Clinical Nutrition: Gastrointestinal & Accessory Organ Problems

Brief Overview of the GI System

  • Gastrointestinal health is important for overall nutrition and wellness.
  • The digestive process is a series of cascading events throughout the GI tract and accessory organs (pancreas, liver, gallbladder).
  • Nutrition therapy must consider the integrated network and the individual.
  • Diseases can affect the GI tract from mouth to anus; the lecture covers the most commonly affected areas.

Mouth: Dental Problems

  • In elderly, tooth loss or ill-fitting dentures can lead to food avoidance and compromised nutrition.
  • High-fiber foods like fruits, vegetables, and meats are often avoided, while high-fat and high-sugar foods are consumed in excess.
  • A mechanical soft diet, with soft-cooked and ground foods mixed with sauces or gravies, can be helpful to reduce chewing.

Mouth: Surgical Procedures

  • Fractured jaw or surgeries involving the mouth and neck can cause eating problems.
  • Nutrients are supplied in high-protein, high-calorie liquids.
  • As healing progresses, soft foods can be added, eventually progressing to a full diet based on tolerance.

Mouth: Oral Tissue Inflammation

  • Oral tissues reflect a person’s general nutrition status.
  • Malnutrition deteriorates oral tissues, leading to infection, injury, pain, and difficulty eating.
  • Conditions contributing to malnutrition:
    • Gingivitis: inflammation of the gums.
    • Stomatitis: inflammation of the oral mucous lining.
    • Glossitis: inflammation of the tongue.
    • Cheilosis: dry, scaling at the corners of the mouth.

Mouth Ulcers

  • Mouth ulcers can arise from:
    • Herpes simplex virus: causes mouth sores or cold sores.
    • Candida albicans: fungus causing candidiasis or thrush.
    • Hemolytic Streptococcus: bacteria causing canker sores.
  • Other causes: toothbrush abrasions, allergies.
  • Patients with cancer or HIV often have mouth ulcers due to diminished immune system.
  • Chemotherapy and radiation destroy fast-replicating cells, causing painful mouth sores.
  • Treatment: Nutritionally dense liquids high in protein and calories, progressing to soft, bland, non-acidic foods at room temperature.
  • Mouthwash with a mild topical local anesthetic can relieve irritation before meals.
  • Nutrition assessment is warranted if severe cases last more than 7-10 days.

Mouth: Salivary Glands Disorders

  • Salivary gland disorders can affect eating and nutrition status.
  • Problems arise from infections like mumps, mucous cysts (mucoceles), and obstructed salivary ducts.
  • Excess salivation occurs with nervous system disorders, mouth infections, injuries, and drug reactions.
  • Dry mouth (lack of salivation) can be temporary due to fear, infection, or drug reaction.
  • Chronic dry mouth (xerostomia) occurs in middle-aged and elderly adults, associated with rheumatoid arthritis, radiation therapy, or drug side effects.
  • Xerostomia causes swallowing and speaking difficulties, taste interference, and tooth decay.
  • Treatment involves adding liquid food items to meals and using artificial saliva solutions.

Mouth: Swallowing Disorders

  • Swallowing involves coordinated actions of the mouth, pharynx, and esophagus and becomes involuntary once initiated.
  • Swallowing difficulty is a common problem with various causes.
  • Temporary difficulty can be due to food lodged in the throat, requiring the Heimlich maneuver.
  • Dysphagia is a more chronic problem common in patients with neurologic disorders (Alzheimer’s, Parkinson’s, stroke).
  • Other causes: head and neck cancer, tooth loss, xerostomia, muscular weakness of the larynx.
  • Diagnosis requires identifying mechanical obstruction or neuromuscular disorder, usually by a speech-language pathologist.
  • Subtle symptoms: unexplained drop in food intake, repeated episodes of pneumonia related to aspiration.
  • Patients with dysphagia have longer hospital stays, compromised nutritional statuses, and increased mortality risks.
  • Warning signs to watch for:
    • Reluctance to eat certain food consistencies
    • Very slow chewing or eating
    • Fatigue from eating
    • Frequent throat clearing
    • Complaints of food “sticking” in the throat
    • Pockets of food held in the cheeks
    • Painful swallowing
    • Regurgitation
    • Coughing or choking during attempts to eat
  • Management involves a team of specialists (physician, nurse, dietitian, speech-language pathologist).
  • Thin liquids are the most difficult to swallow.
  • Diet is adapted to individual needs, progressing through stages of thickened liquids and pureed foods.
  • Pureed foods are generally the consistency of mashed potatoes or pudding.
  • Pureed foods can be shaped using food molds to resemble original food form.

