Differential acute effects of selenomethionine and sodium selenite on the severity of colitis

Navigating the microbial maze: unraveling the connection between gut microbiome and pediatric kidney and urinary tract disease

The gut microbiome is made up of trillions of bacteria, viruses, archaea, and microbes that play a significant role in the maintenance of normal physiology in humans. Recent research has highlighted the effects of the microbiome and its dysbiosis in the pathogenesis and maintenance of kidney disease, especially chronic kidney disease (CKD) and its associated cardiovascular disease. While studies have addressed the kidney-microbiome axis in adults, how dysbiosis may uniquely impact pediatric kidney disease patients is not well-established. This narrative review highlights all relevant studies focusing on the microbiome and pediatric kidney disease that were published between 7/2015 and 7/2023. This review highlights pediatric-specific considerations including growth and bone health as well as emphasizing the need for increased pediatric research. Understanding microbiome-kidney interactions may allow for novel, less invasive interventions such as dietary changes and the use of probiotics to improve preventive care and ameliorate long-term morbidity and mortality in this vulnerable population.

Selenium, Immunity, and Inflammatory Bowel Disease

Dietary intervention is a subject of growing interest in the management of inflammatory bowel disease (IBD), as new incident cases across the globe are rapidly rising, suggesting environmental factors as contributing elements. Dietary components and micronutrients have been associated with IBD pathogenesis or reductions in disease severity. Selenium, a diet-derived essential micronutrient that is important for proper immune system function, has received limited attention in the context of IBD. Selenium deficiency is a common finding in patients with IBD, but few clinical trials have been published to address the consequences of this deficiency. Here, we review the physiological and immunological roles of selenium and its putative role in IBD, and draw attention to knowledge gaps and unresolved issues, with the goal of stimulating more research on selenium in IBD.

Nano-Selenium Alleviates Cd-Induced Chronic Colitis through Intestinal Flora

BACKGROUND

Cadmium (Cd) is an environmental contaminant that poses risks to human and animal health. Selenium (Se), a beneficial element, alleviates the detrimental consequences of colitis and Cd toxicity. Se is found in food products as both inorganic Se (sodium selenite) and organic Se (typically Se-enriched yeast). Nano-selenium (nano-Se; a novel form of Se produced through the bioreduction of Se species) has recently garnered considerable interest, although its effects against Cd-induced enterotoxicity are poorly understood. The aim of this study was to investigate the impact of nano-selenium on mitigating cadmium toxicity and safeguarding the integrity of the intestinal barrier.

METHODS

For a total of two cycles, we subjected 6-week-old C57 mice to chronic colitis by exposing them to Cd and nano-selenium for two weeks, followed by DSS water for one week.

RESULTS

The application of nano-selenium mitigated the intensity of colitis and alleviated inflammation in the colon. Nano-selenium enhanced the diversity of the intestinal flora, elevated the concentration of short-chain fatty acids (SCFAs) in feces, and improved the integrity of the intestinal barrier.

CONCLUSIONS

In summary, nano-Se may reduce intestinal inflammation by regulating the growth of intestinal microorganisms and protecting the intestinal barrier.

Nutritional Support: The Use of Antioxidants in Inflammatory Bowel Disease

The problem of treating inflammatory bowel disease continues to be a topic of great interest for researchers. Despite the complexity surrounding their treatment and strategies to prolong periods of remission, there is a promising exploration of various compounds that have potential in combating inflammation and alleviating symptoms. Selenium, calcium, magnesium, zinc, and iron are among these compounds, offering a glimpse of hope in the treatment of IBD. These essential minerals not only hold the promise of reducing inflammation in these diseases, but also show the potential to enhance immune function and possibly influence the balance of intestinal microflora. By potentially modulating the gut microbiota, they may help support overall immune health. Furthermore, these compounds could play a crucial role in mitigating inflammation and minimising complications in patients with IBD. Furthermore, the protective effect of these compounds against mucosal damage in IBD and the protective effect of calcium itself against osteoporosis in this group of patients are notable.

Selenium metabolism and regulation of immune cells in immune-associated diseases

Selenium, as one of the essential microelements, plays an irreplaceable role in metabolism regulation and cell survival. Selenium metabolism and regulation have great effects on physiological systems especially the immune system. Therefore, selenium is tightly related to various diseases like cancer. Although recent research works have revealed much about selenium metabolism, the ways in which selenium regulates immune cells' functions and immune-associated diseases still remain much unclear. In this review, we will briefly introduce the regulatory role of selenium metabolism in immune cells and immune-associated diseases.

