Tropical enteropathy protects against Western diseases in environments of poor sanitation.

This hypothesis suggests that tropical enteropathy protects against Western diseases in environments of poor sanitation, and that the absence of tropical enteropathy contributes to the increased incidence of Western diseases in settings of improved sanitation. The hypothesis is supported by four observations: (1) The prevalence of tropical enteropathy is inversely related to the incidence of Western diseases, (2) The bowel is a major immune and neuroendocrine organ, and inflammation of the gut results in profound local and systemic changes, (3) Tropical enteropathy can account for the subtle clinical differences observed between individuals living in third world environments and industrialized societies, and (4) The concept that tropical enteropathy protects against Western diseases in environments of poor sanitation is consistent with the observations upon which the "Hygiene and Fetal Origins Hypotheses" are based. Identifying tropical enteropathy as a mechanism that protects against Western diseases in environments of poor sanitation creates a new testable hypothesis for some of the most common non-communicable diseases of industrialized societies.