Agenda

1. Agenda • I do not have all of the exams graded • Thursday • ACT Survey • Wrap up Proteins • Begin Lipids

2. ACT Survey • In social security box put student ID • Yellow sheet is for questions P and Q in section I. • The second document is for use with section V. • Must be done with #2 Pencil.

3. Lecture 7: Proteins Will Brown 01/31/2012

4. Objective and Outline • Objective: To better understand the role proteins play in the body • Outline • How the body uses proteins • The bodies protein needs

5. How does the body use proteins?

6. Protein: Vital Structures • Protein make up most of the structure with in the body; ie: muscle, connective tissue, extra-cellular matrix, etc. • If protein is not the main structure than protein does impacts it in some way; ie: proteins and enzymes involved in bone remodeling

7. Protein: Vital Structures • Your body is in a constant state of change • Build up vs. Break down • “Each kind of tissue has its own turnover time, related at least partially to the workload endured by its cells. Epidermic cells, forming the easily damaged skin of the body, are recycled every two weeks or so. Red blood cells, in constant motion on their journey through the circulatory system, last only 4 months. As for the liver, the human body's detoxifier, its cells' lives are quite short - an adult human liver cell has a turnover time of 300 to 500 days. “ - h ttp://dbs.cordis.lu/cgi-bin/srchidadb?C ALLER=NHP_EN_NEWS&ACTION=D&SESSION=&RCN= EN_RCN_ID:24286 Previous Item Back to Titles Print Item

8. Protein: Vital Structures • Proteins breakdown • Enzymes, like amylase, that are secreted into the intestines are digested and the amino acids reused • Certain proteins as part of their function are consumed by what ever process they are involved in – CYP3A4 and drug detoxification • Old proteins suffer environmental damage so are recycled • Proteins can be deliberately targeted for breakdown – ubiquitination • Your body degrades and recycles about 250g of protein a day

9. Take your bones for example. Osteoclast differentiation and activation: William J. Boyle, W. Scott Simonet and David L. Lacey Nature 423, 337-342(15 May 2003) doi:10.1038/nature01658

10. Proteins: Fluid Balance • Blood pressure forces fluid out of the capillaries • Capillaries are semi-permeable membrane • Hydrostatic pressure • Proteins are to large to be forced out of the capillary • As the protein concentration inside ↑, it draws back the water • Osmotic pressure

12. Proteins: Other Key Functions • Act as buffers in the blood or secrete buffers into the blood • Provide immunity – antibodies • Sugar regulation – glycogen breakdown done by enzymes, or protein can be catabolized into glucose • Cause satiety – makes you feel fuller longer

14. Leptin induces Satiety Vossman: 2007

15. Protein Needs: Protein Equilibrium • How much protein is needed? • For most adults, only need to replace what is broken down or used • RDA for protein is 0.8 g/kg of body weight (BMI =19-25) • For a 160 lb man = 58.4 g • Equals ~ 10% of total calories = Some dieticians recommend 15% • Upper limit is 35% of total calorie intake • Average protein intake = 100g for men, 65g for women

16. Protein Needs: Positive Protein Balance • When you need more protein than you metabolize • Pregnant or lactating women: 25 g/day in addition to your normal protein intake • This amounts to 3 extra cups of milk a day • Children and infants • Exercise • Especially when weight or resistance training • Recovering from illness

17. Protein Needs: Negative Protein Balance • When you consume less protein than you burn • Illness causes reduced desire to eat • Fasting • Celiac disease • Kidney disease • Acute injury – Fever, Burns, Infections • Improper calorie intake

18. Problems with High Protein Diets • Are they harmful? • Eating extra protein is not bad in and of itself • Problem is most high protein diets rely on animal protein • What are the problems with high animal protein diets? • Typically, will also increase amount of fat and cholesterol • Reduce intake of beneficial plant substances; vitamins & fiber • What do studies show? • Processed forms of red meat is linked to colon cancer • High protein consumption increases urea output which can overburden kidneys-leads to kidney stone formation

19. So… Are High Protein Diets Harmful? • The jury is still out. • A Swedish study concluded that in elderly the hazard ration is 1.2 for over-all mortality and 1.4 for cardiovascular related mortality • A different study determined that women on a high protein diet had the same or less risk as those on a high-carb/low-fat diet. • Despite rumurs… Dr. Atkins did not die of heart attack, he died of head injury from a fall.