Supplementary selenium in the form of selenylation α-D-1,6-glucan ameliorates dextran sulfate sodium induced colitis in vivo

The deficiency of selenium has been found in clinical IBD patients and supplementation selenium is recognized as beneficial for colitis treatment. In this study, an organic selenium compound-selenylation α-D-1,6-glucan (sCPA) was prepared, and the effect of sCPA on DSS induced colitis mice was investigated. The results suggested that sCPA prevented the weight loss, colon length shortening, and stool loose of colitis mice. It protected colon mucosal barrier by promoting tight junction protein ZO-1 and Occludin expression. Moreover, sCPA reduced oxidative stress via regulating SOD and MDA levels, and decreased the contents of inflammatory proteins NF-κB and NLRP3 and adjusted TNF-α, IFN-γ, IL-1β, and IL-10 inflammatory cytokines. Furthermore, sCPA repaired intestinal microbiota composition especially Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria that altered by DSS in colitis mice. Meanwhile, SCFAs produced by gut microbiota were restored by sCPA close to the level in the normal group. In conclusion, these findings indicated that the sCPA might be a potential dietary selenium supplementation for the prevention and treatment of colitis.

The Trace Element Selenium Is Important for Redox Signaling in Phorbol Ester-Differentiated THP-1 Macrophages

Physiological selenium (Se) levels counteract excessive inflammation, with selenoproteins shaping the immunoregulatory cytokine and lipid mediator profile. How exactly differentiation of monocytes into macrophages influences the expression of the selenoproteome in concert with the Se supply remains obscure. THP-1 monocytes were differentiated with phorbol 12-myristate 13-acetate (PMA) into macrophages and (i) the expression of selenoproteins, (ii) differentiation markers, (iii) the activity of NF-κB and NRF2, as well as (iv) lipid mediator profiles were analyzed. Se and differentiation affected the expression of selenoproteins in a heterogeneous manner. GPX4 expression was substantially decreased during differentiation, whereas GPX1 was not affected. Moreover, Se increased the expression of selenoproteins H and F, which was further enhanced by differentiation for selenoprotein F and diminished for selenoprotein H. Notably, LPS-induced expression of NF-κB target genes was facilitated by Se, as was the release of COX- and LOX-derived lipid mediators and substrates required for lipid mediator biosynthesis. This included TXB2, TXB3, 15-HETE, and 12-HEPE, as well as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Our results indicate that Se enables macrophages to accurately adjust redox-dependent signaling and thereby modulate downstream lipid mediator profiles.

Selenium in cereals: Insight into species of the element from total amount

Selenium (Se) is a trace mineral micronutrient essential for human health. The diet is the main source of Se intake. Se-deficiency is associated with many diseases, and up to 1 billion people suffer from Se-deficiency worldwide. Cereals are considered a good choice for Se intake due to their daily consumption as staple foods. Much attention has been paid to the contents of Se in cereals and other foods. Se-enriched cereals are produced by biofortification. Notably, the gap between the nutritional and toxic levels of Se is fairly narrow. The chemical structures of Se compounds, rather than their total contents, contribute to the bioavailability, bioactivity, and toxicity of Se. Organic Se species show better bioavailability, higher nutritional value, and less toxicity than inorganic species. In this paper, we reviewed the total content of Se in cereals, Se speciation methods, and the biological effects of Se species on human health. Selenomethionine (SeMet) is generally the most prevalent and important Se species in cereal grains. In conclusion, Se species should be considered in addition to the total Se content when evaluating the nutritional and toxic values of foods such as cereals.

Antioxidant Therapy in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are a group of chronic, incurable diseases of the digestive tract, the etiology of which remains unclear to this day. IBD result in significant repercussions on the quality of patients’ life. There is a continuous increase in the incidence and prevalence of IBD worldwide, and it is becoming a significant public health burden. Pharmaceuticals commonly used in IBD management, for example, mesalamine, sulfasalazine, corticosteroids, and others, expose patients to diverse, potentially detrimental side effects and frequently do not provide sufficient disease control. The chronic inflammation underlies the etiology of IBD and closely associates with oxidative/nitrosative stress and a vast generation of reactive oxygen/nitrogen species. Relative to this, several substances with antioxidant and anti-inflammatory properties are now intensively researched as possible adjunctive or independent treatment options in IBD. Representatives of several different groups, including natural and chemical compounds will be characterized in this dissertation.

