Nutrition Exam 1

Celiac Disease

A genetic autoimmune disorder that causes damage to the small intestine when foods containing gluten are consumed It is caused by an abnormal reaction to the protein gluten, found in rye, wheat, and barley Symptoms Reoccurring abdominal bloating Cramping and/or gas Diarrhea Foul-smelling stools Weight loss Anemia Bone or joint pain How serious is celiac disease? Increased risk for osteoporosis, diminished growth, seizures Diagnosis is made with a blood test & small intestine tissue biopsy How is it treated? Follow a gluten-free diet (GFD) Eliminate all foods that contain wheat Cross contaminated foods GFD include milk, meat, eggs, fruits, vegetables, rice, potatoes, beans, millet Gluten-free diets have become a fad People not diagnosed with celiac disease should not avoid gluten-containing foods. Why? Gluten-free diets are not healthier; many nutritious foods are eliminated from the diet Gluten itself does not provide nutritional benefits Gluten-containing foods contain nutrients that offer health benefits (fiber, vitamins, minerals) Many gluten-free products are made with refined, unenriched gluten-free grains that are high in fat, low in essential nutrients Gluten-free products are expensive

State of Nutrition

A person's state of nutrition is defined as: Healthy Malnourished Undernourished Overnourished A Registered Dietitian Nutritionist (R D N) can help determine your nutrition status. R D Ns obtain a college degree in nutrition from an Academy of Nutrition and Dietetics (A N D) accredited program and pass an exam

Added sugars

Added sugars Sugars added to processed foods and sweets Keep products moist Provide brown color to pastries and baked goods Function as preservatives and thickeners Work with yeast to make bread rise Make foods taste sweet Provide empty calories

Food Choices: Advertising

Advertising influences food selection, especially for children and adolescents Manufacturers spend $10 billion to $15 billion annually on food advertising The most advertising dollars are spent on breakfast cereals, candy, gum, and carbonated soft drinks Advertising for fruits and vegetables is rare

Carbohydrates are Absorbed as Monosaccharides

After carbohydrates are digested to monosaccharides they are: Absorbed through the intestinal cell mucosa Transported to the liver via the portal vein Metabolic needs direct the fate of the monosaccharides. Galactose and fructose Used by the liver for energy Converted to glucose Glucose Used for energy Converted to glycogen through glycogenesis Excess glucose is converted to glycerol and fatty acids for storage in adipocytes

What Are Alcohol Abuse and Alcoholism?

Alcohol abuse: When a person allows alcohol to interfere in his or her life Binge drinking Definition Males: 5+ drinks in a short time Female: 4+ drinks in a short time Associated with injuries, unsafe sexual practices, sexual assaults, aggression, hypertension, heart attack, suicide, homicide, and child abuse Can result in blackouts Can result in alcohol poisoning Drinking and driving Driving in the United States with a B A C of 0.08 or higher is illegal Underage drinking The average age of the first drink for Americans from 12 to 20 years is 14 Alcohol can interfere with brain development and lead to permanent cognitive and memory damage in teens The earlier a person starts drinking, the higher the chances that alcohol will become a problem later in life Alcoholism is a disease, also known as alcohol dependence Four classic symptoms: Craving alcohol Developed a higher tolerance for alcohol Can't control or limit intake once drinking starts A developed dependency on alcohol Risk factors for developing alcoholism Risk for alcoholism is 50% genetic Home life Drinking habits of family and friends Social pressures Access to alcohol

Alcohol affects the brain

Alcohol affects the central nervous system and other body systems It is a depressant of the central nervous system, slowing communication between neurons The more alcohol consumed, the more areas of the brain are affected Cerebral cortex: Individual becomes more talkative, less inhibited, and more confident Hippocampus: Prevents short-term memories from becoming long-term memories; individual may experience exaggerated emotions and may blackout Cerebellum: Individual loses ability to walk in a straight line Brain stem: Impaired breathing and heart rate

How is Alcohol Absorbed, Circulated, and Metabolized in the Body?

Alcohol is absorbed in the stomach and small intestine Does not require digestion; is absorbed by simple diffusion through the gastric mucosa Majority is absorbed through the duodenum of the small intestine

What is alcohol and how is it made?

Alcohol: A group of organic chemicals in which one or more hydroxyl (O H) groups are attached to the carbon atoms in place of the hydrogen atoms Ethanol: Ethyl alcohol; found in alcoholic beverages Considered safe for consumption Excess can be toxic, can damage the body, and can be lethal Glycerol: Found in food and in the body; the backbone of triglyceride Methanol: Found in industrial compounds such as antifreeze, poisonous Isopropanol: Rubbing alcohol, poisonous

What Are the Recommendations for Daily Intake of Triglycerides and Cholesterol?

Americans' fat intake is within the guidelines at 33% of total kilocalories, but the type of fat consumed must be considered A M D R recommendation 20-35% of daily kilocalories should come from fat Excess fat consumption does not lead to weight gain unless excess kilocalories are eaten Because fat contains concentrated kilocalories, a diet high in fat is more likely to result in excessive kilocalorie intake For heart health: Consume no more than 10% of total kilocalories from saturated fat (<7% of total kilocalories is ideal) Replace saturated fats with monounsaturated and polyunsaturated fats Limit trans fats to <%1 of total kilocalories

Collecting Anthropometric Data

Anthropometric data measures body size or body composition Common anthropometric measures Height Weight B M I Ideal body weight Usual body weight Waist-to-hip ratio Waist circumference Growth chart (for children and adolescents 0-20y) Body composition

Consume Antioxidants and Phytochemicals

Antioxidants and phytochemicals neutralize free radicals, stimulate the immune system to repair tissue damage, and reduce heart disease risk Vitamin E, vitamin C, and beta-carotene Garlic may help lower cholesterol Flavonoids may help prevent L D Ls from oxidizing Nuts reduce L D L levels

Heart Disease Begins with Atherosclerosis

Atherosclerosis in the arteries leading to the brain can cause a stroke Progression of atherosclerosis Injury to the lining of the arteries promotes inflammation L D Ls and other lipid substances accumulate at the injured site and become oxidized by reacting with free radicals and metal ions Macrophages are attracted to the oxidized L D Ls and then form plaques

Dietary Guidelines recommendations

Balance kilocalories Enjoy your food, but eat less Avoid oversized portions Increase the following foods Make half your plate fruits and vegetables Make at least half your grains whole grains Switch to fat-free milk or low-fat (1%) milk Reduce the following foods Compare sodium in foods such as soup, bread, and frozen meals—and choose the foods with lower numbers Drink water instead of sugary drinks The takeaway message Balance kilocalories daily and choose nutrient-dense foods from each food group Choosing nutrient-dense foods lowers fat and sugar in the diet Being physically active helps with weight management and reducing risk for disease

What are lipids

Basic functions in the body Store and provide energy Provide insulation Help manufacture steroids and bile Play a role in transporting fat-soluble nutrients in the blood Used to manufacture major sex hormones Key to the structure of cell membranes

Disorders of the stomach

Belching Generally caused by swallowing amounts of air It usually happens as a result of eating too fast, drinking carbonated beverages, or anxiety It can also occur during gum chewing or smoking Stomach flu Symptoms can include nausea, vomiting, diarrhea & abdominal cramping Treat symptoms through rest, rehydration & eating soft foods Foodborne illness Consuming food or drink contaminated with a pathogenic microbe such as E. coli, Salmonella, or Campylobacter Most are self-limiting, require rest & rehydration Ulcers A sore or erosion in the lining of the lower region of the stomach or upper part of the duodenum Helicobacter pylori, a bacterium, is often involved in the creation of ulcers Common symptoms are vomiting, fatigue, bleeding, general weakness & burning pain Treatment can include prescription drugs, dietary changes, and/or surgery An untreated ulcer can result in peritonitis, scar tissue that can obstruct food, cause vomiting, weight loss & greater risk for stomach cancer

Why is Dietary Fiber So Important for Promoting Health?

