2. PROTEINS

3. Organic compounds Acid and amino group * nitrogen**** * side group

4. AMINO ACID STRUCTURE

5. AMINO ACID EXAMPLES

6. AMINO ACIDS Basic building blocks of protein 20 amino acids 9 essential or indispensable-2 totally essential deprived of essential AA body breaks down own proteins 11 non-essential or dispensable body can make if proper amount of C, H, O, N Conditionally essential Linked by peptide bonds Dipeptide, tripeptide, polypeptide

7. CONDENSATION

8. AMINO ACIDS Squencing: > specific order-exquisite and precise order > genetically determined > error  sickle cell disease > 6 th amino acid valine is substituted for glutamine > RBC collapses, cannot carry oxygen  illness  even death

9. AMINO ACIDS Denaturation Change may be irreversible Heat, alcohol, acids, salts of heavy metals disrupt normal chain Excess acidity or alkalinity damages body’s proteins

10. DENATURATION

11. DIGESTION/ABSORPTION Mouth  breaks up food Stomach  HCl  activates pepsinogen to pepsin Pepsin  breaks down large polypeptides Beginning of protein digestion

12. DIGESTION – SMALL INTESTINE Intestinal proteases and pancreatic proteases break down polypeptides  oligopeptides, tripeptides, dipeptides Intestinal peptidases convert peptides to amino acids Intestinal villi  amino acids  portal vein to liver Liver – monitors protein synthesis and frees amino acids to circulation CATABOLISM – no storage Bloodstream

13. TRANSPORT OF AMINO ACIDS Transport by diffusion Villi  portal vein  liver Liver monitors: 1. Protein synthesis 2. Free amino acids to circulation 3. Catabolism Proteins are NOT stored- constant synthesis and catabolism Represents ~ 15-20% of REE

14. FUNCTIONS OF PROTEIN Growth, maintenance Enzymes Hormones Antibodies Fluid and electrolyte balance Acid-base balance Transportation Blood clotting Visual pigments Energy

15. GROWTH, MAINTENANCE Growth – manufacture cells Repair – collagen Replacement Protein turnover – synthesis and degradation

16. ENZYMES - CATALYSTS

17. ANTIBODIES Antigens are invaders (bacterium, toxins, virus, allergens) Body detects antigens  works to make antibodies Antibody made with amino acids – pattern stored in DNA memory Adequate protein aids immune system in making antibodies

18. FLUID BALANCE Proteins  amino acids Amino acids  transported to cell –crosses cell wall Inside cell build proteins Large proteins do not cross over cell wall Proteins made inside cell hold water inside Proteins in bloodstream will draw fluid back into blood

19. FLUID BALANCE Blood pressure from pumping action of heart forces fluid into tissue spaces Proteins in bloodstream draw water back into bloodstream as pressure declines Without sufficient protein fluid remains in tissue spaces  EDEMA

20. EDEMA

21. ACID-BASE BALANCE Normal blood pH = 7.35-7.45 Protein act as BUFFERS Acidosis - acid (Low pH) = H+ ions Proteins accept H+ ions Alkalosis - base ( pH) = H+ ions Proteins release H+ ions Proteins can (+) or (-) H+ ions to maintain balance If proteins not available or full  coma or death

22. TRANSPORT PROTEINS Specific for compound or group of related compounds Cell membranes-maintain equilibrium * in and out of cells * move into membrane but shuttle side to side Carrier 1. Vitamins and minerals Fe – captured by protein (ferritin) in intestinal wall ferritin holds in bone marrow or other tissue until body needs Fe Protein (transferrin) carries Fe through bloodstream 2. Oxygen transport and use protein (hemoglobin) combines with Fe to carry O2 in fluids or myoglobin (protein) in muscle cells 3. Lipids- lipoproteins

23. BLOOD CLOTTING Tissue injured  Fibrin made Stringy protein fibers to plug leak Also need Vit K and Calcium

24. BLOOD CLOTTING - FIBRIN

25. PROTEIN FOR ENERGY Low priority use of protein Energy needs must be meet Increased need for water

26. ENERGY Deamination Nitrogen stripped off ammonia  liver carbon skeleton + CO2  urea gluconeogenesis excreted by kidneys energy OR stored as fat

27. PROTEIN EXCESS NO storage – store as fat May overload kidneys May contribute to excess calorie intake May contribute to calcium excretion Use of animal proteins increase fat and cholesterol intake Fat and CHO are protein sparing

28. PROTEIN RECOMMENDATIONS As % of total energy needs = 10-15% of calories Grams/kilogram of body weight/day = 0.8-1.0 grams of protein/kilogram RDA = 0.8 grams/kg of body weight Protein needs affected by: illness, stress, age Low protein diet  fatty liver, low skeletal mass

