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Understand GI anatomy, digestion, common disorders, and medical nutrition therapy. Explore GI tract structures, absorption processes, and specific concerns such as inflammatory bowel disease. Tips for dietary management included.
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Nutrition and Gastrointestinal Disorders Amanda Gordon, RD, LD, CNSCAdvanced Practice Clinical DietitianThe George Washington University HospitalWashington, DCamanda.gordon@gwu-hospital.com
Agenda and Goals • Review Anatomy and Physiology • Review Digestion and Absorption of Macro and Micronutrients • Introduce Common Clinical Presentations of GI Disorders • Highlight MNT (Medical Nutrition Therapy) for each GI Disorder
The GI Tract: Anatomy • Mouth • Esophagus • Stomach • Small Intestine (Small Bowel) • Duodenum • Jejunum • Ileum
The GI Tract: Anatomy • Large Intestine (Large Bowel) • Cecum • Colon • Ascending • Transverse • Descending • Sigmoid • Rectum • Anal Canal
The GI Tract: Accessory Organs • Salivary Glands • Tongue • Teeth • Liver • Gallbladder • Pancreas • Appendix • Peritoneum • Mesentery
The GI Tract The digestion of nutrients from dietary food sources requires a coordinated process of mechanical and chemical processes. Defects in any of these phases of digestion or absorption can lead to maldigestion or malabsorption of nutrients.
The Esophagus • Function: The Transport Tube • Protected on two sides by two sphincters • Upper Esophageal Sphincter • Lower Esophageal Sphincter
Disorders of the Esophagus : GERD • LES malfunction, does not close properly • Stomach contents leak back, or reflux, into the esophagus and irritate it • Can cause Barrett’s Esophagus (tissue changes in the esophagus) • Treatment: • Antacids (Maalox, Tums, Mylanta) • H2 blockers (Pepcid, Zantac, Tagamet) • Proton pump inhibitors (Prevacid, Protonix, Prilosec)
★GERD: MNT • Limit or avoid peppermint, spearmint, chocolate, alcohol, caffeinated and carbonated beverages • Limit or avoid high fat foods • Wait 3 hours after eating before lying down • Raise the HOB by 6-9 inches • Eat several small meals throughout the day
GERD: Surgical intervention Nissen Fundoplication www.clevelandclinic.org
The Stomach • Where it all begins… • Anatomy • Fundus • Body • Pylorus • Pyloric Sphincter • Physiology • Chief cells • Parietal cells (HCl) • Endocrine cells (gastrin, ghrelin)
The Stomach: Digestion • Process of emptying takes 2-6 hours • Most occurs in the pyloric region • Beginning of protein digestion (proteolysis) via Pepsin
Disorders of the Stomach: Gastroparesis • Caused by delayed gastric emptying • Often occurs in people with Type 1 or Type 2 Diabetes • Symptoms include nausea, vomiting, early satiety, erratic BG MNTProkinetic agents (Reglan), small, frequent meals (4-6x day), avoid high fat foods, full liquids if needed, jejunostomy tube
The Bowel: Digestion/Absorption Remember: The intestines can adapt/compensate
The Small Bowel • Where the REAL action is… • Anatomy • Duodenum, Jejunum, Ileum • Villi and Microvilli • Physiology • Gastric Inhibitory Peptide • Secretin: stimulates bicarbonate • CCK: stimulates ejection of bile from gallbladder
Small Bowel Disorders: Inflammatory Bowel Disease Crohn’s Disease • Inflammatory disease in the terminal ileum • Weight loss, anorexia, diarrhea • B12 deficiency • Medications: Antibiotics, Sulfasalazine, Corticosteroids Ulcerative Colitis • Ulcerative disease of the colon • Bloody diarrhea, weight loss, anorexia • Medications: Mesalamine, Corticosteroids, Anti-diarrheals
Small Bowel Disorders: Inflammatory Bowel Disease Malnutrition and Nutrient Deficiency Concerns: • Iron deficiency • Zinc deficiency • Folate deficiency (with use of Sulfasalazine) • Vitamin B12 deficiency (Crohn’s Disease) • Vitamin D and Calcium (bone disease concerns with long term steroid use)
★ IBD: MNT • Maintain/correct fluid and electrolyte imbalances • High calorie, high protein diet (BEE x 1.5, 1-1.5 g/kg protein) • Low residue/low fiber diet (during flare ups) • Repletion and supplementation of micronutrients • Bowel Rest/TPN for acute flare-ups • Anti-diarrheal agents • Monitor closely for lactose intolerance
★ IBD: MNT Specific Concerns After an Intestinal Resection • Integrity of the ileocecal valve • Encourage early PO or enteral nutrition • Villi adaption • Feeding transitions/overlapping feeding modalities • Use of soluble-fiber (pectins) may be beneficial • Low-fat diet, lactose-free diet
Small Bowel Disorders: Short Bowel Syndrome (SBS) • Diarrhea/steatorrhea malabsorption malnutrition • Occurs after extensive small bowel resection (Crohn’s Disease, Radiation Enteritis, Weight loss surgery)
Small Bowel Disorders: Short Bowel Syndrome (SBS) • Typically a 70-75% loss of small bowel (100-120 cm of small bowel without a colon or 50 cm of SB with a colon) • Resultant short-term and long-term problems with malabsorption which lead to fluid imbalance, weight loss, micronutrient deficiencies
Small Bowel Disorders: Short Bowel Syndrome (SBS) • Disruption of Ileocecal valve and Ileal break • Small bowel bacterial overgrowth • Role of bile salts in ileum • Unabsorbed bile salts enter colon and cause osmotic diarrhea • Bile salt deficiency can lead to fat malsorptionand steatorrhea Comparison of Normal to Adapted Villi http://www.shortbowel.com/information/beyond/intestinal.adaptation.asp
Small Bowel Disorders: Short Bowel Syndrome (SBS) • Medications: • Proton Pump Inhibitors (Nexium, Protonix, Prilosec, Prevacid) –acid reduction • H2 Receptor Antagonists (Tagamet, Pepcid, Zantac) – acid reduction • Anti-secretory agents (Octreotide) – reduce electrolyte and fluid losses • Anti-diarrheals (Immodium, Lomotil, Paragoric) • Antibiotics – treat small bowel bacterial overgrowth • Bile Acid Sequesters (Cholestyramine) – preserve bile acids to aid with fat absorption/prevent steatorrhea
★ SBS: MNT • Whole food diet • High calorie (often 200-400% over their needs) • Adequate fat (as calorie source, despite risk of steatorrhea • Avoid concentrated sweets/simple carbs • Lactose free (only if lactose intolerant) • Moderate fiber (if colon is intact) • Oral rehydration agents • Nutrition support (TPN versus enteral nutrition) • Replace vitamins and minerals (zinc, potassium, Magnesium, fat soluble vitamins, Vitamin B12)
The Large Bowel • The often overlooked powerhouse… • Anatomy • Cecum, Colon, Rectum, Anus • Physiology • Absorptive cells (water, Na, Cl, Vit K) • Goblet cells (secrete mucus) • Functions • Absorption • Bacterial digestion • Defecation
Large Bowel Disorders: Diverticular Disease • Diverticulosis: small pouches in lining of colon that bulge outward through weak spots • Diverticulitis: small pouches become inflamed, usually treated with antibiotics • Role of fiber: High fiber versus low fiber?
