NTR Midterm review, Chapters 1-7 and quizzes with verified solutions., Exams of Nutrition and Aging

Download NTR Midterm review, Chapters 1-7 and quizzes with verified solutions. and more Exams Nutrition and Aging in PDF only on Docsity! NTR Midterm review, Chapters 1-7 and quizzes with verified solutions. Nutrition is the branch of science that ONLY focuses on identifying the nutrients that are in foods. - ANS false Which of the following individuals have the training, expertise, and education necessary to provide accurate nutrition information and recommendations? (Select 2) - ANS correct: - PhD-level (Degreed) Nutritionist - Registered Dietitian Incorrect: - Certified Nutritionist - Personal Trainer - Nutritional Consultant What is an essential nutrient? - ANS correct: - A nutrient that is needed but must be obtained from food (because the body cannot make it). Incorrect: - A nutrient that you can only get from supplements. - A nutrient that is helpful but not needed. - A nutrient that is needed but can be made by the body. Which of the following substances are inorganic (select 2)? - ANS correct: - Minerals - Water Incorrect: - Vitamin A - Lipids Which of the following substances does not provide energy? - ANS correct: -minerals Incorrect: - Proteins - Alcohol - Carbohydrates What essential nutrient is involved in nearly all body processes (like metabolic reactions, fluid balance, nerve impulses, muscle contractions, and nutrient transport)? - ANS correct: P a g e 1 | 54 - Water Incorrect: - Oxygen - Vitamin D - Carbon A half-cup of vanilla ice cream contains 29 grams of carbohydrate, 2 grams of protein and 20 grams of fat. How many total kilocalories does this ice cream contain? - ANS answer: - 304 kcals (calories) Steps: A veggie burger patty is 136 kilocalories and contains 15 grams of carbohydrate, 10 grams of protein and 4 grams of fat. What percentage of the energy in the burger comes from carbohydrate? - ANS answer: - 44% Steps: The AMDR for protein is between - ANS correct: - 10-35% of total energy intake Notes: The AMDR for carbohydrate is between - ANS correct: - 45-65% of total energy intake Notes: A person is 'doing keno' and consumes 20 g of carbohydrates/day in a 2000 kilocalorie diet. How does this amount fit with the AMDR? - ANS correct: - It's below the AMDR Why: The pack of cookies that your roommate purchased has the following nutrients facts panel: - Serving Size: 32g (3 cookies), - Servings per Container 11 - Calories 160 - Total Fat 8g, Saturated fat 2.5g, Cholesterol 0mg, and Trans Fat 0g - Sodium 105mg - Total Carbohydrate 21g - Added Sugars 15g P a g e 2 | 54 Mucus - ANS protect the cells of the GI tract Match the definitions with the 'best' digestion 'helper.' Enzymes - ANS break down foods into smaller molecules through hydrolysis Match the definitions with the 'best' digestion 'helper.' Hormones - ANS signals to the gallbladder to release bile Match the definitions with the 'best' digestion 'helper.' Chemicals - ANS provide an acid or basic environment to optimize digestion Negative Feedback - ANS The hormone, CCK, is secreted into the blood in response to fat entering into the small intestine. CCK then simulates the pancreas to release bicarbonate and enzymes. It also stimulates the gallbladder to release bile. All of these processes begin to break down the fat in the small intestine. The partially digested fat no longer stimulates CCK release. If there is no CCK, then the pancreas and gallbladder are not stimulated and nothing is released. What type of homeostatic feedback loop is this situation describing? Fiber - ANS non-digestible carbohydrates that promote GI health, increase satiety, and reduce risks of heart disease, diseases, and some cancers? Small intestine - ANS where does chemical digestion of table sugar (sucrose) begin? Functions of each component of the digestive tract. Illeocecal valve - ANS allows passage of chime from the small intestine to the large intestine Functions of each component of the digestive tract. Epiglottis - ANS protects airway during swallowing Functions of each component of the digestive tract. Lumen - ANS continuous space that carries nutrients through the GI tract that are waiting to be absorbed Functions of each component of the digestive tract. P a g e 5 | 54 Pyloric sphincter - ANS releases small portions of chime from the stomach into the small intestine What monosaccharide has the sweetest taste? - ANS fructose Which of the following are considered to be polysaccharides? (Select 3) - ANS - starch - Glycogen - Fiber Which of the following provides carbohydrates in the diet? - ANS - all of these foods are sources of carbohydrate: Fruit, grains, beans, vegetables Which of the following locations doe’s enzymatic (chemical) digestion of carbohydrates take place? (Select 2) - ANS small intestine and mouth What is the common name of the disaccharide molecule that contains glucose + GA lactose? - ANS milk sugar Which statement is true about polysaccharides? - ANS true: - Chemical digestion of starch begins in the mouth False: - Starch is indigestible. - Fiber is the storage form of glucose in the body. - Glycogen is the storage form of glucose in plants. What are the recommended dietary strategies for individuals with lactose intolerance? (Select 2) - ANS - Gradually increase milk intake & consume it with other foods - Consume yogurt or lactose-free milk Brain - ANS organ is the primary user of glucose in the body? Insulin and glucagon - ANS When blood glucose rises, the pancreas secretes ________ to promote glucose update into the cells. However, when blood glucose falls, the pancreas secretes ________ to breakdown glycogen into glucose for use. When we consume inadequate amounts of carbohydrates (<50 g/d), how does the body respond? (Select 2) - ANS correct: - Fat gets broken down to form ketone bodies (for fuel) - Protein gets broken down to form glucose Wrong: - Fiber gets broken down to form glucose P a g e 6 | 54 - We immediately go into cardiac arrest and die The primary reason why a diet high in added sugars is 'harmful' is because the foods/beverages containing the added sugar are nutrient poor but energy dense and displace the consumption of nutrient dense foods. - ANS true The recommended fiber intake in adults