Esophagus: Central Tube

  • The esophagus is a muscular tube from the throat to the stomach, bound by sphincters acting as valves.
  • The upper sphincter prevents airflow into the esophagus and stomach, opening during swallowing and closing afterward.
  • Disorders disrupting normal swallowing include muscle spasms, uncoordinated contractions, stricture (narrowing) due to scar tissue, injury, chemicals, tumors, or esophagitis.
  • Treatment involves medical attention via stretching procedures or surgery, drug therapy for inflammation, and a diet ranging from liquid to soft based on tolerance.

Lower Esophageal Sphincter Defects

  • Lower esophageal sphincter (LES) defects result from changes in smooth muscle or the nerve, muscle, and hormone control of peristalsis.
  • Achalasia: LES muscles maintain excessive tone, failing to open when swallowing.
  • Symptoms: difficulty swallowing, frequent vomiting, feeling of fullness in the chest, weight loss, malnutrition, pulmonary complications/infections from aspiration of food particles.
  • Surgical treatment: dilating or cutting (esophagomyotomy) the LES muscles.
  • Postoperative nutrition therapy starts with oral liquids, progressing to a regular diet within days based on tolerance.
  • Patients should avoid very hot or cold foods, citrus juices, and highly spiced foods to prevent irritation.
  • Frequent small meals are recommended, eaten slowly with small bites and thorough chewing.

Gastroesophageal Reflux Disease

  • Gastroesophageal Reflux Disease (GERD) involves constant regurgitation of acidic gastric contents into the lower esophagus, resulting in erosive esophagitis.
  • Impaired esophageal peristalsis, prolonged LES relaxation, and hiatal hernias contribute to chronic GERD.
  • Typical Symptoms: frequent and severe heartburn within an hour after eating, dysphagia, and excessive belching.
  • The pain sometimes moves into the neck or jaw or down the arms.
  • Long-term complications: stenosis (narrowing of the esophagus), esophageal ulcer, and Barrett’s esophagus.
  • Acid reflux may be attributed to pregnancy, pernicious vomiting, or extended use of nasogastric tubes.
  • Elderly patients tend to experience more severe cases and complications of GERD.
  • Risk increases with obesity and waist circumference.
  • Conservative measures and dietary goals, proton pump inhibitors (PPIs) are the mainstay of pharmacologic treatment.
  • Laparoscopic fundoplication restores LES function and esophageal peristalsis, treating the condition, recommended for patients who cannot be managed with PPI therapy.
  • Table 18-2 Dietary Care of Gastroesophageal Reflux Disease
    • Decrease esophageal irritation
      • Avoid common irritants such as coffee, strong tea, chocolate, carbonated beverages, tomato and citrus juices, spicy foods, smoking, and alcoholic beverages
    • Increase lower esophageal sphincter pressure
      • Ensure adequate intake of lean protein foods
      • Avoid excessive high-fat meals (e.g., fried foods, high-fat meats, cream)
      • Avoid peppermint and spearmint
      • Avoid medications that reduce LES pressure (e.g., anticholinergics, calcium channel blockers, opiates, progesterone)
    • Decrease reflux frequency and volume
      • Eat small, frequent meals
      • Sip small amounts of liquid with meals; drink mostly between meals
      • Avoid constipation by consuming adequate fiber and water and avoiding sedentary behaviors; straining increases abdominal pressure reflux
    • Clear food materials from the esophagus
      • Avoid eating at least 3 to 4 hours before going to bed
      • Sit upright at the table, and elevate the head of the bed
      • Do not recline for ≥2 hours after eating
      • Wear loose-fitting clothing, especially after a meal

Hiatal Hernia

  • Hiatal Hernia occurs when a portion of the upper stomach protrudes through the opening in the diaphragm (hiatus).
  • Common in obese adults, for whom weight reduction is essential.
  • Patients advised to eat small amounts of food, avoid lying down after meals, and sleep with the head of the bed elevated.
  • Frequent use of antacids helps control heartburn symptoms.
  • Large/sliding hernias may require surgical repair.

