Normal Physiology of the Gastrointestinal Tract and Gender Differences

This chapter discusses what is known of physiologic gender differences of the gastrointestinal (GI) tract. Women seem to have keener taste, smaller tongue volume, and less tongue strength compared with men. Women tend to have less salivary flow than men do, and their saliva differs in content of bicarbonate and sodium. There are differences between men and women regarding both esophageal function and anatomy. Men appear to have fewer defense mechanisms to prevent against esophageal reflux disease. There are clear differences in gastric acid output (GAO) between men and women. It would seem that women of smaller stature have smaller stomachs and decreased parietal cell mass resulting in decreased gastric acid secretion. However, studies have shown that estrogen may actually play a role in the regulation of acid secretion. There appear to be differences in gastric motility between men and women, although these findings may depend, in part, on the type of testing done, and the lack of standardization in technique. Gender-related differences in enzymes of the small intestine may affect drug metabolism as well as differences in the absorption/handling of certain minerals and ions. Many studies suggested that women have slower gallbladder emptying than men. These differences may in part explain the greater propensity for women to develop gallstones.