Worldwide, the number of individuals suffering from visual impairment, as well as those affected by blindness, is about 600 million and it will further increase in the coming decades. These diseases also seriously affect the quality of life in working-age individuals. Beyond the characterization of metabolic, genetic, and environmental factors related to ocular pathologies, it is important to verify how lifestyle may participate in the induction of the molecular pathways underlying these diseases. On the other hand, scientific studies are also contributing to investigations as to whether lifestyle could intervene in modulating pathophysiological cellular responses, including the production of metabolites and neurohormonal factors, through the intake of natural compounds capable of interfering with molecular mechanisms that lead to ocular diseases. Nutraceuticals are promising in ameliorating pathophysiological complications of ocular disease such as inflammation and neurodegeneration. Moreover, it is important to characterize the nutritional patterns and/or natural compounds that may be beneficial against certain ocular diseases. The adherence to the Mediterranean diet (MeDi) is proposed as a promising intervention for the prevention and amelioration of several eye diseases. Several characteristic compounds and micronutrients of MeDi, including vitamins, carotenoids, flavonoids, and omega-3 fatty acids, are proposed as adjuvants against several ocular diseases. In this review, we focus on studies that analyze the effects of MeDi in ameliorating diabetic retinopathy, macular degeneration, and glaucoma. The analysis of knowledge in this field is requested in order to provide direction on recommendations for nutritional interventions aimed to prevent and ameliorate ocular diseases.

The number of individuals affected by dementia and cognitive decline is progressively increasing, becoming a serious global health challenge. Several investigations underline the role of nutrition and dietary habits as a preventive strategy. Recent studies suggest that dietary supplementation with polyphenols may constitute an efficient preventive strategy. Indeed, it is emerging that polyphenols exhibit a neuroprotective effect because of their pronounced antioxidant and anti-inflammatory activity. Notably, several studies underline the role of the gut microbiota in the metabolism of the polyphenols, producing bioactive molecules that are absorbed through the gastrointestinal tract. They may exhibit beneficial effects on the central nervous system. Moreover, dietary polyphenols modulate gut microbiota composition, demonstrating a reciprocal regulation between gut microbiota and polyphenol-induced effects on brain functions. Thus, polyphenols are proposed to have an important role on the gut–microbiota–brain axis regulation. The literature search for this narrative review was conducted across three electronic databases PubMed, Scopus, and Web of Science as well as the NIH ClinicalTrials.gov registry, covering the period from January 2000 to 10 February 2026. The following search terms were used: “polyphenols”, “microbiota”, “gut–brain axis”, “dementia”, “cognitive function”, “polyphenols and cognitive dysfunction”, and “polyphenols and microbiota”. The study selection process was performed in two sequential stages: (i) screening of titles and abstracts, followed by (ii) full-text assessment for eligibility. Articles were included if they were peer-reviewed studies (in vitro, in vivo, or clinical trials), published in English, and addressed the effects of polyphenols on cognitive outcomes, gut microbiota composition, or the gut–microbiota–brain axis. Exclusion criteria included non-peer-reviewed sources, studies lacking relevant cognitive or microbiota-related endpoints, and publications not available in full.