Selenium-Containing Amino Acids Protect Dextran Sulfate Sodium-Induced Colitis via Ameliorating Oxidative Stress and Intestinal Inflammation

Background

Inflammatory bowel disease (IBD) is characterized by chronic relapsing inflammation of the gastrointestinal tract. Oxidative stress plays a pivotal role in the pathogenesis of IBD. Selenium-containing amino acids reportedly have anti-oxidative and anti-inflammatory properties, but it remains unknown if selenium-containing amino acids can be used to treat IBD. This study aimed to investigate the effects of two selenium-containing amino acids - selenocysteine and selenocystine - on oxidative stress and chronic inflammation in a mouse model of dextran sulfate sodium (DSS)-induced IBD.

Methodology

C57BL/6 mice were randomly assigned to the following six groups: control, DSS, DSS+selenocysteine, DSS+selenocystine, DSS+sodium selenite, and DSS+N-acetylcysteine (NAC). IBD was induced by 3% DSS. Pro-inflammatory cytokines [interleukin-1β (IL-1β), monocyte chemotactic protein 1 (MCP-1), IL-6, and tumor necrosis factor-α (TNF-α)] and markers for oxidative and anti-oxidative stress [malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase (SOD), and glutathione peroxidase (GPx)] were measured using immunohistochemical analysis.

Results

Selenocysteine and selenocystine significantly attenuated IBD-related symptoms, including preventing weight loss, decreasing disease activity index (DAI) scores, and increasing colon length. Selenocysteine and selenocystine significantly ameliorated the DSS-induced oxidative stress, as demonstrated by a reduction in ROS and MDA activity and an increase in SOD and GPx activity. IL-1, MCP-1, IL-6, and TNF-α levels were significantly increased in the IBD mice, while treatment with the selenium-containing amino acids significantly reduced the levels of these pro-inflammatory cytokines. In vivo safety analysis showed minimal side effects of the selenium-containing amino acids.

Conclusion

We found that selenocysteine and selenocystine ameliorated DSS-induced IBD via reducing oxidative stress and intestinal inflammation, indicating that selenium-containing amino acids could be a novel therapeutic option for patients with IBD.

Absorption and Distribution of Selenium Following Oral Administration of Selenium-Enriched Bifidobacterium longum DD98, Selenized Yeast, or Sodium Selenite in Rats

Selenium (Se) is one of the essential elements required to maintain human health. Although various kinds of Se supplements are now available on the market, their biological activities and toxicities vary based on the transportation characteristics of Se. In this study, we compared the absorption and distribution of Se in rats administered with different Se supplements: Se-enriched Bifidobacterium longum DD98 (Se-DD98), selenized yeast (Se-Y), and sodium selenite (Na₂SeO₃). Se-DD98, Se-Y, and Na₂SeO₃ were orally administered to rats. The plasma Se content at different time points after administration was determined within 72 h. Pharmacokinetic parameters were analyzed to reveal the absorption of Se. Se-DD98, Se-Y, and Na₂SeO₃ were also repeatedly administered by oral gavage for 30 days, and Se content of the heart, liver, spleen, lungs, kidneys, and muscle was determined to analyze the distribution of Se. The results showed that the organic Se supplements (Se-DD98 and Se-Y) were more easily absorbed into the blood and retained longer in the plasma than the inorganic Na₂SeO₃ was. Moreover, Se-DD98 induced better absorption of Se in plasma than Se-Y did. Furthermore, significantly higher concentrations of Se were found in the heart, liver, spleen, kidneys, and muscle of rats administered with organic Se supplements (Se-DD98 and Se-Y) than those administered the inorganic Na₂SeO₃. Rats administered Se-DD98 accumulated more Se in the spleen, lung, and kidney than those administered Se-Y, while Se-Y led to higher concentration of Se in the liver compared to Se-DD98. These results suggest that the organic form of Se was better absorbed and accumulated than the inorganic form was. Se-enriched B. longum DD98 induced greater absorption of Se in plasma and accumulation of Se in several organs than the selenized yeast did, which could suggest the potential superior nutritional function of Se-DD98.