Stomach and Duodenum: Peptic Ulcer Disease

  • Peptic Ulcer Disease occurs because the mucosal lining protects the tissue from corrosive gastric acid and enzymatic secretions
  • The mucosa is weakened or disturbed and cannot protect against acidic gastric contents, the tissue is damaged.
  • Ulcers are common in the duodenal bulb as gastric contents emptying there are the most concentrated.
  • A peptic ulcer is a crater-like lesion in the stomach or duodenum wall resulting from continuous tissue erosion.
  • In extreme cases, the ulcer can perforate.

Etiology

  • The two most common causes of peptic ulcer disease (PUD) are H. pylori infection and the long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs).
  • Lesion generally results from an imbalance among some or all of the following three factors:
    • (1) the amount of gastric acid and pepsin secretions
    • (2) the extent of Helicobacter pylori infection
    • (3) the degree of tissue resistance and mucosal integrity
Helicobacter pylori
  • H. pylori are common, spiraling, rod-shaped bacteria inhabiting the GI area around the pyloric valve.
  • Acidic environments favor H. pylori colonization.
  • Infection by H. pylori is a major determinant of chronic active gastritis and is critical along with gastric acid and pepsin, in the ulcerative process.
  • H. pylori infection is common worldwide, but not all infected people develop an ulcer.
  • As a result of aggressive treatment for H. pylori infection, the global incidence rate of PUD has decreased during recent years.
Nonsteroidal antiinflammatory drugs
  • NSAIDs (e.g., ibuprofen, aspirin) are widely used medications that irritate the gastric mucosa, decrease mucosal integrity, and may result in erosion, ulceration, and bleeding with prolonged or excessive use.
  • NSAIDs distinguish them from steroid drugs, which are synthetic variants of natural adrenal hormones.
Psychologic factors
  • Individuals with highly stressful lives were significantly more likely to develop an ulcer, independent of other known risk factors such as H. pylori infection or the use of NSAIDs.
  • Several neurologic and physiologic changes that result from severe or long-term stress have negative effects on the GI tract.
  • Such changes include alterations in gut motility, gastric secretions, mucosal permeability, and barrier function; changes in visceral sensitivity; compromised recovery from injured mucosa; and reduction in blood flow.
  • Although the relationship between psychologic stress and the development of PUD is not completely understood, such stressed-induced GI changes and lifestyles may exacerbate the development of gastric ulcer disease in susceptible persons.

Clinical Symptoms

  • General symptoms of PUD include increased gastric muscle tone and painful contractions when the stomach is empty.
  • With duodenal ulcers, the amount and concentration of hydrochloric acid secretions are increased; with gastric ulcers, the secretions may be normal.
  • Some patients will have increased pain following a meal while others experience relief from the presence of food in the GI tract.
  • Hemorrhage may be one of the first signs.
  • Low plasma protein levels, anemia, and weight loss reveal nutrition deficiencies. Diagnosis is confirmed by radiographs and by visualization with gastroscopy.

Medical Management

  • There are four basic goals for the treatment of patients with PUD:
    • (1) alleviate or minimize the symptoms
    • (2) promote healing
    • (3) prevent recurrences by eliminating the cause
    • (4) prevent complications
Drug therapy
  • Advances in knowledge and therapy have provided physicians with the following four types of drugs for the management of PUD:
    • Antibiotics, which address the H. pylori infection (e.g., amoxicillin, clarithromycin, tetracycline, metronidazole).
    • Antacids, which counteract or neutralize the acid. Magnesium and aluminum compounds are the typical antacids of choice for the treatment of PUD
    • Hydrochloric acid secretion controllers:
      • Histamine H2-receptor antagonists (H2-blockers) reduce hydrochloric acid production and secretion. These medications are available over-the-counter and include cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), and nizatidine (Axid).
      • Proton pump inhibitors reduce hydrochloric acid production by inhibiting the hydrogen ion secretion that is needed to produce hydrochloric acid. These drugs include lansoprazole (Prevacid), omeprazole (Prilosec), esomeprazole (Nexium), pantoprazole (Protonix), and rabeprazole (AcipHex).
    • Mucosal protectors, which deactivate pepsin and produce a gel-like substance to cover the ulcer and to protect it from acid and pepsin while it heals itself (e.g., bismuth subsalicylate, sucralfate [Carafate]).

