Diet plays a fundamental role in the nutritional status, in the homeostasis and in the capacity of an individual to adapt to the environment. A proper or an inadequate nutrition has an impact on the persistence, remission and incidence of various conditions, including the infectious diseases. Consequently, nutrition has a crucial importance on survival rates and health recovery of individuals or even populations around the globe. The synergistic relationship between nutritional needs and infectious processes has been demonstrated conclusively in diverse studies. This chapter will discuss the most important nutrients, their most common natural dietary sources, the different digestive processes for each one as well as the absorption, transport, storage, excretion and function of each of the nutrients within the organism. We also go through some concepts on the interaction between nutrition and the immune system, as well as examples on the influence of nutrition or specific nutrients on some infectious diseases, and their influence on the gene expression.
Keywords: Disease; Immunonutrition; Infection; Metabolism; Nutrient; Nutrigenetic.