Benefits Helps lower risk of Bowel irregularity Constipation and diverticulitis Obesity Heart disease Cancer Diabetes

Digestion begins in the mouth

Both mechanical and chemical digestions begin in the mouth Mechanical digestion: Breaking down food through chewing, grinding, squeezing & moving food through the GI tract by peristalsis & segmentation Chemical digestion: Saliva Dissolves small food particles Contains amylase In adults, no other chemical digestion takes place in the mouth Once food has been adequately chewed & moistened, the tongue rolls it into a bolus and it enters the pharynx to be swallowed After the food leaves the mouth, it enters the esophagus The esophagus transports food & fluids to the stomach There are two sphincters in the esophagus: Upper esophageal sphincter (U E S): Lower esophageal sphincter (L E S):

Many Lipids Are Comprised of Fatty Acids

Building blocks for triglycerides and phospholipids A chain of carbon and hydrogen atoms with a carboxyl group at the alpha end and a methyl group at the omega end Fat has more kilocalories than carbohydrates or proteins because of the higher ratio of carbon and hydrogen to oxygen Fat: 9 kilocalories per gram Carbohydrate and protein: 4 kilocalories per gram There are many different fatty acids, which vary by:

Carbohydrate-, Protein-, or Fat-Based Fat Substitutes

Carbohydrate-based Majority of fat substitutes Use plant polysaccharides to help retain moisture and provide a fatlike texture Protein-based Created from the protein in eggs and milk Provide a creamy texture in the mouth Fat-based Modified fats that provide the physical attributes of fat for fewer kilocalories than regular fat or interfere with the absorption of fat Overconsumption of kilocalories from regular, low-fat, or fat-free products can lead to weight gain

Length of Fatty Acids

Carbon length of fatty acids is 2 to 80 carbons long Short-chain fatty acids Medium-chain fatty acids Long-chain fatty acids Long-chain fatty acids are the most common type in foods and take longer to digest than short- or medium-chain

The Nervous System Communicates with the GI Tract

Nervous system tells you when to eat, drink & stop Extrinsic nerves: Communicate changes in the G I tract & stimulate motility Originate in the brain or spinal cord Intrinsic nerves: Receive the message from the extrinsic nerves & respond by stimulating the release of digestive juices Interwoven in the linings of the esophagus, stomach, small & large intestines Hormones talk to the brain to communicate feelings of hunger or satiety: Ghrelin P Y Y

What Are the Best Food Sources of Protein?

Not all protein is created equal High-quality protein: Is digestible Contains all essential amino acids Provides sufficient protein to synthesize nonessential amino acids Several methods have been developed to determine the protein quality of foods Amino acid score Composition of essential amino acids of a protein compared with a standard, usually egg protein Protein digestibility corrected amino acid score (P D C A A S) Includes the digestibility of the protein and the amino acid score Used by the F D A to determine the %D V of proteins in a serving of food Biological value How quickly the nitrogen from the absorbed protein is synthesized into body protein Complementary and complete proteins Complete proteins Contain all nine essential AA Usually, animal sources are complete proteins Exception: Soy protein Are considered higher quality Incomplete proteins Low in one or more essential Aas, referred to as limiting amino acids Usually plant sources Complemenatry proteins Combining an incomplete protein with a food that supplies the limiting amino acids (e.g., combining grains and legumes) Eggs, meat, fish, soy and dairy contain significant amounts of protein A 3-ounce serving of cooked meat, poultry, or fish: Provides 21 to 25 grams of protein Provides about 7 grams of protein per ounce Is about the size of a deck of cards Is an adequate amount for one meal Eating a wide variety of foods is the best approach to meeting protein needs Taking protein supplements is unnecessary and generally not recommended

Nutrient density

Nutrient density is the measurement of the nutrients in a food compared to the kilocalorie content High in nutrients and low in kilocalories Provide more nutrients per kilocalorie Low in fat and added sugar Some nutrient-dense foods are high in kilocalories (e.g., avocado, peanut butter). Be mindful of the kilocalories in these foods; consume them in moderation

How are Nutrients Transported Throughout the Body?

Nutrients are absorbed into the bloodstream or lymphatic system Water-soluble nutrients are absorbed into the cardiovascular system through the hepatic portal vein to the liver Carbohydrates, amino acids & water-soluble vitamins Fat-soluble nutrients are absorbed into the lymphatic system Fat-soluble vitamins, long-chain fatty acids & proteins are too large to be transported via the capillaries The waste products that remain after nutrient absorption are removed by the excretory system The kidneys filter the blood, allowing waste products to be concentrated in the urine and excreted

Nutrients are Essential Compounds in Food

Nutrients are compounds in foods that serve as building blocks for body components and sustain body functions. The nutrients found in foods are also found in the body. Six categories of nutrients Carbohydrates Fats (lipids) Protein Vitamins Minerals Water Foods contain nonnutrient compounds Nondigestible fiber Chemicals are added by food manufacturers to: Enhance color Enhance flavor Add texture Extend shelf life

Calculating energy in foods

Each energy-yielding nutrient provides a set number of kilocalories per grams Energy-yielding nutrients Carbohydrate = 4 kilocalories/gram Protein = 4 kilocalories/gram Fat (lipid) = 9 kilocalories/gram Alcohol, a nonnutrient, also provides kilocalories. Alcohol = 7 kilocalories/gram

Eat More Fish and Plant Foods

Eat at least two, 3.5 ounce servings of fatty fish rich in omega-3 fatty acids per week Choose baked, broiled, or poached fish Limit consumption of E P A and D H A to 3 grams or less per day Increases risk for excessive bleeding May raise both blood glucose and L D L levels Intakes >3 g only occur with supplementation Omega-3 fatty acid supplements should be taken with medical supervision Pregnant women and children should consume no more than 12 o z of fatty fish per week Consume more plant foods Canola oil, soy, flaxseeds, walnuts are rich in A L A Choose plant foods rich in soluble fiber Consume at least 2 grams of plant sterols a day Shown to lower L D L levels by 10% Foods rich in plant sterols include soybean oil, many fruits, vegetables, legumes, nuts, and other plant foods as well as margarine made with plant sterols

Food Choices: Social Life and Trends

Eating with others creates social bonds and influences food choices and amount consumed Group size Individuals eat more food when eating with others Meal size increases by over 40 percent More food is eaten as the group size increases Activities Food intake increases when eaten during an activity Example: Patrons are more likely to eat popcorn at a movie theater when they are with friends Popular trends also affect food choices Frozen vegetables in the 1950s Prewashed, peeled, sliced, or diced fresh vegetables today "Organic" foods

Energy density

Energy density is a measurement of the kilocalories in a food compared with the weight of the food Most high-fat foods are energy dense Low-energy-dense foods Eating low-energy-dense foods can promote weight loss and weight management Eating low-energy-dense foods means eating larger portions for the same number of kilocalories, which may improve satiety and decrease hunger

Nutrients providing energy

Energy is the capacity to do work The body derives energy from nutrients in foods that store energy in the chemical bonds. adenosine triphosphate (A T P) is released when the bonds are broken Energy-yielding nutrients Carbohydrates Lipids (fats) Proteins Nonnutrient source of energy Alcohol

Energy in the body

Energy is trapped within bonds that keep molecules together Bonds break and energy is released Energy is used in multiple bodily functions Individual energy needs vary according to age, gender, and activity level Unused energy is stored predominantly as fat Using more energy than is consumed results in fat breakdown

Four Other Hormones Regulate Glucose Metabolism

Epinephrine and norepinephrine: Raise blood glucose Stimulate glycogenolysis and gluconeogenesis Released from the adrenal glands Cortisol: Increases blood glucose Stimulates gluconeogenesis Reduces uptake of glucose by the muscle cells Growth hormone: Conserves blood glucose Stimulates fat breakdown for energy Reduces uptake of glucose by the muscle cells Increases glucose production in the liver

Essential, Nonessential, and Conditional Amino Acids

Essential Must be consumed in the diet Nine essential amino acids Nonessential Can be synthesized in the body Eleven essential amino acids Conditionally essential Nonessential amino acids that become essential because the body cannot make them Examples: Tyrosine and glycine

Essential nutrients

Essential nutrients Must be consumed from food Cannot be made in the body in sufficient quantities to meet its needs and to support health Nonessential nutrients Can be made in sufficient quantities in the body to meet the body's requirements and to support health Conditionally essential nutrients Nonessential nutrients become essential under some circumstances

Food labels regulated by FDA

Every packaged food must be labeled with: Name of food Net weight—the weight of the food in the package, excluding weight of the package or packing material Name and address of the manufacturer or distributor List of ingredients in descending order by weight Nutrition Labeling and Education Act in 1990 mandated: Uniform nutritional information Serving sizes Specific criteria for nutrient descriptors & health claims Additional requirements for the label since 1990 include: Nutrition information: total kilocalories, kilocalories from fat, total fat, saturated fat, trans fats, cholesterol, sodium, total carbohydrate, dietary fiber, sugars, vitamin A, vitamin C, calcium, and iron Uniform serving sizes among similar products Indication of how a serving of the food fits into an overall daily diet Uniform definitions for descriptive label terms such as "light" and "fat free" Health claims that are accurate and science-based, if made about the food or one of its nutrients Presence of the eight common allergens Some foods are under the F D As voluntary point-of-purchase program Raw fruits and vegetables and fresh fish do not have a label Stores must post the nutrition information on the most commonly eaten fruits, vegetables, and fish near where the products are sold Meat and poultry is regulated by the U S D A Food labels in grocery stores are required and must indicate in which country the animal was born, raised, and slaughtered

Most nutrients are organic

Nutrients that contain carbon in their chemical structures are "organic" Organic nutrients include: Carbohydrates Proteins Lipids Vitamins Inorganic nutrients include: Minerals Water

What is nutrition?

