Intro Human Nutrition Lecture Notes PDF

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Intro Human Nutrition Lecture Notes...

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NHM 101 Lecture Notes

Human Nutrition 101 Chapter 1 January 13, 2017 An Overview of Nutrition Nutrition, Food, and Diet Nutrition: The science of nutrients in foods and their actions within the body Nutrients actions within the body include ingestion, digestion, absorption, transport, metabolism, and excretion Refers to human behaviors related to food and eating Nutrition = pure science and social science Diet: foods and beverages someone eats Society does not use this simple definition

Food Products from plants and animals Yield energy and nutrients when consumed for growth and maintenance Many factors influence food choices Preferences: • Habit • Culture • Social Interactions • Income • Positive and negative food associations • Emotions • Values • Body weight and image • Health benefits Ethnic Foods: foods associated with a particular ethnic group Cultural Competence: having an awareness and acceptance of cultures and the ability to interact with people of diverse cultures

The Body Needs Energy and Nutrients Energy Energy in food is chemical energy Nutrients Chemical substances obtained by food Used in the body to provide energy and support growth, maintenance, and repair of tissues

Six Major Classes of Nutrients 1. Carbohydrates 2. Proteins 3. Lipids (fats) 4. Vitamins 5. Minerals 6. Water

Categories of Nutrients Essential Nutrients: must be obtained from foods Gathered from outside the body Nonessential Nutrients: can be synthesized within the body Nonnutrients: compounds that do not fit into the six classes of nutrients Phytochemicals: nonnutrient compounds in plants that have biological activity in the body

Energy-Yielding Nutrients AKA Macronutrients ▪ Carbohydrates ▪ Lipids ▪ Proteins

Vitamins and Minerals Commonly referred to as micronutrients Vitamins and minerals do not provide energy They may assist with energy release processes Vitamins are organic and complex and can be destroyed Minerals are inorganic and are indestructible Bind and hinder absorption or leach into water

Measuring Energy in Food Calories: measure of heat energy and units used to measure energy Food energy is measured in kilocalories 1000 calories = 1 kcal 1 kilocalorie = energy required to raise 1 kg of water 1 degree Celsius

Energy From Food Carbohydrates = 4kcal/gm Proteins = 4kcal/gm Lipids = 9kcal/gm Alcohol = 7kcal/gm

Energy Density vs. Nutrient Density Energy density: measure of energy a food provides relative to weight of the food Nutrient density: measure of nutrients a food provides relative to the weight of food

Dietary Reference Intakes (DRIs) Estimated Average Requirement (EAR) Average daily amount of a nutrient that will maintain a specific function in hald the healthy people of a given age and gender Recommended Dietary Allowance (RDA) Amount of nutrient needed to meet the requirements of almost all healthy individuals Adequate Intake (AI) Average daily amount of a nutrient that appears sufficient Tolerable Upper Intake Level (UL) Highest level of daily nutrient intake that is unlikely to have adverse effects

Establishing Energy Recommendations Estimated Energy Requirement (EER) Average dietary energy intake that maintains energy balance and good health Based on age, gender, weight, height, and physical activity Acceptable Macronutrient Distribution Ranges (AMDR) 45-65% kcal from carbohydrate 20-35% from fat 10-35% kcal from protein

Using Nutrient Recommendations DRIs apply to most health people Recommendations are not minimal requirements Recommendations apply to average daily intakes

Why are they providing this information? Nothing seems to be trying to be sold, however, there are other ads on the page Healthline.com is to provide people with nutritional information they can use in their lives What is the message? Does it contradict other sources? College students are unable to find nutritional food on campus which risks their health and academic performance. (being food insecure) It does contradict other sources such as college or universities claiming they have unlimited supplies of healthy options Does the message tell you to eliminate entire groups of foods? No

Red Flags • • • •

Diet or product claims to be "natural" Quick and easy fixes • If it sounds too good to be true, it is most likely too good to be true One product or food does it all • Ex; grapefruit diet Lack of scientific proof

Human Nutrition Chapter 2: Planning A Healthy Diet Objectives: 1. Explain how each of the diet-planning principles can be used to plan a healthy diet. 2. Identify the recommendations of the Dietary Guideline for Americans 3. Assign foods to the five major food groups 4. Identify foods that have a high nutrient density. 5. Identify the information required on the Nutrition Facts panel and calculate nutrient information from the label. 6. Identify the energy-providing nutrients and calculate the energy available from foods. 7. Recognize reliable health claims on food labels. 8. Define the types of vegetarian diets

