We also speculate possible involvements of ω-3 PUFAs and FFAR4 in other types of inflammatory disorders.

Icosapent ethyl alleviates acetic acid-induced ulcerative colitis via modulation of SIRT1 signaling pathway in rats

Ulcerative colitis (UC) is a global inflammatory bowel disease. This study aimed to assess the effects of icosapent ethyl on acetic acid-induced colitis in rats as well as the underlying mechanisms involved. 36 male Wister rats were equally divided into six groups: control, UC, mesalamine 100 mg/kg, icosapent 150mg/kg, icosapent 300 mg/kg, and EX527-icosapent 300 mg/kg groups. Except for control group, UC was induced by acetic acid instillation into colon. Drugs were administered once daily for one week then under thiopental anaesthesia, colons were excised. Colitis macroscopic and microscopic scores were assessed. A part of colon was homogenized for detection of malondialdehyde (MDA), inerleukin1 (IL-1β), tumor necrosis factor (TNF-α), superoxide dismutase (SOD), phosphorylated Akt (pAkt) and caspase 3 levels. Silent information regulator 1 (SIRT1), heme oxygenase 1 (HO-1), and nuclear factor erythroid 2 (Nrf2) mRNA expressions were detected. Mallory-stained colonic sections were examined for collagen fibres detection. Immunohistochemistry of NF-κB and p53 expressionsin colonic sections were assessed. Acetic acid induced colitis with increments in MDA, IL-1β, TNF-α, and caspase 3 levels while decreased SOD, pAkt, SIRT1, HO-1, and Nrf2 with increased collagen fibres as well as NF-κB and p53. Icosapent decreased macro& microscopic colitis scores, MDA, IL-1β, TNF-α, and caspase 3 levels while increased SOD, pAkt, SIRT1, HO-1, and Nrf2 with decreased collagen fibres as well as NF-κB and p53. The effects of icosapent 300 mg/kg were similar to mesalamine. Icosapent effects were antagonized by EX527. Icosapent alleviated acetic acid-induced colitis via its anti-inflammatory, antioxidant, and anti-apoptotic effects mediated in part by SIRT1 pathway activation.

Greater Adherence to Cardioprotective Diet Can Reduce Inflammatory Bowel Disease Risk: A Longitudinal Cohort Study

Background: The cardioprotective diet was reported to be associated with several chronic cardiometabolic diseases through an anti-inflammation effect. However, the association between the cardioprotective diet and the risk of inflammatory bowel disease (IBD) was unclear and deserved to be further explored. Methods: We calculated the cardioprotective diet score based on the consumptions of seven common food groups using the validated food frequency questionnaire data in the UK Biobank. Incident IBD was ascertained from primary care data, inpatient data, and the death registry. Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between the cardioprotective diet score and the risk of IBD. Results: During a mean follow-up of 12.1 years, we documented 2717 incident IBD cases, including 851 cases of Crohn’s disease and 1866 cases of ulcerative colitis. Compared to participants with a cardioprotective diet score of 0−1, we observed a decreased risk of IBD among participants with cardioprotective diet scores of 3 (HR 0.85, 95% CI 0.73−0.99), 4 (HR 0.84, 95% CI 0.72−0.98), and 5−7 (HR 0.77, 95% CI 0.66−0.89) (p-trend < 0.001). Conclusions: A greater adherence to the cardioprotective diet was associated with a lower risk of IBD. Our finding highlighted the importance of focusing on the cardioprotective diet to prevent IBD.

Dietary Patterns and Gut Microbiota Changes in Inflammatory Bowel Disease: Current Insights and Future Challenges

Inflammatory bowel disease (IBD) is a result of a complex interplay between genes, host immune response, gut microbiota, and environmental factors. As one of the crucial environmental factors, diet plays a pivotal role in the modulation of gut microbiota community and the development of IBD. In this review, we present an overview of dietary patterns involved in the pathogenesis and management of IBD, and analyze the associated gut microbial alterations. A Westernized diet rich in protein, fats and refined carbohydrates tends to cause dysbiosis and promote IBD progression. Some dietary patterns have been found effective in obtaining IBD clinical remission, including Crohn's Disease Exclusion Diet (CDED), Mediterranean diet (MD), Anti-Inflammatory Diet (AID), the low-"Fermentable Oligo-, Di-, Mono-saccharides and Polyols" (FODMAP) diet, Specific Carbohydrate Diet (SCD), and plant-based diet, etc. Overall, many researchers have reported the role of diet in regulating gut microbiota and the IBD disease course. However, more prospective studies are required to achieve consistent and solid conclusions in the future. This review provides some recommendations for studies exploring novel and potential dietary strategies that prevent IBD.

Anti-Inflammatory Diet Prevents Subclinical Colonic Inflammation and Alters Metabolomic Profile of Ulcerative Colitis Patients in Clinical Remission

A relationship between ulcerative colitis (UC) and diet has been shown in epidemiological and experimental studies. In a 6-month, open-label, randomized, placebo-controlled trial, adult UC patients in clinical remission were randomized to either an “Anti-inflammatory Diet (AID)” or “Canada’s Food Guide (CFG)”. Menu plans in the AID were designed to increase the dietary intake of dietary fiber, probiotics, antioxidants, and omega-3 fatty acids and to decrease the intake of red meat, processed meat, and added sugar. Stool was collected for fecal calprotectin (FCP) and microbial analysis. Metabolomic analysis was performed on urine, serum, and stool samples at the baseline and study endpoint. In this study, 53 patients were randomized. Five (19.2%) patients in the AID and 8 (29.6%) patients in the CFG experienced a clinical relapse. The subclinical response to the intervention (defined as FCP < 150 µg/g at the endpoint) was significantly higher in the AID group (69.2 vs. 37.0%, p = 0.02). The patients in the AID group had an increased intake of zinc, phosphorus, selenium, yogurt, and seafood versus the control group. Adherence to the AID was associated with significant changes in the metabolome, with decreased fecal acetone and xanthine levels along with increased fecal taurine and urinary carnosine and p-hydroxybenzoic acid levels. The AID subjects also had increases in fecal Bifidobacteriaceae, Lachnospiraceae, and Ruminococcaceae. In this study, we found thatdietary modifications involving the increased intake of anti-inflammatory foods combined with a decreased intake of pro-inflammatory foods were associated with metabolic and microbial changes in UC patients in clinical remission and were effective in preventing subclinical inflammation.

