Carbohydrates, Proteins and Lipids
Carbohydrates, Proteins and Lipids 224-004
Popular in Human Nutrition
Popular in Nutrition and Food Sciences
This 14 page Bundle was uploaded by ayla on Wednesday November 11, 2015. The Bundle belongs to 224-004 at University of New Mexico taught by Diana Gonzales in Summer 2015. Since its upload, it has received 62 views. For similar materials see Human Nutrition in Nutrition and Food Sciences at University of New Mexico.
Reviews for Carbohydrates, Proteins and Lipids
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 11/11/15
Carbohydrates What Are Carbohydrates? Macronutrient Glucose Photosynthesis CO 2 + 2H O + Energy 6= C H O 2+O Preferred energy source Simple and Complex Carbohydrates Simple carbohydrates: Pass through GI tract undigested or partially digested. Raffinose, Stachyose Monosaccharides: Simple Carbohydrates One molecule Disaccharides: Simple Carbohydrates contain two molecules Complex carbohydrates Oligosaccharides: Simple Carbohydrates 3 to 10 monosaccharides Polysaccharides: Complex Carbohydrates 100’s-‐1000’s glucose molecules Complex Carbohydrates: Starch Plants store CHO as starch Amylose—straight chain of glucose Amylopectin—branched chain of glucose Resistant starch (fiber)—glucose molecules linked by beta bonds are largely nondigestible Complex Carbohydrates: Glycogen Storage form of glucose for animals (humans) Not found in food Stored in liver and muscles Soluble Fiber Dissolves in water Viscous Fermentable Increase intestinal transit Decrease glucose absorption and cholesterol Pectin, gum, mucilage citrus fruits, berries, oats, beans Insoluble Fiber (roughage) Does not dissolve in water Non-‐viscous Non-‐fermentable Reduce colon transit time Increase stool bulk lignin, cellulose, hemicellulose whole grains, seeds, legumes, fruits, and vegetables Carbohydrate Digestion & Absorption Mouth Salivary amylase Stomach Salivary amylase inactivated Small Intestine Pancreatic amylase Sucrase Maltase Lactase Carbohydrate Digestion – Large Intestine We do not have the enzymes necessary to digest fiber Bacteria in the large intestine can break down some fiber Resistant starches à SCFA’s (butyrate, acetate, propionate) + gas Butyrate – energy for the intestinal cells Most fiber remains undigested and is excreted in the feces Blood Glucose Regulation Blood glucose must be closely regulated Hormones control blood glucose levels: Insulin Glucagon Epinephrine Norepinephrine Cortisol Growth hormone Blood Glucose Regulation Terminology Glycogenesis – Formation of glycogen from glucose molecules Lipogenesis – Formation of triglyceride from excess glucose molecules (stored in liver and adipose tissue) Glycogenolysis –Conversion of stored glycogen to glucose molecules Gluconeogenesis – Conversion of amino acids to glucose by the liver Blood Glucose Regulation: Epinephrine and Norepinephrine Low blood glucose à Epinephrine and norepinephrine secreted by the adrenal glands and nerve endings Glycogenolysis Responsible for our "fight-‐or-‐flight" reactions to danger Blood Glucose Regulation: Cortisol and Growth Hormone Secreted by the adrenal glands to act on the liver, muscle, and adipose tissue Cortisol increases gluconeogenesis and decreases muscle glucose use Growth hormone decreases muscle glucose uptake, increases fatty acid mobilization and use, and increases liver glucose output Glycemic Index A rating of the potential of foods to raise blood glucose and insulin levels High glycemic index foods cause a surge in blood glucose followed by a large increase in insulin Low glycemic index cause low to moderate fluctuations in blood glucose Not easy to predict Glycemic Load Used to determine the effect of a food on a person's glucose response Grams of carbohydrates in a food are multiplied by the glycemic index Glycemic index and glycemic load remain controversial Evidence of health benefits is weak The Role of Carbohydrates Insufficient energy from carbohydrates Fat breakdown (ketosis) à ketones Excess ketones increase blood acidity and cause ketoacidosis Protein breakdown (gluconeogenesis) à amino acids à glucose Why is ketoacidosis and gluconeogenesis problematic? Sugars Natural occurring sugars Sugar naturally found in foods Fresh fruits and milk Added sugars Sugar sources added during processing Sugar, HFCS, honey, dextrose, corn