Selenium Donors at the Junction of Inflammatory Diseases

Selenium is an essential non-metal trace element, and the imbalance in the bioavailability of selenium is associated with many diseases ranking from acute respiratory distress syndrome, myocardial infarction and renal failure (Se overloading) to diseases associated with chronic inflammation like inflammatory bowel diseases, rheumatoid arthritis, and atherosclerosis (Se unload). The only source of selenium is the diet (animal and cereal sources) and its intestinal absorption is limiting for selenocysteine and selenomethionine synthesis and incorporation in selenoproteins. In this review, after establishing the link between selenium and inflammatory diseases, we envisaged the potential of selenium nanoparticles and organic selenocompounds to compensate the deficit of selenium intake from the diet. With high selenium loading, nanoparticles offer a low dosage to restore selenium bioavailability whereas organic selenocompounds can play a role in the modulation of their antioxidant or antiinflammatory activities.

Compositional alterations of gut microbiota in children with primary nephrotic syndrome after initial therapy

Background

Primary nephrotic syndrome (PNS) is a common glomerular disease in children. T cell dysfunction plays a crucial role in the pathogenesis of PNS. Moreover, dysbiosis of gut microbiota contributes to immunological disorders. Whether the initial therapy of PNS affects gut microbiota remains an important question. Our study investigated compositional changes of gut microbiota after initial therapy.

Methods

Fecal samples of 20 children with PNS were collected before and after 4-week initial therapy. Total bacteria DNA were extracted and the V3-V4 regions of bacteria 16S ribosomal RNA gene were sequenced. The composition of gut microbiota before and after initial therapy was analyzed by bioinformatics methods. The function of altered gut microbiota was predicted with PICRUSt method.

Results

The richness and diversity of gut microbiota were similar before and after 4-week initial therapy. Gut microbiota at the phylum level was dominated by four phyla including Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria, but the increased relative abundance after initial therapy was found in Deinococcus-Thermus and Acidobacteria. At the genus level, the increased abundance of gut microbiota after initial therapy was observed in short chain fat acids (SCFA)-producing bacteria including Romboutsia, Stomatobaculum and Cloacibacillus (p < 0.05). Moreover, the predicted functional profile of gut microbiota showed that selenocompound metabolism, isoflavonoid biosynthesis and phosphatidylinositol signaling system weakened after initial therapy of PNS.

Conclusions

Initial therapy of PNS increased SCFA-producing gut microbiota, but might diminish selenocompound metabolism, isoflavonoid biosynthesis and phosphatidylinositol signaling system in children.

Preparation and characterization of selenium enriched-Bifidobacterium longum DD98, and its repairing effects on antibiotic-induced intestinal dysbacteriosis in mice

The aim of this study was to investigate the characteristics of a novel selenium-enriched Bifidobacterium longum DD98 (Se-B. longum DD98) supplement food and its repairing effects on the intestinal ecology of mammals. We assessed the growth, Se accumulation, and Se biotransformation of B. longum DD98 and its effects on antibiotic-induced intestinal dysbacteriosis in mice. The viable bacterial count at the end of fermentation was not significantly affected by the presence of Se. Bifidobacterium longum DD98 took up inorganic Se from the medium and biotransformed it into Se-containing proteins and selenoamino acids. The dominant Se species was selenomethionine (SeMet), which comprised 87% of the total Se in Se-B. longum DD98. Furthermore, Se-B. longum DD98 showed better regulation of the disrupted intestinal microbiota back to normal levels and repaired damaged colon tissues compared to the natural recovery and B. longum DD98 treatments. These findings suggest that B. longum DD98 efficiently biotransformed inorganic Se into more bioactive organic Se forms and may have therapeutic potential for the restoration of antibiotic-induced intestinal dysbacteriosis.

Micronutrient Deficiencies in Medical and Surgical Inpatients

Inpatients are threatened by global malnutrition, but also by specific micronutrient (i.e., trace element and vitamins) deficiencies that frequently are overseen in the differential diagnosis of major organ dysfunctions. Some of them are related to specific geographic risks (iodine, iron, selenium, zinc, vitamin A), while others are pathology related, and finally many are associated with specific feeding patterns, including low dose enteral feeding. Among the pathologies in which laboratory blood investigations should include a micronutrient outwork, anemia is in the front line, followed by obesity with bariatric surgery, chronic liver disease, kidney disease, inflammatory bowel disease, cardiomyopathies and heart failure. The micronutrients at the highest risk are iron, zinc, thiamine, vitamin B12 and vitamin C. Admission to hospital has been linked with an additional risk of malnutrition—feeding below 1500 kcal/day was frequent and has been associated with a structural additional risk of insufficient micronutrient intake to cover basal needs. Although not evidence based, systematic administration of liberal thiamine doses upon admission, and daily complementation of inpatients’ food and enteral feeding solutions with multi-micronutrient tablets might be considered.