Where Do We Stand in the Behavioral Pathogenesis of Inflammatory Bowel Disease? The Western Dietary Pattern and Microbiota-A Narrative Review

Despite the increasing knowledge with regard to IBD (inflammatory bowel disease), including ulcerative colitis (UC) and Crohn’s disease (CD), the etiology of these conditions is still not fully understood. Apart from immunological, environmental and nutritional factors, which have already been well documented, it is worthwhile to look at the possible impact of genetic factors, as well as the composition of the microbiota in patients suffering from IBD. New technologies in biochemistry allow to obtain information that can add to the current state of knowledge in IBD etiology.

Nutraceuticals for the Treatment of IBD: Current Progress and Future Directions

Inflammatory bowel disease (IBD) is a chronic relapsing-remitting inflammatory disease of the gastrointestinal tract. Patients are usually diagnosed in adolescence and early adulthood and need lifelong treatment. In recent years, it has been found that diet plays an important role in the pathogenesis of IBD. Diet can change intestinal barrier function, affect the structure and function of intestinal flora, and promote immune disorder, thus promoting inflammation. Many patients believe that diet plays a role in the onset and treatment of the disease and changes their diet spontaneously. This review provides some insights into how nutraceuticals regulate intestinal immune homeostasis and improve intestinal barrier function. We reviewed the research results of dietary fiber, polyphenols, bioactive peptides, and other nutraceuticals in the prevention and treatment of IBD and sought better alternative or supplementary treatment methods for IBD patients.

Use of polyunsaturated fatty acids in prevention and treatment of gastrointestinal diseases, obesity and cancer

Fatty acids are important structural and functional elements of human body. We can distinguish several types: among others polyunsaturated fatty acids, which include omega-3 fatty acids (ω-3PUFA) and omega-6 fatty acids(ω-6PUFA). The first group has pleiotropic health-promoting effects, while the second group, ω-6PUFA, negatively affects the homeostasis of the human body and contributes to the development of numerous diseases. Both the amount and the relative ratio of these acids in the diet is an important factor affecting health and quality of life.

Laboratory and clinical studies indicate that ω-3PUFA have a positive effect on the therapy of illnesses such as obesity and inflammatory bowel disease (IBD). ω-3 PUFA supplementation also appears to have a helpful effect in the adjuvant treatment of colorectal cancer and recovery.

Probiotics Interact With Lipids Metabolism and Affect Gut Health

Probiotics have attracted much attention due to their ability to modulate host intestinal microbe, participate in nutrient metabolism or immunomodulatory. Both inflammatory bowel disease (IBD) and bowel cancer are digestive system disease, which have become a global public health problem due to their unclear etiology, difficult to cure, and repeated attacks. Disturbed gut microbiota and abnormal lipid metabolism would increase the risk of intestinal inflammation. However, the link between lipid metabolism, probiotics, and IBD is unclear. In this review, we found that different lipids and their derivatives have different effects on IBD and gut microbes. ω-3 polyunsaturated fatty acids (PUFAs) docosahexaenoic acid, eicosapentaenoic acid, and their derivatives resolvin E1, resolvin D can inhibit oxidative stress and reactive oxygen species activate NFκB and MAPk pathway. While ω-6 PUFAs linoleic acid and arachidonic acid can be derived into leukotrienes and prostaglandins, which will aggravate IBD. Cholesterol can be converted into bile acids to promote lipid absorption and affect microbial survival and colonization. At the same time, it is affected by microbial bile salt hydrolase to regulate blood lipids. Low denstiy lipoprotein (LDL) is easily converted into oxidized LDL, thereby promoting inflammation, while high denstiy lipoprotein (HDL) has the opposite effect. Probiotics compete with intestinal microorganisms for nutrients or ecological sites and thus affect the structure of intestinal microbiota. Moreover, microbial short chain fatty acids, bile salt hydrolase, superoxide dismutase, glutathione, etc. can affect lipid metabolism and IBD. In conclusion, probiotics are directly or indirectly involved in lipids metabolism and their impact on IBD, which provides the possibility to explore the role of probiotics in improving gut health.

Potential Matrix Effects in Iodometry Determination of Peroxides Induced by Olefins

Peroxides (H₂O₂, ROOR, and ROOH) are an important reaction intermediate involved in a number of natural processes, including atmospheric autoxidation and lipid peroxidation in oils and animal tissues. Iodometry is an established spectroscopic technique that has been widely used to quantify total peroxide concentration in food, indoor, and outdoor samples. Iodometry provides selectivity toward peroxides through a quantitative reaction between I^- and peroxides to form I₃^- via a molecular iodine (I₂) intermediate. However, equilibrium changes caused by a potential interaction between olefinic species and I₂ can suppress I₃^- formation, thereby underestimating peroxide concentration. For the first time in the current study, this unrecognized interference posed by olefins (OEs) is systematically investigated to gauge its effects on the accuracy of iodometry. A number of model molecules were investigated. The interference was observed to be unique to OEs, but universally affecting different peroxide species such as H₂O₂, tert-butyl hydroperoxide, and aerosol-bound peroxides. A simple kinetic box model was built to explain this chemistry. The measured rate constant for 3-octenoic acid was found to be 0.84 ± 0.02 M^-1 s^-1. Overall, our results show matrix effects induced by OEs can underestimate peroxide concentration determined by iodometry for edible oils, indoor environments, and animal fat, but absent in most of the atmospheric samples. Nonetheless, our results point out the importance of this interfering chemistry in matrices enriched with OEs.

