Now that we’ve covered the structures and functions of the digestive system, it should be clear that the digestion of food requires the coordinated action of multiple organs. If any of these aren’t working well, it can wreak havoc on the function of the entire system and interfere with health and quality of life. Let’s look at some common discomforts and disorders of the GI tract.

Heartburn and Gastroesophageal Reflux

Heartburn is a burning, often painful, sensation in the chest (behind the breastbone) or throat. Heartburn is caused by gastroesophageal reflux (GER), when the acidic chyme in the stomach escapes back into the esophagus and even into the mouth. Normally, this reflux is prevented by the lower esophageal sphincter (a tight ring of muscle) that sits between the esophagus and stomach. The muscles of the sphincter contract to keep it closed, only relaxing to allow food boluses and liquid to pass from the esophagus into the stomach and then quickly contracting again to keep the contents of the stomach separate from the esophagus. The lower esophageal sphincter can be weakened because of increased pressure on the abdomen from obesity or pregnancy, exposure to tobacco smoke, and some medications, so the risk of GER is increased in these scenarios.^[1]

Occasional heartburn is a common complaint, especially after eating large, greasy, or spicy meals. However, if it occurs more than twice per week, it may be diagnosed as gastroesophageal reflux disease (GERD), which should be treated not only to relieve the discomfort that it causes but also to prevent damage to the tissues of the esophagus, which can increase the risk of cancer. In addition to heartburn, GER and GERD can cause difficulty and pain with swallowing, a persistent sore throat or cough, a sense of a lump in your throat, and nausea and vomiting.

Symptoms of GER and GERD can often be managed with diet and lifestyle changes:

• Avoid trigger foods such as greasy or spicy foods, chocolate, coffee, peppermint, alcohol, and acidic foods (e.g., tomatoes, citrus).
• Eat smaller, more frequent meals.
• Avoid eating within 3 hours of bedtime and remain upright after meals.
• Wear loose-fitting clothing around the abdomen.
• Elevate the head of the bed by 6–8 inches.
• Quit smoking and avoid secondhand smoke.
• Lose weight, if needed.

Over-the-counter antacids (e.g., Maalox, Mylanta, Rolaids) may relieve occasional heartburn. If symptoms are frequent or persistent, consult a healthcare provider to evaluate for GERD and discuss additional treatment options.

Peptic Ulcers

Peptic ulcers are sores on the tissues lining the esophagus, stomach, or duodenum (the first section of the small intestine). They occur when the mucous coating of the GI tissues is damaged, exposing the tissue to pepsin and hydrochloric acid. This further erodes away the tissues, causing pain if it damages a nerve and bleeding if it damages a blood vessel. Ulcers are most serious when they perforate the wall of the GI tract, which can lead to a serious infection. Peptic ulcers cause stomach pain, often when the stomach is empty, and may go away after eating or taking antacids. In the most serious cases, blood may be seen in vomit and/or the stool, and the patient may have very sharp and persistent stomach pain.^[2]

Doctors once believed that stress and excess stomach acid caused peptic ulcers, so treatment focused on bland diets, stress reduction, and acid-suppressing medications. However, these approaches often failed because they did not address the underlying cause.

We now know that peptic ulcers have two main causes. The most common is infection with Helicobacter pylori (H. pylori). About 50% of the world’s population carries this bacterium, often without symptoms. It is not fully understood how people become infected or why only some develop ulcers.

H. pylori can survive in the stomach’s acidic environment and damage the protective mucous lining, making it more vulnerable to acid and pepsin. Treatment includes antibiotics to eliminate the bacteria along with acid-suppressing medications to promote healing.

The second major cause of peptic ulcers is long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen. These medications can reduce the production of protective substances in the stomach lining, increasing the risk of ulcers when used frequently over time.

Treatment typically involves stopping or reducing NSAID use, along with acid-reducing medications to allow the tissue to heal.

