Role of nutrients in modulating microbiota and immunity in COVID-19 disease

COVID-19 is a novel disease with a broad range of clinical patterns. Several patients show dysbiosis in the intestinal tract, with evidence of reduced beneficial bacteria, such as Bifidobacteria and Lactobacilli. It is well established that human gut microbiota dysbiosis is associated with several clinical conditions, including respiratory tract diseases due to the gut-lung axis. This narrative review discusses the role of nutrients in the relationship between the gut microbiota and the immune response in SARS-CoV-2 infection. In particular, we will focus on the benefits offered by vitamins and micronutrients on different aspects of COVID-19 disease while also discussing which diets seem to provide the most advantages.