Plasma concentrations of perfluoroalkyl substances and risk of inflammatory bowel diseases in women: A nested case control analysis in the Nurses' Health Study cohorts

BACKGROUND

Perfluoroalkyl substances (PFASs) are synthetic compounds used in a wide variety of industrial and consumer applications. An association between PFAS exposure and risk of ulcerative colitis (UC) has been reported in a highly exposed population. However, data are limited on risk of inflammatory bowel diseases (IBD) among individuals with background population levels of PFAS exposure.

OBJECTIVES

We set out to examine the association between plasma PFAS concentrations and risk of IBD among women in two population-based, prospective cohort studies in which pre-diagnostic blood specimens were available.

METHODS

We conducted a nested case-control study in the Nurses' Health Study and Nurses' Health Study II cohorts. We identified 73 participants with incident Crohn's disease (CD) and 80 participants with incident UC who had provided blood samples before diagnosis. Cases were matched 1:2 to IBD-free controls. Plasma concentrations of five major PFASs were measured by liquid chromatography and tandem mass spectrometry. We used conditional logistic models to estimated odds ratios for risk of IBD according to log10-transformed PFAS concentrations, adjusting for potential confounders.

RESULTS

In multivariable models, we observed inverse associations between plasma concentrations of three PFASs and risk of CD (all P ≤ 0.012 for a standard deviation increase in log10PFAS). The inverse association with CD was strongest for perfluorodecanoate, where, compared to the lowest tertile, the odds ratio (OR) for the highest tertile was 0.39 (95% confidence interval, 0.17-0.92). No associations were observed between PFAS concentrations and UC risk.

DISCUSSION

Our results do not support the hypothesis that elevated PFAS exposure is associated with higher risk of UC. Contrary to expectation, our data suggest that circulating concentrations of some PFASs may be inversely associated with CD development.

EPA and DHA differentially coordinate the crosstalk between host and gut microbiota and block DSS-induced colitis in mice by a reinforced colonic mucus barrier

Background: Ulcerative colitis (UC) is a chronic inflammatory disorder of the colon with a continuously remitting and relapsing course. Its etiology is closely related to abnormal interactions between host and gut microbiota. The mucus barrier lining the gastrointestinal tract is necessary to coordinate host and gut microbiota interaction by nourishing and modulating the microbiota. Differential effects of the anti-inflammatory fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on UC progression in mice were firstly addressed by our previous work; here, the mechanism for their respective effects were further uncovered from host-microbiome crosstalk based on mucus barrier modulation to pave the way for UC therapy. Methods: Assessment of the disease activity index and histopathology score was conducted in mice with dextran sodium sulfate (DSS)-induced colitis pre-treated with different doses of EPA and DHA. Mucin generation, glycosylation and secretion were evaluated by a combination of electron microscopy, specific mucous staining, and qPCR. Western blotting was used to analyze the underlying molecular events. Fecal short chain fatty acids were detected using gas chromatography, and the gut microbial composition was analyzed using 16S rRNA sequencing. Results: Compared with DHA, the more potent inhibitory effect of high dose EPA on DSS-induced colitis was reconfirmed, which was underlain by a reinforced mucus layer as indicated by increased mucin granule release, mucus layer stratification and markedly upregulated expression of the key modulators involved in goblet cell differentiation. In turn a remarkably enhanced mucus barrier in the EPA group functioned to modulate the gut microbiome, as demonstrated by the enriched abundance of the phylum Bacteroidetes and mucin-degrading bacterium Akkermansia muciniphila producing acetic and propionic acids. Conclusions: EPA and DHA differentially coordinate the interaction between the host and the gut microbiota and relieve mucus barrier disruption in DSS-induced colitis. EPA may develop into a promising adjunctive therapy for UC.

Diet-Microbiota Interplay: An Emerging Player in Macrophage Plasticity and Intestinal Health

Inflammatory bowel diseases (IBD) are chronic disorders of the gastrointestinal tract with an increasing prevalence worldwide. Targeted therapies for IBD are limited by several factors, including the therapeutic ceiling and the high incidence of non-responders or loss-of-response. In order to improve therapeutic efficacy, there is critical need to decipher disease pathogenesis, currently not well understood. Macrophages, innate immune cells that exhibit high plasticity, perpetuate inflammatory signalling in IBD through excessive release of inflammatory mediators. In recent years, pioneering research has revealed the importance of the interplay between macrophages and gut microbiota in maintaining intestinal homeostasis. Particular attention is focusing on microbiota-derived metabolites, believed to possess immunomodulatory properties capable of manipulating macrophage plasticity. Microbiota-derived short-chain fatty acids (SCFAs) and indole compounds, along with dietary sourced omega-3 (ω-3) polyunsaturated fatty acids (PUFA), exert anti-inflammatory effects, attributable to interactions with macrophages. Before we can effectively incorporate these metabolites into IBD therapies, a deeper understanding of microbiota-macrophage interactions at a molecular level is necessary. Therefore, the aim of this review is firstly to detail current knowledge regarding how diet and microbiota-derived metabolites modify macrophage plasticity. Later, we discuss the concept of therapeutic strategies directed at microbiota-macrophage interactions, which could be highly valuable for IBD therapies in the future.