Nutrition is the science that studies how nutrients and compounds in foods nourish the body and affect body functions and overall health. Exploration of how food is: Digested Absorbed Transported Metabolized Used or stored in the body

Assessing Dietary Intake through Questionnaires and Interviews

Obtaining dietary intake and diet history data is an important aspect of nutrition assessment Two tools to collect dietary intake data Food frequency questionnaires (F F Qs) Identifies patterns of intake over time Dietary interviews Food record Diary of the foods and beverages eaten, how much, and when they are eaten over a period of time 24-hour recall Quick assessment by a trained interviewer Asks client to recall all food and drinks eaten in the previous day

Oligosaccharides Have Fewer Sugar Units

Oligosaccharides contain 3 to 10 monosaccharides Similar to both monosaccharides and polysaccharides Monosaccharides: Similar in length Polysaccharides: Both make up cellulose in plant cell walls and, like fiber, both escape digestion Food sources: Found in human breast milk

Food Choices: Nutrition Knowledge

Perception of foods as healthy or unhealthy Example: Avoid high-sodium foods to reduce blood pressure Current state of health affects food choices Example: Avoid foods associated with weight gain or loss

Phospholipids and Cholesterol Make up Cell Membranes

Phospholipids: Cholesterol:

What are Carbohydrates and How Are They Classified?

Produced by plants during photosynthesis After eating plant foods, humans convert the carbohydrates Glucose Most abundant carbohydrate Preferred source of energy for the body Carbohydrate-rich plant foods make up the foundation of diets all over the world

What Are the Immediate and Short-Term Effects of Alcohol Consumption on the Body?

Products of alcohol metabolism—acids and acetaldehyde—can harm the body and brain Effects can be short-term (while the individual is intoxicated) and long-term (>72 hours following intoxication)

MyPlate proportionality

Proportionality is the relationship of one entity to another Vegetables and fruits should be consumed in higher proportion than dairy and proteins in the diet Fruits & vegetables should make up half the plate Smaller portions should come from grains and lean protein sources

How is Protein Metabolized?

Protein can be used for gluconeogenesis If too few carbohydrates are consumed, the body converts glucogenic AA into glucose Excess protein is converted to fatty acids and stored as triglycerides in adipose tissue If too few kilocalories are consumed, protein will be oxidized for energy

What Are the Key Steps in Digesting and Absorbing Protein?

Protein digestion begins in the stomach The bolus enters the stomach Gastrin stimulates the release of H C l H C l denatures the protein and converts pepsinogen to pepsin Pepsin breaks polypeptides into shorter chains Digestion continues in the small intestine Polypeptides enter and are broken down into smaller peptides Cholecystokinin stimulates the release of proteases by the pancreas Proteases break apart the polypeptides to tripeptides and dipeptides Dipeptidases and tripeptidases break the dipeptides and tripeptides into AA AA absorption AA are absorbed in the small intestine AA acids are transported to the liver from the intestines via the portal vein. In the liver, AA are: Used to synthesize new proteins Converted to energy, glucose, or fat Released to the bloodstream and transported to cells throughout the body Occasionally proteins are absorbed intact

Proteins Differ Structurally from Carbohydrates and Lipids

Protein is made up of chains of amino acids (AA) that are made based on an individual's D N A Excess dietary protein cannot be stored in the body Proteins contains carbon, hydrogen, oxygen and nitrogen Some protein foods contain sulfur - not in carbohydrates or lipids

What Functions Do Carbohydrates Perform in the Body?

Provide energy 4 kilocalories per gram Maintain blood glucose levels Glucose is the primary fuel for the brain Glycogenolysis occurs 4 hours after a meal Muscle glycogen cannot be used to raise blood glucose levels Spare protein Prevents ketosis

What is the Function of Protein in the Body?

Provide structural support and enable movement Act as a catalyst Enzymes speed up reactions Act as a chemical messenger Hormones regulate cell actions Regulate fluid balance Help maintain acid-base balance Transport substances throughout the body Transport proteins shuttle oxygen, waste products, lipids, some vitamins and sodium and potassium through the blood and cell membranes Contribute to a healthy immune system Antibodies are proteins that bind and neutralize pathogens that would harm the body Provide energy 4 kilocalories/gram Improve satiety and appetite control

Stability of Fatty Acids

Rancidity: Spoiling of fats through oxidation Manufacturers have enhanced the stability of fatty acids by reducing rancidity Adding antioxidants Limiting food exposure to oxygen, heat, and light Hydrogenation

The Accessory Organs Secrete Digestive Juices

Salivary glands Dissolve small food particles to ease the process of swallowing food The body produces 1 quart of saliva per day Saliva contains water, mucus, electrolytes & a few enzymes Liver Largest internal organ in the body, weighing 3 pounds Major player in the digestion, absorption & transport of nutrients Essential in carbohydrate metabolism Makes proteins Manufactures bile salts that are used to digest fats Site of alcohol metabolism, removes & degrades toxins & excess hormones Gallbladder Receives bile from the liver via common hepatic duct Concentrates bile Releases bile into small intestine via common bile duct Pancreas Endocrine function: Exocrine function:

Dietary Fat Aids the Absorption of Lipid Compounds

Several essential nutrients require dietary fat for absorption Fat-soluble vitamins Carotenoids Cholesterol Phospholipids Twenty grams per day are needed to stimulate chylomicrons that transport fat-soluble vitamins

Conducting Physical Examination

Several parts of the body can be inspected during the physical examination for evidence of poor nutrition Areas of the body that show signs of malnutrition Hair Skin Eyes Fingernails Tongue Lips

Classification of carbohydrates

Simple carbohydrates Monosaccharide Disaccharide Perceived as sweeter than complex carbohydrates Mix with saliva and react with taste buds Oligosaccharides Complex carbohydrates

Two types of fiber

Soluble fiber Dissolves in water Easily fermented by bacteria in the intestine Examples: Pectins, mucilages, beta-glucans Health benefits Insoluble fiber Does not dissolve in water Not easily fermented by bacteria in the intestine Examples: Cellulose, lignins, some hemicelluloses Health benefits

Whole Foods are the Best Sources of Carbohydrates

Some carbohydrate-rich foods are nutritionally better than others Focus on whole foods such as grains, vegetables, fruits, and beans Best choices should include: Nutrient-dense, low-saturated-fat foods, with low amounts of simple carbohydrates Higher amounts of fiber and complex carbohydrates Whole grains Whole grains are abundant in complex carbohydrates, including starch and fiber Whole grains are associated with reduced risk of chronic diseases MyPlate recs at least 3 servings of whole grains a day Examples include: Whole-grain breads and cereals with 2 to 3 grams of fiber per serving Bulgur, brown rice, quinoa, oatmeal, and whole-wheat pasta Low-fat and fat-free dairy products Contain 1 to 17 grams of lactose Choose low-fat or fat-free products Fruits and vegetables provide simple sugars, starch, and sugar Focus on 100% juices, whole fruits & vegetables The flesh of fruits contains simple sugars and pectin The skin of fruits contains cellulose Vegetables contain starch and fiber Legumes, nuts, and seeds Legumes provide an average of 4 grams of fiber per serving Nuts and seeds contain very little starch but are good sources of fiber Packaged foods can be good sources of carbohydrates Good sources of starches but can also contain high amounts of added sugars, fat, sodium, and kilocalories Consume in moderation

What are the Dietary Reference Intakes (D R Is)?

