Nutrition GI Disease (11)

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Nutrition GI Disease (11)
2013-12-13 13:24:24
Final Exam
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  1. 11 - Gastrointestinal Disease
  2. Congenital Lactase Deficiency
    • absence of lactase activity at birth
    • infants with this condition who're breastfed will get diarrhea from the milk
  3. Congenital Lactase Intolerance
    • a defect in absorption, NOT a defect of digestion
    • lactose is usually absorbed in the intestine but in THIS case it's absorbed in the stomach & circulates in the blood stream as lactose which is abnormal & problematic
    • not usually done & can cause multi-organ damage or dysfunction
  4. Hypolactasia
    • partial or complete loss of brush border lactase activity
    • acquired or congenital - acquired is more common
  5. Lactase Nonpersistence (LNP)
    • ACQUIRED Hypolactasia
    • Primary: autosomal recessive genetically programmed loss of lactase gene expression & activity that occurs after weaning; often starts at 3-5 years
    • Secondary: caused by disease, injury, drugs, radiation,
    • surgery, or infection
  6. Which is permanent & which is reversible, primary or secondary Acquired Hypolactasia (LNP)?
    • PRIMARY is permanent because it's caused by a genetic mutation
    • secondary is reversible after whatever stimulus is causing the brush border impairment is removed
  7. What type of people tend to have more lactase (preserved)?
    • Primary Acquired Lactase Nonpersistence is genetically based
    • Caucasians/Europeans have the most lactase & therefore the greatest ability to digest lactose
    • Asians & African Americans tend to have higher rates of primary LNP which can cause lactose intolerance
  8. Lactose Intolerance
    • LNP causes lactose maldigestion or lactose intolerance if SYMPTOMS occur
    • symptoms result from:
    • osmotic load, where unabsorbed lactose leads to water influx into SI
    • cramping, distention
    • lactose fermentation
    • abdominal pain
    • increased motility
  9. What do colonic bacteria do to (undigested) lactose?
    • they can ferment it resulting in
    • 1) short chain FAs: these are absorbed by colonocytes but if unabsorbed cause DIARRHEA
    • 2) Gas: 50% H2 + methane & CO2 which causes cramps, flatus, & increased motility
  10. What determines the severity of lactose intolerance symptoms?
    • Degree of LNP: the more enzyme, the fewer symptoms
    • Lactose load: amount ingested, rate of delivery to the SI, rate of gastric emptying; a mixed meal might slow release of lactose in intestines, help body keep up with lactase production
    • Ability to ferment + absorb short chain FAs: flatus still produced in that situation
  11. Dietary Approaches to Lactose Intolerance
    • 1. avoiding lactose-containing foods
    • 2. limit RATE of lactose delivery to small intestine
    • 3. eat β-galactosidase rich food (YOGURT)
    • 4. add β-galactosidase to food
  12. What might be a concern for people avoiding lactose-containing foods due to lactose intolerance?
    • that they might not get enough Calcium or Vitamin D because most people depend on dairy products for those micronutrients
    • deficiencies of these puts people at risk for osteoporosis
    • it is possible to get them outside of dairy, or one could eat dairy with less lactose like hard cheeses over soft ones (bacteria digest the lactose during the aging process)
  13. How can a person limit RATE of lactose delivery to small intestine?
    • by having a mixed meal
    • eg. fat slows digestion from the stomach
  14. β-galactosidase (β-gal)
    • a hydrolase enzyme that catalyzes the hydrolysis of β-galactosides (eg. lactose) into monosaccharides
    • enzyme can be found in bacteria which itself is found in different foods (yogurt)
    • bacteria are lysed in the upper GI tract upon food ingestion, liberating the β-galactosidase which can digest lactose
    • can also take a capful of β-galactosidase or have β-galactosidase-enriched food (lactaid milk)
  15. Celiac Disease (Celiac Sprue)
    • an immune-mediated (IgA) response to dietary gluten
    • it's more common in people of European descent
    • it's UNDER diagnosed (1/133 people in the US)
    • a person is at increased risk for Celiac's if a 1st degree relative has the disease (prevalence goes to 1/22)
  16. What other types of diseases is Celiac's associated with?
    • AUTOIMMUNE diseases
    • type 1 Diabetes Mellitus 
    • thyroid disease liver disease
    • selective IgA deficiency
    • inflammatory bowel disease (IBS)
    • eosinophilic esophagitis
    • down syndrome…
  17. Gluten
    • a protein found in wheat, barley, rye, possibly oats, many medications, & hygiene products, where it's used as a filter/preservative
    • ingestion of gluten if intolerant leads to destruction of the small intestine mucosa
    • this manifests as diarrhea, bloating, nutrient malabsorption, & sometimes dermatitis herpetiformis, an itchy skin rash
  18. What is the hypothesis behind gluten's activation of an immune response against the small intestine mucosa?
    • 1. indigestible fragments of gluten induce enterocytes to release zonulin → LOOSENS tight junctions between mucosal cells
    • 2. gluten may move through now opened spaces between cells & accumulate underneath
    • 3. enterocytes secrete IL-15 in response to deposited gluten → intraepithelial leukocytes squeeze through mucosa to target area
    • 4. tissue transglutaminase (TTG) modifies the gluten, which is now picked up by APCs, presented to T cells, initiating an immune response
    • 5. T cell activation occurs, B cells make Ig's to gluten, & damage mucosal enterocytes in the destruction process
  19. How is Celiac Disease diagnosed?
    • by measuring tissue transglutaminase (TTG), the enzyme that modifies gluten before it's presented in MHC class II molecules, activating an immune response
    • a tissue biopsy is often collected for confirmation
  20. How is Celiac Disease managed?
    • Consult w/ a skilled dietician
    • Educate about the disease
    • Lifelong adherence to a gluten-free diet*
    • Identify + treat nutritional deficiencies
    • Access should be provided to advocacy groups
    • Continuous long-term follow up (by a multidisciplinary team)
  21. Why might someone not respond to a gluten-free diet?
    • 1. could be blatant non-compliance to the diet
    • 2. accidental ingestion of gluten
    • 3. complete misdiagnosis
    • 4. a concurrent disorder: another condition affecting GI tract (eg. cholitis)
    • 5. refractory sprue: when someone never improves on a gluten-free diet
    • 6. something completely unrelated (eg. ulcerative jejunitis, intestinal lymphoma)
  22. Why is it important to follow a gluten-free diet when diagnosed with Celiac Disease?
    • because if you don't that can result in intestinal damage which causes malabsorption
    • manifests as diarrhea/steatorrhea, weight loss, vitamin deficiency, & mineral deficiency
    • *in some cases unexplained IRON deficiency may be the first sign of Celiac Disease
  23. What foods you might not expect to have gluten contain gluten?
    • grain & many grain products
    • grain vinegar - found in most condiments
    • food starches added or dusted on many foods
    • beer & grain alcohol
    • medications
    • hygiene products
    • *because gluten-free diets can be difficult to follow, can focus on what a patient CAN have as opposed to what they can't (especially if they've had weight loss)
  24. Gluten-free Labeling
    • 1. cannot contain wheat, rye, barley, or crossbreeds of these grains
    • 2. any ingredient derived from these grains must have been processed to remove gluten
    • 4. cannot contain 20 ppm or more gluten
  25. Why is it important for a person with Celiac Disease to follow a gluten-free diet even if they don't have serious symptoms?
    • because damage to the GI tract will put them & risk for micronutrient deficiencies & the associated conditions that can result
    • Osteoporosis ~ vitamin D + Calcium [also vitamin K]
    • Lactose Intolerance ~ example of secondary persistence
    • Small Bowel Lymphoma ~ related to intestine damage or immunosuppression treatment involved
    • Pregnancy Complications ~ women w/ unmanaged Celiac's have poor pregnancy outcomes or trouble getting pregnant
    • Stunting in children ~ if a child isn't absorbing nutrients they're not going to grow
  26. Oral Rehydration Solution
    • in some areas of the world children don't have a clean water supply
    • as a result many get infectious diarrhea & die from dehydration
    • eg. cholera toxin destroys GI tract & causes net pooling + secretion of water in GI tract lumen
    • however transporters are still functional, so providing a sodium/glucose solution causes water to passively follow sodium into the circulatory system to maintain osmolality
    • can pull fluid in across basolateral membrane & hydrate individual using such a solution
  27. Pancreatitis
    • inflammation of the pancreas
    • may be acute or chronic (chronic presents with more long-term abdominal pain; smoking contributes to both types)

