April 15 and 18 Lectures

April 15 and 18 Lectures - Transportation of Dietary Fat:...

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Unformatted text preview: Transportation of Dietary Fat: chylomicrons Transportation of Synthesized Fat: Very low density lipoproteins LDL HDL Transportation of dietary fat chylomicron Triglyceride LIPOPROTEIN LIPASE PLASMA STORE AS FAT Transportation of Synthesized Fat Fat and cholesterol made primarily by the liver Very Low Density Lipoprotein (VLDL) released from liver Low Density Lipoprotein (LDL) High density lipoproteins (HDL) Efficient clearance of cholesterol HDL versus LDL cholesterol LIVER esterol L-chol LD LDL-cholestero l LDLchole sterol Many other extra-hepatic tissues HDL versus LDL LIVER esterol L-chol LD esterol L-chol D HLDL -cholesterol HDL-cholest erol LDLchole sterol HDLcholes terol Many other extra-hepatic tissues Lowering LDL cholesterol Reduce dietary saturated fat and cholesterol Increase MUFA and PUFA Increase dietary fiber (soluble) Results in only minor changes in cholesterol Cholesterol and Diet Average person consumes from 400 to 800 mg/day Synthesis by the body is between 1,000 and 2,000 mg/day As intake increases, synthesis decreases and vice versa Must inhibit synthesis statin drugs Raise the HDL Physical activity At least 45 min./day, 4 days a week Avoid smoking Eat regularly Eat less total fat Moderate intake of alcohol increases HDL Blocked Arteries Risk Factors for Heart Disease Family history Smoking (even second hand) High blood pressure High blood cholesterol (hyperlipidemia) >200 mg/dl of total cholesterol HDL < 40 mg/dl Diabetes Lack of regular exercise and obesity Calculate risk On the online thing Smoking increased risked to 7% Blood pressure only increased it to 2% Recommendation for fat No RDA 4% of total kcal should come from essential fatty acids No more than 15% from PUFA Current diet supplies ~33% of total kcal from fat much from animal, whole milk, pastries, cheese, margarine, and mayo The American Heart Association For high risk individuals <20-30% of total kcal from fat/day <7-10% from saturated fat (includes trans fatty acid) <200-300 mg cholesterol a day Other Recommendations Fat intake can be higher as long as saturated and trans fatty acid are minimal Eat diet with plenty of fruits and vegetables Cut down on red meats Cut down on simple sugars and refined CHO PROTEINS Proteins Overview Basics Structure, Functions, Sources Nutritional Quality Digestion and absorption Deficiency Diseases Proteins Proteins = polymers of amino acids Must be digested and hydrolyzed into amino acids to be absorbed Used to make new proteins or converted to energy ~ 20% of human body is protein Functions of Proteins Enzymes: Trypsin, Pepsin Storage: Ovalbumin, Ferritin Transport: Hemoglobin Contractile: Actin, Myosin Protective: Antibodies, Thrombin Hormones: Insulin, Growth hormone Structural: Keratin, Collagen, Elastin Sources of Protein Eggs Milk Legumes Meat Fish 4Kcal/gram Amino Acids Building blocks of proteins Contain an amino group (NH2) and an acid group (COOH) 20 different amino acids 100,000 different proteins in our body Generic Amino Acid Structure NH2 O R C C OH H R group Amine group Acid group Peptide Bond Bond formed between amino acids Result of the reaction of an amino group (NH2) of one with an acid group (COOH) of another Strong, not normally broken by cooking Peptide Bond Condensation vs. Hydrolysis Condensation = removal of H2O and formation of peptide bond Hydrolysis = addition of H2O and breaking of peptide bond Condensation Reaction {*Figure 2*} Water is lost in forming an amide bond. {*Figure 2*} Water is lost in forming an amide bond. Essential Amino Acids Human body can make 11 of 20 amino acids Humans must consume the 9 amino acids cannot make Essential AA Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine Nonessential AA Alanine Arginine Asparagine Aspartic Acid Cysteine Glutamic acid Glutamine Glycine Proline Serine Tyrosine On Exam Shhh! Arginine becomes an