Maintenance drug therapy

  • Maintenance drug therapy is imperative to stabilize the growth rate of bacteria.
  • A continuous low-dose drug therapy follows initial treatment, with intermittent full-dose treatment or symptomatic self-care with the same agents that are used to heal the initial ulcer infection.
  • Success rates depend on the relative risk factors that influence recurrence.

Lifestyle factors

  • Adequate rest, relaxation, and sleep have long been the foundation of general care to enhance the body's natural healing process.
  • Incorporating positive coping and relaxation skills into daily life may help patients to better deal with personal psychosocial stress factors.
  • Habits that contribute to ulcer development (e.g., smoking, alcohol use) should be eliminated, and irritating drugs (e.g.,NSAIDs) should be avoided. Sometimes sedatives are prescribed to aid rest.

Nutrition Intervention

  • In the past, a highly restrictive and bland diet was used for the care of patients with PUD. A bland diet has long since proved to be ineffective and lacking in adequate nutrition support for the healing process.
  • Such a restrictive diet is unnecessary today, because more effective medication regimens are available to control acid secretions and to assist with healing.
  • Thus, current diet therapy is based on a liberal personalized approach that is guided by individual responses to food in an effort to maintain or improve nutritional status. Two basic goals guide food habits.
Eating a well-balanced and healthy diet
  • Supply a well-balanced, regular, healthy diet to help with tissue healing and maintenance. A hearty intake of dietary antioxidants and avoidance of foods/supplements known to increase oxidative stress (e.g., trans fats, excessive supplementation with iron or copper, high alcohol intake) help to restore gastrointestinal well being.
  • Nutrient needs are outlined in the current Dietary Reference Intakes and expressed in the simple food choices
Avoiding acid stimulation
  • Avoid stimulating excess gastric acid secretion, which irritates the gastric mucosa. Few food-related habits affect acid secretion:
    • Food quantity: Avoid stomach distention by not eating large quantities at meals. Avoid eating immediately before going to bed.
    • Irritants: Individual tolerance is the rule, but some food seasonings such as hot chili peppers, black pepper, and chili powder may irritate an already weakened mucosal layer. Caffeine, chocolate, and alcohol may increase acid secretions or prevent healing.
    • Patients will need to independently determine which foods are tolerated and which foods worsen symptoms.
    • Smoking: Complete smoking cessation is best, because smoking provokes GI mucosal injury and hinders ulcer healing in several biochemical and physiologic pathways. It also affects gastric acid secretion and hinders the effectiveness of drug therapy.

Small Intestine Diseases

  • Diseases within the small intestine generally result in malabsorption as a result of the impaired function of the organ.
  • Malabsorption syndromes are characterized by a defect in the absorption of one or more of the essential nutrients.
  • Malabsorption results from a disturbance in the normal digestive process or absorptive pathway, and the defect may include any of the following processes:
    • Digestion of macronutrients: Carbohydrates, proteins, and fats are broken down in the small intestines into their basic building blocks (i.e., monosaccharides and disaccharides, amino acids, and fatty acids and glycerol, respectively) with the help of salivary and pancreatic enzymes, hydrochloric acid, and bile acid.
    • Terminal digestion at the brush border mucosa: Disaccharides and peptides are hydrolyzed by disaccharidases and peptidases for the final step of digestion.
    • Absorption: The end products of macronutrient digestion, micronutrients (i.e., vitamins, minerals, and electrolytes) and water are absorbed across the epithelium of the small intestine into the general or lymphatic circulation.
  • Several organ systems and functions are affected by malabsorption disorders. Chronic deficiencies of vitamins, minerals, and macronutrients can lead to several forms of anemia (e.g., iron, pyridoxine, folate, vitamin B12); osteopenia and tetany from calcium; vitamin D and magnesium deficiency; and other musculoskeletal, endocrine, and nervous system abnormalities.
  • The most common symptoms of malabsorption disorders are chronic diarrhea and steatorrhea.
  • Two specific conditions triggering malabsorption are cystic fibrosis (CF) and inflammatory bowel disease (IBD)