Specific amounts of each nutrient one needs to consume to: Maintain good health Prevent chronic diseases Avoid unhealthy excess D R I s are updated periodically by a group of U.S. and Canadian scientists and health experts. Committees are organized by the Institutes of Medicine

Polysaccharides Consist of Many Sugar Units

Starch Plants store glucose in chains of starch Amylose: Straight chain of polysaccharides found in starch; 40% of starch is amylose Resistant starch is not digested in the G I tract May improve health of digestive tract May improve glucose tolerance May stimulate growth of beneficial intestinal bacteria Amylopectin: Branched chains of polysaccharides found in starch; 60% starch is amylopectin Fiber Most forms are nondigestible polysaccharides and occur naturally as a structural component called cellulose Most plant foods contain both soluble and insoluble fibers Overall fiber intake is the most important aspect of the diet rather than the type eaten Animal products do not contain fiber Functional fiber is a type of fiber that has been extracted or isolated from a plant or manufactured by the food industry, and has been shown to have health benefits Glycogen Storage form of glucose in animals Long, branched chains of glucose Stored in liver and muscle Liver glycogen response to blood glucose (B G) levels: Muscle glycogen can be broken down for energy to the muscle Animal products do not contain glycogen

Food Choices: Taste and Enjoyment

Taste and texture influence food choices Taste is the most important factor in food selection Preferences for sweet, high fat, and specific textures begin early in life Taste preferences Salt and sweet are most preferred Starts in infancy Degree of preference is influenced by genetics and can change with age. Humans have a taste for fat May be genetically linked Texture influences enjoyment of foods

D R I s Encompass Several Reference Values

The D R I s cover five reference values: Estimated Average Requirement (E A R) Recommended Dietary Allowance (R D A) Adequate Intake (A I) Tolerable Upper Intake Level (U L) Acceptable Macronutrient Distribution Range (A M D R) The R D A or A I (not both), the A M D R, and the U L are used to assess the quality of meals Estimated Average Requirement (E A R) Amount of a nutrient projected to meet the needs of 50% of healthy Americans by age and gender Based on measurement that determines whether an individual is at risk for deficiency E A Rs are not established when there is insufficient research to develop an appropriate measurement for a nutrient Once set, the E A Rs are used to calculate R D A s Recommended Dietary Allowance (R D A) Recommendation for each nutrient that should meet the needs of nearly all (97-98%) of the individuals in a specific gender and age group Higher than the E A R Not available for all nutrients For nutrients with no R D A, Adequate Intake (A I) can provide an alternative guideline Adequate Intake (A I) Estimate based on the judgment of the Food and Nutrition Board (F N B) members, according to current research Next best scientific estimate of the amount of a nutrient that groups of similar individuals should consume to maintain good health Set without having established E A Rs Only estimation for nutrients to determine dietary adequacy in infants Tolerable Upper Intake Level (U L) Highest amount of a nutrient that is unlikely to cause harm if consumed daily Consumption above this level increases risk of toxicity Not all nutrients have U Ls Acceptable Macronutrient Distribution Range (A M D R) Ensure that intake of nutrients is adequate and proportionate to physiological needs Carbohydrates: 45 to 65 percent of daily kcals Fats: 20 to 35 percent of daily kcals Proteins: 10 to 35 percent of daily kcals Estimated Energy Requirement (E E R) Amount of daily energy needed to maintain a healthy body weight and meet energy needs based on age, gender, height, weight, and activity level No D R I has been set for energy intake Individuals who consume more energy than needed will gain weight

The Liver Uses Cholesterol to Make Hormones, Bile, and Vitamin D

The body uses cholesterol as starting material for: Vitamin D and sex hormones such as estrogen and testosterone Bile acid

How Do We Maintain Blood Glucose Levels?

The body wants to keep blood glucose between 70 milligrams/deciliter and 110 milligrams/deciliter Two hormones are responsible for maintaining this level Insulin: Needed for glucose to enter the cell from the bloodstream Liver, kidney & brain cells can use glucose without insulin Stimulates glycogenesis Stimulates lipogenesis Inhibits lipolysis Glucagon: Increases blood glucose levels Stimulates the release of glucose into the blood Stimulates glycogenolysis Stimulates glucose production Promotes the conversion of lactic acid to glucose

Saturation of Fatty Acids

The degree of saturation of a fatty acid is determined by whether the carbons are held together by a double or single bond Saturated Fatty Acids Unsaturated Fatty Acids Monounsaturated fatty acid (M U F A) Polyunsaturated fatty acid (P U F A)

Triglyceride Digestion Begins in the Mouthand Stomach

The digestion of fat begins in the mouth with chewing Food mixes with saliva and lingual lipase Lingual lipase hydrolyzes the medium-chain fatty acids The bolus of food travels through the esophagus into the stomach Gastrin is released from the gastric pits lining the stomach and stimulates the release of gastric juices, rich in gastric lipase Gastric lipase hydrolyzes one fatty acid from the triglyceride, which produces a free fatty acid and a diglyceride

How Do Hormones and the Nervous System Regulate Digestion?

The endocrine & nervous systems work together to coordinate digestion, absorption & excretion of waste products Digestion runs smoothly when the endocrine system communicates with the nervous systems built into the G I tract Digestion is also controlled by the enteric nervous system, a meshwork of nerve fibers that innervate the G I tract, pancreas & gallbladder The enteric nerves monitor stomach contractions after eating & the secretions of the cells in the G I tract

The exchange system

The exchange system is a diet planning tool used to create meal plans based on the macronutrient content and total kilocalories of foods. Groups foods together based on carbohydrate, protein, and fat content Provides specific portion sizes for each food so each food in the group provides a similar amount of kilocalories per exchange Six food groups in the exchange lists Starch Fruit Milk Vegetables Meat Fat Useful tool to control kilocalories, protein, and fat intake

Does Moderate Alcohol Consumption Provide Health Benefits?

The health benefits of moderate alcohol consumption are inconclusive One to two drinks of red wine may promote heart health May reduce the accumulation of oxidized L D L on the arterial walls May inhibit the stickiness of platelets in the blood May increase H D Ls May reduce inflammation Reduces high blood pressure It appears to only benefit males >45 years and females >55 years Moderate consumption may reduce the risk of diabetes Moderate consumption may increase insulin sensitivity in Type 2 diabetes Limit consumption to one to two drinks per day and drink with a meal to prevent hypoglycemia Moderate consumption is associated with longevity Wine consumption and dark-colored beer offer the most protection compared to light beer and liquor

Lipoproteins Transport Lipids

Four lipoproteins carry lipids in the circulatory system V L D Ls, L D Ls, and H D Ls Globular molecule with a lipid center surrounded by a plasma membrane Density determines function More protein = higher density

Water

Function: Makes up the majority of all body fluid Part of every cell in the body Essential during metabolism, digestion and absorption Transport medium that delivers nutrients and oxygen to cells and excretes waste products through urine Maintenance of body temperature Lubricant for joints, eyes, mouth, and intestinal tract Cushions vital organs Cannot be stored; must replenish daily

Functional foods/Phytochemicals

Functional foods: Foods that may provide additional health benefits beyond the basic nutrient value See table 1.2 Phytochemicals: Nonnutritive plant chemicals found in foods that reduce risk for developing chronic diseases In foods, 900 different phytochemicals work with other nutrients in foods to offer disease-fighting characteristics Zoochemicals Nonnutritive animal compounds that play a role in fighting chronic diseases Example: Omega-3 fatty acids from fish may improve heart health and reduce inflammation

Esophageal Problems

Gastroesophageal Reflux Disease (G E R D) (also known as indigestion or acid reflux) The lower esophageal sphincter doesn't close properly, allowing H C l from the stomach to flow into the esophagus Chronic heartburn & stomach acid reflux are typical symptoms Factors generally associated with G E R D include: Chocolate, fatty foods, coffee, soda, onions, garlic Smoking, being overweight or obese, drinking alcohol, wearing tight-fitting clothing, eating large evening meals, reclining after eating Dietary changes, behavior modification, antacids, prescription drugs, or surgery may help Esophageal cancer This is one of the most common cancers of the digestive tract Sufferers are typically males over age 50, living in urban areas, who smoke and drink heavily Treatment can include surgery, radiation & chemotherapy

Gender, Genetics, and Ethnicity Affect Blood Alcohol Levels

Gender Women feel the narcotic effect of alcohol sooner than men Females have 20-30% less alcohol dehydrogenase and less body water Genetics Individuals with genetic polymorphisms of alcohol dehydrogenase feel the effects of alcohol more readily Ethnicity Some ethnic groups feel the effects of alcohol more readily than others

Glycemic Index and Glycemic Load Can Be Used for Meal Planning

Glycemic Index (G I) is a rating scale of the likelihood of foods to increase the levels of blood glucose and insulin Concerns: Glycemic load (G L) is the amount of carbohydrate in a food multiplied by the amount of the G I of that food

How much protein do you need daily?