syrup, corn syrup solids, molasses, corn starch What makes a Whole Grain? Complex Carbohydrates: Whole Grains Most Americans eat too little complex carbohydrates Enriched foods -‐ foods in which nutrients that were lost during processing have been added back so the food meets a specified standard Fortified foods -‐ have nutrients added that did not originally exist in the food or existed in insignificant amounts Health Benefits of Complex Carbohydrates May reduce the risk of : colon cancer Heart disease T2DM Diverticulosis Obesity Helps prevent: hemorrhoids, constipation, and other intestinal problems Sweeteners Nutritive Provide energy Sugars and sugar alcohol Non-‐nutritive/Alternative Sweeteners Do not provide energy Saccharin Acesulfame-‐K Aspartame Sucralose (Splenda) Stevia Diabetes Type 1 diabetes No insulin, requires insulin injections Autoimmune disease, genetic link Often develops early Uncontrolled diabetes can cause long term complications Diabetes Type 2 diabetes Insulin resistance Metabolic syndrome Genetics, obesity, physical inactivity increase risk Onset Tx – lifestyle modification, medications Diabetes Gestational diabetes Diabetes diagnosed during pregnancy Often resolves after delivery Increased risk for development of type 2 diabetes for both mother and infant Healthy Eating for Diabetes Follow DRI’s Moderate exercise Control Carbohydrate For T2DM – weight loss Alcohol in moderation Hypoglycemia Blood sugar less than 60 mg/dl Symptoms -‐ shakiness, sweating, anxiety, weakness Inconsistent insulin response Reactive hypoglycemia Fasting hypoglycemia High risk for people taking insulin or medication Hypoglycemia Diabetes Medication/meal mismanagement Non-‐diabetes Reactive hypoglycemia: pancreas secretes too much insulin after a high-‐ carbohydrate meal Fasting hypoglycemia: pancreas produces too much insulin, even when someone has not eaten Lactose Intolerance Insufficient enzyme lactase GI symptoms: gas, cramping, diarrhea Variations in intolerance Not milk allergy Avoid dairy and dairy products Soy milk, almond milk, lactaid Need alternate sources of calcium High Fructose Corn Syrup debate Increased in overweight and obesity associated with increased availability of HFCS Intake of sugar sweetened beverage associated with non-‐alcoholic fatty liver disease, HTN Proteins What Are Proteins? Large, complex molecules found in cells of all living things DNA instructions Contain carbon, hydrogen, oxygen, nitrogen 20 different amino acids Amino Acids Nine essential amino acids 11 Nonessential amino acids Essential Amino Acids I – Isoleucine Love – Leucine Lucy – Lysine Very – Valine Much – Methionine Please – Phenylalanine Try -‐ Tyrptophan To – Threonine Help – Histidine Arginine – Arginine (semi-‐essential) How Are Proteins Made? Amino acid chains Peptide bonds Gene expression Protein Synthesis Transcription (nucleus): Gene: provide the instructions for amino acid assembly Genetic information is transcribed into messenger RNA Translation (Cytoplasm): Ribosomes translate the genetic information the amino acid sequence of a protein Sources of Amino Acids for Protein Synthesis Food Proteins secreted into the GI tract Endogenous protein Bacterial and other microorganisms in the intestine Protein Denaturation Change in the 3 dimensional structure Damaging substances: Heat Light Change in pH Heavy metal Alcohol Motion Protein function is lost Protein in the Diet Protein synthesis àall essential amino acids must be available to the cell Limiting amino acid Essential amino acid that is missing or in the smallest supply Slows down or halts protein synthesis Inadequate energy consumption Limits protein synthesis Protein Quality Complete protein: Contain all nine essential amino acids Incomplete protein: Lack or low supply of one or more essential amino acids Protein Digestion Mouth Mechanical Stomach HCL Denatures the protein Pepsinogen à Pepsin Gastrin Protein Digestion Small intestine Pancreatic enzymes (proteases) Dipeptidases and Tripeptidases Special sites (small intestine) transport amino acids, dipeptides, tripeptides Functions of Proteins Cell growth, repair, maintenance Enzymes and hormones Fluid and electrolyte balance Acid−base balance Immune system Energy source Deamination Urea excretion Positive Nitrogen Balance Negative Nitrogen