CYSTIC FIBROSIS

  • CF is a generalized genetic disease of childhood that is inherited as an autosomal recessive trait that can include multiple defects.
  • Previously, children with CF lived to approximately the age of 10 years, dying from complications such as damaged airways and lung infections as well as fibrous pancreas and malnutrition. However, the discovery of the CF gene and the underlying metabolic defect has improved the management of the disease and helped push the life expectancy of these individuals into adulthood.
  • The metabolic defect of CF inhibits the normal movement of chloride and sodium ions in body tissue fluids. These ions become trapped in cells, and this causes thick mucus to form and clog ducts and passageways. Involved organ tissues are damaged so that they no longer function normally.
  • The typical CF symptoms include the following:
    • Thick mucus in the lungs: causes damaged airways, more difficult breathing, persistent coughing, and pulmonary infections (e.g., bronchitis, pneumonia)
    • Pancreatic insufficiency: leads to a lack of normal pancreatic enzymes to digest macronutrients and a progressive loss of insulin-producing β cells and eventual diabetes mellitus in approximately 15% of adult patients.
    • Malabsorption: food is left undigested and unabsorbed, with consequential malnutrition, stunted growth, delayed puberty, and infertility.
    • Liver and gallbladder disease: clogged bile ducts lead to a progressive degeneration of functional liver tissue.
    • Inflammatory complications: including arthritis, finger clubbing, and vasculitis.
    • Increased salt concentration: in body perspiration, thereby leading to salt depletion.
Nutrition management
  • Nutrition therapy is a critical component of the treatment regimen for CF, and it can have a significant impact on successful growth. Patients who are able to maintain an age-appropriate body mass index percentile have better overall health outcomes.
  • Treatment is augmented with the following:
    • (1) increased knowledge of the disease process
    • (2) early newborn screening and diagnosis
    • (3) improved pancreatic enzyme replacement products

Inflammatory Bowel Disease

  • Inflammatory bowel disease (IBD) is a general term that is used to describe chronic inflammation of the GI tract and the persistent activation of the mucosal immune system against the normal healthy gut flora. Chronic inflammation disrupts the protective epithelial barrier until ulceration of the mucosal surface destroys segments of the GI tract.
  • As a result of lesions, portions of the GI tract are not functional, which causes malabsorption. The related condition of short-bowel syndrome may result if the repeated surgical removal of parts of the small intestine is necessary as the disease progresses.
  • Crohn’s disease and ulcerative colitis are the two most common forms of inflammatory bowel disease; both of these are idiopathic diseases.
Crohn’s disease
  • Crohn’s disease may affect any portion of the GI tract from the esophagus to the anus, but it is most commonly localized to the ileum and the colon.
  • Risk factors include a family history of the disease, Jewish ancestry, and smoking. Inflammation may skip sections of the GI tract and affect more than one section at a time.
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  • Patients may experience long asymptomatic periods between flare-ups, or they may experience continuous and progressive attacks.
  • Malnutrition and micronutrient deficiencies are common with Crohn’s disease as a result of malabsorption, poor food intake, and drug-nutrient interactions. Specifically, vitamins A and D, iron, zinc, and protein-energy malnutrition are frequently observed.
  • Iron-deficiency anemia is particularly of concern among patients with Crohn’s disease due to the additional issue of blood loss.
  • Protein-energy deficiency is also problematic because the protein needs are higher than normal to allow for tissue healing.
  • Nutrient interactions with necessary medications result in additional complications. For example, long-term corticosteroid use increases the risk for osteoporosis.
  • Surgical removal of portions of the GI tract further exacerbates malabsorption. Malnutrition decreases quality of life, and it can have long-term negative consequences; thus, screening, early detection, and treatment are important parts of the management of this disease.
Ulcerative colitis
  • Ulcerative colitis (UC) is an inflammatory disease that is limited to the colon.
  • Symptoms include urgent diarrhea with blood and mucus, abdominal pain, weight loss, fever, and rectal pain.
  • The inflammation does not skip sections of the bowel rather, it is progressive from the anus.
  • With the exception of iron-deficiency anemia, UC is not associated with as many micronutrient deficiencies as Crohn’s disease because of the location of the inflammation.
  • Dehydration and electrolyte imbalances are more common in UC.
  • However, as pain increases, food intake decreases, or inflammation extends beyond the colon, the same deficiencies as are seen with Crohn’s disease may occur.
  • All inflammatory bowel conditions can have severe and often devastating nutrition results as more and more of the absorbing surface area becomes involved or surgical removal is required.
  • Malnutrition can exacerbate an attack and hinder the healing process.
  • Restoring positive nutrition is a basic requirement for tissue healing and health.
  • Enteral nutrition support of either polymeric formula or elemental formula is helpful for many patients to restore nutritional balance and induce remission.
Nutrition therapy
  • Principles of continuing dietary management of IBD include the following:
    • During periods of inflammation:
      • Use enteral or parenteral nutrition feedings, if necessary
      • Progress to low-fat, high-protein, high-kilocalorie, small, frequent meals when returning to a normal diet as tolerated.
      • The diet should be low in fiber only during acute attacks or with strictures. Otherwise, fiber should be increased gradually.
      • Vitamin and mineral supplementation should include vitamin D, zinc, calcium, magnesium, folate, vitamin B12, and iron.
    • During periods of remission:
      • Meet energy and protein needs that are specific for weight, and replenish nutrient stores.
      • Avoid foods that are high in oxalates for patients with Crohn’s disease.
      • Increase antioxidant intake, and consider supplementation with omega-3 fatty acids and glutamine.
      • Consider the use of probiotics and prebiotics.

