Clinical Nutrition 1

1. Clinical Nutrition 1  Basics of nutrition

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3. Significance of Nutrition energy well-being body mass health

4. Energy Transfer nutrients O2 NH3 CO2 H2O ATP chemical energy transfer • mechanical energy muscles • osmotic energy transport of substances • chemical energy biosynthesis, reactions

5. Energy Units 1 kJoule: quantity of energy needed to move 1 kg 1 m forward by the power of 1 Newton (1 kJ = 0,24 kcal) 1 kcal: quantity of energy needed to warm 1 kg water from 14,5 up to 15,5 °C (1 kcal = 4,186 kJ) Energy density of nutrients kcal/g kJ/g carbohydrates 4 17 fat 9 38 protein 4 17 alcohol 7 29

6. Energy Requirement total metabolism= basal metabolism+ activity metabolism basal metabolism = energy required in the state of complete resting (fasting  12 h) to maintain body functions activity metabolism = energy required in addition to basal metabolic rate obligat for • musculation • digestion and metabolism • cellular reactions

7. Determination of Energy Requirement basal metabolic rate (BMR) in kcal according to Harris-Benedict (1919)f = 655,1 + 9,56 x body weight (kg) + 1,85 x height (cm) - 4,7 x age (years)m = 66,5 + 13,75 x body weight (kg) + 5 x height (cm) - 6,8 x age (years)p general estimation: 25 - 35 kcal/kg body weight female (f), male (m)

8. Total Energy Metabolism (in kcal) according to Long et al. 1979 bed rest x 1,1little activity x 1,3 total metabolism = basal metabolism x activity factor x illness factor activity factor illness factor serious operation x 1,2 cancer x 1,2 - 1,5 fever infections - little x 1,3- serious (sepsis) x 1,6 - burn x 1,5 - 2,0 for each increased °C + 13 %example: 38 °C x 1,13 39 °C x 1,26  not in addition to illness factor

9. Increased Requirement of Energy growth diseases stress metabolism convalescence loss of energy-rich substances hormone disorders pregnancy (+ 300 kcal/d) lactation period (+ 700 kcal/d)

10. Digestion mouth stomach • food intake • chewing and insalivation • registration of taste • initiation of digestion of starch • transportation • desinfection of chyme • initiation of digestion of fat and protein • dilution of chyme to decrease osmolarity • deposition in portions into small intestine (functioning as a reservoir) esophagus • transportation • esophageal sphincter prevents reflux

11. Digestion pancreas gall bladder • excretion of enzymes into small intestine - -amylase ( digestion of carbohydrates) - pancreas-lipase ( digestion of fat) - peptidase ( digestion of protein) • excretion of hormones into blood - insulin - glucagon • storage of bile acids • of bile acids into duodenum (emulsification of fats)

12. Digestion small intestine large intestine • reabsorption of water • resorption of electrolytes • bacterial fermentation of - not digested carbohydrates and proteins - dietary fibers ( short-chain fatty acids and gases) - duodenum (0,3 m) - jejunum (1,3 m) - ileum (1,6 m) - ileocecal valve • enzymatic decomposition of nutrients • resorption of nutrients and water • reabsorption of bile acids

13. Location of Resorption for Different Nutrients pancreatic enzymes bile electrolytes, short-chain fatty acids peptides, amino acids fat water water magnesium bile salts colon stomach mono- saccharides vitamines calcium ferrum vitamin B12

14. Areas of Resorption of Fats, Proteins and Carbohydrates ileum stomach duodenum jejunum fat protein carbohydrates resorption in reserve

15. Metabolism Liver • synthesis of fatty acids, ketone bodies, some proteins (for instance albumin, transferrin, acute-phase proteins) • regulation of amino acid pool in the blood • production of bile acids • storage organ for glycogen, vitamines • detoxification of alcohol, drugs, ammonia Blood • transport of nutrients, oxygen and decomposition products • transport of nutrients to organs

16. Body Composition 1 kg ~ 1,5 % carbohydrates ~ 13,8 % fat 9 kg ~ 17,0 % protein 11kg water ~ 61,6 % 40 kg 4 kg ~ 6,1 % minerals = 65 kg

17. Nutrients carbohydrates Macronutrients Micronutrients water vitamines protein minerals trace elements phytochemicals fat dietary fibers

