What change occurs in the GI system as a person ages?

As people age, there are several changes that take place in the gastrointestinal (GI) system, and one significant change is that the salivary glands produce less saliva. This reduction in saliva can lead to dry mouth, which can affect digestion and also impact a person's ability to chew and swallow food comfortably. Saliva is crucial for breaking down food and helps in the digestive process, so decreased production can lead to complications such as difficulty in swallowing, changes in taste perception, and increased dental issues.

The other options describe changes that are not typically associated with aging in the GI system. For example, the sense of smell does not necessarily increase with age; in fact, many older adults may experience a diminished sense of smell and taste. Digestion does not become more efficient as one ages; in fact, it often slows down due to various factors such as reduced enzyme production and decreased muscle tone in the digestive tract. Additionally, peristalsis, which refers to the wave-like muscle contractions that move food through the digestive system, tends to slow down rather than speed up in older individuals, which may lead to issues like constipation. Thus, the reduced production of saliva is a well-documented change that directly impacts the GI system as individuals age.