Dietary Alaska Pollock Protein Attenuates the Experimental Colitis Induced by Dextran Sulfate Sodium via Regulation of Gut Microbiota and Its Metabolites in Mice

Protein derived from fish has not only nutritional properties but also health-promoting properties. Few studies have examined the effect of dietary Alaska pollock protein (APP) on the anticolitis effect reported to be associated with metabolic syndrome (MetS). This study investigated the effect of APP intake on colitis symptoms, gut microbiota, and its metabolites in the experimental colitis mouse model induced by dextran sulfate sodium (DSS). Male C57BL/6J mice were divided into three groups: (1) DSS-untreated mice fed an American Institute of Nutrition (AIN) 93G diet (protein source is casein), (2) DSS-treated mice fed an AIN93G diet, and (3) DSS-treated mice fed an APP diet. After the mice were fed the diets for 21 days, experimental colitis was induced by three cycles of 2% DSS administration for 5 days followed by washouts over the course of 5 days. APP-reduced body weight loss increased the disease activity index, and elevated spleen weight and alleviated colon length shortening and colonic tissue damage. Furthermore, APP altered the structure and composition of the microbiota and short-chain fatty acids in feces. Since APP intake alleviates experimental colitis induced by DSS administration through alterations in the gut microbiota and its metabolites, we deduced that APP would inhibit MetS progression via colitis suppression.

Habitual Fish Oil Supplementation and Risk of Incident Inflammatory Bowel Diseases: A Prospective Population-Based Study

Background

Inflammatory Bowel Diseases (IBDs) have been emerging in recent years with the advance of global industrialization and diet pattern transformation. Marine n-3 polyunsaturated fatty acids (n-3 PUFAs), enriched in fish oils, have well-known human health promotion. Evidence on the association of fish oil supplementation with the risk of developing IBDs was scarce. This study aimed to examine the association between the use of fish oil supplements and the risk of developing inflammatory bowel diseases (IBDs) among the general population.

Methods

We conducted a prospective cohort study of 447,890 participants aged 40-69 years from the UK Biobank. A touch screen questionnaire was used to get the data about fish oil intake at baseline. Incident diagnoses of IBDs were ascertained by the International Classification of Diseases (ICD-9 and ICD-10) or self-report. Cox proportional hazards model was applied to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of developing IBDs and their subtypes.

Results

We documented 1,646 incident cases of IBDs, including 533 incident cases of Crohn's disease (CD) and 1,185 incident cases of ulcerative colitis (UC) during an average of 8 years of follow-up. After multivariate adjustment, the use of fish oil was associated with a 12% lower risk of IBDs (HR: 0.88, 95% CI: 0.78-0.99, p = 0.03) compared with non-consumers. For subtypes of IBDs, fish oil supplementation was inversely associated with a 15% lower risk of UC (HR: 0.85, 95% CI: 0.75-0.99, p = 0.02) but was not correlated with the risk of CD (p = 0.22). Besides, fish oil supplementation showed a significant inverse correlation with baseline CRP levels (β = -0.021, p < 0.001) and a positive association with baseline albumin levels (β = 0.135, p < 0.001) after adjustment for multiple variates.

Conclusion

Habitual intake of fish oil supplements was associated with a lower risk of IBDs and UC. Fish oil users tended to have lower baseline C-reactive protein levels and higher baseline albumin levels compared with non-users. It was concluded that fish oil supplement use may be recommended for the prevention and control of IBDs.

The Inverse Association of Leg Fat Mass and Osteoporosis in Individuals with Type 2 Diabetes Independent of Lean Mass

PURPOSE

Recent studies revealed that high levels of thigh fat were independently associated with better glucose and lipid metabolism, as well as lower risk of hypertension and cardiometabolic disease. Therefore, the purpose of this study was to evaluate the association between leg fat mass (FM) and osteoporosis (OP) in individuals with type 2 diabetes (T2DM).

PATIENTS AND METHODS

In this cross-sectional study, a total of 1,259 individuals aged 50 years or older with T2DM (female 536, male 723) were included. A bioelectrical impedance analyser was used to assess the segment body composition containing FM and lean mass (LM) of arms, legs, and trunk. Bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry.

RESULTS

Leg FM was positively correlated with BMD of all sites in females and BMD of femoral neck and total hip in males after adjusting age, diabetes duration, glucose and lipid metabolism indexes, and lifestyle (all P<0.05). LM was positively associated with BMD at almost sites (P<0.001), while leg FM/LM ratio had no relationship with BMD at any skeleton sites (P>0.05). Compared with the bottom tertile group of leg FM, the risk of OP was significantly lower in the top tertile group both in females (T3 vs T1: OR=0.206, 95% CI=0.098-0.433, P<0.001) and males (T3 vs T1: OR=0.385, 95% CI=0.182-0.815, P<0.05), even after adjusting for LM.

CONCLUSION

In the present study, higher leg FM was correlated with the lower risk of OP in both men and postmenopausal women with T2DM independently of total LM.

Dietary Supplementation with Vitamin D, Fish Oil or Resveratrol Modulates the Gut Microbiome in Inflammatory Bowel Disease

Gastrointestinal health is influenced by the functional genes and metabolites generated by the human microbiome. As the volume of current biomedical and translational research indicates, the importance and impact of this ecosystem of microorganisms, especially those comprising the gut microbiome on human health, has become increasingly apparent. Changes to the gut microbiome are associated with inflammatory bowel disease (IBD), which is characterized by persistent intestinal inflammation. Furthermore, the lifetime dietary choices of their host may positively or negatively affect both the gut microbiome and its impact on IBD. As such, "anti-inflammatory" dietary supplements, their impact, and mechanisms in restoring gut microbiota homeostasis during IBD is an area of intensive research. Dietary supplementation may represent an important adjuvant treatment avenue for limiting intestinal inflammation in IBD. Overall, this review addresses the development of the gut microbiome, the significance of the gut microbiome in IBD, and the use of dietary supplements such as vitamin D, fish oil, and resveratrol in the mitigation of IBD-associated gut dysbiosis and intestinal inflammation.

