The prevalence of allergic diseases is rising dramatically. There is also an increase in other immune-mediated disorders (e.g. autoimmune disease and type 2 diabetes), suggesting a common root cause. The nutrition may have a crucial role in preventing these diseases collectively referred to as non-communicable diseases. It is also important for the immune system to defend against infection. Immunonutrition can be defined as the study of the direct and indirect effects of nutrients, on immune system development and function. Recently there has been an increase in understanding that dietary habits may prevent non-communicable diseases and responses to infections. Current research focuses on improvement in understanding interactions between nutrient intake, host microbiome, metabolism, immune systems and disease outcomes. It is also important to understand that nutrient excesses (e.g. high fat, highly processed dietary patterns or over supplementation of nutrients) as well as deficiencies effect immune system function. The “complicated tango” between nutrients, microbiome, epithelial barriers, metabolism and the immune system may be just as important for disease prevention as for disease treatment. There is a generally accepted consensus, accelerated during the current pandemic, that there is a need to increase our knowledge on the effects of nutrients on the immune system, especially the basic mechanisms and processes underpinning immunonutrition.