Because of the large functional reserve capacity of most of the gastrointestinal (GI) tract, aging has relatively little effect on GI functioning. The digestive system is made up of the mouth, teeth, tongue, salivary glands, pharynx, esophagus, stomach, pancreas, liver, gallbladder, large intestine, and small intestine. Essentially, normal digestion and absorption occur in the elderly; however, there are many changes in the digestive system that parallel the age-related changes seen in the other systems. Like other systems, the rate of new cell growth declines and tissues become more susceptible to damage.
Due to a decrease in smooth muscle tone along a majority of the aging GI tract, food moves through the system more slowly as the contractions necessary for the movement and breakdown of food become weaker. Constipation becomes a problem along with hemorrhoids. Weakening of the cardiac sphincter, a muscle that regulates the flow of food from the esophagus into the stomach, can lead to esophageal reflux which causes “heart burn.”
When toxins, such as alcohol and chemicals, are absorbed by the digestive tract and transported to the liver for processing or storage, the liver cells are not immune to the effects of these compounds. Chronic exposure leads to damage and disease in the liver and many other organs.
With age, cancer rates increase, especially in the colon and stomach. Plus, changes in other systems have direct and indirect effects on the digestive system. For example, the reduction in bone mass and calcium content in the skeleton is associated with erosion of the tooth sockets and tooth loss.