[Aging and digestive diseases: at the view of the functional change of gastrointestinal tract].

Although it is difficult to define the term "aging" consensually, in medical fields, usually it means the progressive accumulation of irreversible degenerative changes leading to loss of homeostasis. It is supposable that there is also modest decline in the structure and function of several digestive organs. However, data about this subject are not enough. Main problem in studying aging digestive organ is that discrimination of primary senile change of the organ with secondary one from other senile diseases is not easy. That is, the prevalence of many non-digestive disorders which can badly affect the digestive functions is increasing by aging; for example, diabetes, malignancy, etc. To prove that some phenomenon is as result of pure senile change, it is necessary to exclude secondary one, but, the process is very complicated and difficult. In spite of this limitation, here, I will discuss the senile change of several digestive organs by aging, especially at the view of the gastrointestinal functions, with review of literatures.