Hlt 138 unit 7

669 views

Published on

Published in: Health & Medicine
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
669
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
11
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Hlt 138 unit 7

  1. 1. Unit 7 – Digestion and Absorption 1
  2. 2. Key Terms 2  Digestion:  Processes that convert ingested food into substances that can be absorbed by the intestinal tract & used by the body  Absorption:  Processes that transfer nutrients from the digestive system into body fluids
  3. 3. Upper Digestive Tract 3  Mouth - chewing and saliva - amylase/lipase  Esophagus - propels food downward to stomach  Stomach - churns and mixes - Pepsin/intrinsic factor/lipase
  4. 4. Lower Digestive Tract 4  Small Intestine  Large Intestine  Rectum  Accessory Organs - Liver - Gallbladder - Pancreas
  5. 5. Digestion – Begins in the Mouth 5  Chewing breaks down food into smaller particles  Mixing with saliva  Adding digestive enzymes
  6. 6. Digestion – Mouth – Carbohydrates 6  Salivary Amylase: Starch  glucose molecules  Teeth and saliva soften fiber for swallowing
  7. 7. Digestion – Mouth – Protein 7  Teeth soften fibers to swallow  NO CHEMICAL DIGESTION OF PROTEIN OCCURS IN THE MOUTH!
  8. 8. Digestion – Mouth – Fat 8  Lingual Lipase: Triglyceride  Monoglyceride + fatty acids  VERY MINIMAL
  9. 9. Digestion - Stomach 9  Churns and mixes contents  Hydrochloric acid secreted  Digestive enzymes secreted
  10. 10. Digestion – Stomach – CHO & Fat 10 Carbohydrates Fat  Hydrochloric acid stops amylase  Very small amount of lipase is secreted  Mixing and churning aids in digestion  Fat tends to separate from the mixture  No digestion of fiber  Last to leave the stomach  delays gastric emptying
  11. 11. Digestion – Stomach - Protein 11  Hydrochloric acid exposes bonds for enzymes  Denaturization: irreversibly disrupt the structure of a protein, ending the function of that protein  Pepsin Protein Smaller Polypeptides AAs
  12. 12. Digestion – Small Intestine 12  MOST DIGESTION & ABSORPTION OCCURS IN THE SMALL INTESTINE  Pancreas secreted digestive enzymes  Liver secretes bile
  13. 13. CHO Digestion – Small Intestine 13 Produced in Small Intestine  Amylase - Starch → Glucose  Produced in Pancreas Maltase - Maltose → Glucose + Glucose  Sucrase - Sucrose → Glucose + Fructose  Lactase - Lactose → Glucose + Galactose
  14. 14. Protein Digestion – Small Intestine 14  Proteases secreted from the pancreas  Break down proteins and peptides into AAs
  15. 15. Fat Digestion – Small Intestine 15  Need BILE made by liver  Gallbladder stores Bile and releases into small intestine  Bile emulsifies fat in the watery intestinal fluid  Makes more surface area for pancreatic lipase to work
  16. 16. Carbohydrate Absorption 16  ONLY Monosaccharides - glucose, fructose, galactose  Absorbed in small intestine and travel to liver for processing  All monosaccharides are converted into glucose in the liver
  17. 17. Carbohydrate Absorption 17  Body is not 100% efficient (≈ 99% efficient)  Small amounts of CHO do not get fully digested and absorbed by small intestine  Indigestible CHO (Fiber) does not get broken down and absorbed  Undigested CHO travels to large intestine
  18. 18. Protein Absorption 18  AAs and small amounts of peptide chains absorbed in small intestine  Need Vitamin B6  AAs Travel to the liver after absorption
  19. 19. Protein Digestion 19 Protein Digestibility  90-99% animal protein  90% soy and legumes  70-90% plant protein
  20. 20. Fat Absorption 20  Micelles – fat particles encircled by bile salts to facilitate absorption  ≈ 95% ingested fat is absorbed  Short and medium-chain fatty acids and glycerol transported to the liver  Monoglycerides and long-chain fatty acids are insoluble in the bloodstream
  21. 21. Fat Absorption 21  Inside intestinal wall – combine to reform triglycerides  Reformed triglycerides and cholesterol are encased with proteins – chylomicron  Chylomicrons travel through lymphatic system before entering bloodstream  Chylomicrons – distribute dietary lipids throughout body
  22. 22. Excretion 22  Undigested CHO provide small amount of energy for microbes in the colon (large intestine)  All undigested food travels through large intestine  Then excreted in stool through the rectum
  23. 23. Disorders of the Digestive Tract 23        Nausea and Vomiting Heartburn (Gastric Reflux) Ulcers Constipation Diarrhea Irritable Bowel Syndrome Lactose Intolerance
  24. 24. Nausea and Vomiting 24  May be related to: -  in HCl secretion -  digestive enzyme activity - gastric irritation - bacterial/viral infection -  intracranial pressure - equilibrium imbalance - liver, pancreatic, and gallbladder disorders - obstruction - drugs and certain medical treatments
