Digestive diseases, also called gastrointestinal diseases, are diseases that affect any part of the digestive system. The digestive system consists of the organs, pathways, and processes that break down ingested food, converting it into energy and absorbable nutrients that can be used by the body.
The National Digestive Diseases Information Clearinghouse of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, reports that 60 to 70 million individuals in the United States are affected at any given time by all digestive diseases, chronic and newly diagnosed. The NIDDK Clearinghouse also reports that digestive problems account for more than 69% of all doctor visits in the United States. About 32 million individuals visited physicians' offices with diseases of the digestive system in 2015, which is slightly less than the 36.6 million who were diagnosed with digestive diseases at office visits in 2010. Hospitalizations for digestive diseases were 21.7 million in 2010, and more than 200,000 of these individuals died.
Individuals of all ages, racial and ethnic groups, and both genders are affected by digestive diseases. Demographic data such as age, gender, lifestyle and geographic location vary considerably between the different digestive diseases, and dietary influences vary among individuals as well. Because these details are associated specifically with each digestive disease, data cannot be generalized across different population subgroups.
The human digestive tract, also called the gastrointestinal tract (GI tract) or alimentary canal, consists of hollow and solid organs. The tract itself is a long tube of hollow organs that extends from the mouth (oral cavity) and esophagus (swallowing tube) through the stomach and the coiled intestines to the rectum. Food taken into the oral cavity passes through the esophagus and into the stomach. From there, the partially digested food passes through the small intestine (20 feet long with three sections: the duodenum, jejunum, and ileum), large intestine/colon, rectum, and finally the anus, from which undigested waste is excreted. As the food particles pass through the GI tract, the solid digestive organs—the pancreas, gallbladder, and liver—secrete enzymes, hormones, and other substances to assist with the digestive process. Rhythmic contractions of the intestines (peristalsis) help the broken-down food move through the system and mix with digestive secretions. Bile from the liver helps to digest fats. The liver also performs a filtering function that removes toxins and waste products from the blood during digestion.
The digestive process starts with chewing food in the mouth to break it down mechanically into particles. The salivary glands secrete digestive enzymes into saliva to begin chemical digestion, which continues in the stomach with the mucous membrane (gastric mucosa), which lines the stomach, secreting enzymes. Protein digestion follows as hydrochloric acid and pepsin are introduced into the paste-like mix. From the stomach, the partially digested food proceeds to the gut (digestive tract), where it is metabolized (digested) further in the duodenum of the small intestine for absorption through the walls of the jejunum and ileum. Any liquified food material not utilized by the body is passed into the large intestine as a waste product of digestion. Waste and water from the digestive process are pushed through the 5- to 6-foot muscular colon by peristaltic contractions, first as a liquid and then in solid form (stool) after excess water has been removed. The stool is mostly food debris and bacteria—useful or “friendly” bacteria that synthesize vitamins, process waste products, and protect against harmful bacteria. Stool passes through the colon over a period of 24 to 36 hours and is emptied into the rectum once or twice a day until it is eliminated through the anus.
The function of the digestive system is to break down ingested food into nutrients and energy (calories) that can be used by the cells in tissues throughout the body. Because of the complexity of the digestive system and the process of digestion, the risk of malfunction in any of the digestive organs is high. Digestive diseases are numerous and can affect any part of the digestive system or may affect several parts of the digestive system.
Diseases of the oral cavity and esophagus include:
Diseases of the stomach, which may sometimes involve the esophagus and/or the first part of the small intestine (duodenum), include:
Diseases of the liver, pancreas, and gallbladder include:
Diseases of the small and large intestines include:
Diseases of the colon, rectum, and anus include:
The causes of some digestive diseases are well-known, especially for those resulting from viral (hepatitis, CMV), bacterial (diarrhea), or parasitic (giardiasis) infections, because the microorganisms can be clearly identified. Most peptic ulcers are also caused by a type of bacteria called Helicobacter pylori, which weakens the protective mucous lining of the gut. Stomach ulcers, however, can also result from the use of anti-inflammatory medications such as aspirin, ibuprofen, or naproxen. Some digestive diseases may overlap with another digestive disorder. GERD, for example, is caused by a weakened LES that opens inappropriately and allows stomach acid to come in contact with cells lining the esophagus. The most common cause for LES weakening is a hiatal hernia, which is the protrusion of part of the stomach through a small opening in the muscular membrane that lies between the chest cavity and the abdomen (diaphragm). Other causes of a weakened LES are obesity, smoking, excess alcohol consumption, pregnancy, and certain acid-producing foods and medications (e.g., blood pressure and heart medications, muscle relaxants, and anxiety medications). Lying down soon after a meal, eating large meals shortly before bedtime, and poor posture may also contribute to development of GERD.
