Exam 2 Study Guide
Exam 2 Study Guide NTR 213-05
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This 29 page Study Guide was uploaded by Elizabeth Weathers on Saturday February 20, 2016. The Study Guide belongs to NTR 213-05 at University of North Carolina - Greensboro taught by Laurie H. Allen in Winter 2016. Since its upload, it has received 78 views. For similar materials see Introductory Nutrition in Environmental Science at University of North Carolina - Greensboro.
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Date Created: 02/20/16
Carbohydrate Functions: To provide energy Cushioning and lubrication Cell membrane signaling Examples of Carbohydrates: Galactose: used by nerve cells and used to make breast milk Ribose & deoxyribose (monosaccharides): used in DNA & RNA Ribose: in B vitamin riboflavin Carbohydrates Complex Simple Polysaccharides: Disaccharides: Monosaccharides: (poly = many) (di = two) (mono = one) Glycogen: used in Lactose: in milk & Galactose: used by animal sugar storage, dairy products, made nerve cells and used to contained in the up of 1 glucose and 1 make breast milk muscles and liver galactose unit Glucose: simple Starch: used in Maltose: a sugar which is the main plant sugar storage disaccharide formed source of energy for Fiber (soluble, from two units of living organisms, glucose, A.K.A. malt circulates in the blood insoluble): used in sugar plant structure Fructose: a six- Sucrose: table carbon sugar found sugar, made from I especially in honey and glucose and 1 fructose fruit, as well as unit vegetables REMINDER: there is a set capacity of glucose the body can store as glycogen, any excess is converted to fat Fiber Soluble Fiber vs. Insoluble Fiber Dissolves in water Does not dissolve in water Partially digested by bacteria in large Not digested by bacteria in large intestine intestine Helps lower cholesterol Increase bulk & prevent constipation Ex: pectins, gums, & some Ex: cellulose, some hemicelluloses, hemicelluloses & lignin REMINDER: the human body cannot break down the bonds in fiber by itself, intestinal bacteria are needed to help the digestion of soluble fiber Whole Grains vs. Refined Grains Whole grains: contain the whole kernel , Refined grains: foods processed including the brain, germ, and endosperm to remove course parts such as the bran and germ which removes the fiber and some vitamins and minerals Enrichment • The process of fortifying grains with some of the nutrients removed during processing • Legislation requires the fortification of grains with some specific nutrients Interpreting Food Labels Refined Sugar Refined sugars contain calories but lack fiber and other nutrients Sugars from whole foods such as fruit and vegetables are more nutrient dense Empty Calories calories derived from food containing little or no nutrients Carbohydrate Digestion Lactose Intolerance Low levels of enzyme lactase in small intestine The disaccharide lactose cannot be broken down into monosaccharides Lactose passes into the large intestines where it is digested by bacteria Symptoms: gas, abdominal distension, cramping, diarrhea Alternate calcium sources: tofu, legumes, dark green vegetables, canned salmon/sardines, calcium-fortified foods, calcium supplements, lactase-treated milk Put It Together question from the textbook chapter: Based on this graph, Americans whose ancestors came from which parts of the world are most likely to have a low calcium intake because they can’t drink milk? Indigestible carbohydrates Fiber: not broken down by human enzymes Oligosaccharides: 3–10 sugar units; some are not broken down by human enzymes Resistant starch: natural structure of the grain protects the starch molecules or cooking and processing alter digestibility Ex: legumes, unripe bananas, and cold cooked potatoes, rice, and pasta Hormones at Work: Insulin: Increased Glucose Decreased blood Insulin Secretion taken into blood glucose cells glucose Glucagon: Decreased Glucagon Glucose Increased blood Secretion released blood glucose from liver glucose Blood Glucose Regulation Think Critically question from textbook chapter: What would happen to blood glucose levels