The role of fatty acids in Crohn's disease pathophysiology - An overview

Crohn's disease (CD) is an inflammatory bowel disease (IBD) which is characterized by chronic and relapsing inflammation of the gastrointestinal (GI) tract. The etiology of CD is unknown, but factors such as epithelial barrier dysfunction, immune system imbalance, microbiota dysbiosis and environmental influences are thought to be involved in its pathogenesis. Recent studies have shown that short chain fatty acids (SCFAs) and long chain fatty acids (LCFAs) play a vital role in pathophysiology and development of CD by various mechanisms affecting pro- and anti-inflammatory mediators, and maintaining the intestinal homeostasis and regulation of gene expression. SCFAs and LCFAs activate signaling cascades that control immune functions through interaction with cell surface free fatty acid receptors (FFARs), i.e. FFAR1, FFAR2, FFAR3, and FFAR4. This review highlights the role of fatty acids in maintenance of intestinal and immune homeostasis and supports the supplementation of fatty acids as a promising adjunctive treatment for CD.

Pharmacological Modulation of Immune Responses by Nutritional Components

The incidence of noncommunicable diseases (NCDs) has increased over the last few decades, and one of the major contributors to this is lifestyle, especially diet. High intake of saturated fatty acids and low intake of dietary fiber is linked to an increase in NCDs. Conversely, a low intake of saturated fatty acids and a high intake of dietary fiber seem to have a protective effect on general health. Several mechanisms have been identified that underlie this phenomenon. In this review, we focus on pharmacological receptors, including the aryl hydrocarbon receptor, binding partners of the retinoid X receptor, G-coupled protein receptors, and toll-like receptors, which can be activated by nutritional components and their metabolites. Depending on the nutritional component and the receptors involved, both proinflammatory and anti-inflammatory effects occur, leading to an altered immune response. These insights may provide opportunities for the prevention and treatment of NCDs and their inherent (sub)chronic inflammation. SIGNIFICANCE STATEMENT: This review summarizes the reported effects of nutritional components and their metabolites on the immune system through manipulation of specific (pharmacological) receptors, including the aryl hydrocarbon receptor, binding partners of the retinoid X receptor, G-coupled protein receptors, and toll-like receptors. Nutritional components, such as vitamins, fibers, and unsaturated fatty acids are able to resolve inflammation, whereas saturated fatty acids tend to exhibit proinflammatory effects. This may aid decision makers and scientists in developing strategies to decrease the incidence of noncommunicable diseases.

Perioperative parenteral fish oil supplementation improves postoperative coagulation function and outcomes in patients undergoing colectomy for ulcerative colitis

OBJECTIVE

Ulcerative colitis (UC) is an independent risk factor for thromboembolism, especially during the perioperative period. This study aimed to determine the effects of perioperative parenteral nutrition (PN) supplemented with fish oil (FO) on coagulation function and postoperative outcomes in patients with UC.

METHODS

This retrospective cohort included 92 consecutive patients who underwent colectomy for UC. Postoperative coagulation indices and outcomes, including thromboelastography (TEG) findings and comprehensive complication index (CCI), were compared. The relative change in serum D-dimer (ΔD-dimer) levels and maximal amplitude (ΔMA) on TEG were also determined.

RESULTS

Patients receiving PN supplemented with FO (n = 48) had lower D-dimer (P = .036) levels on postoperative day (POD) 5 and a higher MA (P < 0.001) on POD 1 than those who did not receive it (n = 44). A lower ΔD-dimer level (P = .048) and ΔMA (P < 0.001) were also observed in patients receiving FO. The incidence of major postoperative complications (6.3 vs 22.7%; P = .017) and CCI (20.9 vs 23.4%; P = .044) were significantly lower in patients receiving FO. In multivariate analysis, FO (odds ratio, 0.231; 95% confidence interval, 0.055-0.971; P = .046) was a positive protector of major postoperative complications.

CONCLUSION

Perioperative PN supplemented with FO improved coagulation function and reduced major postoperative complications in patients with UC requiring colectomy. These results may provide cues in formulating management strategies for preventing thromboembolisms and postoperative complications in patients with UC.

Systematic review with meta-analysis: dietary intake in adults with inflammatory bowel disease

BACKGROUND

Poor dietary intake is associated with the development of malnutrition, micronutrient deficiencies, anaemia and osteoporosis in individuals with inflammatory bowel disease. While trials are underway to manipulate the diet of people with IBD, there has been no comprehensive systematic review of the dietary intake of adults with IBD.

AIMS

To conduct a systematic evaluation and meta-analysis of the dietary intake of adults with IBD, including macronutrients, micronutrients and food group data.

METHODS

CINAHL, Embase, Medline and Scopus were searched from 1 January 2000 to 25 September 2020 for cohort, case-control or cross-sectional studies that reported usual dietary intake in adults. Data were pooled and reported as weighted mean intake for: all adults with IBD; Crohn's disease; ulcerative colitis; active disease; remission; males; females. A random-effects meta-analysis model compared intake with healthy individuals.

RESULTS

Forty studies were identified and 19 were included in the meta-analysis. All subgroups of adults with IBD consumed inadequate energy (mean intake in adults with IBD 1980 ± 130 kcal), fibre (14 ± 4 g), folate (246 ± 33 mg) and calcium (529 ± 114 mg) per day. Intake of breads and cereals, legumes, fruit, vegetables and dairy were inadequate. Compared to healthy individuals, adults with IBD consume significantly less dietary fibre (SMD -0.59; 95% CI: -0.73, -0.46).

CONCLUSIONS

This review provides improved clarity about the dietary intake of adults with IBD. Future attention is required to improve diet quality and increase understanding of factors influencing dietary intake in IBD.

Long-term effects of increasing omega-3, omega-6 and total polyunsaturated fats on inflammatory bowel disease and markers of inflammation: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIM

Effects of long-chain omega-3 (LCn3) and omega-6 fatty acids on prevention and treatment of inflammatory bowel diseases (IBD, including Crohn's Disease, CD and ulcerative colitis, UC), and inflammation are unclear. We systematically reviewed long-term effects of omega-3, omega-6 and total polyunsaturated fats (PUFA) on IBD diagnosis, relapse, severity, pharmacotherapy, quality of life and key inflammatory markers.