Some digestive diseases, however, lack definitive causes, which can make them difficult to treat. Colitis and Crohn's disease, for example, are thought to develop due to an immune system response to a virus or bacterium that produces ongoing inflammation in the intestinal wall. Undue stress is thought to aggravate or even cause these diseases. Results of research suggest that people affected by IBS seem to have a colon that is more sensitive than normal to a variety of foods and stress, whereas other evidence points to a malfunctioning immune system.
In addition to bacterial or parasitic infections, the digestive system can be damaged by poor diet, food additives, and prescription drugs, especially antibiotics.
Symptoms vary widely among the many types of digestive diseases, depending mainly on the organ or the process that is affected. Telltale signs of digestive disorders are stomach upset or indigestion, nausea and vomiting, abdominal discomfort and bloating, blood in the stool, changes in bowel habits, and weight loss. Additionally, physicians look for symptoms that may include one or more of the following:
Digestive diseases share similar symptoms, sometimes making diagnosis difficult. For instance, celiac disease is commonly misdiagnosed as IBS, Crohn's disease, or diverticulitis. Physicians believe that the key to an accurate diagnosis is taking a careful and detailed personal medical history and understanding the individual's lifestyle, including dietary habits and stress levels. Tests and procedures used to assist diagnosis may include:
The treatment of digestive diseases varies depending upon the condition being treated. Almost all treatment addresses the relief of symptoms and may include medications and modification of diet. Surgical options may be used for more serious digestive disorders, which may involve removal of the diseased organ in some cases.
GASTROESOPHAGEAL REFLUX DISEASE (GERD). Treatment typically involves lifestyle and dietary changes, such as avoiding alcohol, coffee, or tea, if not tolerated; decreasing dietary fat intake to 45 grams or less per day; avoiding spicy or high-fat/high-carbohydrate foods; eating more frequent but smaller meals; and losing weight. Antacid medications such as Alka-Seltzer, Maalox, Mylanta, Pepto-Bismol, Rolaids, and Riopan may be used to help relieve heartburn. Among prescription drugs, foaming agents (Gaviscon) that work by covering the stomach contents with foam to prevent reflux may be tried first. H2 blockers that help reduce acid production, including cimetidine (Tagamet HB), famotidine (Pepcid AC), nizatidine (Axid AR), and ranitidine (Zantac 75), may be prescribed. The most commonly prescribed drugs are proton pump inhibitors (PPIs), including omeprazole (Prilosec), lansoprazole (Prevacid), pantoprazole (Protonix), rabeprazole (Aciphex), and esomeprazole (Nexium). Surgery is only advised when medications do not work or esophageal erosion has progressed to a more serious stage. The standard surgical treatment is fundoplication, which wraps the upper part of the stomach around the lower esophageal sphincter to strengthen it and prevent acid reflux. However, although fundoplication is effective in treating GERD, the procedure needs to be repeated every few years.
GASTROPARESIS. Because gastroparesis is associated with diabetes, treatment seeks to control blood glucose levels using insulin and oral medications such as metoclopramide (Reglan) to stimulate stomach muscle contractions and enhance stomach emptying. In more severe cases, intravenous feeding may be required to bypass the stomach entirely. This is achieved by inserting a jejunostomy tube through the skin of the abdomen into the small intestine. The procedure allows nutrients and medication to be delivered directly into the small intestine, bypassing the stomach.