if insulin were not available? TEACHER’S TIP: Students often confuse glucagon and glycogen. A way to remember glucagon is: “when your glucose is gone, you are happy you have glucagon.” Cellular Respiration: How Cells use Glucose to Harvest Energy C H O + O 6 12 6 2 glucose + oxygen CO + H O +ATP 2 2 Carbon dioxide + water + energy Glycemic Index vs. Load vs. Response Glycemic index: Glycemic load: Glycemic response: ranking of how a food compares the measures how affects blood glucose effect of typical quickly and how relative to an equivalent portions of food on high blood glucose amount of carbohydrate blood glucose levels rise after from a reference food, carbohydrate such as white bread or consumption pure glucose Ex: white bread = 100, kidney beans = 25 What Happens when Carbs are Limited Ketones Ketones/Ketone bodies: acidic molecules produced by fat breakdown when carbohydrates are not available to cells Heart, muscle and kidneys use ketones for energy Brain adapts to use ketones after 3 days Produced with starvation, and/or low-carb diets, diabetes The use of ketones for energy helps spare glucose & decrease the amount of protein needed to be broken down Ketosis: increased ketones in blood Ketoacidosis: acidic blood from increased ketones in blood Ketogenic Diet Used in treating certain health conditions: Epilepsy Traumatic Brain Injury Metabolic Disorders Possibly Alzheimers Parkinsons disease Carbohydratesin HealthandDisease Diabetes Mellitus Diseases characterized by high blood glucose Type I: decreased insulin secretion Autoimmune destruction of insulin-secreting cells in the pancreas Type II: insulin resistance The body either resists the effects of insulin or doesn't produce enough insulin to maintain a normal glucose level Gestational: first observed during pregnancy Diabetes Mellitus Signs & Symptoms High blood glucose since insulin does not signal cells to take up glucose Causes weight loss since the body breaks down fat Causes increased hunger Increased glucose in urine Water tries to dilute glucose causing increased excretion of water causing dehydration and thirst Blurred vision Water tries to dilute glucose in the eye Diabetes Mellitus Management Control blood sugar levels Limit carbohydrate intake Increase whole grains, decrease refined sugars Type I & some Type II patients need insulin injections Type II patients often take oral drugs Exercise Exercise and weight loss in Type II helps prevent, reverse, and manage the disease Low saturated fat, low trans fat Diabetes Mellitus Complications Hypoglycemia Low blood sugar levels Caused by: Overmedication with insulin Abnormal insulin or other hormone secretion or response Fasting hypoglycemia: when a person has not eaten and usually has some other condition Reactive hypoglycemia: too much insulin response after a high-carbohydrate meal Dental caries (cavities) Bacteria in mouth digest carbohydrates and produce acid which damages tooth enamel Increased risk: Increased intake of sucrose and starch Frequent exposure Carbohydrates & Weight Management Weight gain caused by excess calories from carbohydrates, protein, fat or alcohol Type of carbs consume effect how hungry you feel Diet high in refined carbs may shift metabolism toward more fat storage Nonnutritive (artificial) Sweeteners Replace sugar in the diet Pros: Decrease dental caries Control blood sugar Cons: Associated with weight gain Present in low nutrient density foods May be dangerous at high doses Cardiovascular Disease High-sugar diets increase blood lipids High blood glucose damages blood vessels Soluble fiber decreases cholesterol absorption and synthesis High-fiber diets decrease blood pressure, weight, blood glucose, and heart disease Diets high in fruits and vegetables increase fiber and protective antioxidants Soluble Fiber & Cholesterol Bowel health High-fiber diets decrease: Constipation (if adequate water is consumed) Hemorrhoids (varicose veins in the anus and rectum) Diverticula (outpouching of the large intestines) Colon cancer?? Carbohydrate Recommendations Enough carbohydrate to meet glucose needs Choosing types for health & disease prevention RDA for