Public Health and Clinical Implications of Nutrition-Infection Interactions

Nutrition and infection have been interacting in humans for millennia, with undernutrition typically increasing susceptibility and exacerbating pathogenicity of infectious agents. In the past half-century, overnutrition as manifested in obesity has emerged as a definitive risk factor for increased severity and higher mortality in the clinical course of a number of infectious diseases, most recently COVID-19. Detailed clinical management of suboptimal nutritional status is the topic of textbooks of clinical nutrition, but we highlight key elements here. Among these are the interactions of nutritional status with major infectious agents causing diarrhea, pneumonia, parasitism, AIDS, bacterial diseases, and others. We highlight paradoxes such as malnutrition down -modulating the severity of malaria. We highlight the clinical implications addressed in the first 15 chapters of this book that are now facing the global community such as the role of obesity in health. We highlight principles in causal thinking, illustrating the complexity associated with unraveling mechanisms responsible for nutrition-infection interactions and their contribution to the health of persons from every background. Finally, we revisit the classic 1968 World Health Organization (WHO) monograph Interactions of Nutrition and Infection, bringing its timeless messages forward a half-century.