Digestive System

Aging affects the digestive system in several ways. But these changes have little effect on function. The muscles of the esophagus contract less forcefully, but movement of food through the esophagus is not affected. Food is emptied from the stomach more slowly, and the stomach cannot hold as much food because it is less elastic. But in most people, these changes are too slight to be noticed.

Certain changes in the digestive system cause problems in some people. The digestive tract may produce less lactase, an enzyme the body needs to digest milk. As a result, older people are more likely to develop intolerance of dairy products (lactose intolerance). People with lactose intolerance may feel bloated or have gas or diarrhea after they consume milk products. In the large intestine, materials move through a little more slowly. In some people, this slowing may contribute to constipation.

The liver also changes. It tends to become smaller (because the number of cells decreases), and less blood flows through it. Certain enzymes produced in the liver work less efficiently. These enzymes help the body process drugs and some other substances. As a result, the liver may be slightly less able to help rid the body of drugs and other substances. And the effects of drugs—intended and unintended—last longer.