Treatment of Caenorhabditis elegans with Small Selenium Species Enhances Antioxidant Defense Systems

SCOPE

Small selenium (Se) species play a key role in Se metabolism and act as dietary sources of the essential trace element. However, they are redox-active and trigger pro- and antioxidant responses. As health outcomes are strongly species-dependent, species-specific characteristics of Se compounds are tested in vivo.

METHODS AND RESULTS

In the model organism Caenorhabditis elegans (C. elegans), immediate and sustained effects of selenite, selenomethionine (SeMet), and Se-methylselenocysteine (MeSeCys) are studied regarding their bioavailability, incorporation into proteins, as well as modulation of the cellular redox status. While all tested Se compounds are bioavailable, only SeMet persistently accumulates and is non-specifically incorporated into proteins. However, the protection toward chemically-induced formation of reactive species is independent of the applied Se compound. Increased thioredoxin reductase (TXNRD) activity and changes in mRNA expression levels of antioxidant proteins indicate the activation of cellular defense mechanisms. However, in txnrd-1 deletion mutants, no protective effects of the Se species are observed anymore, which is also reflected by differential gene expression data.

CONCLUSION

Se species protect against chemically-induced reactive species formation. The identified immediate and sustained systemic effects of Se species give rise to speculations on possible benefits facing subsequent periods of inadequate Se intake.

Varied doses and chemical forms of selenium supplementation differentially affect mouse intestinal physiology

Varied doses and chemical forms of selenium supplementation differentially affect mouse intestinal physiology and perturbed the fecal metabolic profiles of and jejunal protein expression in mice.

Roles for selenium and selenoprotein P in the development, progression, and prevention of intestinal disease

Selenium (Se) is a micronutrient essential to human health, the function of which is mediated in part by incorporation into a class of proteins known as selenoproteins (SePs). As many SePs serve antioxidant functions, Se has long been postulated to protect against inflammation and cancer development in the gut by attenuating oxidative stress. Indeed, numerous studies over the years have correlated Se levels with incidence and severity of intestinal diseases such as inflammatory bowel disease (IBD) and colorectal cancer (CRC). Similar results have been obtained with the Se transport protein, selenoprotein P (SELENOP), which is decreased in the plasma of both IBD and CRC patients. While animal models further suggest that decreases in Se or SELENOP augment colitis and intestinal tumorigenesis, large-scale clinical trials have yet to show a protective effect in patient populations. In this review, we discuss the function of Se and SELENOP in intestinal diseases and how research into these mechanisms may impact patient treatment.

New Insights into the Role of Trace Elements in IBD

Micronutrient deficiencies are common in inflammatory bowel disease and have clinical impact, being both a sign of complicated disease and a cause of morbidity. The involved systemic inflammatory response is responsible for altering the concentration of a wide range of trace elements in the serum, including zinc and selenium. This review summarizes recent advances and evidence-based knowledge regarding the impact of selenium and zinc on oxidative stress and microbiota changes in IBD patients. Getting new insight into the impact of malnutrition, particularly on the micronutrients' impact on the development, composition, and metabolism of microbiota, as well as the influence of oxidative stress and the mucosal immune response, could help in implementing new management strategies for IBD patients, with focus on a more integrated approach.

Dietary Selenium and Human Health

Next year (2017), the micronutrient Selenium (Se) is celebrating its birthday—i.e., 200 years after first being identified by the Swedish chemist Jöns Jakob Berzelius. Despite its impressive age, research into the functions of this essential trace element is very alive and reaching out for new horizons. This special issue presents some recent fascinating, exciting, and promising developments in Se research in the form of eight original contributions and seven review articles. Collectively, aspects of Se supply, biochemical, physiological, and chemotherapeutic effects, and geobiological interactions are covered by leading scientists in the areas of nutritional, basic, and clinical research. It is obvious from the contributions that the bicentennial anniversary will celebrate a micronutrient still in its infancy with respect to being understood in terms of its biomedical importance.

Individual effects of different selenocompounds on the hepatic proteome and energy metabolism of mice

BACKGROUND

Selenium (Se) exerts its biological activity largely via selenoproteins, which are key enzymes for maintaining the cellular redox homeostasis. However, besides these beneficial effects there is also evidence that an oversupply of Se might increase the risk towards developing metabolic disorders. To address this in more detail, we directly compared effects of feeding distinct Se compounds and concentrations on hepatic metabolism and expression profiles of mice.