Healthy adults should be in nitrogen balance Consume enough to replace what is used every day Individuals in positive nitrogen balance Pregnant woman, people recovering from surgery or injury, and growing children Should consume enough to build new tissue Individuals in negative nitrogen balance Immediately after surgery, fighting an infection, or severe emotional trauma Need to consume enough kilocalories and protein to meet demand

Fiber Helps Prevent Heart Disease, Diabetes, and Cancer

Heart disease Viscous, soluble fiber helps lower elevated blood cholesterol levels Soluble fiber interferes with the reabsorption of bile acids, which contain cholesterol, by sequestering the bile acids Fiber and bile acids are excreted in the feces Slow-moving, viscous, soluble fiber may reduce the rate at which fat and carbohydrate are absorbed Decreasing the level of fat in the blood and improving insulin sensitivity may decrease the risk of heart disease Insoluble fiber has been shown to promote heart health Diabetes Viscous soluble fiber helps slow digestion and absorption of glucose, helping control blood glucose levels Higher consumption of fibers from cereals has been shown to reduce the risk of developing diabetes Fiber helps reduce the incidence of several cancers Decreases the amount of time cancer-promoting substances spend in contact with the intestinal lining Encourages the growth of colon-friendly bacteria and their fermentation by-products Reduces concentration of bile acids in the colon

Hormones in the G I Tract Regulate Digestion

Hormones regulate digestion by controlling: The release of gastric & pancreatic secretions Peristalsis Enzyme activity Enterogastrones are produced & secreted by the cells lining the stomach & small intestine They influence G I motility, stomach emptying, gallbladder contraction, intestinal absorption & hunger

Foods with Trans Fats

Hydrogenation: Replacing saturated fat with hydrogenated fat During the hydrogenation process, some of the double bonds are reconfigured The unstable cis fatty acids in the double bond form trans fatty acids Some trans fats are naturally occurring Trans fat may actually be worse for heart health than are saturated fats Raise L D L and lower H D L cholesterol The F D A requires trans fat to be listed on food labels

Hypoglycemia Results When Blood Glucose Drops Below Normal

Hypoglycemia is a blood glucose level < 70 milligrams/deciliter Occurs with excess insulin production Signs and symptoms: Hunger, dizziness, feeling light-headed, confused, weak, or beginning to sweat Treatment

Macronutrients and micronutrients

Macronutrients Nutrients the body needs in large amounts Carbohydrates, fats (lipids), proteins, and water Micronutrients Essential nutrients the body needs in smaller amounts Vitamins and minerals

What are proteins?

Macronutrients found in each cell in the body Participate in every cellular activity that helps the body to function All enzymes are made of proteins Some hormones are made of proteins

Phospholipids Differ from Triglycerides

Made of a glycerol backbone and two fatty acids, a phosphate group, and different nitrogen-containing compounds Hydrophilic on one end; hydrophobic on the other Make up the phospholipid bilayer in the cell membrane Lecithin (aka phosphatidylcholine) is a type of phospholipid Synthesized by the liver Functions

Sterols Are More Complex Than Triglycerides

Made of four connecting rings of carbon and hydrogen They do not contain glycerol or fatty acids They do not provide energy Cholesterol is the best known sterol Found in every cell in the body Helps with numerous body processes Precursor to vitamin D, sex steroids, and adrenal corticoids Phytosterols and phytostanols are major plant sterols

Treatment for P E M

Medical and nutritional treatment can dramatically reduce the mortality rate Should be implemented carefully and slowly Step 1: Address life-threatening factors Severe dehydration Fluid and nutrient imbalances Step 2: Restore depleted tissue Gradually provide nutritionally dense kilocalories and high-quality protein Step 3: Transition to foods and introduce physical activity

Minerals

Minerals assist in body processes and are essential to the structure of hard and soft tissues like bone and red blood cells Major Need at least 100 milligram/day Found in amounts of at least 5 grams in the body Trace Need less than 100 milligram/day Found in amounts of less than 5 grams in the body

Moderation

Moderation is the dietary principle of consuming reasonable but not excessive amounts of foods and nutrients All foods can be included in a healthy diet as long as they are consumed in moderation Consume foods high in added sugars and fat in smaller amounts Limit portions and number of servings of nutrient-dense and energy-dense foods such as nuts

Monosaccharides Are Single Sugar Units

Monosaccharide Three nutritionally important monosaccharides Glucose Most abundant monosaccharide in the body and foods Fructose Sweetest of natural sugars Found abundantly in fruits Part of high-fructose corn syrup Galactose Commonly occurs as part of the disaccharide lactose Rarely found on its own The structure of the three monosaccharides is a hexose.

A Healthy Diet Can Positively Affect Gene Expression

Most chronic diseases stem from the interplay among our genetic makeup, our environment, and our diet Some genes have variations that make us more susceptible to diseases, whereas other gene variants enhance our ability to resist chronic disease Nutritional genomics studies the relationship among gene expression, nutrition, and health

Triglycerides Are the Most Common Lipid

Most common lipid in both foods and the body Make up about 95% of lipids found in foods A triglyceride molecule has three fatty acids connected to a glycerol backbone Functions Add texture to baked goods Make meats tender Preserve freshness Stored as adipose tissue for energy

Surveys are Used to Assess the Nutritional Status of a Population Group

National surveys have been developed by federal agencies to assess the health and nutritional status of Americans The National Health and Nutrition Examination Survey (NH ANES) Series of surveys that evaluate the nutritional status of Americans of all ages The Framingham Heart Study Collection of data on two generations and over 10,000 people to establish recommendations for cardiovascular disease

The Best Food Sources Are Low in Saturated Fat

To replace or lower saturated fats with unsaturated fats, consume the following foods: Increase alpha-linolenic acid (Omega-3 fatty acids) by consuming: Avoid cod-liver oil It is impossible to eliminate all saturated fat from the diet Primary saturated fat sources Tips for lowering saturated fats Limit intake of foods rich in saturated fat Consume lower fat versions of fat-containing foods Read the Nutrition Facts panel to help you choose foods that are low in fat

Nonessential Amino Acids Are Synthesized through Transamination

Transamination is the process of forming nonessential AAs by transferring the nitrogen from one AA to a keto acid to form a new nonessential AA

The Building Blocks of Proteins Are Amino Acids

Twenty AA are used to make proteins Proteins are classified by the # of AA in the chain Peptides: Fewer than 50 AA Dipeptides: 2 AA Tripeptides: 3 AA Polypeptides: More than 10 AA Proteins: More than 50 AA Typically 100 to 10,000 amino acids linked together Anatomy of an AA Contains an amine group (N H2), a carboxylic acid group (C O O H), and a side chain (R group) The side chains make each AA unique and influence the function of each amino acid Peptide bonds Form when the carbon of the acid group of one amino acid joins with the nitrogen atom of the amine group of a second amino acid Formed through condensation Broken through hydrolysis

Hormones in the G I Tract Regulate Digestion: types

Types of hormones Gastrin: Stimulates H C l production & the release of gastric enzymes Secretin: Stimulates the pancreas to release bicarbonate to the small intestine Cholecystokinin (C C K): Stimulates the pancreas to release lipase & the gallbladder to release bile Gastric inhibitory peptide (G I P): Inhibits gastric motility & stomach secretions

Variety

Variety is the dietary principle of including a mixture of different food groups and foods within each group Eating a variety of foods improves diet quality No food or food group contains every single nutrient needed to be healthy Individuals should choose a variety of foods within groups and among groups to achieve a healthy diet

Lipoproteins Transport Fat

Very-low-density lipoproteins (V L D Ls) Transport triglycerides (T Gs) and cholesterol from the liver to the cells Lipoprotein lipase located on the outside of adipocytes and muscle cells cleave fatty acids (F As) from T Gs FAs move into the adipocyte and muscle cells and stored for later use Increases the ratio of protein to lipids Process converts V L D Ls to L D Ls H D L and L D L biomarkers are used to determine the health of arteries L D Ls H D Ls

Vitamins

Vitamins function as coenzymes—they help enzymes catalyze reactions in the body Two classifications Water-soluble Not stored in the body Need to be consumed daily Eight B-complex vitamins and vitamin C Fat-soluble Stored in the body Vitamins A, D, E, and K

Deamination Removes the Amine Group from Amino Acids

When the AA pool reaches capacity, the AA are broken down to their component parts for other uses Deamination occurs when the amine group is removed from the AA Ammonia is formed Ammonia is converted to urea in the liver Urea is subsequently excreted in the urine. Carbon-containing remnants are: Converted to glucose (if they are glucogenic AA through gluconeogensis) Converted to fatty acids and stored as triglycerides in adipose tissue Oxidized for energy via metabolic pathways

How is Food Chemically Digested?