PEPTIC ULCER. Ulcers caused by Helicobacter pylori are treated with drugs to kill the bacteria, reduce stomach acid production, and protect the stomach lining. Systemic antibiotics are usually prescribed. The acid-suppressing drugs used most commonly are H2 blockers and PPI. Medications such as bismuth subsalicylate (Kaopectate and PeptoBismol, among others) are also used to treat stomach (gastric) ulcers. Sometimes, when other treatments have failed, surgery may be required. A procedure known as a vagotomy resects parts of the vagus nerve that transmits messages from the brain to the stomach. This interrupts messages to the stomach to produce acid, which reduces acid secretion. Dietary changes to reduce the acidity of the stomach include avoiding alcoholic beverages without food intake; limiting coffee intake to a few cups per day; limiting acid-producing foods such as red meat, preserved meats, and refined carbohydrates; and not lying down any sooner than two to three hours after eating.
BUDD-CHIARISYNDROME. Treatment usually involves sodium restriction, diuretics to control the accumulation of fluid in the abdominal cavity (ascites), and the use of anticoagulants such as heparin and warfarin. Surgical shunts may be required to divert blood flow around the obstruction or the liver. In advanced cases, liver transplantation is the only effective treatment.
CHOLECYSTITIS. In acute cholecystitis, treatment may require hospitalization to reduce stimulation of the gallbladder by food consumption or to remove the gallbladder (cholecystectomy) if the acute inflammation is recurrent or risk of complications is high. Antibiotics are prescribed if infection is present in the gallbladder drainage system and acid-suppressing medications are sometimes prescribed as well.
CIRRHOSIS. Treatment depends on the cause of the cirrhosis and the presence of complications. Alcoholic cirrhosis is first treated by completely abstaining from alcohol. Hepatitis-related cirrhosis is treated with medications specific to the different types of hepatitis, including interferon for viral hepatitis and corticosteroids for autoimmune hepatitis. Treatment also includes the use of diuretics to help remove fluid from the body. When complications cannot be controlled or when the liver damage is so severe that it compromises function, a liver transplant is required.
HEPATITIS. Hepatitis A is treated by bed rest and medications to relieve symptoms such as fever, nausea, and diarrhea. Hepatitis B is treated with a course of interferon injections, usually for many months. Additionally, drugs such as lamivudine and dipivoxil are prescribed for a period of one year. Over time, hepatitis B may cause the liver to stop functioning and require a liver transplant. Hepatitis C is treated with peginterferon, usually in combination with ribavirin. Hepatitis C may also require a liver transplant.
NONALCOHOLIC FATTY LIVER DISEASE (NAFLD). No single truly effective treatment has yet been found. Obese or overweight patients are encouraged to lose weight and to follow a balanced diet. Increasing physical activity and avoiding alcohol is also recommended.
PANCREATITIS. If no complications occur, acute pancreatitis usually improves on its own. Repeat bouts of acute pancreatitis may lead to chronic pancreatitis, eventually reducing pancreatic function and increasing risk of diabetes. Treatment seeks to support pancreatic function and to prevent complications such as pseudocyst formation, infection, or kidney failure. Hospitalization is usually necessary to treat pancreatitis and may include fasting for several days until the inflammation clears, taking pain medications, and receiving intravenous fluids. Surgery to remove gallstones or pancreatic surgery to remove damaged tissue from long-standing inflammation may be needed.
PRIMARY BILIARY CHOLANGITIS. As with other forms of cirrhosis, no treatment has yet been shown to effectively slow the progression of PBC. Treatment focuses on relieving symptoms, preventing and treating any complications, and preventing other conditions that may cause more liver damage. Medications may include ursodiol (Actigall) or obeticholic acid (Ocaliva), which move bile out of the liver and into the small intestine and decrease the production of bile acids by the liver. Vitamins and calcium may be prescribed to help prevent bone loss (osteoporosis), a common complication.
