Most people correctly associate diabetes with problems related to blood sugar, insulin, and metabolism in general. But what many don’t realize is that diabetes can have a significant impact on other bodily systems like the gastrointestinal tract. In fact, both type 1 and type 2 diabetes can disrupt normal digestion in various ways, leading to problems such as gastroparesis or esophageal dysmotility. These complications are less well known than blood sugar issues, but they can still cause significant discomfort and often require evaluation by a gastroenterologist.

How Diabetes Affects Digestion

Diabetes disrupts normal digestive function primarily through damage to the nerves and blood vessels that control gastrointestinal motility. Chronic high blood sugar levels, known as hyperglycemia, gradually injure the autonomic nervous system, which regulates involuntary bodily functions including digestion. This nerve damage, called diabetic neuropathy, can affect any part of the digestive tract from the esophagus down to the rectum, though some areas are more commonly affected than others.

The vagus nerve plays a particularly crucial role in digestive health, as it controls stomach muscle contractions that move food through the digestive system. When diabetes damages this nerve, the stomach may empty more slowly than normal, a condition known as gastroparesis. Similar nerve damage can affect the small intestine and colon, leading to irregular motility patterns that cause constipation, diarrhea, or alternating between both. Blood vessel damage from diabetes can also reduce blood flow to digestive organs, further impairing their function and healing capacity.

The relationship between blood sugar control and digestive symptoms creates a challenging cycle for many patients. Poor blood sugar management accelerates nerve damage, worsening digestive problems, while digestive complications can make it harder to maintain stable blood glucose levels. This is particularly problematic with gastroparesis, where unpredictable stomach emptying makes it difficult to time insulin doses with food absorption, leading to dangerous blood sugar fluctuations.1

Gastroparesis: The Most Common Digestive Complication

Gastroparesis is the most recognized digestive complication of diabetes. It occurs when the muscles of the stomach lose their ability to contract normally, which slows the emptying of food into the small intestine. Although gastroparesis can affect people without diabetes, it is most often seen in those who have lived with the disease for many years. Studies suggest that about five percent of people with type 1 diabetes and one percent of those with type 2 eventually develop the condition, usually after long periods of poor blood sugar control.

The symptoms of gastroparesis can interfere with both daily life and diabetes management. Nausea and vomiting are common, and many patients describe bringing up undigested food hours after eating. Bloating, abdominal discomfort, and feeling full after only small amounts of food are also frequent complaints. These problems can make it difficult to maintain proper nutrition. Some people lose weight because they cannot tolerate enough food, while others gain weight by eating small, frequent meals in an effort to minimize symptoms.

Other Digestive Complications of Diabetes

While gastroparesis is the most familiar digestive complication of diabetes, it is far from the only one. Nerve and blood vessel damage can affect nearly every part of the gastrointestinal tract, leading to a wide variety of problems that may look very different from patient to patient. Some of these complications are less common, but all can have a significant impact on quality of life and often require careful evaluation:

  • Esophageal dysmotility: Nerve damage can impair the esophagus’s ability to move food and liquids down to the stomach, leading to swallowing difficulties, chest pain, and increased risk of gastroesophageal reflux disease. Some patients experience food getting stuck or a sensation of incomplete swallowing.
  • Diabetic diarrhea and constipation: Autonomic neuropathy affecting the small intestine and colon can cause unpredictable bowel movements, ranging from chronic diarrhea that’s often worse at night to severe constipation. These symptoms can alternate unpredictably, making management challenging.
  • Fecal incontinence: Damage to the nerves controlling the anal sphincters can result in loss of bowel control, a particularly distressing complication that significantly impacts quality of life. This often occurs alongside other forms of diabetic neuropathy.
  • Small intestinal bacterial overgrowth (SIBO): Slowed intestinal motility allows bacteria to multiply abnormally in the small intestine, leading to bloating, gas, diarrhea, and malabsorption of nutrients. SIBO can worsen blood sugar control by affecting how carbohydrates are absorbed.
  • Nonalcoholic fatty liver disease (NAFLD): Type 2 diabetes significantly increases the risk of developing fatty liver disease, which can progress to liver inflammation, fibrosis, and even cirrhosis. This condition affects up to 70% of people with type 2 diabetes and often develops silently without obvious symptoms.
  • Gallbladder disease: People with diabetes have higher rates of gallstones and gallbladder dysfunction, possibly related to changes in bile composition and gallbladder motility. These complications can cause severe abdominal pain and may require surgical intervention.2

Managing Digestive Symptoms in Diabetes

Managing the digestive complications of diabetes begins with controlling blood sugar as consistently as possible. High glucose levels accelerate nerve damage and make existing gastrointestinal problems worse, so keeping blood sugar in range is the most important step for long-term improvement. Even when symptoms have already developed, stabilizing blood sugar can help prevent them from progressing further.

Beyond glucose control, lifestyle adjustments can make a significant difference in how patients feel day to day. Eating smaller and more frequent meals is often easier on the digestive system than traditional large meals. Choosing foods that are lower in fat and fiber can also reduce strain, since these nutrients are harder to digest in the setting of slowed motility. Staying hydrated and maintaining physical activity can support more regular bowel function, which may help with constipation.

When symptoms remain difficult to manage, medications are often used alongside lifestyle changes. Prokinetic drugs can stimulate the movement of food through the stomach and intestines, although they are prescribed cautiously because of side effects. Antibiotics may be used for bacterial overgrowth in the small intestine, while acid-reducing medications can help with reflux or esophageal discomfort. Probiotics are sometimes added to help restore a healthier balance of bacteria in the gut.

Because digestive issues in diabetes often involve more than one part of the gastrointestinal tract, patients usually benefit from coordinated care. Gastroenterologists, endocrinologists, and dietitians may all play a role in treatment planning. Regular follow-up allows doctors to monitor symptoms, adjust medications, and check nutritional status, while also helping patients learn how diet, activity, and blood sugar control interact to affect their digestive health.

Contact Cary Gastro for Expert Digestive Care

Digestive symptoms related to diabetes can be challenging, but they do not have to disrupt daily life. The gastroenterologists at Cary Gastro have experience diagnosing and treating the full range of diabetes-related digestive conditions, from gastroparesis to bacterial overgrowth and liver or gallbladder problems. If you are living with diabetes and experiencing persistent gastrointestinal symptoms, contact Cary Gastro to request an appointment.




1https://www.cdc.gov/diabetes/diabetes-complications/diabetes-and-digestion.html
2https://www.ncbi.nlm.nih.gov/books/NBK553219/