The Mediterranean diet is considered one of the most worldwide healthy dietary patterns thanks to a combination of foods rich mainly in antioxidants and anti-inflammatory nutrients. Many studies have demonstrated a strong and inverse relationship between a high level of Mediterranean diet adherence and some chronic diseases (such as cardiovascular diseases, diabetes, etc.) and cancer. Given its protective effects in reducing oxidative and inflammatory processes of cells and avoiding DNA damages, cell proliferation, and their survival, angiogenesis, inflammations and metastasis, the Mediterranean diet is considered a powerful and manageable method to fight cancer incidence. The aim of this narrative review was to determine the magnitude of interaction between the Mediterranean diet and more widespread types of cancer so as to give a first and useful overview on this relationship identifying, with a nutritional approach, those nutrients of Mediterranean diet able to reduce cancer incidence.

Inflammatory bowel disease (IBD) is a chronic relapsing–remitting systemic disease of the gastrointestinal tract, characterized by an inflammatory process that requires lifelong treatment. The underlying causes of IBD are still unclear, as this heterogeneous disorder results from a complex interplay between genetic variability, the host immune system and environmental factors. The current knowledge recognizes diet as a risk factor for the development of IBD and attributes a substantial pathogenic role to the intestinal dysbiosis inducing an aberrant mucosal immune response in genetically predisposed individuals. This review focused on the clinical evidence available that considers the impact of some nutrients on IBD onset and the role of different diets in the management of IBD and their effects on the gut microbiota composition. The effects of the Specific Carbohydrate Diet, low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet, gluten free diet, anti-inflammatory diet and Mediterranean diet are investigated with regard to their impact on microbiota and on the evolution of the disease. At present, no clear indications toward a specific diet are available but the assessment of dysbiosis prior to the recommendation of a specific diet should become a standard clinical approach in order to achieve a personalized therapy.

SARS-CoV-2, the cause of the COVID-19 disease, is posing unprecedent challenges. In the literature, increasing evidence highlights how malnutrition negatively affects the immune system functionality, impairing protection from infections. The current review aims to summarize the complex relationship between SARS-CoV-2 infection and nutritional status and the effects of malnutrition in terms of disease severity, patients’ recovery time, incidence of complications and mortality rate. Current studies evaluating the possibility of modulating nutrition and supplementation in combination with pharmacological treatments in the clinical setting to prevent, support, and overcome infection are also described. The discussion of the most recent pertinent literature aims to lay the foundations for making reasonable assumptions and evaluations for a nutritional “best practice” against COVID-19 pandemic and for the definition of sound cost-effective strategies to assist healthcare systems in managing patients and individuals in their recovery from COVID-19.

Hypovitaminosis D is frequently present in inflammatory bowel disease (IBD) with a higher incidence in Crohn’s disease (CD) than in Ulcerative Colitis (UC). Given the involvement of the alimentary tract, many factors can contribute to hypovitaminosis D. The aim of the study was to investigate the association of disease activity, body mass index (BMI) and phase angle with vitamin D deficiency in patients with IBD. A cross-sectional study was conducted on a cohort of 206 IBD patients (October 2016–September 2018). Of these patients, 32.6% were affected by hypovitaminosis D (CD: 38.6%; UC: 25.6%; p < 0.01). Negative and significant associations (p < 0.01) were found between BMI and vitamin D serum levels both in CD and UC patients. BMI represented a determinant of hypovitaminosis D (Odds Ratio (OR) = 1.12, p < 0.01) only in UC patients; phase angle was associated to hypovitaminosis D in both groups (CD: OR = 0.64, p < 0.05; UC: OR = 0.49, p < 0.01). Results of the present study confirm a higher incidence of hypovitaminosis D in patients with CD than in those with UC, and show that nutritional status plays a crucial role in the incidence of vitamin D deficiency in patients with IBD.

The gut microbiome, a collection of gut microorganisms, is crucial in the development and progression of inflammatory bowel diseases (IBD). Therefore, diet and dietary interventions are promising strategies to shape the gut microbiota for IBD management. Of all the diets studied in the IBD field, the Mediterranean diet has the least restrictive nature, promoting long-term adherence. The Mediterranean diet is rich in plants, with a high daily intake of fruits and vegetables (high in fiber, antioxidants, and vitamins), olive oil, whole grains, legumes, and nuts. It includes the moderate consumption of animal products such as oily fish (rich in mono- and polyunsaturated fatty acids), dairy products, and poultry, with a limited intake of red meat and processed foods. This diet is associated with a decreased risk of chronic diseases, including IBD. However, the mechanisms of specific nutrients behind these effects in the Mediterranean diet remain under investigation. Therefore, in this review, we aim to provide an overview of the nutrients that are abundant in the Mediterranean diet and their effects on IBD, with a main focus on preclinical evidence. While several nutrients like fructo-oligosaccharide, chitosan, plant-derived protein, polyphenols, omega-3 polyunsaturated fatty acids, and resveratrol have shown potential beneficial effects in preclinical models, clinical evidence is often limited. However, understanding the complex interactions between specific nutrients and IBD is essential to developing a tailored, multidisciplinary, and personalized approach for disease management; therefore, further research is required.

Malnutrition poses a critical challenge in inflammatory bowel disease, with the potential to detrimentally impact medical treatment, surgical outcomes, and general well-being. Parenteral nutrition is crucial in certain clinical scenarios, such as with patients suffering from short bowel syndrome, intestinal insufficiency, high-yielding gastrointestinal fistula, or complete small bowel obstruction, to effectively manage malnutrition. Nevertheless, research over the years has attempted to define the potential effects of parenteral nutrition on the intestinal barrier and the composition of the gut microbiota. In this narrative review, we have gathered and analyzed findings from both preclinical and clinical studies on this topic. Based on existing evidence, there is a clear correlation between short- and long-term parenteral nutrition and negative effects on the intestinal system. These include mucosal atrophic damage and immunological and neuroendocrine dysregulation, as well as alterations in gut barrier permeability and microbiota composition. However, the mechanistic role of these changes in inflammatory bowel disease remains unclear. Therefore, further research is necessary to effectively address the numerous gaps and unanswered questions pertaining to these issues.