20. Proteins for Plant Based Diets • Concerns for Vegan or Vegetarian diets • Most plants are deficient in at least one essential amino acid • Grains lack Lysine • Lack of key minerals and vitamins • Iron, Vitamin B-12, Zinc, Iodine • How to compensate for these issues • Eat foods that are fortified with the additional nutrients • Vary your food choices

21. How to mix and match your proteins Grains Limited in Lysine Legumes Limited in Methionine Vegetables Limited in Methionine Nuts Limited in Lysine

22. Concerns for Children & Infants • Kids can be picky • Different calorie and nutrient needs • Of chief concern is Vitamin B-12, iron, Vitamin-D, and Calcium • May need to decrease fiber • Fiber can give a feeling of fullness • Small stomach size • Can lead to lower intake of calories • Again, fortified foods can help children meet their needs

23. Lipids FAT!

24. Lipids • They are important in the diet and there are some fat that is necessary in the diet • So, why all the talk/negative press about fat? • Is a high-fat associated with obesity? • High-Fat, Low-Fat, No-Fat diets: Does it matter? • What are good fats? • What fats should be avoided?

25. Common Properties • Do not dissolve in water • Called Hydrophobic • Can have a very diverse chemical structure • Some common ones in the body • Triglycerides • Cholesterol • Phospholipids

26. Triglycerides Courtesy of Wikipedia

27. Cholesterol

28. Phospholipids University of Florida Agricultural and Biological Engineering, Web site of David P. Chynoweth MSPH, Ph.D

29. Lipid and Fat: What is the difference? • Lipid is a term that means “any of various substances that are soluble in nonpolar organic solvents (as chloroform and ether), that are usually insoluble in water, that with proteins and carbohydrates constitute the principal structural components of living cells, and that include fats, waxes, phosphatides, cerebrosides, and related and derived compounds .” – www.webster.com • Fat is typically referred to as a lipid that is solid at room temp • Oil is a lipid that is liquid at room temp

30. Fatty Acids • Long chains of carbons with an acid group on one end and a methyl group on the other • Simplest form of fat Acid Group Methyl group

31. Saturated & Unsaturated Fatty Acids • Saturated fat: all of the carbons within the backbone have single bonds and are “saturated” with hydrogens • Butter, steak fat, Coconut oil • Unsaturated fats: at least one of the carbons-carbon links are a double bond • Monounsaturated = One double bond • Canola and Olive oil • Polyunsaturated = >1 double bond • Corn, Soybean, Sunflower • Fats are classified by which fat is in highest concentration

32. Linoleic Acid – Polyunsaturated fat

33. Unsaturated fats • What is meant by the term omega-3 fatty acid vs. omega-6 fatty acids? • Omega-3 are fatty acids that have the first double bound at the 3rd carbon from the methyl end. • Alpha-linoleic acid • Omega-6 are fatty acids with the first double bond at the 6th carbon • Linoleic Acid • There are also omega-9 fatty acids. Guess where their first double bond is. • Oleic Acid

34. Cis and Trans Fats • What is the difference between cis and trans fats? • Why such a big deal? – although unsaturated, trans fat acts like unsaturated fat • Commonly found in margarine and shortening • Some trans fats occur naturally – may have health benefits Elaidic acid - Trans Oleic acid - Cis

35. Triglycerides • Backbone of glycerol • Three fatty acid chains

36. Phospholipids • Backbone of glycerol • One of the fatty acids replaced with phosphorus containing group • Lecithin is a phospholipid

37. Sterols • Looks nothing like the other lipids • Consists of a multi-ringed structure • Forms the basis for hormones such as testosterone and estrogen • The body can make all it needs • Cholesterol

38. Lipids in food • Very abundant in the North American diets • American Heart Association suggests 70g of fat a day • Roughly 30% of daily caloric intake • Fat calories in certain foods • 80% of calories: Bacon, avocado, nuts, and bologna • 75%: Peanut butter and cheddar cheese • 60% Marbled steak and hamburgers • 50% Doughnuts, ice cream and whole milk • 35% Lean cuts of meat (sirloin), eggs, cupcakes • 15% Bread • Virtually no calories from fat: cornflakes, sugar, fat-free milk

39. Let’s pause for a moment and reflect on our old friend… the doughnut.

40. Let’s pause for a moment and reflect on our old friend… the doughnut. • Why are they sooooo bad? • Let’s review • High in refined carbohydrates • 50% of calories come from fat • Don’t be fooled by “Vegan” choices • No animal products • Mighty O doughnuts • 42% calories from fat • National Doughnut Day • First Friday of every June

41. It’s not just about how much, what kind? • Saturated fat • Main fat in animal products • 40-60% of total fat in dairy and meat • Unsaturated fat • Main fat in plant oils • Monounsaturated fat – canola and olive oil(49-77%), also some animal fats (30-47%) • Polyunsaturated fats – Safflower and soy (54-77%) • Phospholipids • Wheat germ, peanuts, egg yolk, soy beans • Lecithin acts as an emulsifier in salad dressings • Egg yolks in mayonnaise

42. A quick word about cholesterol • Found only in animal foods • As mentioned before, your body can produce all it needs • Eggs are the primary source of cholesterol in the North American diet • Contain ~210 mg • Don’t be fooled by “Cholesterol free” labeling • Any plant based product is naturally cholesterol free • Plant products have their own type of sterols but not considered a health risk