18. Carbohydrates Polysaccharides Monosaccharides = simple sugars • glucose (grape sugar; glc) • fructose (fruit sugar; fru) • galactose (gal) • xylose starch (glc-reserve in plants) dextrins (fragments of starch) glycogen (glc-reserve in animals) dietary fibers Disaccharides = dual sugars Glucose-substitutes • saccharose (glc-fru) = unrefined sugar • maltose (glc-glc) = starch hydrolysate • lactose (glc-gal) = milk sugar • sorbitol (alcohol of glucose) • xylitol (alcohol of xylose)

19. Digestion of Carbohydrates organ enzyme reaction mouth-amylase starch  dextrin maltose stomach --- --- --- pancreas-amylase starch  dextrin maltose small intestine saccharase saccharose  glc + fru maltase maltose  glc + glc lactase lactose  glc + gal large intestinebacterial degradation of indigestible carbohydrates

20. Function of Carbohydrates energy substrate 1 g glucose = 4 kcal energy storage in form of glycogen in liver and muscels component of membranes and intercellular substance

21. Significance of Glucose • the only energy source utilized by all body cells • obligatory fuel for: 1. central nervous system (supply with energy after long periods of fasting also by ketone bodies) 2. erythrocytes 3. renal medulla 4. bone marrow 5. granulation tissue • daily minimum requirements: ca. 150 g

22. Glycemic Index example: glycemic index of oranges (53 %) 25 g glucose = 25 g carbohydrate 280 g oranges = 25 g carbohydrate time (minutes) time (minutes) glycemic index = comparison of blood glucose above the fasting value after administrating glucose and after test meal.

23. Glycemic Index Substrate specific: • quantity and quality of dietary fibers • amount of indigestible starch • processing of foods • composition of meal Subject specific: • individual metabolism • individual digestion • medication (e. g. insulin)

24. Digestion of Long-Chain Triglycerides (LCT) organ release of reaction/function stomach acidic lipase TG  1 FFA (free fatty acid) + diacylglycerol cholecystis bile acid emulsification of fats pancreas pancreas-lipases TG  2 FFA + monoacylglycerol monoacylglycerol  1 FFA + glycerol small intestine- intestinal lumen --- resorption of FFA, mono- and diacylglycerol, glycerol - intestinal cell --- resynthesis to TG in chylomicrons, release into lymphatic system

25. Cellular Metabolism ofTriglycerides LCT MCT transport hydrolysis in blood and in liver transport liver transport into mitochondrions lipoprotein-bound as free triglycerides fast as triglycerides slowly as remnants of chylomicrons and VLDL activation by coenzyme A carnitine-dependent transport

26. Cellular Metabolism ofTriglycerides LCT MCT rate of oxidation hepatic stress stress of RES* tissue-pexis protein-saving effect immune system * reticuloendothelial system low high high high low high low low low high immuno-modulation immunological neutral

27. Advantages of MCT-Fats compared to LCT-Fats fast resorption direct transport via portal vein into liver more efficient oxidation immunological neutral  low liver burden protein-saving effect maintenance of immune-functions

28. Functions of Fats energy substrate (triglycerides) 1 g fat = 9 kcal energy storage (triglycerides) cell structure component of membrane (phospholipids) bioactive substances (for instance for prostaglandins)

29. Recommendations for Fat Uptake relation of fatty acids saturated/monounsaturated/ polyunsaturated fatty acids w-3 fatty acids: maximum of 3 % kcal relation of w-6 to w-3 fatty acids: 3 - 5 : 1 polyunsaturated fatty acids: maximum of 10 % kcal

30. Recommendations for Linoleic Acid Uptake • requirement of linoleic acid (w-6FA) :7 - 10 g/day (healthy subjects) • in case of serious stress-metabolism requirement may double • excessive supply of linoleic acidimbalances of the pattern of fatty acids • disorders of immune system • deficiency of linoleic acid (essential fatty acid deficiency/EFAD)disorders in wound healingskinalterations: xerosis, redness, incrustationthrombocytopenia

31. Classes of Fatty Acids example oleic acid w-9 = COOH C 18:1 = = linoleic acid example w-6 COOH C 18:2 w-3 -linolenic acid example = = = COOH C 18:3

32. Protein Structure • smallest unit: amino acid (AA) • 20 proteinogenous amino acids • peptide bond between acid- and aminogroup • peptides: chain of amino acids - dipeptide: 2 AA - oligopeptide: 3 - 10 AA - polypeptide: > 10 AA • globoid structure of amino acid chain by folding

