The development of colorectal cancer, responsible for 9% of cancer-related deaths, is favored by a combination of genetic and environmental factors. The modification of diet and lifestyle may modify the risk of colorectal cancer (CRC) and prevent neoplasia in up to 50% of cases. The Western diet, characterized by a high intake of fat, red meat and processed meat has emerged as an important contributor. Conversely, a high intake of dietary fiber partially counteracts the unfavorable effects of meat through multiple mechanisms, including reduced intestinal transit time and dilution of carcinogenic compounds. Providing antioxidants (e.g., vitamins C and E) and leading to increased intraluminal production of protective fermentation products, like butyrate, represent other beneficial and useful effects of a fiber-rich diet. Protective effects on the risk of developing colorectal cancer have been also advocated for some specific micronutrients like vitamin D, selenium, and calcium. Diet-induced modifications of the gut microbiota modulate colonic epithelial cell homeostasis and carcinogenesis. This can have, under different conditions, opposite effects on the risk of CRC, through the production of mutagenic and carcinogenic agents or, conversely, of protective compounds. The aim of this review is to summarize the most recent evidence on the role of diet as a potential risk factor for the development of colorectal malignancies, as well as providing possible prevention dietary strategies.

(1) Background: Vitamin D is an immunoregulatory factor influencing intestinal homeostasis. Recent evidence supports a central role of this micronutrient in the course of Inflammatory Bowel Diseases (IBD). This narrative review aims to provide a general overview of the possible biological mechanisms of action of vitamin D and its therapeutic implications in IBD. (2) Methods: A systematic electronic search of the English literature up to October 2021 was performed using Medline and the Cochrane Library. Only papers written in English that analyzed the role of vitamin D in IBD were included. (3) Results: In vitro and animal studies reported that vitamin D signaling improves epithelial barrier integrity regulating the expression of several junctional proteins, defensins, and mucins, modulates the inflammatory response, and affects gut microbiome composition. Recent studies also suggest that vitamin D deficiency is highly prevalent among IBD patients and that low serum levels correlate with disease activity and, less clearly, with disease course. (4) Conclusions: An increasing body of evidence suggests some role of vitamin D in the pathophysiology of IBD, nonetheless the underlying mechanisms have been so far only partially elucidated. A strong correlation with disease activity has been reported but its implication in the treatment is still undefined. Thus, studies focused on this issue, the definition of vitamin D levels responsible for clinical effects, and the potential role of vitamin D as a therapeutic agent are strongly encouraged.

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the Western world. Early detection decreases incidence and mortality. Screening programs based on fecal occult blood testing help identify patients requiring endoscopic examination, but accuracy is far from optimal. Among the alternative strategies, volatile organic compounds (VOCs) represent novel potentially useful biomarkers of colorectal cancer. They also represent a promising tool for the screening of both intestinal inflammation and related CRC. The review is focused on the diagnostic potential of VOCs in sporadic CRC and in inflammatory bowel diseases (IBD), which increase the risk of CRC, analyzing future clinical applications. Despite limitations related to inadequate strength of evidence, differing analytical platforms identify different VOCs, and this unconventional approach for diagnosing colorectal cancer is promising. Some VOC profiles, besides identifying inflammation, seem disease-specific in inflammatory bowel diseases. Thus, breath, urine, and fecal VOCs provide a new and promising clinical approach to differential diagnosis, evaluation of the inflammatory status, and possibly the assessment of treatment efficacy in IBD. Conversely, specific VOC patterns correlating inflammatory bowel disease and cancer risk are still lacking, and studies focused on this issue are strongly encouraged. No prospective studies have assessed the risk of CRC development by using VOCs in samples collected before the onset of disease, both in the general population and in patients with IBD.