is - ANS 25 g/day for women 38 g/day for men Prediabetes - ANS If you have a fasting blood glucose of 115 mg/ld., what range are you in 50% - ANS What percent of the grains that you consume should be whole grains? False - ANS Fiber supplements are just as effective as consuming fiber-rich foods. Which energy-yielding nutrient supplies about 60% of the body's energy needs during rest? - ANS fat What are the 3 types of Lipids? (Select all that apply) - ANS Triglycerides Phospholipids Sterols Not: Monosaccharides Polypeptides Triglycerides are made up of: (Select all that apply) - ANS - 3 fatty acids - Glycerol Not 1 fatty acid/amino acids Which type of fatty acids have double bonds (and thus less hydrogen’s on their chemical backbone) which contribute to their protective nature in reducing the risk of chronic disease? - ANS Unsaturated Fatty Acids Which of the following blood lipids are associated with an increased risk of chronic disease? (Select 2) - ANS - LDL cholesterol - Triglycerides The health effects of dietary fats are only dependent on the quantity that is consumed. - ANS false Which of the following statements are true about polyunsaturated fats? (Select 3) - ANS - spoils readily - Liquid at room temperature P a g e 7 | 54 Not nutrition experts - ANS - Non-nutrition degree, un-trained 'titled' individuals - (Most) physicians and healthcare professionals What's the problem? - ANS - Dietary advice is everywhere & is ever-changing (even from experts) - Difficulty in understanding current & accurate information Which food contains the greatest carbohydrate content by weight? - ANS Orange Food choices - ANS - diet - Personal preference - Habit - Ethnic heritage and regional cuisine - Social interactions - Marketing - Availability, convenience and economy - Positive and negative associations - Emotions - Values - Body weight, health, allergies - Nutrition content Inorganic nutrients - ANS - Do not contain carbon - Minerals and water Organic nutrients - ANS - Contain carbon (essential component of all living organisms) - Carbohydrates, lipids (fats), proteins, vitamins - More complex: H + O + C + more! Food contains - ANS Six classes of nutrients and other contents Six classes of nutrients - ANS - Protein, carbohydrates, lipids, vitamins, minerals and water - Energy-yielding: body uses for energy - Essential nutrients: must be provided by diet Other contents that food contains - ANS - Phytochemicals: compounds from plants - Pigments, additives, alcohols, etc. The body contains - ANS - Water: 60% - Fat: 18-21% (men); 23-26% (women) - Other nutrients: the rest Macronutrients - ANS - Required in relatively large amounts - Energy-yielding P a g e 10 | 54 - Carbohydrates, lipids, proteins Micronutrients - ANS - Required only in small amounts - Vitamins and minerals Alcohol does not equal nutrient - ANS Interferes with growth, regulation and repair of body Energy from food = - ANS kilocalories = calories = calories Total food energy (i.e. calorie content) depends on nutrient distribution - ANS - Carbohydrate = 4 kcal/g - Protein = 4 kcal/g - Fat = 9 kcal/g Most foods are - ANS a mixture of energy-yielding nutrients Exceptions to mixture of energy-yielding nutrients - ANS sugar (pure carbohydrate) and oil (pure fat) Vitamins, minerals and water do NOT provide - ANS energy/calories Energy-yielding nutrients (using nutrients for energy) - ANS Bonds between nutrients atoms break -> energy released - Heat and energy for body functions Excess energy: storage (e.g. fat) - Used between meals and overnight - Increased energy in storage = weight gain Other roles - Materials for building body tissues - Regulation of bodily activities: digestion, energy metabolism Carbohydrates - ANS - Primary source of fuel for the body (especially for brain function and physical exercise) - Composition: chains of carbon, hydrogen and oxygen - Common foods: grains (wheat, rice), vegetables, fruits, legumes (lentils, beans, peas), seeds, nuts and milk products Lipids - ANS - Insoluble in water - Major form of stored energy *Stored as adipose tissue (body fat)*Energy source during rest or low- to moderate intensity exercise* - Provide fat-soluble vitamins and essential fatty acids - Include triglycerides, phospholipids and sterols - Composition: carbon, hydrogen and oxygen - Common foods: oils, animal fats, seeds and nuts P a g e 11 | 54 Proteins - ANS - Support tissue growth, repair and maintenance - Composition: amino acid chains of carbon, hydrogen, oxygen and nitrogen - Common foods: primarily in meat, dairy, seeds nuts and legumes *Small amounts also found in vegetables and whole grains* Vitamins - ANS - Organic molecules (contain carbon) - Do not supply energy to our bodies - Micronutrients (required in smaller amounts) - 13 vitamins assist in regulating various body processes *Facilitate the release of energy from carbohydrate, fat, protein (metabolism)*Build and maintain healthy bones and tissues*Support immune system*Ensure healthy vision* - Vulnerable to destruction: heat, light and chemical agents Minerals - ANS - Inorganic substances (do not contain carbon) - Do not supply energy to our bodies - Food and the body contain major minerals and trace minerals - 16 minerals essential for body processes: *Regulate fluid balance*Assist in energy production *Essential for bone and blood health* - Indestructible not vulnerable to heat, light or chemical agents Water - ANS - Inorganic (does not contain carbon) - Essential nutrient - Water is involved in nearly all body processes: Metabolic reactions, Fluid balance and nutrient transport, Nerve impulses, Body temperature, Muscle contractions, Nutrient transport, Excretion of waste products Determinants of health? - ANS Nutrition, lifestyle, environment, genetics, medical care What is NOT the science of nutrition - ANS - NOT about our food preferences? - NOT about identifying good food and bad food (eat this, not that) - NOT about how (eating) food impacts the environment - NOT about our opinions or beliefs about nutrients or foods The science of nutrition - ANS - The integration of many other sciences: Biology, Chemistry, Anatomy and Physiology - Nutrition is the branch of science examining: the nutrients in foods and (their actions within the body)/ (impact on health) - All