Principles and Guidelines Diet Planning Principles • Adequacy- diet that provides sufficient energy and enough of all the nutrients to meet the needs of healthy people • Balance- helps to ensure adequacy; enough but not too much • kCalorie (energy) control- selecting foods high in nutrient density • Nutrient Density- promotes adequacy and kcalorie control; no empty kcal foods • Moderation- contributes to adequacy, balance, and kcalorie control • Variation- improves nutrient adequacy; "eat the rainbow" Dietary Guidelines 1. Follow a healthy eating pattern across lifespan 2. Focus on variety, nutrient density, and amount 3. Limit calories from added sugars and saturated fats 4. Shift to healthier food and beverage choices 5. Support healthy eating patterns for all • Emphasizes variety in fruits, vegetables, whole grains, and fat free and low fat milk products • Includes lean meats, poultry, seafood, legumes, eggs, seeds, and nuts • Low in saturated and trans fats, cholesterol, salt, and added sugars • Stays within your daily energy needs for your recommended body weight

Diet Planning Guides USDA Food Patterns Food group plans- build a diet from clusters of foods that are similar in nutrient content A healthy food pattern includes: • Variety of vegetables • Fruits • Grains

Fat Free or Low-Fat Dairy Protein Foods Oils Groups and Subgroups • Fruits • Vegetables • Grains • Protein Foods • Milk and Milk Products • Oils • • •

Food Labels Nutrition Facts Panel • Serving Sizes • Nutrient Quantities • Daily Values Claims on Labels • Health claims must meet FDA definitions • Must have evidence to back this statement • Structure-function claims do not require FDA approval Consumer Education • Be a wise consumer • Do your research!

Human Nutrition Chapter 3 Digestion, Absorption, and Transport Objectives: List segments of the digestive tract Explain mechanical and chemical processes of digestion in order List the 5 organs and their secretions Explain how nutrients are routed in their circulatory systems from GI tract Describe how bacteria influence health and activities of GI tract Definitions: • Digestion: process by which food is broken down • Absorption: uptake of nutrients by the cells of small intestine for transport into either the blood or lymph system • Gastrointestinal (GI) tract- digestive tract flexible muscular tube that extends from mouth to anus o Lumen: inner space within the GI tract and is continuous from one end to the other Anatomy of Digestive Tract 1. Mouth 2. Esophagus 3. Stomach 4. Small intestine 5. Large intestine (colon) 6. Rectum 7. Anus  Mouth •

• •

Process of digestion begins in the mouth • Chewing and crushing food pieces • Fluids from food/beverages and from salivary glands blend with food for easy swallowing Food is swallowed  passes through pharynx  epiglottis closes off airway  food enters esophagus as the upper esophageal sphincter opens Carbohydrate digestion begins here

*What Is A Sphincter? • Circular muscle surrounding, able to close a body opening • Keeps flow of food in one direction • Multiple throughout the GI tract that regulate the flow of food particles o Upper esophageal sphincter (mouth/pharynx to esophagus) o Lower esophageal sphincter (esophagus to stomach) o Pyloric sphincter (stomach to small intestine) o Ileocecal valve (small intestine to large intestine) o Two sphincters of the anus  Esophagus Upper esophageal sphincter opens and food enters into the esophagus Sphincter muscle at each end of the esophagus Food moves through the esophagus  Stomach • •

• • • •

Food particles enter stomach upon the opening of lower esophageal sphincter Food slowly transfers from the upper portion of stomach to the lower portion o At the same time, juices are added to the food and ground into a semi liquid mass called chyme Chyme is released as the pyloric sphincter opens and goes into the small intestine Strongest muscle of GI tract with thickest walls Pyloric sphincter opens about 3 times per minute to allow chyme (food contents) into the small intestine Digestion of carbs continue in the stomach and the digestion of fat and protein begin in the stomach

 Small Intestine (HUGE intestine!!) • 10 feet of tubing • Chyme enters the small intestine as the pyloric sphincter opens o Pyloric sphincter only allows a small amount of food at one time to pass by • Chyme bypasses the opening of the common bile duct which drips fluid o Fluid is from gallbladder and pancreas • Chyme travels through the 3 segments 1. Duodenum 2. Jejunum 3. Ileum • Most digestion occurs in the SI How does food move through the GI tract? • Peristalsis: wavelike muscular contractions of the GI tract that push the contents o Occurs continuously

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GI tract is ringed with circular muscles and surrounding the rings are longitudinal muscles Circular muscles tighten and long muscles relax; tube is constricted Circular muscles relax and long muscles tighten; tube bulges Stomach has third layer of diagonal muscles Sphincters open and close periodically