Balance In Nitrogen Balance RDA for Protein RDA = 0.8 g per kg body weight per day Recommended percentage of energy is 10−35% of total energy intake Increased protein needs during growth and development Recommended protein for athletes Nonvegetarian endurance athletes 1.2-‐1.4 g/kg Nonvegetatian strength athletes 1.2-‐1.7 g/kg Vegetarian endurance athletes 1.3-‐1.5 g/kg Vegetarian strength athletes 1.3-‐1.8 g/kg Protein supplements Recommended protein for older adults 1.2 g/kg/d êloss of LBM and é fxn in adults 65 yrs Increase protein intake in the morning Excess protein Amino acids are not stored Animal-‐protein rich diets (é saturated fat) Increased risk high cholesterol and heart disease High-‐protein diets increase calcium excretion Increased risk for bone loss Can Too Much Protein Be Harmful? Kidney disease High protein intake associated with an increased risk among susceptible individuals People with diabetes have higher rates of kidney disease and may benefit from a lower-‐protein diet Maximum of 2 g/kg/d is safe for healthy people Animal Protein Sources Meats Milk-‐based products Plant Based Protein Sources Soy products Legumes Whole grains Nuts Seeds Vegetarian Diets Vegetarianism: restricting the diet to foods of plant origin People chose vegetarianism for: Health benefits Ecological reasons Religious reasons Ethical reasons Concerns over food safety Benefits of a Plant Based Diet Lower fat and total energy intake Lower blood pressure Reduced risk of heart disease Fewer digestive problems Reduced risk of some cancers Reduced risk of kidney disease, kidney stones, and gallstones Vegetarian Diets Defined Semivegetarian/Flexitarian Pescovegetarian Lacto-‐ovo-‐vegetarian Lactovegetarian Ovovegetarian Vegan Macrobiotic Fruitarian Challenges of Vegetarian Diets Can be low in some nutrients Soy and complementary proteins Special attention to vitamins: D B 12 riboflavin (B )2 minerals zinc and iron Protein-‐Energy Malnutrition Protein-‐energy malnutrition: caused by inadequate protein and energy intake Common forms: Marasmus Kwashiorkor Marasmus Grossly inadequate energy and protein intake Consequences of marasmus: Wasting and weakening of muscles (heart) Stunted brain development and learning Stunted physical growth Fluid and electrolyte imbalances Depressed metabolism Stunted physical growth Fluid and electrolyte imbalance Kwashiorkor Disease resulting from low protein intake Kwashiorkor symptoms include: Some weight loss and muscle wasting Delayed growth and development Edema, distention of the belly Skin problems and hair loss Loss of appetite, sadness, irritability, apathy Skin problems and hair loss Fatty degeneration of the liver Reversible if protein & energy given in time Genetic Disorders related to proteins Phenylketonuria Sickle cell anemia Cystic fibrosis Phenylketonuria Unable to break down phenylalanine Lipids: Fats & Oils What Are Lipids? diverse class of molecules that are insoluble in water triglycerides fatty acids phospholipids sterols Triglycerides (TG) Glycerol molecule 3-‐C alcohol (backbone) Fatty acids (FA) long chains of C & H atoms FA are classified by: length of the C chain level of saturation shape Chain length short chain (<6C) medium chain (6-‐12C) long-‐chain (>14C) Saturation Saturated + H atoms saturate all C atoms-‐no double bonds-‐ generally solid at room temperature butter, cream, whole milk, beef fat, tropical oils (coconut, palm) Saturated Fat: Food Sources Cheesecake Beef ribs McD’s Quarter Pounder Taco Bell salad with shell KFC Double Down burger Cream cheese Hot dogs Pepperoni Haagen Dasz ice cream Whole milk Foods with LOW or NO Saturated Fat! Bagels, pita bread Pasta, rice Most breakfast cereal (except granola) Fig bars Popcorn All vegetables & fruits, juices Skim milk Fat free yogurt and cheeses Legumes—beans, split peas, lentils Monounsaturated 1 double bond liquid at room temperature olive oil, canola oil, nuts Polyunsaturated >1 double bond vegetable oils (corn, sunflower, safflower), margarine Food Sources of Fat Shape Determined by the saturation of the C chains Saturated FA can pack tightly together & are solid at room temperature animal fats, butter, lard Shape + cis – H + atoms on same side of the C chain trans – H atoms on opposite sides of the C chain Hydrogenation: the addition of H atoms to unsaturated FA