Diarrhea

  • Diarrhea typically is not a disease of the small intestine but rather a symptom or result of another underlying condition.
  • In some cases, diarrhea may result from intolerance to specific foods or nutrients, such as in lactose intolerance or acute food poisoning from a specific food-borne organism or toxin.
  • A variety of parasites (e.g., Giardia lamblia, Cryptosporidium parvum, Cyclospora cayetanensis, Entamoeba histolytica), bacteria (e.g., Campylobacter, Clostridium difficile, Escherichia coli, Listeria monocytogenes, Salmonella enteritidis, Shigella), and viral infections (rotavirus, norovirus) are known causes of diarrhea.
  • Traveler’s diarrhea, which is often attributed to irregular meals, unfamiliar foods, and travel tensions, is also a well-known GI disturbance; E. coli, norovirus, and rotavirus are its most common cause.
  • Chronic diarrhea (i.e., diarrhea that lasts for more than 2 weeks) can be a life-threatening illness, especially for young children or individuals with compromised immune systems. Diarrheal disease is the fourth leading cause of death globally. Acute infectious diarrhea is the second most common cause of death among children in developing countries.
  • Intravenous fluid and electrolyte replacement may be necessary, or oral rehydration solutions such as Pedialyte, Resol, Ricelyte, CeraLyte, and Rehydralyte may be used. As soon as it is tolerated, a regular refeeding schedule is needed to avoid malnutrition.
  • Nutrition therapy will depend on the underlying causative agent. Determining and treating the cause of diarrhea is paramount to restoring nutritional parameters.
  • For severely malnourished patients, the resumption of nutrient intake should be carefully monitored.

Refeeding syndrome

  • Refeeding syndrome is a potentially fatal metabolic disturbance that involves fluid and electrolyte imbalances and that can result in cardiac failure.
  • When malnourished patients are started on a feeding schedule that is too aggressive, sudden shifts in electrolytes leave low serum levels of phosphate, potassium, magnesium, glucose, and thiamine.
  • Malnourished patients require a measured reintroduction to nutrients and close monitoring.