carbohydrate =130 g/day Acceptable Macronutrient Distribution Range for carbohydrate = 45–65% of total calorie intake Adequate Intake for fiber = 38 g/day for men & 25 g/day for women 2010, 2015 Dietary Guidelines and MyPlate Dietary Guidelines specifically recommend reducing intake of sugar-sweetened beverages MyPlate recommends 6 oz of grains (half should be whole grains), 2 cups of fruit, and 2 2 cups of vegetables for a 2000-calorie diet • increase whole grains, fruits and vegetables, and reduced-fat dairy products • limit foods high in refined grains and added sugars Roles of Fat In food: provide texture, flavor, aroma In our body: Help cushion our internal organs Provide insulation lubricate body surfaces Necessary for cell membranes Myelin coating for brain and nerves Provide energy and storage of energy Absorption of fat soluble vitamins (Vitamin A, D, E, and K) Needed for steroid hormones Essential fatty acids needed for growth, fertility, eye health, brain development and immunity among other roles TIP: typically, animal sources have more saturated fat Sources of Dietary Fats Animal sources: Plant sources: “Hidden” dietary fat: Meat vegetable oils French fries Cheese nuts Pizza Butter avocados pasta dishes Lard coconut baked goods salad dressings Fat Intake in the 1970’s and Today NOTE: the values on this graph are influenced by a third factor – that our daily intake has increased over the past few decades Lipids Called ‘fats’ in the diet Triglycerides: Phospholipids: Sterols: Made up of 3 fatty acids & Lipids with a unsaturated steroid 1 glycerol phosphate group alcohols Saturated fats In cell membranes in cell membranes Unsaturated fats Starting material starting material Cholesterol Triglyceride: Glycerol, fatty acids: chains of carbon atoms, acid at end Phospholipid: Glycerol, fatty acids, phosphate group Sterols: interconnected rings of carbon atoms Fatty acids in Triglycerides Chain of carbon atoms Each carbon can form 4 bonds Vary in length and location of carbon-carbon bonds in the chain Classified as saturated or unsaturated Carbon bonding Saturated vs. Unsaturated Fats Saturated fats: carbons are saturated by hydrogens Unsaturated fats: carbons not saturated Saturated vs. unsaturated fats in foods Butter, Cheese, Red meat are high in Corn, Safflower, Canola oil are high saturated fatty acids in unsaturated fatty acids NOTE: unsaturated food items are more vulnerable to lipid oxidation, which can pose a risk for cardiovascular disease & some cancers Unsaturated fatty acids: Monounsaturated vs. Polyunsaturated fats Monounsaturated fats: one double bond Canola oil Peanut oil Olive oil Polyunsaturated fats: more than one double bond Omega-6 corn oil Omega-3 (salmon, flax seed) Omega-3 vs. Omega-6 Polyunsaturated fats rd Omega-3: first double bond at 3 bond from omega end th Omega-6: first double bond at 6 bond from omega end NOTE: our diets consist of a lot of Omega-6, but little Omega-3 Essential fatty acids Essential vs. non-essential fatty acids Essential fatty acids cannot be made in the body, so they are essential in the diet Needed for cell membrane, growth, brain development Ex: linoleic acid (omega-3) and alpha-linolenic (omega-6) Non-essential fatty acids can be made by the body, so they are not essential in the diet or that are not necessary for the body Omega-9 fatty acids saturated fatty acids Hydrogenation: Cis vs. trans-fats Hydrogenation: hydrogen atoms are added to carbon-carbon double bonds making an unsaturated fatty acid more saturated. Increases shelf life. NOTE: Trans Fat – decreases good cholesterol, increases bad, increases risk of heart disease Saturated Fat – increases bad cholesterol In June 2015, legislation voted to ban trans fat & should be gone by 2018 If food has >0.5g trans fat, it can say 0g: look for partially hydrogenated oils in ingredients Trans-fat (trans-fatty acids) Phospholipids Fatty acids at one end soluble in fat, phosphate end soluble in water Act as emulsifiers Component of cell membranes Used to synthesize acetylcholine Present in small amounts in food and in the body Sterols Best known sterol is cholesterol Cholesterol is produced by