METHODS

We searched Medline, Embase, Cochrane CENTRAL, and trials registries, including RCTs in adults with or without IBD comparing higher with lower omega-3, omega-6 and/or total PUFA intake for ≥ 24 weeks that assessed IBD-specific outcomes or inflammatory biomarkers.

RESULTS

We included 83 RCTs (41,751 participants), of which 13 recruited participants with IBD. Increasing LCn3 may reduce risk of IBD relapse (RR 0.85, 95% CI 0.72-1.01) and IBD worsening (RR 0.85, 95% CI 0.71-1.03), and reduce erythrocyte sedimentation rate (ESR, SMD - 0.23, 95% CI - 0.44 to - 0.01), but may increase IBD diagnosis risk (RR 1.10, 95% CI 0.63-1.92), and faecal calprotectin, a specific inflammatory marker for IBD (MD 16.1 μg/g, 95% CI - 37.6 to 69.8, all low-quality evidence). Outcomes for alpha-linolenic acid, omega-6 and total PUFA were sparse, but suggested little or no effect where data were available.

CONCLUSION

This is the most comprehensive meta-analysis of RCTs investigating long-term effects of omega-3, omega-6 and total PUFA on IBD and inflammatory markers. Our findings suggest that supplementation with PUFAs has little or no effect on prevention or treatment of IBD and provides little support for modification of long-term inflammatory status.

Encapsulation and Protection of Omega-3-Rich Fish Oils Using Food-Grade Delivery Systems

Regular consumption of adequate quantities of lipids rich in omega-3 fatty acids is claimed to provide a broad spectrum of health benefits, such as inhibiting inflammation, cardiovascular diseases, diabetes, arthritis, and ulcerative colitis. Lipids isolated from many marine sources are a rich source of long-chain polyunsaturated fatty acids (PUFAs) in the omega-3 form which are claimed to have particularly high biological activities. Functional food products designed to enhance human health and wellbeing are increasingly being fortified with these omega-3 PUFAs because of their potential nutritional and health benefits. However, food fortification with PUFAs is challenging because of their low water-solubility, their tendency to rapidly oxidize, and their variable bioavailability. These challenges can be addressed using advanced encapsulation technologies, which typically involve incorporating the omega-3 oils into well-designed colloidal particles fabricated from food-grade ingredients, such as liposomes, emulsion droplets, nanostructured lipid carriers, or microgels. These omega-3-enriched colloidal dispersions can be used in a fluid form or they can be converted into a powdered form using spray-drying, which facilitates their handling and storage, as well as prolonging their shelf life. In this review, we provide an overview of marine-based omega-3 fatty acid sources, discuss their health benefits, highlight the challenges involved with their utilization in functional foods, and present the different encapsulation technologies that can be used to improve their performance.

Tilapia head glycolipids protect mice against dextran sulfate sodium-induced colitis by ameliorating the gut barrier and suppressing NF-kappa B signaling pathway

The purpose of this study was to evaluate the relieving effect of tilapia head glycolipids (TH-GLs) on dextran sulfate sodium (DSS)-induced colitis in mice and to further explore its mechanism. Mice were orally administered 3% (w/v) DSS to establish a model of ulcerative colitis (UC), and subsequently treated with TH-GLs or sulfasalazine. In addition, the expression of key targets in the intestinal mucosal barrier and the inflammatory signal pathway were studied by combining immunochemical analysis techniques. The results showed that varying doses of TH-GLs can significantly improve colon lesions caused by DSS, reduce histological scores, increase mucus secretion, extend colon length, increase weight, and inhibit the occurrence of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), Interleukin-1β (IL-1β), and Interleukin- 6 (IL-6). Further, studies have shown that TH-GLs increase the secretion of MUC2 and up-regulate the expression of tight junction related proteins, such as ZO-1 and Occludin. In addition, TH-GLs significantly down-regulated the protein expression levels of TNF-α, IKK-β, and nuclear factor-κB (NF-κB). Here, we have elucidated the potential mechanism of TH-GLs in protecting mice with colitis. In general, this study shows that TH-GLs could improve the symptoms of UC by improving the gut barrier and inhibiting inflammatory signals, which provides a scientific basis for future clinical applications.

Fish Sidestream-Derived Protein Hydrolysates Suppress DSS-Induced Colitis by Modulating Intestinal Inflammation in Mice

Inflammatory bowel disease is characterized by extensive intestinal inflammation, and therapies against the disease target suppression of the inflammatory cascade. Nutrition has been closely linked to the development and suppression of inflammatory bowel disease, which to a large extent is attributed to the complex immunomodulatory properties of nutrients. Diets containing fish have been suggested to promote health and suppress inflammatory diseases. Even though most of the health-promoting properties of fish-derived nutrients are attributed to fish oil, the potential health-promoting properties of fish protein have not been investigated. Fish sidestreams contain large amounts of proteins, currently unexploited, with potential anti-inflammatory properties, and may possess additional benefits through bioactive peptides and free amino acids. In this project, we utilized fish protein hydrolysates, based on mackerel and salmon heads and backbones, as well as flounder skin collagen. Mice fed with a diet supplemented with different fish sidestream-derived protein hydrolysates (5% w/w) were exposed to the model of DSS-induced colitis. The results show that dietary supplements containing protein hydrolysates from salmon heads suppressed chemically-induced colitis development as determined by colon length and pro-inflammatory cytokine production. To evaluate colitis severity, we measured the expression of different pro-inflammatory cytokines and chemokines and found that the same supplement suppressed the pro-inflammatory cytokines IL-6 and TNFα and the chemokines Cxcl1 and Ccl3. We also assessed the levels of the anti-inflammatory cytokines IL-10 and Tgfb and found that selected protein hydrolysates induced their expression. Our findings demonstrate that protein hydrolysates derived from fish sidestreams possess anti-inflammatory properties in the model of DSS-induced colitis, providing a novel underexplored source of health-promoting dietary supplements.