PRIMARY SCLEROSING CHOLANGITIS. PSC can be managed with effective treatment of certain symptoms, including the use of azathioprine ursodiol (Actigall) or cholestyramine (Questran) to control the itching (pruritis) that results from too much bile in the bloodstream. Swelling of the abdomen and feet due to fluid retention is usually treated with diuretics. In some cases, surgical procedures may be used to open blockages in the bile ducts. Liver transplant may be performed in severe cases.
INFECTIOUS DIARRHEA. In normally healthy people, the usual practice is to let the illness take its course, which can last from a few days to a week. Drinking plenty of liquids is required, and electrolyte replacement beverages such as Pedialyte, Ceralyte, and Infalyte may be used to help restore electrolyte balance. Treatment with antibiotics is increasingly complicated because of drug-resistant bacteria.
CELIAC DISEASE. The only treatment for celiac disease is a gluten-free diet, which helps to prevent symptoms; there is no cure for this condition.
CROHN'S DISEASE. Crohn's disease can be managed by controlling inflammation in the intestines and reducing symptoms such as pain, diarrhea, and bleeding. Medications prescribed to reduce inflammation include sulfasalazine (Azulfidine), mesalamine (Asacol, Apriso, Delzicol), or 5-ASA rectal enemas such as mesalamine suspension (Rowasa, Pentasa, Asacol). More severe cases usually require more powerful drugs such as prednisone, antibiotics, or medications that suppress immune system function, including azathioprine (Imuran), 6-mercaptopurine, or 6-MP (Purinethol), methotrexate (Rhematrex, Trexall), or the monoclonal antibody infliximab (Remicade). Dietary planning must be individualized to ensure nutrition status. The diet should provide 1.5–2.0 grams of protein per kilogram of body weight, plus the calories needed for growth and maintenance. Supplements of vitamins or minerals may be given. Low-fiber foods are usually tolerated well, and a low-fat intake is usually helpful.
LACTOSE INTOLERANCE. Removing dairy and other products that contain lactose from the diet is the standard treatment. Some people may be able to consume certain dairy products (e.g., some cheeses, yogurt). Lactase enzymes can also be added to milk or taken in capsule or chewable tablet forms prior to eating foods with lactose that cause digestive problems.
APPENDICITIS. Surgery is performed to remove the appendix, and pain medications are prescribed. Antibiotics are typically given by injection at the time of surgery.
ULCERATIVE COLITIS. Treatment seeks to control acute attacks, prevent new attacks, and promote healing of the colon. Corticosteroids are usually prescribed to reduce inflammation. Medications may include mesalamine (Asacol, Apriso, Delzicol), azathioprine (Imuran), and 6-mercaptopurine (Purinethol). In severe cases, the colon may be removed surgically.
DIVERTICULOSIS. A fiber-rich diet is helpful in long-term management. During an attack, a clear liquid diet followed by a low-fiber diet will allow the colon to rest so healing can occur. Specific treatment depends on symptoms. In severe cases, patients may require intravenous antibiotics to reduce infection or surgery to remove the affected portion of the colon.
DYSENTERY. Rest and drinking plenty of fluids is the usual treatment. Hospitalization may be required for intravenous therapy.
GIARDIASIS. Anti-infectious medications such as metronidazole (Flagyl, Protostat) or quinacrine (Atabrine) may be used. In pregnant women, treatment is not started until after delivery, because the drugs may be harmful to the fetus.
IRRITABLE BOWEL SYNDROME (IBS). Management of IBS is difficult because no definitive cause is known. Treatment for symptoms may include dietary changes, medication, and stress-relief therapy. Research has shown that 75% of people affected by IBS may find relief by following the FODMAP diet, which excludes the dietary sugars Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols.
HEMORRHOIDS. Corticosteroid creams and lidocaine ointments are used to reduce itching, pain, and swelling. Stool softeners may be prescribed to ease bowel movements. For severe cases, the hemorrhoids may be removed surgically (hemorrhoidectomy).
ANAL FISSURES. Hydrocortisone cream may be applied topically to the anal area to help relieve irritation. Oral pain medications such as acetaminophen, or a stool softener such as Colace or Surfak, may be used to prevent constipation until the fissure heals. Soaking the anal area in a warm chamomile infusion for 20 minutes may help prevent infection and provide soothing relief. Avoidance of strenuous effort to pass stool will prevent further complications. Surgery may be required if conservative measures fail to heal the fissure.