converts liquid oils Ê solid form used to create margarine from plant oil longer shelf life creates trans fatty acids £ CVD risk Essential Fatty Acids linoleic acid (omega-‐6 FA) Ê arachidonic acid α-‐linolenic acid (omega-‐3 FA) Ê EPA, DHA Omega-‐3 fatty acids found in fish & fish oil EPA DHA Reduce risk of heart disease Stimulate prostaglandins and thromboxanes that reduce inflammatory responses Reduce blood clotting and plasma triglycerides Linoleic acid (omega 6 fa) sunflower, corn, soy & safflower oils, vegetable oil based margarine Alpha linolenic acid (omega 3 fa) flaxseed & flaxseed oil, soy, walnuts, canola oil, shellfish, salmon, tuna American Heart Association recommends eating good sources of omega 3 fats 2x/week mackerel lake trout herring sardines albacore tuna salmon Should you take fish oil supplements? Fish Oil supplements Benefits vs. Drawbacks Lower TG & BP Lower risk of CVD Lower risk of stroke Safe for most people in low doses e.g. </= 3g/d £ risk of bleeding Reduce immune activity Belching, fish odor, heartburn, nausea, loose stools, rash, nosebleeds £LDL at high doses Interfere with meds e.g. BC, BP, ASA, Coumadin… Phospholipids Phospholipids: glycerol backbone 2 fatty acids +phosphate soluble in water not essential—but abundant in foods part of all cell membranes Sterols Complex ring-‐like structures Cholesterol: most common sterol in our diet Plant sterols phytosterols compete with the absorption of dietary cholesterol Cholesterol synthesized in the liver Functions: cell membrane integrity synthesis of sex hormones, adrenal hormones, vitamin D, bile salts butter, egg yolks, whole milk, meats, poultry, seafood Food Sources of Cholesterol (recommended intake <300 mg/day) Cheddar cheese, Skim milk, 1 cup Whole milk, 1 cup Butter, 1 tbsp Beef, 3 oz Chicken, 3 oz Salmon, 3 oz Digestion of Lipids Mouth lingual lipase little lipid digestion occurs here Stomach gastric lipase muscular contractions help mix fat with enzymes ~2-‐4 hours Small Intestine Cholecystokinin (CCK) hormone causes gallbladder to contract and release bile Bile emulsifies fats Pancreas lipase bicarbonate £s pH for activation of lipases Digestion of Lipids Duodenum bile assists in fat digestion by emulsifying the fats lipases: pancreas, brush border Bile Composed of: Bile salts (cholesterol), bile pigments, phospholipids (lecithin) Function of bile emulsifies fat micelles are formed as a result of emulsification ’s surface area for lipase action After use, bile is either: reabsorbed & recycled (enterohepatic circulation) binds to fiber in large intestine & is excreted Fat Absorption Micelles: absorbed across intestinal mucosal cells distal duodenum, jejunum SCFA, MCFA [ bloodstream LCFA [ reassembled into TG w/in absorptive cells & coated with a thin layer of cholesterol, protein and phospholipids to form chylomicrons Chylomicrons are absorbed by cells of the small intestine, then: Travel through the lymphatic system Transferred to the bloodstream Short-‐ and medium-‐chain fatty acids are absorbed more quickly since they are not arranged into chylomicrons Lipid Transport Lipoproteins transport lipids through the bloodstream Chylomicrons VLDL LDL HDL Chylomicrons: appear in bloodstream shortly after a meal & cleared ~6-‐8 hrs later lymph system [ thoracic duct _ blood Functions of Fats In Food Essential fatty acid linoleic: 5-‐10% of total E alpha-‐linolenic acid: 0.6-‐1.2% of total E Energy (9 kcals/gm) Carrier of fat soluble vitamins minimum of 10% of total calories for adequate absorption Satiety Palatability flavor, texture In the Body Energy reserve (adipose) unlimited capacity Regulation of body functions prostaglandin precursors Insulation/ temperature control Protects internal organs Nerve cell transmission Cell membrane structure Cardiovascular Disease Risks Obesity Smoking High fat diet HTN Diabetes Family Hx Lifestyle modification for CVD prevention & risk reduction Total fat intake 20-‐35% (?) ê saturated fat < 7% of total kcals é omega-‐3 fatty acids éWhole grains, fruits, vegetables 400 mcg folate Stop smoking Maintain an active lifestyle No added salt diet Add plant sterols Obesity & Cancer Colon Kidney Pancreatic Esophageal Endometrial Breast cancer Calorie restriction may protect against various types of tumors
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'