essential amino acid meaning you have to obtain it from your diet, your body makes it but under certain conditions we may have to obtain it, unique protein. Protein Synthesis Enzymes: Storage: Transport: Contractile: Protective: Hormones: Structural: Trypsin, Pepsin Ovalbumin, Ferritin Hemoglobin Actin, Myosin Antibodies, Thrombin Insulin, Growth hormone Keratin, Collagen, Elastin Protein Synthesis DNA contains coded instructions Copies of codes are transferred to the cytoplasm (via mRNA) Amino acids added one at a time with aid of tRNA Amino acids tRNA mRNA DNA All-or-none concept The depletion of just one essential amino acid will prevent protein synthesis High quality protein dietary proteins that contain all nine essential amino acids Typically animal sources Low quality protein dietary proteins that are low in or lack one or more essential amino acids Typically plant sources All-or-none concept The depletion of just one essential amino acid will prevent protein synthesis Limiting Amino Acid Limiting Amino Acid When necessary amino acids are present, protein synthesis occurs If even one necessary amino acid is missing, protein synthesis stops = Specific amino acid present in the lowest quantity compared to need Limiting Amino Acids: "Keep off the Grass" K 75 E 250 P 250 O 100 F 120 T 100 H 100 G 65 R 100 A 100 S 250 How many signs could you make with these letters? 60 signs What is the limiting letter? F because you need 2 F's and can only do that 60 times Limiting Amino Acids Cereals: Corn, Rice, Wheat, Oats, Barley Legumes & Oilseeds: Black bean, Peanut, Chick pea, Soy, Green bean, Potato, Milk LYSINE METHIONINE Complementary Relationships By combining a protein deficient in a specific amino acid with a protein that has an excess of that amino acid, protein quality is increased! Complementary Relationships Food Rice Black beans Rice (70%) + Black beans Rice (60%) + Black beans Rice (50%) + Black beans Corn Corn + Black beans PER 2.30 nil 2.70 2.60 1.30 1.41 2.05 Protein efficiency ratio = gain in body weight (g) __________________ Protein intake (g) Additional Needs for Nitrogen Synthesis of pyrimidines (T, C, U) and purines (A,G) for nucleic acids Synthesis of ATP (adenosine tri phoshpate) Synthesis of porphyrin (binds Fe) for oxygenbinding proteins Does the kind of protein matter? Carnivore meat eaters Omnivore plants & animals Vegetarian no red meat Vegan no animal products. Yes, Protein Quality Matters Describes nutritive value of a protein related to amino acid composition & digestibility Ultimately related to ability of a protein to provide the amino acids necessary for body to synthesis new proteins Protein Quality Ideal protein would have all the essential amino acids in the correct proportions for optimum rates of growth & maintenance Does such a food exist? Measuring Protein Quality 3 main indices Protein Efficiency Ratio (PER) Net Protein Utilization (NPU) Biological Value (BV) Protein Efficiency Ratio (PER) = weight (g) gained per gram protein consumed Weight gain ~ measure of nutritional adequacy PER Values Egg Soy Cotton seed meal Sesame seed Chick pea Peanuts Corn Kidney beans 3.90 2.32 2.25 1.77 1.68 1.65 1.41 0.88 Evaluation of Biological and Biochemical Quality of Whey Protein Whey protein: by product of cheese production Extensively used as a dietary supplement Compare quality to casein (cow's milk) Whey protein has a higher PER than casein Supports growth better than casein Protein Quality Egg Total EAA PER NPU BV 512 3.9 94 94 Cow's Beef Milk 504 3.1 82 84 480 3.0 67 74 Fish 485 3.5 79 76 Soy bean 466 2.3 61 73 Protein Utilization Factors affecting Protein Utilization: -Ratios of essential amino acids -Amount of protein in the diet -Physiological state of the subject -Digestibility Digestion of Protein in the Stomach Proteins are denatured by cooking and acid in the stomach Gastrin stimulates the release of acid and pepsin Pepsin is activated and breaks down proteins into peptones Digestion of Protein in the Small Intestine Stimulates the release