Chemical digestion is: Carried out by digestive enzymes & other substances Regulated by hormones Completed by the time the food reaches the large intestine Enzymes are proteins that drive the process of digestion They catalyze (or speed up) hydrolysis: The chemical reaction that uses water to split chemical bonds of digestible nutrients The hydroxyl group (O H) from water joins one molecule while the hydrogen ions (H) join the other molecule Three conditions are required for enzymes to work 1. The compatible enzyme & nutrient are both present Enzymes are compatible only with a specific compound or nutrient (substrate) They are named according to the substrate they act upon, plus the suffix -ase Example: Sucrase hydrolyzes sucrose 2. The p H of the surrounding environment must fall within the correct range Enzymes are most active & efficient within a certain range of acidity & alkalinity Outside of that range, the enzyme activity is decreased or halted 3. The temperature of the environment must be optimal Enzyme activity is slowed with too low temperature and halted when the temperature is too high

The Large Intestine Absorbs Water and Some Nutrients

Chyme enters the large intestine through the ileocecal valve The large intestine is 5 feet long & 2.5 inches in diameter The large intestine has three segments: Cecum: The beginning of the intestine Colon: The largest part of the intestine Rectum: Final 8-inch portion of the large intestine Bacteria produce vitamin K, thiamin, riboflavin, biotin & vitamin B12, but only biotin & vitamin K can be absorbed Bacteria in the colon ferment some undigested & unabsorbed carbohydrates into simpler compounds, methane gas, carbon dioxide & hydrogen In the large intestine, 1 liter of fluid material is gradually reduced to 200 grams of brown fecal material The intestinal matter passes through the large intestine in 12 to 70 hours, depending on the person's health, age, diet & fiber intake Stool is propelled through the large intestine until it reaches the rectum The anus is the opening of the rectum or end of the G I tract The final stage of defecation is under voluntary control It is also influenced by age, diet, prescription medications, health & abdominal muscle tone

Nutrient content claims

Claims on the food label that describe the level or amount of a nutrient in the food Terms such as free, high, low, reduced, extra lean, or lite are examples of nutrient content claims

Structure/function claims

Claims on the label describe how a nutrient or dietary compound affects the structure or function of the human body Structure/function claims cannot state that the nutrient or compound can be used to treat a disease or condition Dietary supplements that use structure/function claims must display a disclaimer on the label stating that the F D A did not evaluate the claim and that the dietary supplement is not intended to "diagnose, treat, cure, or prevent any disease." These claims are the weakest

Vitamins/Minerals in metabolism

Composition: Vitamins: Carbon, hydrogen, and oxygen Minerals: Just the mineral Function: Do not provide energy Metabolism regulation Deficiencies in vitamins and minerals cause: Fatigue Stunted growth Weak bones Organ damage

Lipids also provide energy

Composition: Carbon, hydrogen, and oxygen Three categories of lipids: Triglycerides Sterols Phospholipids Function: Provide energy to cells, structural component to cell membranes Food sources: Margarine, butter, oils, and animal products

Carbohydrates are the Primary Energy Source

Composition: Carbon, hydrogen, and oxygen Function: Supply glucose, the primary energy source for many body cells (red blood cells & brain cells) Food sources: Plants: Breads, cereals, legumes, nuts, fruits, and vegetables Animal: Dairy products are the only animal products that provide significant carbohydrates.

Proteins Provide the Building Blocks for Tissue Synthesis

Composition: Carbon, hydrogen, oxygen, and nitrogen (some contain sulfur) Function: Contribute the basic building blocks (amino acids) that are used to synthesize, grow, and maintain tissues Primary source of tissues in muscles, bones, and skin Participate as neurotransmitters Play a role in the immune system Act as enzymes Energy source, but not a primary energy source

Fiber Helps Prevent Constipation and Diverticulosis

Constipation is caused by sluggish muscle contractions in the colon that move the stool too slowly leading to excessive water absorption Causes formation of hard, dry stools that are painful to expel Treatment: Insoluble fiber helps reduce transit time of foods in the colon Soluble fiber helps make stool easier to pass by increasing bulk and softening texture Chronic constipation can lead to diverticulosis and diverticulitis Diverticulosis is a condition in which increased pressure in the colon causes weak spots along the wall, forming pouches called diverticula Infection of the diverticula is diverticulitis

Health claims

Contain two important components A food or a dietary compound (e.g., fiber) A corresponding disease or health-related condition that is associated with the substance There are three types: Authorized health claims Health claims based on authoritative statements Qualified health claims

Lactose intolerance

Deficiency of lactase, the enzyme that digests lactose Lactose maldigestion: Lactose intolerance: When symptoms of lactose maldigestion result in nausea, cramps, bloating, flatulence, and diarrhea Diet recommendations for lactose maldigestion Most individuals can continue to consume milk, cheese, and yogurt without any side effects Diet recommendations for lactose maldigestion (cont'd) Vary depending on the individual's threshold Consume small amounts of dairy throughout the day Eat lactose-containing foods with a meal or snack Whole milk tends to be better tolerated than skim milk Cheese has less lactose than milk, especially hard, aged cheese such as Swiss, cheddar, blue, and parmesan Consume yogurt with live, active cultures Consume lactose-reduced products or take lactose pills or drops with foods

Denaturation of Proteins Changes Their Shape

Denaturation (unfolding) of proteins occurs in the presence of: Heat Acids Bases Salts Mechanical agitation Altering the shape of the protein alters its function Primary structure is unchanged by denaturing

Diabetes

Diabetes mellitus (DM) is a medical condition in which an individual doesn't have enough insulin or is resistant to the effects of insulin, which results in a rise in blood glucose levels An estimated 29.1 million Americans have diabetes Of these, 8.1 million are not diagnosed There is a steady rise in Type 2 DM in children Medical cost associated with DM is $170 billion annually in the United States Type 1 Diabetes Autoimmune disease where the immune system destroys beta cells of the pancreas No insulin produced Usually begins in childhood or early adulthood 5 to 10 percent of diabetics Common symptoms of elevated blood sugar Polydipsia: Uncontrollable thirst Polyuria: Excessive urination Polyphagia: Strong desire to eat Requires daily insulin injections and blood glucose monitoring Type 2 Diabetes Overweight & obesity increase risk for developing Type 2 DM 90-95% percent of diabetics Produce insulin but have become insulin resistant Pancreas overproduces insulin and eventually decreases production from overuse Can go undiagnosed for some time Damages vital organs without individual being aware of it Screening Everyone over 45 years of age should be tested every 3 years; overweight people should be tested earlier Overweight children should be screened at age 10 and older Gestational diabetes Diagnosed when a woman develops it during pregnancy with no previous diagnosis of diabetes The cause is the ineffectiveness of insulin, most likely due to the influence of pregnancy-related hormones Uncontrolled glucose can cause a larger newborn baby and complications during pregnancy

Gallbladder Disease

Diagnosed most frequently in women & older Americans Obesity & rapid weight loss are contributing factors An unhealthy gallbladder can create gallstones Stones are formed from cholesterol in the gallbladder or bile duct Treatment includes surgery for gallbladder removal, prescription medication, shock-wave therapy, or a combination of therapies The body eventually adapts to the removal of the gallbladder by secreting bile directly into the duodenum

Planning healthy diet

Dietary Reference Intakes (D R I s) Provide recommendations on nutrient needs for individuals Dietary Guidelines for Americans Provides broad dietary and lifestyle advice MyPlate (ChooseMyPlate.gov) Web-based tool that helps individuals implement the recommendations of the D R I s and Dietary Guidelines Exchange System Groups foods according to macronutrient content to be used for meal planning Nutrition Facts Panel Provides the Daily Values and information to help consumers choose healthy foods

Cholesterol and Plant Sterols

Dietary cholesterol The cholesterol produced in plant cell walls and oils Phytosterols and stanols Are found in soybean oil, many fruits, vegetables, legumes, sesame seeds, nuts, cereals, and other plant foods

What are the Processes and Organs Involved in Digestion?