Diarrhea and Constipation

Both diarrhea and constipation can occur when the normal movement of the gastrointestinal (GI) tract is disrupted. If waste moves too quickly through the large intestine, not enough water is absorbed, resulting in loose, watery stools characteristic of diarrhea. This is most often caused by contaminated food or water containing bacteria (e.g., E. coli, Salmonella), viruses (e.g., norovirus, rotavirus), or parasites (e.g., Giardia). Food allergies and intolerances can also cause diarrhea. Complications include dehydration and nutrient malabsorption.^[3]

Constipation is the opposite problem and is defined as infrequent bowel movements (fewer than three per week) with hard, dry, or difficult-to-pass stools. It can occur when stool is delayed, allowing more water to be absorbed and making it harder to pass. Constipation may also result from changes in diet, travel, medications, pregnancy, aging, or reduced physical activity. Chronic constipation should be evaluated by a healthcare provider.

Constipation often improves with lifestyle changes, such as increasing fiber intake (whole grains, fruits, vegetables, legumes, and nuts), drinking more fluids, and engaging in regular physical activity. Establishing a routine—such as trying to have a bowel movement after meals—can also help. Fiber supplements (e.g., Metamucil, Citrucel, Benefiber) may provide short-term support, but whole foods are preferred. Laxatives may be used occasionally but are not recommended for long-term use, as dependence can develop.^[4]

Irritable Bowel Syndrome 

Irritable bowel syndrome (IBS) is a type of functional GI disorder, meaning that it’s caused by a disruption in the signals between the brain and gut. People suffering from IBS often experience abdominal pain, bloating, the feeling that they can’t finish a bowel movement, as well as diarrhea or constipation or both, often in cycles. IBS is common; about 12% of people in the U.S. are thought to have it. It’s more common in women, seems to run in families, and is often associated with stress, history of trauma, or severe GI infections. IBS isn’t well understood. It’s not clear what causes it, and it may have different causes in different people.^[5]

Of course, since the cause of IBS isn’t understood, that lack of understanding makes it difficult to treat. Some people find that eating more fiber-rich foods and increasing physical activity improve their symptoms, so these are good first steps (and good for health regardless of their effect on IBS). Others find that following a low-carbohydrate diet, called FODMAPs, helps reduce their symptoms. FODMAPs are fermentable carbohydrates found in many foods and can usually be eaten without issue by most people. Foods high in FODMAPs include fruits, vegetables, legumes, dairy products, wheat, and honey, making this a very restrictive diet that should only be attempted under the guidance of a dietitian. Without careful planning, a low-FODMAP diet can be deficient in fiber, vitamins, and minerals. It is usually followed for just a few weeks, and if it helps with symptoms, foods are gradually added back to see what can be tolerated. ^[6]

In addition to dietary strategies, physicians sometimes prescribe medications to treat the symptoms of diarrhea or constipation associated with IBS.

Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease (IBD) includes two types of disorders: ulcerative colitis and Crohn’s disease. Ulcerative colitis is specific to the large intestine (colon) and rectum, whereas Crohn’s disease can affect any part of the GI tract. Both are chronic inflammatory conditions in which symptoms may periodically flare and become more severe. IBD is often confused with IBS, because of the similarities in their names and some symptoms. However, they are different disorders with different causes. IBD is generally more severe and long-lasting, and it causes damage to the GI tract that can be seen on endoscopy (when a camera is inserted into the GI tract to visualize the interior). It’s important to get an accurate diagnosis of IBD in order to treat the disorder appropriately.^[7]

Common symptoms of IBD are diarrhea, cramping and abdominal pain, feeling tired, and weight loss. IBD may be caused by autoimmune reactions (in which the immune system attacks the body’s own cells, in this case, the cells of the GI tract) or certain genes, and other causes are being investigated. IBD often develops in people during adolescence or in their 20s. It may be treated with medications to reduce inflammation or modulate the immune system, or sometimes surgery.

attributions

This section is an adaptation of “Disorders of the GI Tract” in Nutrition: Science and Everyday Applications, V.1.0 by Alice Callahan, Heather Leonard, and Tamberly Powell under a Creative Commons Attribution-NonCommercial 4.0 International License.