Fish Oil for Inflammatory Bowel Disease: Panacea or Placebo?

Dietary supplements have increasingly gained popularity over the years not only to replete micronutrient deficiencies but for their use in treatment of disease. The popularity of dietary supplements for inflammatory bowel diseases (IBD) arises from their perceived ease of use, potential disease-modifying benefits, and perceived safety. Overall, randomized controlled trials have not consistently shown a benefit of fish oil for the maintenance of remission with Crohn's disease. The inconsistency of these findings highlights the need for more studies that are powered to clarify the context in which omega-3 fatty acids might have a role in the treatment algorithm of IBD.

The effect of gut microbiota on the intestinal lipidome of mice

Gut microbiota significantly influence the plasma and liver lipidome. An interconnecting metabolite is acetate generated after degradation and fermentation of dietary fiber by the gut microbiota, which is metabolized in the liver into longer chain fatty acids and complex lipids reaching the circulation. Whether these systemic changes are accompanied by alternations of the intestinal lipidome is unclear. Therefore, we quantified glycerophospholipids, sphingolipids and sterols in ileum and colon, the two segments containing the highest densities of microbes in the gastrointestinal tract, of germfree and specific pathogen free mice using mass spectrometry-based lipidomics. We found that the presence of gut microbes lowers the free cholesterol content in colon while elevating phosphatidylcholine levels. Further, PUFA-containing phosphatidylcholine and -ethanolamine fractions are increased in ileum and colon of germfree compared to SPF mice. A total fatty acid analysis by GC-MS revealed higher levels of arachidonic and docosahexaenoic acid in the ileum of germfree mice indicating that the gut microbiota inhibits PUFA metabolism in the small intestine.

Trend of nutrition research in endocrine disorders, gaps, and future plans: a collection of experiences of an endocrinology research institute

BACKGROUND

Nutrition plays a pivotal role in the prevention and treatment of endocrine disorders. The aim of this study was to provide a window in order to display the 25-year activities of Endocrinology & Metabolism Research Institute (EMRI), and the gaps and future plans in the field of nutrition and endocrine disorders.

METHODS

To collect papers affiliated to the EMRI in field of nutrition from the inception to December 1st 2019, the electronic databases including PubMed/Medline, Web of Science, and Scopus were searched. Publications in English and Persian languages were included. Scientific Landscapes (VOS viewer) software version 1.6.13 was used to provide bibliometric maps.

RESULTS

Of 4082 studies identified in the initial search, 319 relevant papers were included. They contributed systematic review and meta-analysis/review (n = 76), clinical trials (n = 58), cross-sectional (n = 171), case-control studies (n = 11), and animal studies (n = 3). Accordingly, most nutrition studies were dedicated to the level of evidence III (cross-sectional studies: 53.60%) followed by systematic review studies (23.82%) with the level of evidence I. There was also an increasing trend in the nutrition studies through years, with a peak in 2019.

CONCLUSION

An increasing trend in the publications related to nutrition science is observed at EMRI. However, nutrition research and publications can grow further through expanding collaborations with other fields related to endocrine. Given nutritional assessments in national projects and focusing on the identification of preventive nutritional strategies, considering the situations of our society can be helpful to make nutritional findings more practical.

Omega-3 Polyunsaturated Fatty Acids and the Intestinal Epithelium-A Review

Epithelial cells (enterocytes) form part of the intestinal barrier, the largest human interface between the internal and external environments, and responsible for maintaining regulated intestinal absorption and immunological control. Under inflammatory conditions, the intestinal barrier and its component enterocytes become inflamed, leading to changes in barrier histology, permeability, and chemical mediator production. Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) can influence the inflammatory state of a range of cell types, including endothelial cells, monocytes, and macrophages. This review aims to assess the current literature detailing the effects of ω-3 PUFAs on epithelial cells. Marine-derived ω-3 PUFAs, eicosapentaenoic acid and docosahexaenoic acid, as well as plant-derived alpha-linolenic acid, are incorporated into intestinal epithelial cell membranes, prevent changes to epithelial permeability, inhibit the production of pro-inflammatory cytokines and eicosanoids and induce the production of anti-inflammatory eicosanoids and docosanoids. Altered inflammatory markers have been attributed to changes in activity and/or expression of proteins involved in inflammatory signalling including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), peroxisome proliferator activated receptor (PPAR) α and γ, G-protein coupled receptor (GPR) 120 and cyclooxygenase (COX)-2. Effective doses for each ω-3 PUFA are difficult to determine due to inconsistencies in dose and time of exposure between different in vitro models and between in vivo and in vitro models. Further research is needed to determine the anti-inflammatory potential of less-studied ω-3 PUFAs, including docosapentaenoic acid and stearidonic acid.

Nutritional Interventions Using Functional Foods and Nutraceuticals to Improve Inflammatory Bowel Disease

The gastrointestinal tract, the second largest organ in the body, plays an important role in nutrient and mineral intake through the intestinal barrier. Dysfunction of intestinal permeability and related disorders commonly occur in patients with inflammatory bowel disease (IBD), one of the health problems in the Western societies that are considered to be mainly due to the Western diet. Although the exact etiology of IBD has not been elucidated, environmental and genetic factors may be involved in its pathogenesis. Many synthetic or biological drugs, such as 5-aminosalicylic acid corticosteroids as anti-inflammatory drugs, have been used clinically to treat IBD. However, their long-term use exhibits some adverse health consequences. Therefore, many researchers have devised alternative therapies to overcome this problem. Many studies have revealed that some functional nutrients in nature can relieve gastrointestinal inflammation by controlling proinflammatory cytokines. In this study, we review the ability of functional nutraceuticals such as phytochemicals, fatty acids, and bioactive peptides in improving IBD by regulating its underlying pathogenic mechanisms.

