It has been known for centuries that what we eat has a profound effect on our immunity. Deficiencies of macro and micronutrients can impair the immune system?s ability to fight off infection and heal wounds. Overconsumption of certain foods and food additives can cause immune dysregulation, leading to obesity, cancer and chronic inflammatory disorders. In contrast, calorie restriction can down-regulate inflammation and increase lifespan. In addition, certain naturally occurring compounds can modulate immune function. More recently, gut microbes have been identified as active intermediaries between dietary intake and the immune response. The emerging field of nutritional immunology encompasses all of these issues. Dr. Rountree?s presentation will review the fundamental principles of innate and acquired immunity, discuss the pathways that disrupt normal function and explore the use of naturally occurring substances to modulate the immune response and improve health.