Nutrition

1. Nutrition Basic Science Lecture Series Umut Sarpel 8/11/05

2. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

3. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

4. Calorie requirements Resting 70 kg male: 1450 kcal/day Post-operative: 1700 kcal/day Sepsis, head trauma, pancreatitis: 2400 kcal/day Burns (depends on size): 3000 kcal/day

5. Protein requirements In healthy adults: 0.8 gm / kg (56 gm / day for 70 kg patient) In stressed patients: 1.2-1.5 gm / kg

6. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

7. Respiratory Quotient RQ = O2 consumption / CO2 production Carbohydrates ~ 1.0 Protein ~ 0.81 Lipids ~ 0.7 Alcohol ~0.66 Normal “American” diet RQ = 0.87 Excess glucose leads to a RQ > 1.0

8. A patient s/p Whipple complicated by a leak with prolonged sepsis is now stable. She has failed 2 extubation attempts. Her RQ is likely 0.66 0.7 0.8 0.9 1.1

9. A patient s/p Whipple complicated by a leak with prolonged sepsis is now stable. She has failed 2 extubation attempts. Her RQ is likely 0.66 0.7 0.8 0.9 1.1

10. Respiratory Quotient An RQ > 1 indicates net lipogenesis Overfeeding syndrome is a common reason for failed extubation The excess glucose, converted to CO2, increases minute ventilation in order to prevent respiratory acidosis Re-evaluate caloric needs

11. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

12. Starvation Glycogen from liver depleted in ~48 hrs The body first catabolizes skeletal muscle amino acids into glucose Certain tissues are highly dependent on glucose for energy, thus some glucose production is always required In prolonged starvation, the body will adjust to using fat stores, and proteolysis decreases

13. Starvation “The metabolic tragedy of sepsis” The normal suppression of proteolysis seen w/ prolonged fasting does not occur in sepsis Breakdown of protein continues Also, high cortisol levels lead to persistent hyperglycemia which inhibits lipolysis Thus septic pts can have enormous untapped fat stores and still catabolize muscle

14. The primary source for glucose in early starvation (1week) comes from Proteins in skeletal muscle Ketone bodies Free fatty acids Glycogenolysis Lipolysis / Acetyl CoA

15. The primary source for glucose in early starvation (1week) comes from Proteins in skeletal muscle Ketone bodies Free fatty acids Glycogenolysis Lipolysis / Acetyl CoA

16. Glucose is the primary fuel source for all the following tissues except Renal medulla Brain tissue WBCs RBCs Peripheral nerves Heart

17. Glucose is the primary fuel source for all the following tissues except Renal medulla Brain tissue WBCs RBCs Peripheral nerves Heart

18. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

19. TPN Pre-operative albumin is a predictor of morbidity and mortality In mildly malnourished patients, pre-op TPN increased infectious complications In severely malnourished patients, TPN decreased non-infectious complications

20. TPN Refeeding syndrome (aka Phosphate steal): new glucose administration leads to rapid intracellular shifts of K, Phos, Mg, because they are used in glucose metabolism. Sudden drop in plasma levels seen. Especially, phosphate depletion leads to muscle weakness, respiratory distress

21. What is the maximum rate of glucose administration in TPN? 1 gm/kg/hr 5 gm/kg/hr 10 gm/kg/hr 15 gm/kg/hr

22. What is the maximum rate of glucose administration in TPN? 1 gm/kg/hr 5 gm/kg/hr 10 gm/kg/hr 15 gm/kg/hr Besides hyperglycemia, higher rates of glucose infusion can also cause vessel thrombosis

23. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

24. Enteral feeding Nutrients are absorbed into portal system and pass through the liver (vs TPN) This allows for hepatic and intestinal production of products that have a role in anabolic signaling, leading to more efficient use of nutrients Full strength tube feeds may cause an osmotic diarrhea Always check residuals (<150cc)

25. Enteral feeding Immunonutrition: enteral diets enhanced with omega-3-fatty acids, RNA, vitamins, arginine, have been shown to reduce infectious complications in patients undergoing surgery for malignancy

26. Enteral feeding: Prevents atrophy of intestinal villi Prevents translocation of intestinal bacteria Prevents immunoglobulin A deficiency Usually causes diarrhea