  25. 25. Nausea and Vomiting 25  Short-term concerns - fluid and electrolyte balance  Intractable vomiting: vomiting that is difficult to manage or cure  Long-term concerns - dehydration - weight loss
  26. 26. Nutrition Therapy for N/V 26          Food is withheld until nausea subsides Progress from clear liquids to regular DAT Small, frequent meals of low fat, readily digested CHO Slow eating Promote good oral hygiene Limit liquids with meals – may cause fullness/bloating Liberal fluids in between meals Serve foods at room temp Avoid foods that contribute i.e. high-fat and spicy
  27. 27. Gastroesophageal Reflux Disease (GERD) 27     Backflow of gastric acid into the esophagus Abnormal relaxation of lower esophageal sphincter Symptoms: - lump in throat - heartburn - regurgitation GERD when symptoms occur ≥2 times/week
  28. 28. Nutrition Therapy for GERD 28 Diet modifications      avoid large and/or fatty meals eat slowly avoid alcohol, caffeinated bevs, coffee, soft drinks avoid spicy foods, chocolate, citrus foods, PEPPERMENT Often called “BLAND DIET” Lifestyle modifications     exercise weight loss if BMI >25 avoid lying down for 3 hours after meal elevate head of bed during sleep
  29. 29. Peptic Ulcer Disease 29     Erosion of the mucosal layer of the stomach (gastric ulcer) or duodenum (duodenal ulcer) Excessive secretion of, or decreased mucosal resistance to, HCl 15% - stomach 85% - duodenum
  30. 30. Peptic Ulcer Disease – H. Pylori 30  H. pylori infection – 70-92% of ulcers  secretes enzyme that depletes gastric mucus  Antibiotics generally cure  Not everyone infected develops ulcer
  31. 31. Nutrition Therapy for Peptic Ulcers 31     Avoid foods that stimulate HCl secretion/irritate - coffee, alcohol, chocolate, pepper, garlic Avoid eating 2 hours before bed Avoid individual intolerances High-fiber diet may reduce risk of duodenal ulcers
  32. 32. Constipation 32  Difficult/infrequent passage of stools that are hard & dry  Usually less than 3 bowel movements per week  Secondary to irregular bowel habits, psychogenic factors, lack of activity, chronic laxative use, inadequate of fiber, metabolic/endocrine disorders, bowel abnormalities (tumors, hernias, strictures)  Medications such as codeine, aluminum hydroxide, iron supplements, morphine
  33. 33. Nutrition Therapy for Constipation 33  TREAT THE UNDERLYING CAUSE  Fiber and water usually works  Insoluble fiber – wheat bran, fruit/veggie skins - increases stool bulk and stimulates peristalsis  Soluble fiber – oats, barley, nuts, seeds - absorbs water to produce softer, bulkier stools
  34. 34. Diarrhea 34     More than 3 bowel movements per day of large amounts of liquid of semiliquid stool Shortened transit time → ↓ time for water, Na, and K absorption → dehydration, hyponatremia, hypokalemia, acidbase imbalance, metabolic acidosis Chronic → malnutrition - impaired digestion, absorption, and intake
  35. 35. Nutrition Therapy for Diarrhea 35    TREAT THE UNDERLYING CAUSE Symptoms may be treated with meds that ↓ motility or thicken consistency of stools Primary Goal: restore fluid and electrolyte balance
  36. 36. Nutrition Therapy for Diarrhea 36  Avoid stimulation of GI motility - alcohol, caffeine, clear liquids, milk (lactose), highfiber and gas-producing foods, sugar alcohols  Mild diarrhea (24-48 hours) requires no intervention other than hydration  Diet ↓ in fat, fiber, lactose diet may ↓GI stimulation  Intractable diarrhea may require complete bowel rest
  37. 37. Nutrition Therapy for Diarrhea 37  Lactose-free diet often ordered  BRAT diet - Banana - Rice - Applesauce - Toast  Both short-term until diarrhea resides
  38. 38. Lactose Intolerance 38   Lactase is absent or deficient Particles of undigested lactose ↑ osmolality of intestinal contents  osmotic diarrhea  Lactose fermented in colon  bloating, cramping, flatulence  Symptoms occur within 15 min – 2 hours after ingestion
  39. 39. Primary Lactose Intolerance 39  Occurs in “well” people who do not secrete adequate lactase  Asians, Native Americans, and Africans  Tolerations vary between individuals  Treatment: avoid lactose-containing foods (permanent)  Lactase enzymes
  40. 40. Irritable Bowel Syndrome (IBS) 40  Most frequently diagnosed digestive disorder in the US  Affections as many as 20% of American Adults  Symptoms: lower abdominal pain, constipation, diarrhea, alternating periods of constipation and diarrhea, bloating, mucus in stool  Can significantly impair quality of life
  41. 41. Nutrition Therapy for IBS 41  No conclusive causes/cures/relief of symptoms  Associated with anxiety and depression  Elimination diet: systematically eliminate foods to identify potential food intolerances or allergies  No single therapy is entirely effective  Treatments address symptoms of abdominal pain, bloating, diarrhea, and constipation  Add soluble fiber, probiotics  Controlled with diet, stress management, and medications

×