PERIANAL ABSCESS. Treatment involves surgical drainage of the abscess, as antibiotics are ineffective. A small incision is made over the area and pus is expelled with manual pressure. The wound is packed with iodophor gauze, removed after 24 hours, and the patient is instructed to take Sitz baths three to four times a day for up to two weeks.
GASTROESOPHAGEAL REFLUX DISEASE. Diets recommended for GERD are usually low fat and include whole grains, vegetables, fruits, and protein-rich plant foods such as soy products, beans, and legumes. Consuming foods that require more acid in the stomach during digestion increases both the likelihood of developing GERD and aggravation of symptoms in established GERD. Not all foods that are acidic require more stomach acid for digestion. The main acid-producing foods include:
GASTROPARESIS. Individuals with gastroparesis are asked to avoid foods that are high in fat because they typically delay stomach emptying after meals. High-fiber foods such as whole grains, broccoli, cabbage, and other fruits and vegetables also tend to stay in the stomach and may be restricted when symptoms are severe. Liquids always leave the stomach faster than solid food, so nourishing liquid foods are recommended.
PEPTIC ULCER. Although individuals with ulcers were at one time told to avoid spicy, fatty, or acidic foods and to drink milk, research results show that these dietary measures are ineffective for treating ulcers. Instead, peptic ulcer disease responds most readily to an anti-inflammatory diet that stresses avoiding caffeinated beverages, alcohol, milk, and milk products, which all increase acid secretion. Other acid-producing foods to avoid are those that cause problems for individuals with gastroesophageal reflux disease.
BUDD-CHIARI SYNDROME. A low-sodium diet is required for the control of ascites.
CHOLECYSTITIS. Consuming smaller meals more frequently is advised, along with avoiding large portions of any food. A low-fat diet with lean protein is usually recommended because excess cholesterol in the gallbladder is sometimes a cause of inflammation. Fried foods should be avoided altogether. Pectin in apples may be beneficial, as well as the cellulose contained in celery and other crisp fruits and vegetables.
CIRRHOSIS. Regardless of the type of cirrhosis, a healthy, low-sodium diet is usually prescribed, with total avoidance of alcohol.
HEPATITIS. Stimulants such as colas, chocolate, coffee, and tea can place stress on the liver and are restricted. Consumption of fruit juices should also be reduced because high levels of concentrated sugar stress the digestive process and the pancreas.
NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD). A healthy diet that controls cholesterol levels, triglycerides, and blood glucose is considered beneficial for NAFLD.
PANCREATITIS. Fasting is often a first treatment in pancreatitis, to give pancreatic function a rest. Stimulants such as coffee, alcohol, and spicy and gas-forming foods are restricted. A generally healthy diet can be consumed once the inflammation has subsided.
PRIMARYSCLEROSINGCHOLANGITIS. Alow-sodium diet is usually recommended to help reduce fluid retention.
CELIAC DISEASE. Individuals with celiac disease often work with a dietitian to design a diet plan that is totally gluten-free. Restrictions include foods that contain wheat, rye, or barley, which is most pasta, cereal, and processed food, unless it is labeled glutenfree. Many grocery stores have a section dedicated to gluten-free foods.
INFECTIOUS DIARRHEA. Diarrhea involves fluid losses that lead to dehydration. Electrolyte balance is sometimes lost with dehydration and must be restored to avoid complications such as heart irregularities. Drinking plenty of water is extremely important. Broth and soups that contain sodium and coconut water, fruit juices, fruits and vegetables that contain potassium (potatoes, sweet potatoes, beets, tomatoes, spinach, chard, navy beans, black beans, soy beans, watermelon) and canned salmon will help somewhat to restore electrolyte levels. Electrolyte replacement beverages such as Pedialyte, Ceralyte, and Infalyte act more quickly to restore electrolyte balance.