29. DO ATHLETES NEED MORE PROTEIN???? Casual aerobics 3 times/week 1 gram/kg more than enough Strength building: to make new muscle Depends on LBM 1 gram/kg of body weight Endurance (marathon, triathlon)-Muscle repair – muscle supplies 10-15% of energy during 1 hour run 2 grams/kg body weight Begin training = 1-1.2 gms/kg INGESTING LARGE QUANTITIES OF PROTEIN DOES NOT CAUSE MUSCLE TO INCREASE IN SIZE

30. HEALTH EFFECTS OF PROTEIN PEM – Protein-energy malnutrition PCM – Protein-calorie malnutrition Most widespread form of malnutrition today Affects adults, but especially children Acute – thin for height Chronic – short for age KWASHIORKOR MARASMUS

31. KWASHIORKOR AND MARASMUS

32. KWASHIORKOR

33. Adequate calories with low protein intake Adipose tissue preserved Skeletal muscle preserved or decreased Relatively normal weight Serum proteins decreased Edema Growth failure Fatty liver Apathy Misery Hair changes – pluckability, color strength, texture

34. MARASMUS

35. Low Kcals and low protein intake Low adipose tissue Low skeletal mass Significant weight loss Serum proteins relatively normal No edema Ketosis Immune system compromised Decreased metabolism Decreased body heat Slows brain development-retardation Growth retardation Looks old and sick

36. NUTRITION THERAPY Fluid balance- electrolytes Low fat milk – protein carriers Add fat Protein repletion

37. MALNUTRITION IN HOSPITALIZED PATIENTS KwashiorkorLow Protein diet Normal Protein but high needs, high losses IV, Clear Liquid, Stress, Trauma, Burns MarasmusLow Kcal Low Protein Starved with chronic disease (Cancer, Malabsorption) CombinedInadequate diet with high protein losses and stress Starved with stress

38. EVALUATE FOR PCM Skeletal muscle Mid-arm muscle circumference Creatinine–height index: 24 hour urine collection – compare to standards Serum proteins Albumin – WNL 3.5-5.0 gm/dl Prealbumin – WNL 20-50 mg/dl Total protein – WNL 6.0-8.4 gm/dl Adipose tissue Circumferences Skin-fold measurements

39. NITROGEN BALANCE POSITIVE BALANCE More of the nutrient is absorbed than lost Growing children Pregnant women Adults recovering from disease EQUILIBRIUMIntake equals losses Healthy adults NEGATIVE BALANCE Losses from body exceed intake Adult with disease (cancer) Fasting/starvation

40. NITROGEN BALANCE

41. CALCULATIONS N balance = protein intake/6.25 – [output (UUN) + 3] Normal UUN = 6-17 gm/day Protein intake = 60 gm/day UUN = 13 gm/day then: 60/6.25 = 9.6 9.6 – [13 + 3] 9.6 - 16 -6.4 gm N/day (catabolism)

42. ANABOLISM Protein intake = 75 gms/day UUN = 6 gm/day then: 75/6.25 = 12 12 – [6 + 3] 12 – 9 +3

43. HIGHEST QUALITY PROTEIN?

44. PROTEIN QUALITY Chemical scoring Biological value (BV) Net protein utilization (NPU) Protein efficiency ratio Reference protein = egg = 100 (FAO of U.N.)

45. PROTEIN QUALITY PROTEINBVCHEMICALNPU EGGS100 MILK93 75 RICE8667 BEEF75 80 FISH75 83 CORN72 56

46. PROTEIN QUALITY LIMITING AMINO ACID Essential amino acid – not enough for protein synthesis COMPLETE PROTEINS All essential amino acids in amounts required by humans COMPLEMENTARY PROTEINS Combining foods with limiting amino acids to make complete protein DIGESTIBILITY

47. COMPLETE/INCOMPLETE

48. PROTEIN SOURCES

49. COMPLEMENTATION

50. VEGETARIAN DIETS VEGANS – avoids all animal foods SEMI – VEGETARIAN – no red meat Lacto-ovo Vegetarian – Avoids meat but uses eggs and dairy products Lacto-Vegetarian – Avoids meat and eggs but uses dairy products Vegetarians may need more total protein in diet: 45 grams of high quality protein vs 65 grams of lower quality protein

51. BENEFITS TO VEGETARIANISM Lower Calories  IBW, Lower BP Higher fiber diet  decreased risk of Cancer  increased digestive function Lower Blood Cholesterol level  decrease in cardiovascular disease Decreased Bone Loss  less calcium loss

52. VEGETARIAN CONCERNS Biological value Nutrient density Complementary amino acids – Mutual supplementation or Complementation High fiber  poor nutrient absorption Risk of low iron, vit. D intake Risk of inadequate zinc Risk of inadequate amino acids Vit B12 deficiency Lacto-ovo may be high fat diet Children at risk for nutritional deficiencies

53. ALLERGIC REACTIONS