Abstract
Increases in life expectancy are contributing to rapid growth in the aging population around the globe. Aging is accompanied by physiological decline and susceptibility to age-related diseases. To enable healthy aging, it is important to understand the independent effects of aging on biological systems and how comorbidities and lifestyle factors may influence the health of these systems. The digestive system is a multifunctional set of tissues and organs that not only enable the digestion and absorption of nutrients, but also serves as a physical and immunological barrier to the external environment and the primary interface to commensal microbes. This review examined current evidence regarding the effects of aging on gastrointestinal function, including digestion, absorption, motility, microbiome, and barrier function. Overall, the digestive system is quite resilient to the normal aging process with comorbidities and other lifestyle factors contributing to most digestive health issues associated with aging. Emerging research on the gut microbiome and barrier function suggests an important role for the digestive system in the etiology of many age-related diseases and demonstrates how diet may be able to modify the effects of chronic diseases.