Bowel Disorders: Irritable Bowel Syndrome (IBS) • Chronic gastrointestinal condition with symptoms including excess flatulence, abdominal discomfort, bloating • Causative factors can include abnormal gut motility, visceral hypersensitivity, imbalance of the gut flora • Lactose intolerance
Foods that Can Aggravate Symptoms of IBS • Milk • Caffeinated beverages • Alcohol • Fruits • Spices • Fast Foods/Chinese Food • Certain vegetables, including cabbage, broccoli, cauliflower and corn • Legumes and beans • Preservatives and artificial flavoring • Baked products
★ IBS: MNT • Maintain food record to help ID problem foods • Eliminate foods that aggravate symptoms (see prior list) • Restrict lactose as needed • Eat small, frequent meals • Aim to consume 6-8 cups of water daily • Exercise regularly • Gradually increase fiber content of diet (goal: 25-30 gm/day) • Role of probiotics
Fiber and the GI System: A Review • Soluble fiber: Dissolves in water, slows intestinal transit time • Pectins, gums, mucilages, some hemicelluloses • Found in oat bran, legumes, psyllium (Metamucil) • Insoluble fiber: Does not dissolve in water, speeds intestinal transit time • Lignans, cellulose, some hemicelluloses • Found in wheat bran, most fruits and vegetables
Diarrhea Many clinical and medical causes. (1st - identify the underlying cause) • Fever • Dehydration • Infection (bacterial, viral) • Hospital/community borne • Secretory (laxatives, bile acids) • Medications, antibiotics • Electrolyte repletion (MagOx, Neutraphos) • Malabsorption • Malnutrition/Hypoalbuminemia • Post-op lactose intolerance • Clear liquid diets • PSBO “Patient presents with diarrhea. Consult nutrition, it’s probably the tube feed.”
Constipation • Common Causes: • Low fiber diet • Inadequate fluid intake/calorie intake • Medication • Vitamin/Mineral supplementation • Food Sensitivities • Treatment: • Fiber supplementation • Potential role of prebiotics/probiotics
The Gallbladder • Physiology • Stores and concentrates bile that enters from the hepatic and cystic ducts • Ejects bile into the duodenum during digestion
Disorders of the Gallbladder, Bile Duct Cholecystitis • Inflammation of the gallbladder • Gallstones (Choleliathsis) Jaundice • Obstruction of the bile duct, bile pigment builds up in the blood stream Cholecystectomy • Surgical removal of the gallbladder MNT Low-fat diet
References • American Dietetic Association, Evidence Analysis Library, Accessed electronically, August 2012. • American Dietetic Association, Nutrition Care Manual. Accessed electronically, August 2012. • Clark, Christian and Mark DeLegge. Irritable Bowel Syndrome: A Practical Approach. Nutr Clin Pract 2008 23: 263. • Hark, L, Morrison, G (eds). Medical Nutrition and Disease: A Case Based Approach: 3rd Edition. 2003: Blackwell Publishing. • Jeejeebhoy, K. Short Bowel Syndrome: a Nutritional and Medical Approach. Canadian Medical Association Journal 2002 166: 1297-1302. • Lykins, TC, Stockwell, J. Comprehensive Modified Diet Simplifies Nutrition Management of Adults with Short-Bowel Syndrome. JADA. 98(3): 309-315. March 1998.
References • Naik, A. and Nanda Venu. Nutritional Care in Adult Inflammatory Bowel Disease. Practical Gastroenterology, June 2012: 18-27. • Rees Parrish, C. The Clinicians Guide to Short Bowel Syndrome. Practical Gastroenterology, September 2005: 67-106. • Sanjeevi, A. et al. The Role of Food and Dietary Intervention in the Irritable Bowel Syndrome. Practical Gastroenterology, July 2008: 33-42. • Schiller, L. Nutrition and Constipation: Cause or Cure? Practical Gastroenterology, April 2008: 43-49 • Thibodeau, G. et al. Anatomy and Physiology: 5th Edition. 2003: Mosby Publishers.