of CCK Pancreas release the protein splitting enzymes: trypsin, chymotrypsin, and carboxypeptidase into the duodenum The enzymes will break peptones into smaller peptides and amino acids Peptides and amino acids are ready for absorption Protein Absorption Active absorption Whole proteins are broken down at the microvilli surface and within the absorptive cells Whole proteins are eventually broken down to amino acids Many different amino acid transport mechanisms Amino acids are sent to the liver via portal circulation RDA for protein Promotes equilibrium 0.8 gm of protein / kg of healthy body weight 154 lb. = 70 kg 2.2 kg/lb. 70 kg x 0.8 g protein = 56 g protein kg healthy body wt RDA for Protein Increased by ~10-15 gm /day for pregnancy Endurance athletes may need 1.5 - 2 gm/kg healthy weight About 8-10% of total kcals Most of us eat more than the RDA for protein Excess protein cannot be stored as protein Is a High-Protein Diet Harmful? Low in plant foods (fiber), vitamins, phytochemicals Intake of animal protein increases risk for heart disease (high in saturated fat) Excessive intake of red meat is linked with colon cancer Burden on the kidney Increase calcium loss National Academy of Sciences recommend no more than 2 x RDA for protein Kwashiorkor Results from diet of sufficient calories but inadequate protein in either quantity or quality Symptoms include bloated belly, apathy, mental retardation, increased need for vitamin A Kwashiorkor Marasmus Results from a diet of deficient in both calories and protein Symptoms include very low body weight and muscle wasting Vegetarian Nutrition Kelly Robert Walsh, RD, LD Notable Vegetarians Pythagoras (580 B.C.E.) The father of vegetarianism? Plato Socrates Voltaire Sir Isaac Newton Leonardo da Vinci (1452-1519) Benjamin Franklin (1706-1790) Dr. J.H. Kellogg (1852-1943) George Bernard Shaw (1856-1950) Mr. (Fred) Rodgers Albert Einstein (1879-1955) Charles Darwin Types of Vegetarianism 1. 2. 3. 4. 5. Lacto-ovovegetarian Lactovegetarian Pescovegetarian Vegan Macrobiotic Lacto-ovo & Lactovegetarian Lacto-ovovegetarian Excludes meat and seafood from diet Includes dairy products and eggs in diet Lactovegetarian Excludes meat, seafood, and eggs from diet Includes dairy products in diet Pescovegetarian Any form of vegetarianism that includes fish as part of the diet. Vegan Exclude all animal products from diet Macrobiotic Very similar to veganism Brown rice is the staple food Vegetables, nuts, seeds, seaweeds, and fruits are included in diet Dr. Norm Millian Why do people choose vegetarianism? Health Religion / cultural factors Environmental factors Conservation of resources Compassion for animals Establish an identity Health Benefits Heart Disease Cancer Hypertension Health Benefits Hypertension (HTN) Dietary Approaches to Stop Hypertension Nearly vegetarian diet 4-5 servings of fruits & vegetables per day Low-fat dairy foods Moderate sodium intake What do Vegetarians Eat? Only difference is the meat category Protein Eggs Dairy products Legumes Soy products Commercial meat analogs Meat Analogs Meat Analogs Protein Quality Complete protein Contains all of the amino acids w/ respect to the body's needs. Animal proteins are complete Plant proteins are not always complete e.g. Legumes (limiting in Methionine) Grains (limiting in Lysine) Eating them together makes them complete. Nutrition Concerns Iron Zinc Calcium B12 The Bottom Line Vegetarianism is a lifestyle It can offer many health benefits Doing it right Balance daily food choices Choose a variety of different foods Practice moderation Vitamin/mineral supplement offers insurance. "Nothing will benefit human health and increase the chances for survival of life on earth as much as the evolution to a vegetarian diet." - Albert Einstein ...
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This note was uploaded on 06/23/2011 for the course NUTRITION 210 taught by Professor Dr.bomser during the Spring '11 term at Ohio State.

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