nutrition recommendations and guidelines developed from scientific evidence! Observational studies - ANS Studies in which large groups of people are observed - Investigators do not interfere or try to influence health outcomes - Used to identify a relationship between a (nutrition) factor and health (or disease) - Large registries and databases Types of data (examples): P a g e 12 | 54 - Focus on meeting food group needs with nutrient-dense foods & beverages, and stay within calorie limits - Limit foods and beverages higher in added sugar, saturated fat and sodium and limit alcoholic beverages Specific limits - ANS - Added sugars: <10% beginning age 2+ - Saturated fat: <10% of calories, ages 2+ - Sodium: <2,300 mg/d, ages 14+ Alcoholic beverages: - Drinking less is better than drinking more - Can choose not to drink or limit intake to less than 2 drinks/day Key Dietary Principles - ANS - Meet nutritional needs primarily from foods and beverages - Choose a variety of options from each food group - Pay attention to portion size 85% - ANS of calories are needed per day to meet food group recommendations healthfully, in nutrient-dense forms (1,700 kcal food groups) 15% - ANS of remaining calories are available for other uses (including added sugars and saturated fat, 300 kcal discretionary) Under nutrition (inadequacy/deficiency) - ANS - Inadequate energy (calories): thin, muscle loss, reduced immune function, increased disease, etc. - Inadequate nutrient(s): skin rash, hair loss, night blindness, bleeding gums, muscle spasms, etc. Over nutrition (surplus/excess) - ANS - Surplus energy (calories): unhealthy weight gain, obesity, type 2 diabetes, cardiovascular disease, etc. - Surplus nutrient(s): hot flashes, yellowing skin, rapid heart rate, low blood pressure, etc. Individual level nutrition assessment - ANS Helpful for detecting malnutrition and correcting problems - Demographics: age, sex, ethnicity, socio-economic status (SES), etc. - Medical history: health status, drug/alcohol use, family history of disease - Diet record: collection of intake over several (3-7) days to assess foods, beverages, supplements and the quantities consumed - Anthropometric measurements: height and weight -> BMI - Physical exam: visual inspection, interview to identify symptoms - Laboratory tests: blood or urine analysis to ID early signs before symptoms appear Population level nutrition assessment - ANS National nutrition surveys (population data) - National health and nutrition examination survey (NHANES) - USDAs Continuing Survey of Food Intakes by Individuals (CSFII) P a g e 15 | 54 What We Eat in America (combination of both surveys above) - Data used for: public policy; research; product development; establishing national health goals National health goals - Healthy people programs: increase the quality the quality and years of healthy life; eliminate health disparities - Healthy eating index (HEI) score: whether Americans are meeting guidelines Dietary principles - ANS 1. Adequacy: energy (kcals) and nutrients 2. Balanced diet: enough but not too much and different types of foods to meet recommendations 3. Energy balance: energy intake = energy expenditure 4. Nutrient density: ratio of recommended nutrients: total energy - High nutrient density = most nutrients for fewest kcals - Low nutrient density = high energy density, least nutrients for greatest kcals 5. Moderation: consume low-nutrient dense, high-energy dense foods occasionally - Ultra - processed foods (added ingredients) - High: sodium, added sugar and or saturated fats *Remember less than or equal to 15% of your diet* 6. Food-first mentality: all nutrient needs can (and should) be fulfilled with foods, not supplements for most individuals 7. Portion size: use portion size guides, choose smallest, ID portion sizes on packages, significantly increased over the past 20 years 8. Variety: increased variety within food groups as not all foods are 'created equally' 3 example patterns within the DGAs - ANS - Healthy US-style dietary pattern - Healthy vegetarian dietary pattern - Healthy Mediterranean-style dietary pattern Healthy Dietary Patterns - ANS - All patterns are 'plant-based' with the majority of calories and foods coming from plants - Vary in the amounts and types of foods included - All patterns limit the amount of added sugar, saturated fat and alcohol Diet Planning Guides - ANS - Need tools and knowledge to plan an ideal diet USDA food patterns: assign foods to five major groups - Recommended daily amounts for each food group - Notable nutrients - Serving equivalents (ounces, cups, etc.) - Nutrient density USDA food patterns - ANS - Notable nutrients - Discretionary calorie allowance (85-15 rule) - Serving equivalents - Mixture of foods Unique diets: vegetarians and ethnic food choices P a g e 16 | 54 My Plate (website) - ANS - Combines USDA food patterns and dietary guidelines - Educational tools on website - Allows for personal planning: height, weight, age, sex, activity level, different phases in lifecycle - Addresses pyramid shortcomings: visual reminder for every meal My Plate Shortcomings - ANS - Not enough information on graphic - Website contains much more detail: Balancing calories, Foods to increase, Foods to reduce Food patterns - ANS sort foods by micronutrient content Food lists - ANS group foods by macronutrient content Putting the plan into action - ANS - Familiarize yourself with each food group - Assign foods from each group into meals and snacks - Aim for nutrient-dense choices Grocery shopping - ANS - Consider foods you enjoy - Make improvements little by little - Processed foods Grains (shopping) - ANS Whole-grain products - Highest nutrients and dietary fiber - Favorite whole grain product Enriched - Replaces some nutrients lost during processing - Doesn't replace all lost nutrients or dietary fiber Refined - Lost many nutrients and fiber - Favorite refined grain product? Protein foods (shopping) - ANS - Meat, poultry, seafood, eggs, legumes, nuts, seeds, soy products - Portion sizes - Reduce fat Milk and milk products (shopping) - ANS Fortified and low-fat options Vegetables and fruits (shopping) - ANS - Think variety, think color - Fresh v canned, frozen or dried - Juices Food labels - ANS - Generally required