Large Intestine Diseases

Diverticular Disease

  • Diverticulosis is a multifactorial disease that is characterized by the formation of many small pouches or diverticula along the mucosal lining in the colon.
  • Segmental circular muscle contractions move waste down the colon to form feces for elimination. When pressures become sufficiently high in a segment with weakened bowel walls, small diverticula may develop.
  • As the diverticula become infected, a condition called diverticulitis, the affected area becomes painful.
  • There is evidence that the underlying age-related pathogenesis develops in response to chronic low-grade inflammation, microbiome shifts, visceral hypersensitivity, and abnormal gut motility.
  • As the inflammatory process advances, increased pain and tenderness are localized in the lower left side of the abdomen, and it is accompanied by nausea, vomiting, distention, diarrhea, intestinal spasm, and fever.
  • Perforation sometimes occurs, and surgery is indicated. Underlying malnutrition may also be present. In acute cases of diverticulitis with bloody diarrhea, patients may be restricted to nothing by mouth or clear liquids until they can progress slowly to a normal, nutritionally adequate diet.
  • The dietary management of diverticulosis includes increasing dietary fiber (particularly insoluble fiber) to 6 to 10 g/ day above the normal recommendations of 20 to 35 g/ day along with adequate fluid intake.
  • Avoiding certain foods (e.g., nuts, seeds) that can accumulate in the small diverticula pouches was historically recommended, but little evidence suggests that this is truly protective against inflammation.
  • Emerging therapies include the use of probiotic and prebiotic food sources to encourage a healthy gut microbiome. Antibiotics are used to treat underlying inflammation.

Irritable Bowel Syndrome

  • Irritable bowel syndrome (IBS) is the most commonly diagnosed GI disorder.
  • The exact prevalence is hard to determine because:
    • (1) the definitions of IBS have varied throughout epidemiologic studies
    • (2) many people with symptoms do not seek medical attention
    • (3) it often overlaps other GI-associated and non-GI disorders (e.g., psychiatric disorders, chronic fatigue syndrome, anxiety, mood disorders)
  • IBS is defined as a functional bowel disorder in which abdominal pain or discomfort is associated with defecation or a change in bowel habit.
  • IBS displays three major types of symptoms:
    • (1) chronic and recurrent pain in any area of the lower abdomen
    • (2) small-volume bowel dysfunction that varies from constipation or diarrhea to a combination of both
    • (3) excess gas formation with increased distention and bloating that is accompanied by rumbling abdominal sounds, belching, and flatulence
  • Accumulating evidence indicates that IBS is a multicomponent disorder that includes a genetic predisposition, altered sensation and motility of the GI tract, infection, inflammation, increased intestinal permeability, dietary intolerances, dysbiosis, and psychosocial stressors.
  • Thus, treatment is designed to minimize symptoms, and it may include a holistic approach including medications, diet and lifestyle (e.g., exercise) interventions, as well as psychologist/behavior therapy. A highly individualized approach to nutrition care is essential, and it should be based on careful nutrition assessment.
  • In general, the food plan should give attention to the following basic principles:
    • Follow a regular diet with an optimal energy and nutrient composition. Assess the need for vitamin and mineral supplementation.
    • Eliminate food allergens and intolerances. Along with any known allergens or intolerances, foods that contain the following should be specifically evaluated for tolerance: fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs).
    • Omit foods that increase gas and flatulence. Some foods are recognized gas formers as a result of known constituents (e.g., indigestible short chains of glucose [oligosaccharides] as in the case of legumes). Others may cause gaseous discomfort on an individual basis.
    • Consider the use of probiotics and prebiotics.
    • Consider the use of food diaries. Tracking nutrient intake, environment, emotions, activity, and symptoms may help to narrow instigating factors for future avoidance.

Constipation

  • "Normal" intestinal elimination is ill-defined and can vary greatly. This common short-term problem usually results from various sources of nervous tension and worry, neurologic or neuromuscular problems, changes in routines, side effects from medications, frequent laxative use, low fiber diets, and sedentary behaviors.
  • The most important aspect of the treatment and prevention of constipation is risk assessment to identify the potential causes of constipation. Improved diet, exercise, and bowel habits may help remedy the situation. Dependency on laxative or enema use should be avoided. There are a variety of over-the-counter medications and prescription medications available, with varying degrees of efficacy.
  • The diet should include increased soluble fiber, fruits that contain natural laxatives (e.g., dried prunes, figs), and adequate fluid intake. Constipation occurs at all ages, but it is almost epidemic among elderly people. In all cases, a personalized approach to management is fundamental.

Food Intolerances and Allergies

  • Several conditions may cause certain food allergies or intolerances. Intolerances—unlike allergies—are not life threatening, and they are not immunologic in nature.
  • The underlying problem of an allergic reaction is the body’s immune system reacting to a protein as if it were a threatening foreign object and then launching a powerful attack against it.