 Large Intestine (Colon) • Remaining contents enter the large intestine through the ileocecal valve • Large intestine withdraws water as intestinal contents pass to the rectum o Leaves a semisolid waste • Rectum and anal muscles hold back waste until rectal muscles relax and 2 anal sphincters open

Nutrition Chapter 5 Lipids (Triglycerides, Phospholipids, Sterols) Objectives: o Recognize chemistry of fatty acids and triglycerides and differences between saturated and unsaturated fats o Describe the chemistry, food sources, and roles of phospholipids and sterols o Summarize fat digestion, absorption, and transport o Outline major roles of fats in the body, including essential fatty acid and omega fatty acids o Identify which fats support health and which impair it

Types of Lipids o Triglycerides (fats and oils) o Most common type of lipid o Phospholipids o Sterol (cholesterol)

Structure of Lipids o Lipids have carbon, hydrogen, and oxygen like carbohydrates o Lipids have more calories because they have more carbon and hydrogens o Lipids are characterized by insolubility to water o All fatty acids have the same basic structure o Methyl group and an acid group with a chain of carbons and hydrogens in the middle Differences Length of chain Saturation (double bonds) Location of double bonds

Structure of Fatty Acids o Saturated Fatty Acid Fully loaded with all hydrogen No double bonds o Unsaturated Fatty Acids At least one double bond o Monosaturated Fatty Acid One double bond Ex; Oleic acid in canola and olive oil o Polyunsaturated Fatty Acid Two or more double bonds

Ex; Linoleic acid in vegetable oils

Structure (continued) o Location of double bonds Name fatty acids by location of double bond Omega number position of double bond closest to the methyl group (CH3) o Omega-3-Fatty Acid Closest double bond 3 carbons from methyl group o Omega-6 Fatty Acid Closest double bond 6 carbons from methyl group

Essential Fatty Acids - (Cannot be made by the body) o Linoleic Acid, and Omega-6 Fatty Acid Supplied by vegetable oils, meats Makes arachidonic acid (in Omega 6 family) o Linolenic Acid, and Omega 3 Fatty Acid Supplied by dark green vegetables, vegetable oils, and flaxseed Makes eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) but only in small amounts Food sources include fatty, cold water fish, shellfish, and human milk

Triglycerides - Lipid o Contain one glycerol and 3 fatty acids o Condensation forms a triglyceride and hydrolysis breaks it down

Characteristics of Fats and Oils o Firmness Degree of unsaturation determines firmness Polyunsaturated fats are liquid at room temperatures Animal or saturated fats are solid at room temperatures o Stability Polyunsaturated fat spoil (rancid) more easily than saturated fats o Hydrogenation Some or all of points of unsaturation (double bonds) are saturated by adding hydrogen molecules

Hydrogenation o Prolongs shelf life of food products by preventing oxidation o Alters textures of foods Hydrogenation makes liquids more solid o Most fats are partially hydrogenated

o

Hydrogenation can cause trans fatty acids

Phospholipids o Phosphate group is water soluble o Lipid component is fat soluble o Ex; widely known is lecithin, used as an emulsifier in mayo, salad dressings, and candy bar Sterols o Multiple ring structure o Ex; cholesterol o Plant sterols o Similar in structure to cholesterol and can interfere with cholesterol absorption o Found in margarine and other functional foods o Roles of cholesterol in the body o Used to make the active from of Vitamin D o Used by the liver to make bile o Used to make stool hormones, such as sex hormones, adrenal hormones o Used in structural component of cell membranes

Lipid Digestion and Absorption Small Intestine When fat enters, cholecystokinin (CCK) is released which signals the release of bile from the gallbladder Bile acts as an emulsifier so the enzymes can act on the fat Most fat digestion occurs in the small intestine Pancreatic lipases and intestinal lipases Lipid Absorption o Glycerol and short and medium chain fatty acids absorbed directly into the bloodstream o Monoglycerides and long chain fatty acids o Lipid transport is made possible by a group of vehicles known as lipoproteins o Chylomicrons • Largest of the lipoproteins • Least dense • Get smaller as triglycerides are removed by the cells o Very low Density Lipoproteins • Composed primarily of triglycerides • Transport liquids to tissues Get smaller and more dense as triglycerides are removed and VLDL becomes LDL o High Density Lipoproteins • Composed primarily of protein • Transport cholesterol from cells to liver o Health Implications

Functions of Lipids o Part of every cell membrane o Energy o Storage of triglycerides in adipose tissue is unlimited o Insulation of body temperature o Protection of vital organs o In foods lipids function to: o Give foods flavor and aroma o Transport fat soluble vitamins o Provide kcalories (triglycerides)

Nutrition Chapter 4 Carbohydrates: Sugars, Starches, Fibers Not all carbohydrates are created equal!!!

