We tend to take the working of the stomach and intestines for granted, until they stop working properly. The digestive tract is closely controlled by the brain, via the autonomic nerves.
Problems come with the development of neuropathy.
Extended periods of time with high blood glucose, or with the uremic toxicity that follows kidney failure, can damage nerve fibers, and when the autonomic nerves are damaged, stomach function can become increasingly unpredictable. As with neuropathy itself, an individual may have mild to severe symptoms of gastroparesis. The nausea, vomiting, and dehydration may become severe enough to require hospitalization. Anorexia, unwillingness to eat, can become a factor. With so much frustration and difficulty digesting food, the person simply chooses not to eat, rather than be sick all the time.