    acute symptoms: sudden onset abdominal pain & elevated serum amylase and lipase

    most common causes: Gallstones & Alcohol

    • • Abdominal injury or surgery
    • • Cystic fibrosis
    • • Genetic predisposition
    • • Hypercalcemia
    • • Hyperparathyroidism
    • • Hypertriglyceridemia
    • • Infection
    • • Medications
    • • Pancreatic cancer
    • • Smoking
  28. Triglyceride-induced Pancreatitis
    • not a particularly common type of pancreatitis however it can be avoided by taking cautionary nutritional measures
    • controlling a persons obesity, diabetes, alcohol intake, or certain hyperlipoproteinemias can help prevent this type of pancreatitis
    • there's also a risk of high triglycerides during pregnancy
  29. Acute Pancreatitis
    • most commonly caused by alcohol & gallstones
    • for a mild/moderate case: nil per os (NPO) + IV fluids for up to a week
    • for a severe case: enteral nutrition to stimulate the GI a little, as failure to do so may worsen the severity of disease
    • VERY severe cases: parenteral nutrition in to prevent further malnutrition
    • *fat in the diet produces the most pain b/c without pancreatic lipase fat digestion doesn't occur
  30. Chronic Pancreatitis
    • permanent impairment of the pancreas
    • can lead to exocrine dysfunction - no production of pancreatic enzymes
    • this leads to fat malabsorption which can lead to Steatorrhea, Weight loss (afraid to eat b/c painful), or Fat soluble vitamin deficiencies
    • originally caused by alcohol, familial predisposition, a juvenile form limited to tropical areas of the developing world, or an unknown cause (idiopathic)
  31. How can you treat Chronic Pancreatitis?
    • pancreatic enzyme replacement therapy
    • large pills that need to be consumed when something with fat is eaten
  32. Constipation
    • less than or 3 stools per week
    • is associated with inadequate fiber intake, dehydration, physical inactivity, medications, & intestinal disease
  33. Diverticular Disease
    • high intracolonic pressure can cause colonic outpouchings, called DiverticulOSIS
    • if in addition you have poor intestinal transit, things such as food, stool, or bacteria can get stuck in the outpouchings
    • DiverticuLITIS: infection & inflammation due to impaction of stool or food particle in colonic outpouchings

    *diverticular disease is managed with a HIGH FIBER diet; in societies with a HIGH fiber intake, there's a LOW prevalence of diverticular disease
  34. How does a high fiber diet help manage diverticular disease?
    • 1. decreases how long it takes for food to move from mouth to anus (Transit Time)
    • 2. causes stool bulking, making it easier for peristaltic action to move it along
    • 3. decreases intracolonic pressure → less diverticulosis

    such a diet should consist of increased fruit, vegetables, & whole grain, adequate hydration, and possibly fiber supplements