27. Enteral feeding: Prevents atrophy of intestinal villi Prevents translocation of intestinal bacteria Prevents immunoglobulin A deficiency Usually causes diarrhea

28. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

29. Vitamin deficiencies Vit A - poor healing, skin keratosis, night blindness Vit D - osteomalacia Vit E - dystrophic changes of retina Vit K – coagulopathy Thiamine – (beri beri) lactic acidosis, altered mental status, DI, hyperbilirubinemia, thrombocytopenia Zinc - poor wound healing, impaired immunity Biotin - alopecia, neuritis, dermatitis Selenium - cardiomyopathy, hair loss, weakness Essential fatty acids - scaly dermatitis

30. Causes of macrocytic anemia Dietary deficiency of B12 Pernicious anemia (autoimmune destruction of gastric mucosa leading to a deficiency of intrinsic factor, which binds B12) Resection / bypass of stomach Resection / bypass of ileum Blind loop syndrome (bacterial overgrowth leads top competition for B12)

31. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

32. Crohn’s disease Diseased terminal ileum Poor uptake of vitamins A, D, E, K Vit D deficiency, when combined with frequent steroid use may lead to osteoporosis Important to avoid multiple SB resections to prevent short gut. Strictuoplasty when possible.

33. What is the etiology of nephrolithiasis in patients with Crohn’s disease? Hypercalcemia Hyperuricosuria Hyperoxaluria Vitamin D deficiency Dehydration

34. What is the etiology of nephrolithiasis in patients with Crohn’s disease? Hypercalcemia Hyperuricosuria Hyperoxaluria Vitamin D deficiency Dehydration

35. Oxalate stones Oxalate is normally bound by calcium However, due to a diseased TI, bile salts and thus lipids are not well absorbed. The intralumenal calcium binds with fat (saponification) instead of oxalate. Oxalate is then absorbed in the colon, leading to hyperoxaluria and stone formation when excreted from kidney

36. What is the minimal length of SB needed to avoid short-gut syndrome? ~40 cm of any portion of small bowel ~60cm with ileo-cecal valve ~120cm with ileo-cecal valve ~120cm without ileo-cecal valve

37. What is the minimal length of SB needed to avoid short-gut syndrome? ~40 cm of any portion of small bowel ~60cm with ileo-cecal valve ~120cm with ileo-cecal valve ~120cm without ileo-cecal valve

38. Overview Calorie / protein requirements Respiratory Quotient Effects of starvation Benefits / risks TPN Enteral feeding Vitamin deficiencies Crohn’s disease Issues in bariatric surgery

39. Bariatric surgery: deficiencies Iron and calcium deficiency (both absorbed in duodenum) B12 deficiency (lack of IF from bypassed stomach) A, D, E, K deficiencies Thiamine deficiency (likely from prolonged emesis) - can cause Wernicke’s

40. EXTRA-CREDIT Some ABSITE favorites…

41. The principle fuel for colonocytes is Butyrate Acetoacetate D-Glucose Glutamine Propionate

42. The principle fuel for colonocytes is Butyrate Acetoacetate D-Glucose Glutamine Propionate

43. Principle fuel for colonocytes Butyrate is the major short-chain fatty acid The colon relies on bacterial fermentation for production of SCFA’s Colonic inflammation is seen in diversion colitis secondary to SCFA deficiency UC patients may have a relative SCFA deficiency, can treat w/ SCFA enemas

44. Branched-chain amino acids are Useful in ESRD Useful in ESLD Useful in pts with COPD

45. Branched-chain amino acids are Useful in ESRD Useful in ESLD Useful in pts with COPD

46. Branched-chain amino acids Leucine, isoleucine, valine Only amino acids that do not require metabolization by liver They can also be oxidized by muscle May be used for patients with liver failure

47. Glutamine is Primary fuel for small bowel Primary fuel for malignant cells Most abundant free amino acid in the body Synthesized by skeletal muscle A conditionally essential amino acid

48. Glutamine is Primary fuel for small bowel Primary fuel for malignant cells Most abundant free amino acid in the body Synthesized by skeletal muscle A conditionally essential amino acid