LACTOSE INTOLERANCE. If milk is removed from the diet, other sources of calcium must be included. Sometimes, fermented milk products such as kafir and yogurt can be tolerated. Nondairy sources of calcium include dark green leafy vegetables such as kale, collard greens, spinach, and broccoli. Foods fortified with added calcium, including soy milk, juices, cereals, and pasta, are also good sources of calcium.
COLITIS. Individuals with colitis are advised to eliminate any foods or beverages from their diet that seem to make symptoms worse. This usually includes limiting foods that increase inflammation and acid production such as red meat, and initiating a low-fat, high-fiber diet, eating small meals, and drinking plenty of water.
DYSENTERY. Patients are asked to fast as long as acute symptoms are present, taking only orange juice and water or buttermilk. After the acute phase, rice, curd, fresh ripe fruits (especially banana and pomegranate), and skim milk are allowed. Solid foods can be reintroduced cautiously to the diet, depending on the pace of recovery.
GIARDIASIS. Drinking water to prevent dehydration is recommended along with replenishing the electrolytes lost as a result of diarrhea. Electrolytes can be restored by drinking electrolyte replacement beverages (Pedialyte, Ceralyte, and Infalyte) or sports beverages such as Gatorade. In the short term, coconut water without added sugar has the same benefits as Gatorade but without the refined sugar, but the quantity of electrolytes can be variable.
IRRITABLE BOWEL SYNDROME. Individuals with IBS are usually asked to avoid food that is high in fat or insoluble fiber and also avoid caffeinated beverages, carbonated sodas, and alcohol. A healthy diet such as that described in the Dietary Guidelines for Americans 2015–2020 may be helpful. High-fiber foods should be consumed cautiously as the sensitive colon may not tolerate large portions or frequent consumption. Vitamin supplements may be needed, especially B vitamins, and if the individual has prolonged diarrhea, minerals may also be needed.
HEMORRHOIDS, ANAL FISSURES, AND PERIANAL ABSCESSES. A high-fiber diet consisting of fruits, vegetables, and whole grains is usually recommended, along with fiber supplements such as Metamucil, Citrucel, and Fibercon. Drinking plenty of water daily is essential if using fiber supplements and also helps to prevent stool hardening.
The management and treatment of digestive diseases is disease specific, and pharmacologic and other therapies are tailored to individual cases based on disease severity and the individual's overall health status. The prognosis for some digestive diseases is excellent, including infectious diseases that resolve once the infectious agent is eradicated. Outcomes for other digestive diseases depend on the underlying causes, severity of the disease, presence of complications, presence of comorbid chronic disease, and overall health of the individual.
The presence and severity of other chronic conditions, including psychological stress, anxiety, and depression, may influence the effectiveness of any type of treatment for digestive disease. Because stress has been shown to be a causative factor in some digestive diseases, stress-relieving therapies are sometimes advised to help ease the nerves and muscles involved in digestion. Some of the stress-relieving therapies are meditation, relaxation techniques, mindfulness-based stress reduction, mindfulness-based cognitive therapy, yoga, therapeutic massage, breath work, and guided-visualization techniques.
A healthy diet can help to prevent some digestive diseases altogether and lessen the chances of developing others. A healthy diet is one that follows the Dietary Guidelines for Americans 2015–2020. Nutrition experts also recommend drinking plenty of water daily to help eliminate ingested toxins and maintain the pH balance of the stomach.
Food contamination must also be prevented because it is directly responsible for infectious digestive diseases. These diseases can be avoided by simple precautions such as washing fruits and vegetables, cooking meat thoroughly, drinking water only from trusted sources, and using basic hygiene while storing, preparing, and eating foods.
See also Casein-free diet ; Celiac disease ; Crohn's disease ; Diverticular disease diet ; Dyspepsia ; Food contamination ; Food poisoning ; Food safety ; Food sensitivities ; Gallstones ; Gastroesophageal reflux disease (GERD) ; Giardiasis ; Gluten-free diet ; Hemorrhoids ; Inflammatory bowel disease ; Irritable bowel syndrome ; Irritable bowel syndrome diet ; Lactose intolerance diet ; Ulcers ; Whole grains .
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L. Lee Culvert