METHODS

Male C57BL6/J mice received either a selenium-deficient diet or diets enriched with adequate or high doses of selenite, selenate or selenomethionine for 20weeks. Subsequently, metabolic parameters, enzymatic activities and expression levels of hepatic selenoproteins, Nrf2 targets, and additional redox-sensitive proteins were analyzed. Furthermore, 2D-DIGE-based proteomic profiling revealed Se compound-specific differentially expressed proteins.

RESULTS

Whereas heterogeneous effects between high concentrations of the Se compounds were observed with regard to body weight and metabolic activities, selenoproteins were only marginally increased by high Se concentrations in comparison to the respective adequate feeding. In particular the high-SeMet group showed a unique response compromising higher hepatic Se levels in comparison to all other groups. Accordingly, hepatic glutathione (GSH) levels, glutathione S-transferase (GST) activity, and GSTpi1 expression were comparably high in the high-SeMet and Se-deficient group, indicating that compound-specific effects of high doses appear to be independent of selenoproteins.

CONCLUSIONS

Not only the nature, but also the concentration of Se compounds differentially affect biological processes.

GENERAL SIGNIFICANCE

Thus, it is important to consider Se compound-specific effects when supplementing with selenium.

Selenomethionine reduces the deposition of beta-amyloid plaques by modulating β-secretase and enhancing selenoenzymatic activity in a mouse model of Alzheimer's disease

Effects on Aβ production and the probable connection among selenoenzymes, GSK3β and Aβ pathology by selenomethionine treatment in AD mice.

Micronutrient deficiencies in inflammatory bowel disease

PURPOSE OF REVIEW

Malnutrition, protein-energy, and micronutrient deficiencies are common among patients with inflammatory bowel disease (IBD). The deficiencies are a manifestation of the complicated disease and a cause of morbidity. The present review summarizes recent advances and evidence-based knowledge regarding micronutrients in relation to patients with IBD.

RECENT FINDINGS

Micronutrient deficiencies occur in more than half of patients with IBD. Most common are deficiencies of iron, B12, vitamin D, vitamin K, folic acid, selenium, zinc, vitamin B6, and vitamin B1. Deficiencies are more common in Crohn's disease than in ulcerative colitis, and more in active disease than at times of remission. Micronutrient deficiency is associated with prolonged and complicated course of disease. Iron deficiency is the most common cause for anemia. Definite diagnosis of B12 deficiency cannot be established by serum levels alone. Vitamin D and vitamin K deficiencies are thought to be associated with heightened inflammatory state. The relationship of these deficiencies with bone disease is controversial. The present review focuses on the significance, epidemiology, treatment options, and recommendations regarding micronutrient deficiencies in IBD.

SUMMARY

Micronutrient deficiencies are common and have clinical significance. High suspicion for micronutrient deficiencies is advocated so that treatable causes of morbidity are treated appropriately and late and irreversible sequlae are prevented.

Selenium and inflammatory bowel disease

Dietary intake of the micronutrient selenium is essential for normal immune functions. Selenium is cotranslationally incorporated as the 21st amino acid, selenocysteine, into selenoproteins that function to modulate pathways involved in inflammation. Epidemiological studies have suggested an inverse association between selenium levels and inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis that can potentially progress to colon cancer. However, the underlying mechanisms are not well understood. Here we summarize the current literature on the pathophysiology of IBD, which is multifactorial in origin with unknown etiology. We have focused on a few selenoproteins that mediate gastrointestinal inflammation and activate the host immune response, wherein macrophages play a pivotal role. Changes in cellular oxidative state coupled with altered expression of selenoproteins in macrophages drive the switch from a proinflammatory phenotype to an anti-inflammatory phenotype to efficiently resolve inflammation in the gut and restore epithelial barrier integrity. Such a phenotypic plasticity is accompanied by changes in cytokines, chemokines, and bioactive metabolites, including eicosanoids that not only mitigate inflammation but also partake in restoring gut homeostasis through diverse pathways involving differential regulation of transcription factors such as nuclear factor-κB and peroxisome proliferator-activated receptor-γ. The role of the intestinal microbiome in modulating inflammation and aiding in selenium-dependent resolution of gut injury is highlighted to provide novel insights into the beneficial effects of selenium in IBD.