Background: Mucosal healing (MH) evaluated by endoscopy is a novel target of therapy in UC as it is associated with improved long-term outcomes. It is defined based on the Mayo endoscopic score (MES), but it is still to define whether a value of MES 0 or 1 should be the target. The purpose of this paper is to present the results of a systematic review with meta-analysis which compares long-term outcomes of patients in steroid-free clinical remission with MES 0 with those with MES 1. Methods: A systematic electronic search of the literature was performed using Medline, Scopus, and CENTRAL through December 2020 (PROSPERO n:CRD42020179333). The studies concerned UC patients, in steroid-free clinical remission, with MES of 0 or 1, and with at least 12-months of follow-up. Results: Out of 4611 citations, 15 eligible studies were identified. Increases in clinical relapse among patients with MES 1 were observed in all the studies included in this review, suggesting that MES of 1 have a higher risk of relapse than a score of 0. MES 0 patients displayed a lower risk of clinical relapse (OR 0.33; 95% CI 0.26–0.43; I² 13%) irrespective of the follow-up time (12-months or longer). On the other hand, no differences were found comparing MES 0 versus MES 1 about the risk of hospitalization or colectomy. Conclusions: MES 0 is associated with a lower rate of clinical relapse than is MES 1. For this reason, MES 0, rather than MES 0–1, should be considered the therapeutic target for patients with UC.

The main role of vitamin D is calcium homeostasis and bone metabolism, although its activity as an immuno-modulator and its anti-inflammatory effect is well-known. Low blood vitamin D levels are common among patients with inflammatory bowel disease (IBD). Whether low vitamin D levels could affect the disease activity or it is an effect of a worse condition of the disease is still unclear. This study aimed to investigate the role of blood vitamin D levels to identify the clinical, endoscopic, and histological activity in a cohort of patients with ulcerative colitis (UC) or Crohn’s disease (CD) on therapy with biological drugs. In this retrospective cohort study, 50 IBD patients (24 UC and 26 CD) that underwent colonoscopy from January 2017 to January 2020 with a concomitant serological evaluation of vitamin D were included. Patients with clinical, endoscopic, and histological activity and those who lost their clinical response to the biological drug had lower vitamin D levels compared to patients in remission or patients that did not change therapeutic regimens. A receiver operating characteristic (ROC) analysis and Youden’s Index were performed to assess the optimal vitamin D levels to identify patients with the active disease. The ROC analysis showed an area under the curve (AUC) of 0.709 (p = 0.005; confidence interval (CI): 0.564–0.829), 0.769 (p < 0.001; CI: 0.628–0.876), and 0.810 (p < 0.001; CI: 0.670–0.910) for the clinical, endoscopic, and histological outcomes, respectively. The optimal vitamin D cut-off was ≤25 ng/mL. The vitamin D level is an additional useful tool in the evaluation of IBD patients with good accuracy to predict their endoscopic and histological activity and clinical response to biologics.

Background: Since its first report in Wuhan, China, in December 2019, COVID-19 has become a pandemic, affecting millions of people worldwide. Although the virus primarily affects the respiratory tract, gastrointestinal symptoms are also common. The aim of this narrative review is to provide an overview of the pathophysiology and clinical manifestations of gastrointestinal COVID-19. Methods: We conducted a systematic electronic search of English literature up to January 2023 using Medline, Scopus, and the Cochrane Library, focusing on papers that analyzed the role of SARS-CoV-2 in the gastrointestinal tract. Results: Our review highlights that SARS-CoV-2 directly infects the gastrointestinal tract and can cause symptoms such as diarrhea, nausea/vomiting, abdominal pain, anorexia, loss of taste, and increased liver enzymes. These symptoms result from mucosal barrier damage, inflammation, and changes in the microbiota composition. The exact mechanism of how the virus overcomes the acid gastric environment and leads to the intestinal damage is still being studied. Conclusions: Although vaccination has increased the prevalence of less severe symptoms, the long-term interaction with SARS-CoV-2 remains a concern. Understanding the interplay between SARS-CoV-2 and the gastrointestinal tract is essential for future management of the virus.