for all packaged foods (with exceptions) - Ingredient list P a g e 17 | 54 - Organ of origin + compound + -as = enzyme *Gastric lipase = stomach enzyme that digests lipids* Saliva - ANS - Moisten food for easy passage - Protective role: teeth, mouth esophagus, stomach - Enzymes initiate carbohydrate digestion Gastric juice - ANS - Protein digestion (hydrochloric acid)*Heartburn* - Mucus protects stomach lining - PH below 2 (more acidic than lemon juice) Pancreatic juice - ANS - Released via ducts into duodenum (small intestine) - Enzymes act on all 3 energy nutrients: Carbohydrates, fats and proteins - Sodium bicarbonate: Basic/alkaline, Neutralizes acid in chime from stomach - Bile: produced liver; Concentrated, stored, and released: gallbladder; squirts into duodenum; Emulsifier (NOT an enzyme)*Disperses fat in watery solutions; Gives digestive enzymes access to fat molecules* The final stage - ANS - Carbohydrate, fat and protein = digested - Vitamins and minerals = absorbed - Undigested residues enter colon (large intestine): Fluids, dissolved salts, fiber - Colon *Intestinal bacteria ferment some fiber: produces water, gas and fat = energy for colon*some fiber passes through unchanged*Water and dissolved salts: recycled for use in other parts of body* - Rectum and anus: eliminate stool Small intestine (absorption) - ANS - Majority of absorption - Ten feet long (surface area = 1 ½ bowling lanes) - Absorption techniques (a)Simple diffusion (b)Facilitated diffusion (c)Active transport Villi (absorption) - ANS - Fingerlike projections on intestinal folds - thousands per fold! - Imagine: like a sea anemone - Select and regulate nutrients absorbed based on needs of body Microvilli (absorption) - ANS Enzymes and "pumps" act on different nutrients Crypts (absorption) - ANS Glands secrete intestinal juices = digestion Goblet cells (absorption) - ANS Secrete mucus = protection P a g e 20 | 54 Simple diffusion - ANS some nutrients (such as water and small lipids) are absorbed by simple diffusion. They cross into intestinal cells freely Facilitated diffusion - ANS some nutrients (such as the water-soluble vitamins) are absorbed by facilitated diffusion. They need a specific carrier to transport them from one side of the cell membrane to the other. (Alternatively, facilitated diffusion may occur when the carrier changes the cell membrane in such a way that the nutrients can pass through) Active transport - ANS Some nutrients (such as glucose and amino acids) must be absorbed actively. These nutrients move against a concentration gradient (from areas of low concentration to areas of high concentration), which requires energy Preparing nutrients for transport - ANS Nutrients are absorbed (crossed into villus cell), enters one of two transport pathways: - Bloodstream - Lymphatic system Bloodstream - ANS - Water-soluble nutrients and smaller products of fat digestion - Guided directly to liver Lymphatic system - ANS - Larger fats and fat-soluble vitamins (insoluble in water) - Intestinal cells assemble products of fat digestion into larger molecules, cluster with proteins to become: Chylomicrons (fat transporters) - umber for fat molecules - Bypass liver at first Vascular System - ANS CLOSED SYSTEM OF VESSELS - Continuous blood flow - Heart = pump BLOOD - Delivers oxygen and nutrients to body tissues - Removes carbon dioxide and wastes from body tissues - Normal blood flow: Heart -> arteries -> capillaries -> veins -> heart - Special route for digestive system blood: Heart -> artery -> capillaries (in intestines) -> hepatic portal vein -> capillaries (in liver) -> hepatic vein -> heart - Liver = hero! *Direct to receive nutrients from GI tract (before heart)*Prepares absorbed nutrients (carbohydrates, fats, proteins, etc.) for use in the body*Detoxifies harmful substances; prepares waste for excretion* Lymphatic system - ANS One-way route, flows toward heart - No pump - Circulation between cells in response to body movement Entry into bloodstream P a g e 21 | 54 - Collects in thoracic duct (behind heart) -> subclavian vein -> bloodstream Nutrients in lymphatic vessels - Large fats and fat-soluble vitamins - Bypass liver at first Who is the superhero of the digestive system? - ANS Liver Gastrointestinal micro biota (gut flora) - ANS 100 trillion microbes: bacteria, viruses, fungi, protozoa, etc. Bacteria alone: 400 species and subspecies Factors influencing micro biota: - Diet: short and long term choices - Plant-based diet: high fiber = energy source for beneficial bacteria - Obese people: less diverse gut microbial life - Prebiotics: encourage bacterial growth and activity - Probiotics: live microbes that change GI conditions in positive way Potential benefits of GI microbes: - ANS alleviate/prevent: constipation, diarrhea, inflammatory bowel syndrome, inflammation, ulcers, allergies, lactose intolerance, colic (infants) enhance immune function; protect against colon cancer; lower blood cholesterol; lower blood pressure (Endocrine and nervous systems) Homeostatic regulation - ANS Body should maintaining "business as usual" - Hormones (endocrine) and nerve pathways (nervous system) coordinate all digestive and absorptive processes - Stimulation and inhibition of digestive secretions as food travels through GI tract (Endocrine and nervous systems) Feedback mechanisms - ANS GI hormones regulate digestion and absorption with negative feedback loops Gastrin - ANS secreted by cells in stomach wall Secretin - ANS secreted by cells in duodenum wall Cholecystokinin (CCK) - ANS secreted by cells in intestinal wall The digestive system at its best - ANS Sensitive and responsive to environment - GI tract cells provide immunity against intestinal diseases - Secretions defend against foreign invaders Health of digestive system - Healthy supply of blood - Lifestyle factors: sleep, physical activity, stress - Types of foods eaten: Balance, moderation, adequacy and variety P a g e 22 | 54 - Fibers: structure (various monosaccharides) - plants Glucose (monosaccharide) - ANS - Most abundant monosaccharide in nature - AKA: blood sugar, dextrose (manufactured from corn, chemically identical to glucose) - Broken down in cells -> produces energy: essential for all body activities - Can be found in: *Disaccharides: maltose, sucrose and lactose*Polysaccharides: glycogen and starch* GA lactose and fructose (monosaccharide’s) - ANS GA lactose: - Very small amounts found as single sugar in foods - When combined with glucose = lactose (disaccharide in milk and other dairy products) Fructose: - One of the sweetest sugars: stimulates taste buds to produce sweetness - Occurs naturally in fruit, honey and vegetables (AKA: fruit sugar) - When combined with glucose = sucrose (table sugar) Disaccharides: Maltose, sucrose, lactose - ANS Maltose (glucose + glucose_ - Produced by breakdown of starch (e.g. during digestion) - Involved in fermentation (e.g. alcohol fermentation) Lactose (glucose + GA lactose): - Found in milk products Sucrose (glucose + fructose): - Sweetest disaccharide - Most abundant disaccharide found in nature Glycogen (polysaccharides) - ANS - Storage form of energy in the body - Glucose units - Found in: meat to a limited extent, not found in plants - Food does not equal significant source - Liver: up to 8% by weight = glycogen (significant source of carbohydrate) Starch (polysaccharides) - ANS - Storage form of energy in plants - Glucose units - Found in: grains, root crops, tubers, legumes - Grains = richest source - Body hydrolyzes starch to glucose uses glucose for energy - Global food staple Dietary fiber (polysaccharides) - ANS - Found in all plant-derived foods - Provide structure in stems, leaves, roots, skins and trunks - Made from a variety of monosaccharide’s (not just glucose) - Bonds between monosaccharides cannot be broken by digestive enzymes (unlike starches) - AKA: no starch polysaccharides - Pass through the body undigested (don't release any glucose) -> - Don't contribute energy/calories P a g e 25 | 54 Polysaccharides: fiber (two types) - ANS Classified by solubility in water: *Insoluble fibers benefit GI health* *Soluble fibers: benefit heart disease, diabetes, cancer, weight management, more viscous and fermentable* - Viscous fibers: form gels in GI tract - Fermentable fibers: digested by GI bacteria - Functional fiber: natural fiber extracted from plants or manufactured, then added to foods or supplements to provide health benefits *Total fiber in foods = dietary + functional* CHO digestion and absorption - ANS Ultimate goal: break ingested foods into smaller molecules for use by the body Digestion - ANS break ingested foods into smaller molecules (when needed) starch -> glucose Absorption - ANS moving the smaller molecules for use in the body (always needed) glucose (digestive tract) -> blood -> body 2 types of digestive processes - ANS - Mechanical digestion: (physical breakdown of food particles) - Chemical digestion: (chemical breakdown of food particles) (hydrolysis via enzymes, - as) CHO digestion - mouth - ANS - Salivary amylase - Polysaccharides (starch) (small amount) - amylase -> smaller polysaccharides CHO digestion - stomach - ANS None - Stomach acid (HCI) neutralizes salivary amylase - No enzymes here for CHO digestion CHO digestion - small intestine - ANS - Most digestion occurs here! - Pancreatic amylase from pancreas) - Other enzymes *Polysaccharides (starch) (remainder) - amylase -> smaller polysaccharides, disaccharides, monosaccharide’s* *Disaccharides - 'aces' -> Monosaccharide’s* CHO digestion - large intestine - ANS - None - Only 1 thing left: fiber - Fermentation: *Bacteria -> enzymes -> fiber* *Non-digestible polysaccharides (fiber) - bacterial enzymes -> Water (soften stools), Gas, Short-chain fatty acids -> Energy (colon) CHO digestion - resistant starches - ANS - CHO-rich foods that are poorly digested P a g e 26 | 54 - Pass through the small intestine - In the large intestine, they act like a fiber - May prevent some chronic diseases: diabetes, colon cancer, obesity CHO digestion - FODMAP - ANS Fermentable Oligosaccharides, Disaccharides, Monosaccharide’s And Polios - CHO-rich foods that are poorly digested - Pass through the small intestine - Fermented by bacteria in colon: Gas, diarrhea/constipation Glucose and GA lactose transport - ANS active transport and requires energy (ATP) -> blood -> body Fructose transport - ANS facilitated transport and no energy is needed -> blood -> liver Lactose intolerance - ANS Defined: reduction in lactose digestion Symptoms of intolerance - Increase in water and feeds GI bacteria (large intestine) - Bloating, abdominal discomfort, gas, diarrhea Cause: reduction in lactase - Age - Genetics - Diseases/Medications - Dietary habits Lactose Intolerance - dietary strategies - ANS - Manage dairy consumption rather than eliminate - Most can tolerate 6 g lactose (½ cup milk) - Gradually increase milk intake (with other foods, etc.) - Consume yogurt or lactose free milk - Tolerance varies - individualize diet Daily recommendation (added sugar) - ANS less than 25g Digestion -> absorption -> - ANS metabolism: biochemical processes that provide energy to living cells (Blood -> cells -> energy) Carbohydrate (CHO) metabolism pt. 1 - ANS - Glucose = central focus of carbohydrate metabolism - Glycogen = stored form of glucose - Condensation (linking) reactions turn glucose -> glycogen (when blood glucose rises) - Hydrolysis (breaking) reactions turn glycogen -> glucose (when blood glucose falls) - Liver = stores ¼ of total glycogen *Released into blood as needed*enough in storage for about one day* - Muscles store ¾ of total glycogen *Hoards glycogen for use during exercise* P a g e 27 | 54 - Factors of tooth decay: > Time food spends in mouth > Sticky foods > Frequency of sugar consumption > 20-30 minutes of acid production after eating Prevention: - Reduce consumption of sugar- and starch- containing foods and beverages - Good oral hygiene Dietary guidelines of sugar - ANS - Most sugar comes from processed foods: SSB, desserts and candy - Read those labels! *New labels separate added sugar from total sugar**1 tsp. sugar = 4 grams carbohydrates = 20 calories* - DRI: no UL for sugar *AHA and WHO < 5% of daily calorie intake: 100 kcals (25g)/day: 6 tsp.