Digestion: Absorption: Transport: Elimination: The G I tract is a 23-foot-long muscular tube comprised of the organs of the digestive tract Five organs make up the G I tract: Accessory organs

How do we digest and absorb carbohydrates?

Disaccharides and starch are digested into monosaccharides Monosaccharides are easily absorbed by the small intestine Fiber passes through the G I tract undigested

Disaccharides Consist of Two Sugar Units

Disaccharides are formed when two monosaccharides join together through a process called condensation Three disaccharides Sucrose (table sugar) Most common Found naturally in sugar cane and sugar beets Lactose (milk sugar) Found in dairy products Maltose Least common Formed from digestion of starches

Most Triglycerides Are Digested and Their Components Absorbed in the Small Intestine

Fat globules in chyme tend to cluster together In the intestine  This allows pancreatic lipase to digest the lipids easily The resulting lipid complex is a micelle Cholecystokinin (C C K) Phospholipids Emulsified by bile during digestion Dismantled into two free fatty acids and the phospholipid remnant Packaged as micelles Transported through intestinal wall Sterols Not digested Carried by the micelle and absorbed intact through intestinal wall Bile emulsifies sterols If lipids are undigested and not absorbed in the small intestine, they: Bind with fiber Are eliminated in the feces

Triglycerides Stored in Adipose Tissue Insulate the Body and Protect Vital Organs *

Fat in subcutaneous tissue Fat protects bones and vital organs from trauma Too much stored fat can be detrimental to health

Fats Are Used for Energy

Fats are a powerful fuel source Preferred by the heart, liver, and resting muscle Spares glucose so it is only used by the central nervous system and red blood cells Provides a backup source of energy between meals Cannot sustain life during prolonged starvation Glucose is needed to metabolize fat The glycerol portion of fat can make small amounts of glucose

Fatty Acids Are Used for Energy

Fatty acids provide a concentrated source of kilocalories 9 kilocalories per gram Readily available when the body needs energy Body's main source of energy throughout the day Excess fat is stored The body has an unlimited ability to store excess energy as fat in adipocytes Fat cells can grow up to 1,000 times their original size Additional fat cells are made when fat stores are filled Some fat is stored in muscle cells

From Sugar to Alcohol

Fermentation of natural sugars in grains (glucose and maltose) and fruits (glucose and fructose) by yeasts Yeast metabolizes glucose into ethanol and carbon dioxid Carbon dioxide bubbles off and a beverage containing alcohol is left Wine: From grapes Beer: From malted cereal grains (barley) Fermentation stops when the alcohol content reaches 11-14% Distillation forms liquors Fermented liquid is heated and ethanol vaporizes Vapors are collected and form liquor Alcohol content is indicated by its proof The number reflects twice the alcohol content in the beverage Eighty proof contains 40 percent alcohol.

Other intestinal disorders

Flatulence results from the formation of intestinal gas In most adults it is released 10 to 20 times a day Caused by: Foods high in fiber and starch Eating quickly Drinking carbonated beverages Lack of exercise Smoking Diarrhea: The passage of watery, loose stools more than three times a day Generally the result of bacterial, viral, or parasitic infections that cause food & fluids to pass too quickly through the colon Chronic diarrhea may be the sign of a more serious problem Untreated diarrhea can lead to malnutrition Diarrhea can lead to dehydration & potentially death, particularly in children and the elderly Treated with fluid & electrolyte replacement Constipation: Infrequent passage of dry, hardened stools Often due to insufficient fiber or water intake Other causes include stress, inactivity, smoking cessation & various illnesses Treatment Exercise, normal eating patterns, proper rest Laxatives should be used sparingly, as they can cause dehydration, salt imbalances & dependency Avoid colon cleansing (enema) as a treatment Hemorrhoids: Swelling of the veins of the rectum & anus Can lead to bleeding, itching, and/or pain Cause unknown but contributing factors include straining to pass dry stools, pregnancy, constant constipation or diarrhea & aging Treatment includes increased dietary fiber & fluid intake Some symptoms (itching & pain) can be relieved through use of creams, ice packs & soaking in a warm bath Severe cases may require surgery Irritable bowel syndrome (I B S): Changes in colon rhythm Those with I B S experience an overresponse to colon stimuli, resulting in alternating patterns of diarrhea, constipation & abdominal pain The exact cause is not known Treatment includes increased dietary fiber, stress management & prescription drugs Ulcerative colitis: A chronic inflammation of the large intestine, resulting in ulcers in the lining of the colon Tends to run in families Afflicts both men & women, beginning between the ages of 15 and 30 There is no known cause or cure Treatment includes drug therapy & surgery Crohn's disease: There is no known cause or cure Treatment includes drug therapy & possibly surgery Colon cancer: The third leading cause of cancer death, but one of the most curable cancers if detected early It begins with polyps on the lining of the colon that are often small, benign & can be surgically removed Polyps can develop into cancerous tumors if not detected early Treatment may include radiation, chemotherapy, or surgery Survival rates vary depending on age, treatment response & stage of cancer diagnosis

MyPlate

Food guidance systems are graphics used to summarize guidelines to healthy eating. MyPlate is a visual depiction of the recommendations in the Dietary Guidelines for Americans, 2010. ChooseMyPlate.gov is a web-based tool that provides: Information, tips, and tools to help people build a healthier diet An interactive food guidance system that provides personalized food plans

How is Food Propelled through the G I Tract?

Food is propelled through the G I tract by strong muscular contractions Two primary contractions are: Peristalsis: Squeezes food forward through the G I tract Mechanical digestion Segmentation: Shifts food back & forth along the G I tract in the intestines Allows contact with surface of small & large intestines & increases absorption Mass Movement Also referred to as 'mass peristalsis' Strong, slow, peristaltic movements, occurring only three to four times per day within the colon, that force waste toward the rectum

Food sources of proteins

Food sources: Animal: Meat, poultry, fish, and dairy Plant: Legumes, soy, nuts, and seeds Minimal protein amounts: Whole grains, vegetables, and some fruits

The Organization and Shape of Proteins Affect Their Function

Four levels of structure Primary structure: Amino acids are linked together to form a simple linear chain. Secondary structure: Geometric shape of the protein that is folded and twisted Tertiary structure: Three-dimensional globular shape of the protein Quaternary structure: Two or more polypeptide chains bond together.

What Are the Long-Term Effects of Alcohol Consumption on the Body?