Beyond cardiovascular medicine: potential future uses of icosapent ethyl

The REDUCE-IT trial demonstrated that icosapent ethyl, an ethyl ester of eicosapentaenoic acid (EPA), reduced cardiovascular events in an at-risk population by a substantial degree. While the cardiovascular protective properties of this compound are now proven, several other potential uses are being actively explored in clinical studies. These areas of investigation include cancer, inflammatory bowel disease, infections, Alzheimer's disease, dementia, and depression. The next decade promises to deepen our understanding of the beneficial effects that EPA may offer beyond cardiovascular risk reduction.

Intake of fish and long-chain n-3 polyunsaturated fatty acids and risk of diseases in a Japanese population: a narrative review

Since the 1970s, the potential benefit of fish intake in terms of noncommunicable diseases has been one of the most important themes in disease prevention. Epidemiological studies have revealed the extent to which fish consumption affects the incidence of and mortality from diseases. Meta-analyses summarized the effect of fish and long-chain n-3 polyunsaturated fatty acid intake on noncommunicable diseases, especially cardiovascular diseases in Western countries. However, few reviews have spotlighted the effect of fish intake in East-Asian countries that have high population levels of fish intake such as Japan. We narratively reviewed the epidemiological studies concerned with the associations of fish and long-chain n-3 polyunsaturated fatty acid intake with risk of noncommunicable diseases, mainly of cardiovascular disease, among Japanese, whose fish intake has been twice or more than that of most Westerners. Overall, fish or long-chain n-3 polyunsaturated fatty acid intake may be beneficial for prevention of noncommunicable diseases, especially coronary heart disease and heart failure in Japanese as well as in Westerners. However, the beneficial effects of their intakes seemed to be nonlinear and varied according to disease severity and culture. Studies on other noncommunicable disease were also narratively reviewed.

Nutritional Lipids and Mucosal Inflammation

Inflammatory bowel disease (IBD) is characterized by chronic relapsing inflammation in the intestine. Given their role in regulation of inflammation, long-chain n-3 polyunsaturated fatty acids (PUFAs) represent a potential supplementary therapeutic approach to current drug regimens used for IBD. Mechanistically, there is ample evidence for an anti-inflammatory and pro-resolution effect of long-chain n-3 PUFAs after they incorporate into cell membrane phospholipids. They disrupt membrane rafts and when released from the membrane suppress inflammatory signaling by activating PPAR-γ and free fatty acid receptor 4; furthermore, they shift the lipid mediator profile from pro-inflammatory eicosanoids to specialized pro-resolving mediators. The allocation of long-chain n-3 PUFAs also leads to a higher microbiome diversity in the gut, increases short-chain fatty acid-producing bacteria, and improves intestinal barrier function by sealing epithelial tight junctions. In line with these mechanistic studies, most epidemiological studies support a beneficial effect of long-chain n-3 PUFAs intake on reducing the incidence of IBD. However, the results from intervention trials on the prevention of relapse in IBD patients show no or only a marginal effect of long-chain n-3 PUFAs supplementation. In light of the current literature, international recommendations are supported that adequate diet-derived n-3 PUFAs might be beneficial in maintaining remission in IBD patients.

Nutritional Indices for Assessing Fatty Acids: A Mini-Review

Dietary fats are generally fatty acids that may play positive or negative roles in the prevention and treatment of diseases. In nature, fatty acids occur in the form of mixtures of saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA), so their nutritional and/or medicinal values must be determined. Herein, we do not consider the classic indices, such as ∑SFA, ∑MUFA, ∑PUFA, ∑n-6 PUFA, ∑n-3 PUFA, and n-6 PUFA/n-3 PUFA; instead, we summarize and review the definitions, implications, and applications of indices used in recent years, including the PUFA/SFA, index of atherogenicity (IA), the index of thrombogenicity (IT), the hypocholesterolemic/hypercholesterolemic ratio (HH), the health-promoting index (HPI), the unsaturation index (UI), the sum of eicosapentaenoic acid and docosahexaenoic acid (EPA + DHA), fish lipid quality/flesh lipid quality (FLQ), the linoleic acid/α-linolenic acid (LA/ALA) ratio, and trans fatty acid (TFA). Of these nutritional indices, IA and IT are the most commonly used to assess the composition of fatty acids as they outline significant implications and provide clear evidence. EPA + DHA is commonly used to assess the nutritional quality of marine animal products. All indices have their advantages and disadvantages; hence, a rational choice of which to use is critical.

Association between fish intake and glioma risk: a systematic review and meta-analysis

Objectives

We investigated the association between the consumption of fresh and processed fish and glioma risk using a meta-analysis approach.

Methods

We selected and analyzed observational studies that discussed the relationships between fresh and processed fish intake on glioma risk from PubMed, Web of Science, Embase, and the SinoMed and Wanfang databases from inception to 31 March 2020. Studies were selected according to pre-established eligibility criteria and data were extracted separately by two researchers. A meta-analysis was conducted based on a random-effects model to provide pooled odds ratios (OR) and 95% confidence intervals (CIs).

Results

Eight studies considered the relationship between fish intake (seven fresh and seven processed fish) and glioma risk and were included in this meta-analysis. The OR effect size for fresh fish intake and glioma risk was 0.72 (95%CI 0.53–0.97) and the overall OR effect size for processed fish intake and glioma risk was 1.88 (95%CI 1.06–3.34).

Conclusion

Dietary intake of fresh fish may reduce the risk of glioma, but consumption of processed fish may increase the risk of glioma. This study had some limitations, and further studies are therefore required to clarify the associations between fish intake and glioma risk.