* - Reduce sugar intake gradually (perceptions of sweetness change) Alternative sweeteners - ANS Artificial sweeteners: saccharin; aspartame; sucralose - Large does may have adverse effects Natural sweeteners: Stevia (Trivia); Monk fruit - Generally recognized as safe (GRAS) Nutritive sweeteners (provide calories) - Sugar alcohols (polios) *Naturally occurring in fruits and vegetables, used in processed foods* - Benefits: low glycemic response, don't contribute to dental caries - Side effects (FODMAP): bloating, gas, GI discomfort, diarrhea - Use in moderation Heart disease - ANS Diet recommendations: Low animal fat, high fiber, vegetable proteins, phytochemicals - Fiber binds with bile acids in GI tract (excreted) -> liver uses cholesterol to make new bile acids -> lower cholesterol = lower blood pressure, improved blood lipids, reduced inflammation Type 2 diabetes - ANS Diet recommendations: Whole grains and soluble fiber - Soluble fibers slow nutrient movement through GI tract -> slows glucose absorption in bloodstream -> glucose surge and rebound is prevented GI health - ANS Diet recommendations: Insoluble fiber (cellulose) and ample fluids - Increases stool weight (more water in stool), eases passage, reduces transit time -> reduces pressure and stress on rectal muscles and lower bowel - Keeps passage around appendix clear -> reduces appendicitis risk - Stimulates and strengthens GI tract muscles -> may prevent diverticulitis P a g e 30 | 54 Weight management - ANS Diet recommendations: - High-fiber foods and whole grains (not supplements) - Less solid fat and added sugar - Fiber attracts dues in GI tract and swells -> feelings of fullness Colorectal cancer - ANS Diet recommendations: High fiber and phytochemicals - Plant foods (vegetables, whole grains, fruits) - Dilute, bind with and remove cancer-causing agents from colon - Bacterial fermentation -> short-chain fatty acids -> activate cancer-killing molecules and inhibit inflammation in colon Excessive fiber - ANS - Small capacity + lots of fiber = possible energy/nutrient deficiency - Foods move too quickly through GI tract = limited nutrient absorption - Rapid increase in fiber intake = abdominal discomfort, gas, diarrhea, or GI obstruction > Increase fiber gradually from various sources > Drink plenty of liquids - Dietary goals: balance, moderation, variety Carbohydrates - ANS AMDR: 45-65% of daily energy RDA: 130 grams per day - Based on average minimum amount of glucose used by brain Fiber - ANS Variety of plant-based food sources (supplements do not have same benefits) - Food labels: 2.5g/serving = good source; 5g/serving = excellent source DRI: 14 grams per 1000 calories - 25g/day (women), 38 g/day (men) Average US intake = 16g/day No UL: fiber is filling (difficult to eat in excess) Grains - ANS - 1 oz., 15g of carbohydrate (mostly starch) - Beware or refined grains, added sugars, excess sodium and solid fat - Three are key: breakfast, lunch, dinner -> ½ of choices should be whole grains Vegetables - ANS - Starchy veggies (peas, corn, potatoes): 15g of carbs per ½ cup - Non-starchy veggies (broccoli, green beans, tomatoes): 5g of carbs per ½ cup Fruits - ANS - Variation in water and fiber content = variation in sugar concentration - 15g of carbs per ½ cup or typical serving (apple, orange, banana) > Mostly sugar (fructose) Milk and milk products - ANS - Milk/Yogurt: 12g of carbs per 1 cup - Cottage cheese: 6g of carbs per 1 cup - Most other cheese: little to no carbohydrates P a g e 31 | 54 Protein foods - ANS - Most proteins: little to no carbohydrates - Exceptions: liver, nuts, legumes Read food labels - ANS - Total carbohydrate = starch + fibers + sugars - Added v natural sugar Obesity and the link to carbohydrates - ANS - Total daily energy intake has increased - Activity levels have declined - Body weight has increased - Restricted calorie intake = weight loss (regardless of which energy nutrient is restricted) Increase in consumption of added sugars - ANS - High-fructose corn syrup - High sugar intake = increased body fat stores Moderation of sugar intake is challenging - ANS - Sugary foods and drinks: cheap, available, easy to consume and tasty - Self-imposed labeling of foods: bad foods are harder to resist! Carbohydrate addictions/cravings: - Not physiological or pharmacological - Increases serotonin in brain (elevates mood) - May stimulate brain regions associated with attention and reward Metabolism - ANS Glucose moves directly to body cells - Stimulates insulin release -> appetite is suppressed Fructose must be converted to glucose (by the liver) - Excess fructose can burden the liver - Excess added sugars become fat (retained in liver or sent to blood and body fat stores) - Does not immediately stimulate insulin release -> appetite is not suppressed Food form impacts fullness - Liquid: provides energy but not fullness - Solid: provides energy and fullness Insulin's response - ANS Surge of insulin levels after meals - Glucose moved into cells; fatty acids stored as fats; protein synthesis - Cell's response to insulin = critical to maintain health Glycemic effect of food - Varies depending many factors: food processing, how food is eaten, etc. Positive association between diets with high glycemic index and body weight - Insulin response varies across people All carbs are not equal (or evil) - Limit added sugars: HFCS and sucrose - Not necessary to cut out all carbohydrates (fruits, veggies, whole grains P a g e 32 | 54 - Versatile: emulsifiers in food industry - Lecithin: best known phospholipid - Part of cell membranes - Vitamin and hormone transport in/out of cells - Emulsifier: keep fat suspended in blood Sterols - ANS - Multiple-ring structure FOOD SOURCES: - Cholesterol: animal sources (meat, eggs, seafood, and poultry, dairy) - Plant sterols: structurally similar to cholesterol -> interfere with cholesterol absorption - > lower blood cholesterol - Vital body compounds made from cholesterol: bile acids, sex and adrenal hormones, vitamin D, cholesterol - 90% of body cholesterol = in cells (does not equal energy) - Cholesterol made in the body = endogenous (synthesized by liver) - Cholesterol made outside the body (foods) = exogenous - Accumulation in artery walls and plaque formation = harmful Lipid Digestion and Absorption - ANS - Ultimate goal: break ingested foods into smaller molecules for use by the body - Digestion: break ingested foods into smaller molecules (lipids->FAs, Glycerol, Mon glycerides) -> absorption: moving the smaller molecules for use in the body (FAs, Glycerol -> blood, monoglycerides) Lipid digestion in mouth - ANS - Small amount of digestion (<5%) - Lingual (tongue) lipase - Triglycerides (milk fats) - (lipase) - > monoglycerides free fatty acids glycerol’s - Lingual lipase - Infants: fatty acids in milk - Adults: less active Lipid digestion in small intestine - ANS - Most digestion occurs here (75%) 1. Fat stimulates CCK secretion (from small intestine) 2. CCK stimulates bile secretion (from the gallbladder) 3. Bile stimulates the breakdown of large fat particles Importance of bile - ANS - Not an enzyme or hormone - Made from cholesterol - Compound that acts as an emulsifier - (Bile acids: hydrophobic (water-hating) - (Amino acids: hydrophilic (water-loving) - Emulsifier: a substance that causes the mixing of two or more substances (that would normally not mix) *oil and water* -> *emulsified oil and water* Lipid digestion in the large intestine - ANS none P a g e 35 | 54 Lipid Absorption - Introduction - ANS - Small molecules (glycerol and fatty acids) are absorbed and go directly into bloodstream - Large molecules (micelles) are absorbed but get broken down and reassembled into new triglycerides - New triglycerides + cholesterol + phospholipids + proteins = chylomicrons - Chylomicrons released into lymphatics - Bypass the liver (allows other organs accessibility) - Released into the circulation later on Lipid transport - in circulation (blood stream) - ANS - Lipoproteins: transport vehicles for fats in blood - Lipoproteins: transport vehicles for lipids in blood VARY BY SIZE AND DENSITY - More triglycerides (TGs) = less dense, larger - More proteins = more dense, smaller LARGEST (most TGs) TO SMALLEST (least TGs) - Chylomicrons - Very-low-density-lipoproteins (VLDL) - Low-density-lipoproteins (LDL) - High-density-lipoproteins (HDL) Chylomicrons - ANS - Transports triglycerides to most cells - As they dump the triglycerides, they get smaller - Liver removes remaining parts - synthesized in small intestine Very Low Density Lipoproteins (VLDL) - ANS - Made from chylomicrons & repackages (in liver) - Smaller proportions of triglycerides greater proportion of cholesterol - Transports triglycerides to most cells - As they dump the triglycerides, they get smaller - Turn into low density lipoproteins - synthesized in liver Low Density Lipoproteins (LDL) - ANS - Made from VLDL - Smaller proportion of triglycerides greater proportion of cholesterol - Transports cholesterol to cells to make hormones And build new cell membranes - Liver regulates cholesterol (removes it from blood) - Too much causes a lot of problems! (Stay tuned) High Density Lipoproteins (HDL) - ANS - Not made from LDL - Made by the liver - Removes cholesterol from cells (Carries it to liver and gets recycled/disposed) - Too little isn't helpful - synthesized in liver P a g e 36 | 54 Does the type of dietary fat alter the lipoproteins? - ANS - yes - Saturated fats lead to the most circulating VLDL & LDLs - Polyunsaturated (PUFA) and monounsaturated (MUFA) have the least Which lipoprotein is strongly associated with cardiovascular disease risk, stroke and mortality? - ANS Fed state (abundance/surplus - after meals) - ANS - Store energy for later use; most efficient place to store this: adipose (fat) tissue - Use as immediate energy in: muscle tissue - Lipoprotein lipase (LPL) hydrolyzes TGs -> FAs - FFAs then enter the muscle and/or adipose Muscle: FFAs -> energy Adipose: FFAs -> TGs (fat) Postprandial (post-meal) response - ANS - Go into circulation at a slower rate than glucose - Stay elevated & peaks - 4 hr. - Stay in circulation - 14 hrs. "Fasted state" (i.e. low energy availability - between meals/overnight) - ANS - Break down stored energy for usable energy to the body tissues - Most efficient place to get this: adipose (fat) tissue - Supplies 60% of energy (at rest) - Hormone-sensitive lipase -> TG -> FA (circulation) - FAs can be used by liver and muscle - FAs cannot be converted to glucose (issue?) - FAs can be converted to Ketone Bodies Blood lipid profile - ANS lipids that are circulating in the blood Health risks - ANS cardiovascular (heart) disease, stroke, etc. Do dietary lipids impact health? - ANS - Depends - Triglycerides - YES, cholesterol - no Cardiovascular heart disease - ANS - Saturated fat increasing blood LDLs & TGs - Trans-fat increasing LDLs and TGs; lowering HDLs - Dietary cholesterol: impacts blood cholesterol very little, if at all Cancer - ANS - Saturated fats and fats from fatty or processed meats pose highest risk - Promotion rather than initiation of cancer - Differs for various types of cancer: colon cancer has strongest association Obesity - ANS Fat yields highest amount of energy (9 kcals/gram) P a g e 37 | 54 Read food labels - ANS - Total fat: saturated fat, Trans fat - Compare products (standard labeling) - % daily value: how much a food contributes to daily fat intake -- Based on: 2000 calorie diet, 35% AMDR for fat = 78 grams/day -- Varies by personal daily calorie intake and fat AMDR (20-35%) - % calories from fat: percentage of a food's total calories that come from fat -- No longer shown on new labels Guidelines for Fake Intake - ANS - Type of fat may be more important than amount of fat - Limit saturated and Trans fat intake - Consume enough beneficial fat for health - DRI recommendations: -- Moderate calories from fat (20-35%) -- Compatible with low rates of disease Olive oil - ANS - Benefits for heart health: reducing LDL cholesterol -> domino effect - Canola and safflower oil = also healthy options - Instead of saturated fats (e.g. butter, stick margarine, animal fats) Nuts - ANS - Fat composition: 80% calories from fat -- 59% monounsaturated; 27% polyunsaturated; 14% saturated - Benefits for heart health: reducing LDL cholesterol -> domino effect - Beware of added sugars and sodium - Instead of other high-fat snack options Fish - ANS - Omega-3 fatty acids -- Benefits for heart health - Beware of environmental contaminants (e.g. mercury) - Instead of fatty meats -- Recommendation: 8 oz. /week Saturated fat = determinant of LDL cholesterol - ANS - Sources of saturated fat in US: fatty meats; whole milk products; tropical oils - Zero saturated fat is not possible - Vegan/Vegetarian diets can lower saturated fat Trans fat - ANS Limit hydrogenated