Impaired digestion, absorption, and nutrient metabolism Decreased secretion of digestive enzymes Interferes with fat digestion and fat-soluble vitamin transport Damages cells in the stomach and intestinal lining, which leads to impaired absorption of water, glucose, sodium, and vitamins Can cause pancreatitis Increased incidence of gastritis Malnutrition, Wernicke-Korsakoff syndrome, and weight gain Primary malnutrition: Individuals compensate for drinking by cutting out nutritious foods Secondary malnutrition: Occurs from alcohol interference with nutrient absorption and metabolism Wernicke-Korsakoff syndrome: Mental confusion and uncontrolled muscle movement due to thiamine deficiency's effect on brain function Weight gain: Alcohol contains 7 kilocalories per gram; data regarding the effect of alcohol consumption on weight are mixed Alcohol can interact with hormones Interferes with insulin and glucagon action, resulting in hypoglycemia Affects parathyroid hormone and other bone-strengthening hormones Increases estrogen levels and possibly increases risk of breast cancer Affects reproductive hormones and is associated with male and female sexual dysfunction and infertility Alcohol can cause liver disease Stage 1: Fatty liver Fat builds up in the liver cells Too much fat buildup causes liver dysfunction Occurs after a few days of excessive drinking Stage 2: Alcoholic hepatitis Liver becomes inflamed Stage 3: Cirrhosis Liver cells die and are replaced with scar tissue Scar tissue prevents the liver from filtering toxins and waste products out of the body More than 50% die within 4 years Alcohol and cardiovascular disease Moderate intake may be cardioprotective More than three drinks per day can be harmful Increases cholesterol synthesis by the liver Increases blood pressure Excessive amounts of alcohol can trigger a cardiac arrhythmia or cause cardiac myopathy Alcohol contributes to cancer risk Increased risk of mouth, esophageal, liver, colon, rectum, and breast cancer How alcohol contributes to cancer is not well understood Alcohol can put a pregnancy at risk Drinking during pregnancy exposes the infant to alcohol and the risk of serious damage to the central nervous system Exposing a fetus to alcohol can lead to fetal alcohol spectrum disorders (F A S Ds) Disorders resulting from the damage of alcohol exposure in utero Physical, mental, and behavioral abnormalities Fetal alcohol syndrome

What are Some Common Digestive Disorders?

Include: Heartburn Esophageal cancer Belching Gastroenteritis Ulcers Gallbladder disease Flatulence Diarrhea/constipation Hemorrhoids Irritable bowel syndrome Ulcerative colitis Crohn's disease Colon cancer Celiac disease

Primary roles of individual nutrients

Individual nutrients serve unique roles in the body Supply energy Regulate metabolism Provide structure

Kilocalorie

Kilocalorie (k cal) or Calorie Amount of energy required to raise the temperature of 1 kilogram of water by 1 degree Celsius Used to express the measurement of energy in foods 1 kilocalorie is equal to 1,000 calories (lowercase "c") Calorie (uppercase "C") is used on nutrition labels to express the energy content of food

Essential Fatty Acids Manufacture Eicosanoids and Cell Membranes

Linoleic acid Converted to arachidonic acid Alpha-linolenic acid (A L A) Converted to eicosapentanoic acid (E P A) Elongated to docosahexanoic acid (D H A) E P A and arachidonic acid make eicosanoids. Hormone-like substances that regulate blood clotting, immune system, inflammation, blood pressure A L A is needed to make healthy cell membranes, particularly in the nerve tissues and retina

Chylomicrons Facilitate Lipid Absorption

Lipids are absorbed based on their structure. Glycerol and short- to medium-chain fatty acids are absorbed directly into the bloodstream Long-chain fatty acids combine with phospholipids and cholesterol to form chylomicrons Chylomicrons are too large to be absorbed directly into the bloodstream Travel through lymph fluid first Exit the lymph and enter bloodstream through thoracic duct next to the heart Lipoprotein lipase (L P L) hydrolyzes triglycerides in the chylomicrons as they travel to the liver via the bloodstream

How Are Lipids Digested, Absorbed, and Transported in the Body?

Lipids from foods are primarily in the form of triglycerides Lesser extent as phospholipids and sterols During digestion, fatty acids form a combination of free fatty acids, glycerol, and monoglycerides Lipases are the enzymes that digest lipids

What Are the Functions of Lipids in the Body?

Lipids serve several critical roles in the body Used as a source of energy Form body structures (including cell membranes) Regulate metabolism Enhance the absorption of fat-soluble vitamins Provide a layer of insulation to help regulate body temperature Help cushion the major organs

How Are Amino Acids Metabolized?

The liver metabolizes AA, depending on bodily needs Most AA are sent into the blood to be picked up and used by the cells If the diet is low in carbohydrate, the AAare converted into glucose AA pools supply the body's ongoing need for protein synthesis The body breaks down and makes proteins daily to maintain body structures such as tissues and organs AA pools provide a ready supply of amino acids the body uses to create proteins on demand Extra protein is used to help the body heal if a person has extensive wounds Protein turnover is the process of degrading and synthesizing proteins. More than 200 grams of protein is turned over daily

Location of the Double Bond

The location of the first double bond from the methyl (or omega) end of unsaturated fatty acids affects the properties of fatty acids Omega-3 fatty acid First double bond is between the third and fourth carbons from the omega end Example: Omega-6 fatty acid First double bond is between the sixth and seventh carbons from the omega end Example:

How are digested nutrients absorbed?

The majority of absorption takes place in Nutrients are absorbed via: Passive diffusion: Facilitated diffusion: Active transport: Endocytosis:

Fluid Absorption Occurs in the Large Intestine

The majority of nutrients have been absorbed when chyme enters the large intestine Water and salt are absorbed in the large intestine The same mechanisms used in the small intestine are also used in the large intestine Water: Sodium:

Most Digestion=Small Intestine

The small intestine consists of three segments: Mechanical & chemical digestions take place in the small intestine Muscular contractions push chyme forward; digestive secretions break down nutrients The surface of the small intestine is lined with villi The contact time in the small intestine is The small intestine is highly adapted for absorbing nutrients. Its length—about 20 feet—provides a huge surface area, and its wall has three structural features—circular folds, villi, and microvilli—that increase its surfacearea by a factor of more than 600.

Alcohol is Metabolized in the Stomach and Liver

The stomach is the first site of alcohol metabolism Alcohol dehydrogenase begins to metabolize alcohol The rate at which it is metabolized is affected by how quickly the stomach empties into the duodenum Longer time in stomach = more time to metabolize = less alcohol in the blood and brain The liver is the main site of alcohol metabolism The amount that can be metabolized per hour is limited by body mass and liver size Alcohol is metabolized through two pathways. The alcohol dehydrogenase pathway remove hydrogens from alcohol to form acetaldehyde Step two: Acetaldehyde dehydrogenase (A L D H) removes more hydrogen and forms acetate Acetate continues through metabolic pathways to form energy or is converted to a fatty acid and stored as fat The microsomal ethanol oxidizing system (M E O S) Used when there is too much alcohol and the liver enzymes cannot keep up Chronic alcohol abuse increases the number of enzymes in this pathway Used to metabolize drugs and other foreign compounds Alcohol takes precedence over drugs, so consuming alcohol and drugs together can result in lethal levels of drugs building up in the bloodstream The more you drink, the more active the M E O S becomes this can result in alcohol tolerance

The Stomach Stores, Mixes, & Prepares Food for Digestion

The stomach mixes food with various gastric juices to chemically break it down into smaller pieces Mechanical digestion occurs in the stomach as the muscles of the stomach mix, churn & push the contents with gastric juices When empty, the stomach holds 1 cup; can expand to hold up to 1 gallon Chyme is Approximately 1 teaspoon of chyme leaves the stomach & enters the small intestine every 30 seconds

Digestion of carbohydrates begins in the mouth

The teeth grind the food and mix it with saliva Saliva contains salivary amylase The food mixture travels down the esophagus to the stomach The amylase continues to break down the starch There are no carbohydrate-digesting enzymes in the stomach The pancreas releases pancreatic amylase when the carbohydrates enter the small intestine Pancreatic amylase continues to break down starch into maltose Maltase, sucrase, and lactase convert all disaccharides into their respective monosaccharides When they reach the large intestine, all starch and simple sugars have been broken down and absorbed Only the indigestible fiber remains

Protein Synthesis is Regulated by Your Genes

Three steps of protein synthesis Transcription: Information about building or repairing old proteins is stored in D N A When a new polypeptide chain is needed, an inverse copy of the D N A is generated forming messenger R N A (m R N A). Translation: m R N A binds to a ribosome The code on the m R N A is "read" and a transfer R N A (t R N A) brings a specific AA to the ribosome, based on the code. Elongation: The translation process continues as AA are collected by transfer R N A (t R N A) and brought to the ribosomes to build a chain in the proper sequence Continues till the sequence is finished and a new protein is released Sickle-cell anemia is a common blood disorder that involves abnormal or flawed protein formation

Food Choices: Time, Convenience, and Cost

Time and convenience are factors for those with busy schedules Average time spent preparing a meal (including cleanup) is less than 30 minutes Supermarkets are providing prepared foods and partially prepared foods People eat out more today than they did a few decades ago Cost Fast foods are often cheaper or perceived as cheaper than nutritious foods and are selected more often Excess fast-food consumption increases risk for obesity Individuals purchase nutritious foods when offered at lower prices