FOOD INTOLERANCES

  • Food intolerances are adverse reactions to foods or food constituents and are not immune mediated. The most common worldwide food intolerance is to the disaccharide lactose.
  • The intolerance is a result of inadequate production of the lactase enzyme to properly digest and absorb the carbohydrate found in milk products into its two monosaccharide components: glucose and galactose.
  • Other food intolerances may present as hives, flushing, or headache. Adverse reactions may be prevented by avoiding the offending food products.

FOOD ALLERGIES

  • FOOD ALLERGIES refers to the abnormal reactions of the immune system to a number of substances in the environment and within food.
  • Common Food Allergens
    • The most common food allergens include the proteins found in egg, cow’s milk, peanut, tree nuts, wheat, crustacean shellfish, and soy. The prevalence of food allergies varies in accordance with many factors, including age, sex, race, nutritional status, comorbidities, and route and exposure to potential food allergens. Children will often outgrow early allergies to milk, egg, soy, and wheat but are less likely to outgrow allergies to peanuts and tree nuts. Although it is more common for food allergies to present during the first 2 years of life, allergies may begin at any age.
Signs and symptoms
  • The most common symptoms of food allergies are hives, nausea, diarrhea, abdominal pain, and respiratory symptoms such as wheezing.
  • Anaphylactic shock is the most severe form of allergic reaction, and it can result in death relatively quickly. Individuals who are in anaphylactic shock have swelling of the face and throat, difficulty breathing, anxiety, increased heart rate, and, if not treated, decreased blood pressure and loss of consciousness.
  • The person's throat, lips, and tongue swell to the point of blocking the airway, ultimately suffocating the individual. Peanut, tree nut, and seafood allergies carry the highest risk of anaphylaxis.
Diagnostics
  • If a patient shows signs of an allergic reaction, the following methods are recommended as diagnostic measures to be used in conjunction with a patient history and physical exam: elimination diet, a skin prick test, allergen-specific serum IgE immunoassays, or an oral food challenge.
  • The Expert Panel Guidelines on Food Allergies recommends that all food allergies be diagnostically confirmed because 50% to 90% of presumed food allergies are not true allergies.
Nutrition management
  • Nutrition care for food allergies is focused on two aspects:
    • (1) avoiding offending foods
    • (2) substituting nutritionally appropriate alternatives for the excluded foods
  • Referring a person with food allergies to a dietitian to provide family support, education, and counseling may be helpful. Guidance regarding food substitutions or special food products and modified recipes to maintain nutrition needs for growth is sometimes necessary.
  • Children tend to become less allergic as they grow older, but cooking guides and family education that address the deciphering of food product labels are essential from the beginning.
  • Furthermore, if anaphylaxis is a known risk, patients should be under the care of a physician for the provision of self- or family administered emergency medications if anaphylaxis occurs.
  • Although many risk factors for the development of food allergies are not modifiable, some dietary factors during pregnancy and early life may help reduce the risk of food allergies in infants.
  • Current recommendations for preventing food allergies are as follows:
    • Pregnant women should strive for a well-balanced healthy diet and not avoid any specific allergens during gestation (unless she has allergies).
    • Exclusively breastfeed infants for a minimum of 4 months. The mother should not avoid eating food allergens during lactation (unless she has allergies).
    • Introduce solid foods to infants between 4 and 6 months. Include allergenic foods after the initial period of weaning.
    • Include probiotics and prebiotics in the diet.

Celiac Disease

  • Celiac disease (CD) is estimated to affect 0.8% of the U.S. population, with significantly more Caucasians than other races being affected
  • Diagnostics
  • There have been significant improvements in the diagnostic testing for CD in recent years. Serologic testing for IgA anti-tissue transglutaminase antibody can identify CD but diagnosis must be confirmed by duodenal mucosal biopsy while the patient is on a gluten-containing diet. Previously used IgA and IgG anti-gliadin antibody (AGA) tests are no longer recommended.
Disease process
  • The pathology of CD is an autoimmune response to a specific sequence of amino acids found in wheat, barley, and rye proteins. The CD-activating proteins are collectively known as gluten.
  • However, gluten protein is only found in wheat products. The proteins in barley and rye that cause an adverse reaction are