Carbohydrate Family Monosaccharides Simple sugars Simple carbohydrates Disaccharides Pairs of monosaccharides Simple carbohydrates Polysaccharides Large Chains of monosaccharides Complex carbohydrates Monosaccharides Three monosaccharides Glucose Fructose Galactose C6H12O6 Each differs in their arrangement in atoms Glucose: Energy source for all cells One of the two sugars in every disaccharide Polysaccharides are made of glucose Mild sweet flavor 6 sided ring Fructose: Intensely sweet flavor Occurs naturally in fruit and honey 5 sided ring Galactose: Does not have a sweet flavor 6 sided ring Position of the hydroxyl group differs from glucose Disaccharides Three Disaccharides Maltose

Glucose + glucose Produced whenever starch breaks down Sucrose Glucose + fructose Sweetest Lactose Glucose + Galactose Carbohydrate in milk (i.e. milk sugar) Contributes half of energy in milk Hydrolysis Chemical reaction breaks a disaccharide into 2 monosaccharides Molecule of water splits to provide hygrogen and OH Commonly occurs during digestion Condensation Chemical reaction that link monosaccharides Hydroxyl group (OH) and a hydrogen atom combine to form water Polysaccharides Three polysaccharides Glycogen Storage from of energy in the body 1/3 stored in liver 2/3 stored in muscle cells Built of glucose units Branched chains Food is not a good source of glycogen Starch Storage form of energy in plants Built of glucose units Branched and unbranched chains Grains are the best source of starch Rice, corn, rye, barley, oars, legumes, and starchy vegetables Fiber Pass through body undigested Soluble fibers Dissolve in water, viscous, and fermentable Oats, barley, legumes, citrus fruits Insoluble fibers Do not dissolve in water, non-viscous, less readibly fermentable Bran and vegetables

Carbohydrate Digestion Mouth Salivary enzyme amylase hydrolyzes starch into smaller molecules (shorter polysaccharides or maltose)

Stomach No new enzymes are introduced to break down carbs Salivary amylase diminishes as stomach acid and protein digesting enzymes break it down Fiber may promote satiety Small Intestine Pancreatic amylase continues breaking down polysaccharides Final digestion takes place on outer membranes of intestinal cells Maltase Breaks maltose into 2 glucose molecules Sucrase Breaks sucrose into glucose and fructose Lactase Breaks lactose into glucose and galactose Mostly glucose molecules remain Large Intestine Fibers remain and attract water Bacteria in GI tract ferment some fibers (mainly soluble) Generates water and gas Fibers do contribute a small amount of energy for the colon (~2kcal/g) Carbohydrate Absorption Primarily takes place in the small intestine Active Transport Glucose and galactose Facilitated diffusion Fructose Fructose and galactose are metabolized by the liver Glucose sent to body cells for energy

Lactose Intolerance Only about 30% of adults have enough lactase Lactose intolerable Symptoms Lactose remains undigested in intestine and attracts water Causes bloating, abdominal discomfort

Nutrition Chapter 6 Proteins Structure of Proteins Made up of amino acids Amino acids contain Nitrogen, Carbon, Hydrogen, Oxygen All amino acids have the same basic structure Central carbon atom Hydrogen atom Acid Group Amino Group Side group varies with each amino acid More complex than that or carbohydrates or lipids due to unique side group Proteins are made up of 20 different amino acids Simplest amino acid is glycine A single hydrogen and its side group Amino acids differ in size, shape, and other characteristics due to unique side group Nonessential Amino Acids More than half the amino acids are nonessential Nonessential: body can synthesize Takes nitrogen and fragments from CHO and fat to form amino acids Essential Amino Acids (9) Body cannot synthesize Must get these from our diets Structure of Proteins Amino acids are linked together to form proteins Linked together by peptide bonds Condensation reactions connect amino acids Dipeptide Two amino acids bonded together Tripeptides Three amino acids bonded together Polypeptide Multiple amino acids bonded together Structure determined by the sequence of amino acids 20 amino acids can be linked together in a variety of structures Secondary structure Determined by weak electrical attraction Positively charged H attract nearby negatively charged O Polypeptide chain twists Breakdown of Protein Structure

Denaturation Loss of shape (uncoiling) of proteins due to heat, agitation, acid Ex; hardening of an egg when it is cooked or stiffening of egg whites when they are whipped Ex; in the body- body proteins denature when e...