33. Proteinogenous Amino Acids phenylalanine threonine essential valine leucine tryptophan lysin isoleucine methionine non essential glycine cysteine aspartic acid glutamic acid arginine histidine tyrosine alanine asparagine proline serine glutamine

34. Digestion of Proteins organ enzyme reaction stomach denaturation of proteins by acidic milieu pepsin protein  polypeptides oligopeptides pancreas trypsin polypeptides  peptides chymotrypsin polypeptides  peptides small intestine peptidases peptides  amino acids large intestine bacterial decomposition of not resorbed protein

35. Functions of Amino Acids and Proteins energysubstrate in case of malnutrition 1 g protein = 4 kcal component for synthesis (amino acids)  muscels  transport protein  structure proteins (organs, connective tissue)  immunoglobulins (antibodies)  enzymes  hormones  membrane proteins

36. Nitrogen Balance NBal = Nin - Nout Nin = N-intake (proteins or amino acids) Nout = N-excretion through urine + correction for feces + skin anabolism positive N-balance = Nin > Nout negative N-balance = Nin < Nout catabolism (N= chemical symbol for nitrogen)

37. Metabolic Pathways in Anabolism and Catabolism anabolism catabolism glucose glycogenesis glycolysis liponeogenesis glycogenolysis fat lipogenesis lipolysis protein protein synthesis proteolysis gluconeogenesis

38. Physiological Significance of Glutamine • most frequent free intra- and extracellular amino acid • non essential proteinogenous amino acid • nitrogen- and carbon-transport molecule • substrate for gluconeogenesis • energy substrate of enteroytes, fibroblasts, lymphocytes • substrate for synthesis of RNA- and DNA-precursors • antioxidative effect (glutathione peroxidase)

39. Glutamine in Critical Illness • release of glutamine from muscels (and lungs), partly from liver and intestinum. • energy substrate for cells of immune system and fibroblasts around wound area. Trauma Sepsis • release of glutamine from muscels (and lungs), partly from intestinum and kidney. • energy substrate forimmune system, liver and intestinum.

40. Water Balance out in food 1 L beverages 1,2 L respiratory air perspiration 950 mL oxidationwater 300 mL urine 1,4 L feces 150 mL

41. Function of Water survival without fluid intake: maximum of 3-4days solvent (dilution) transport medium temperature regulation (perspiration)

42. Dietary Fibre Carbohydrates, which cannot be broken down bythe enzymes in the human intestinal tract(indigestible) as well as lignin

43. Classification of Dietary fibre Indigestible polysaccharidesdepending on the analyses methods used classified as - NSP = non-starch polysaccharides - TDF = total dietary fibre This definition does not include other indigestible constituents of food, which act similar to dietary fibre in the intestine, e.g.: - Polyalcohols - indigestible proteins - Polydextroses - indigestible lipids, waxes and fat replacement substances - Fructo-oligo-saccharides - Maillard products

44. Indigestible Constituents of Food are only indigestible for human digestive enzymes reach the colon virtually unchanged can be fermented by bacterial enzymes

45. Dietary Fibre Insoluble Soluble Gums (gummi arabicum, guar) ß-Glucanes (oats, barley) Pectin Mucous substances Inulin Fructo-oligo-saccharides (FOS) Lignin Cellulose Hemi-cellulose Resistant starches

46. Dietary Fibre

47. Fermentation of Dietary Fibres by Bacteria in the Colon Short-chain fatty acids - Butyric acid (butyrate) - Propionic acid (propionate)- Acetic acid (acetate) Dietary Fibre  Decomposition Products Lignin Cellulose Hemi-cellulose Pectin Gums Mucous substances Inulin Oligo-fructose Resistant starches • Gases - Carbon dioxide (CO2) - Hydrogen (H2) - Methane (CH4)

48. Effects of Dietary Fibres •  Fermentation products: short-chain fatty acids •  Faecal volume - - Water binding- Biomass/bacteria  Reduction of diarrheas and obstipation •  Gastro-intestinal transit time •  Carcinogenesis by diluting carcinogens and toxins in the faeces • Blood sugar levels • Cholesterol

49. Long-Term Effects of Dietary Fibres  Gall stones  Inflammatory intestinal illnesses  Ulcus duodeni  Haemorrhoids  Irritable intestine  Colon carcinomas

50. Prebiotics Indigestible constituents of food, which have an effect on the organism (man), which • selectively and specifically promote the growth and/or the activity of one or a limited number of bacteria in the intestine • have the potential to improve health (Gibson & Roberfroid, 1995)