liver and consumed in diet (animal sources only) Needed for cell membranes and to make other sterols and hormones: Vitamin D bile acids, testosterone and estrogen Lipid Digestion and Absorption Bile Bile is stored in the gall bladder before entering the small intestines Bile emulsifies (breaks up larger particles) dietary fat so it is more accessible to lipases (lipid-digesting enzymes) Dietary fiber binds cholesterol to keep it from being reabsorbed into the body from the small intestines (so more is excreted from the body) NOTE: excess cholesterol can be used to make bile Lipoproteins in blood Lipid Transport and Delivery Lipid transport and delivery: Lipoproteins Dietary lipids (such as cholesterol and triglycerides) are packaged into lipoprotein particles Chylomicrons Transport triglycerides, cholesterol, and fat-soluble vitamins from the small intestines to the liver Triglycerides in chylomicrons are broken down into glycerol and fatty acids by lipoprotein lipase (in blood vessels) to cross membranes then are reassembled into triglycerides in cells Chylomicron remnants are returned to the liver VLDL particles are made in the liver particles function similar to chylomicrons (transport triglycerides which are broken down by lipoprotein lipase) LDL particles deliver cholesterol to cells LDL particles bind to LDL receptors on cells to help cholesterol move from the blood into cells HDL particles transport cholesterol from cells to the liver The liver uses cholesterol to make bile Lipid Functions Necessary to maintain health Absorb fat soluble vitamins Component of cell membranes and myelin coating Insulation Lubrication Stored energy EFA: eye, brain development, fertility, eicosanoids Conversion of fatty acids to energy Feasting vs. Fasting Eicosanoids Synthesis Ratio of Omega-3s to Omega-6s Ratio of Omega-3 to Omega-6 affects health US diet contains higher ratio of omega-6 to omega- 3 Omega-3 anti- inflammatory, Omega-6 pro- inflammatory Atherosclerosis development Blood vessel injury, inflammation and LDL oxidization generates plaques blood vessel walls in atherosclerosis Antioxidants (found in fruits and vegetables) can limit oxidation of LDL Atherosclerosis can narrow blood vessels and limit blood flow to tissues so that fewer nutrients and oxygen molecules are delivered Risk Factors for Atherosclerosis and Cardiovascular Disease Diet Smoking Diabetes High blood pressure (hypertension) Obesity Sedentary Blood lipids (high LDL, triglycerides; low HDL) Family history, age, gender, race LDL vs. HDL in heart disease LDL LDL particles transport cholesterol from the liver to body cells Work to decrease your blood levels of LDL (“you want your low to be low”) HDL HDL particles transport cholesterol from body cells to the liver so they can be excreted Work to increase your blood levels of HDL (“you want your high to be high”) Decrease your LDL and increase HDL Decrease dietary trans-fat, saturated fat Increase dietary polyunsaturated fats and monounsaturated fats Quit smoking Exercise Mediterranean and DASH diets may Decrease Cardiovascular Disease Total Diet 1/g day of EPA and DHA Replace sat fat with MUFA and PUFA Consume 5 oz nuts per week High intake of fruits and vegetables (especially bright colors) Fewer animal proteins Avoid trans fat High total fiber Limit sodium < 2400mg Dietary Fat and Obesity Fat has 9 calories (kcals) per gram Carbohydrates & proteins have 4 calories per gram Ex: 1 teaspoon of olive oil contains 5 grams of fat, 5 grams x 9 kcals/gram = 45 kcals from fat Fat is efficiently stored Dietary recommendations Total fat: 20%–35% of total calories 30–40% for ages 1–3 & 25–35% for ages 3–18 Saturated fat: less than 7% of total calories Cholesterol: less than 300 mg per day-no longer part of dietary guidelines Trans-fat: limit Food Labels Fat Replacers Types of Fatty Acids Fatty Acids Saturated Fats Unsaturated Fats Animal fats, tropical fats Industrialized (trans- fat) Monounsaturated Baked goods, Polyunsaturated Olive oil, canola oil processed foods Omega 3 Omega 6 Flax seed, walnuts, Vegetable oils, nuts cold-water fatty fish
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