foods (processed and convenience foods) The Mediterranean Diet - ANS - Eating pattern: -- Low in saturated fat and very low in Tran’s fat -- Rich in unsaturated fat, complex carbohydrates, fiber, phytochemicals, and other nutrients -- US restaurants aren't the same... - High fat consumption but low heart disease risk P a g e 40 | 54 Main Roles of Proteins - ANS 1. Growth and maintenance 2. Enzymes 3. Hormones (some) 4. Regulators of fluid balance 5. Acid-base regulators 6. Transporters 7. Antibodies 8. Energy/Glucose Growth and maintenance - ANS - Building blocks for most body structures - Allows for movement and function - Major structural component of all cells in the body - Collagen (protein): most abundant protein in the body -- Material for ligaments and tendons -- Basis of bone and tooth formation -- Provides the "glue" between cells of artery walls (withstand pressure from pumping blood) -- Tissue repair (scars) - Replacement of dead or damaged cells -- Average life of skin cell is 30 days -- GI tract cells turn over every few days Enzymes - ANS - Break down (catabolic) substances - Build up (anabolic) substances - Transform substances - Enzymes = catalysts -- Facilitate reactions -- They remain intact Hormones (some) - ANS Examples: insulin Messenger molecules Transported in blood from glands to target tissues Elicit responses in target tissues to maintain homeostasis Acid-base regulators - ANS Proteins = buffers that maintain acid-base balance in body Transporters - ANS - Carry nutrients/other molecules (e.g. hemoglobin) - Cell membrane "pumps" Antibodies - ANS - Defend body against - Body detects antigens (invaders) and makes antibodies (protein molecules that combat specific antigens) Energy/Glucose - ANS Starvation or insufficient CHOs: PRO -> AAs -> Energy Priority: help maintain blood glucose (which may cost lean body tissue) P a g e 41 | 54 Amino acids (AAs) are the building blocks of protein - ANS - AAs Atoms: -- Carbon ©, hydrogen (H), oxygen (O)...just like CHO and lipids -- Plus: nitrogen (N): amino = nitrogen-containing - AA structure: -- Central carbon © with four bonds -- (H) One hydrogen -- Amino group (NH2) -- Acid group (COOH) -- Unique side group for each amino acid Twenty different amino acids - ANS - Similar chemical structure - Different characteristics (side groups): size, shape, electrical charge Essential amino acids (n=9) - ANS - Body needs but cannot make - Essential to derive them from food Nonessential amino acids (n=11) - ANS - Body can synthesize - Present, but not needed in the diet Peptide bonds connect amino acids to form proteins (condensation) - ANS - 2 AAs bonded: dipeptide - 3 AAs bonded: dipeptide - 4+ AAs bonded: polypeptide - Most proteins contain 10s to 100s of AAs Building Proteins - ANS 1. DNA (carries PRO info.) 2. Transcription (1 DNA strand -> mRNA) 3. Translation (mRNA -> Tran (AAs)) 4. Protein formation Breaking down proteins (denaturation) - ANS - Exposure to heat, acid, other conditions - Disruption of polypeptide bonds - Protein structure uncoils, loses its shape and stability -- Lose functionality -- Irreversible at certain point -- Examples: curdling milk (acid); cooking eggs (heat); digesting proteins in stomach (acid) PRO Digestion and Absorption - ANS Ultimate goal: break ingested foods into smaller molecules PRO digestion in mouth - ANS nothing Where does most protein digestion occur? - ANS PRO digestion in stomach - ANS - Small amount of digestion (10-15%) P a g e 42 | 54 Optimizing Protein: Weight Management - ANS - Effects of increased dietary protein + energy restriction -- Increased dietary protein leads to greater weight & fat loss with improvements in muscle (during energy restriction) - Effects of increased dietary protein following weight loss -- Increased dietary protein leads to less weight re-gain (following weight loss) - Effects of Increased dietary protein on food intake -- Consuming more calories from protein leads to 'voluntary' reductions in daily food intake - Increased dietary protein improves appetite control, satiety and cravings -- Down homeostatic hunger -- Down hedonic hunger -- Up homeostatic satiety -- Up hedonic satisfaction Recommended Dietary Protein Intake: - ANS Assumptions of RDA: - Healthy person - Mixed-quality protein - Energy intake is "adequate" - PRO consumed with sufficient CHOs and FATS Dietary Guidelines for Americans - Consume: Seafood Lean meats and poultry; eggs Legumes (beans and peas), nuts and seeds and soy - Limit: Red and processed meats Assumptions of source - All PRO are 'created equal' - All red meats are 'created equal' Protein Quantity - Recommended vs. Optimal - ANS RDA? Yes Optimal? No Protein Quantity - Optimal (PER Eating Occasion) - ANS Optimal intake components - 90-120 g/d - 30 g/occasion - Need more protein? - Breakfast is best Protein Quantity - Athletes - ANS - Made by the American College of Sports Medicine - Depends on type and amount of exercise PROTEIN INTAKE: - Endurance athletes: 1.2-1.4 g protein x kg body weight^-1 x day^-1 - Strength/power athletes: 1.2-1.7 g protein x kg body weight^-1 x day^-1 P a g e 45 | 54 - During energy restriction: up to 2.0 protein x kg body weight^-1 x day^-1 What's your protein RDA? - ANS - Convert your (health) body weight in pounds to kilograms weight (lbs.)/2.2 = weight (kg) - Multiply your kg weight by 0.8 to get your RDA in grams of protein weight (kg) x 0.8 = YOUR RDA protein (g protein/day) What's your optimal protein intake? - ANS - Multiply your weight in kilograms by 1.2 and 1.6 to get 'optimal amount' in grams of protein - Divide your protein by 3 or 4 to represent eating occasions Protein Quality - ANS DIGESTIBILITY - Proteins must be digested before they can provide AAs to the body - Digestibility depends on source and other foods eaten with protein -- Animal proteins: 90-99% digestible -- Plant proteins: 70-90% digestible AA COMPOSITION - To enable protein synthesis (and prevent lean muscle breakdown), dietary PRO must supply the 9 essential AAs - Limiting AA: essential amino acid supplied in < amount needed for normal protein synthesis -- Body can't make "partial" proteins HIGH-QUALITY PROTEINS: (essential AAs in proportions needed by humans) - Animal proteins: generally provide most complete complement of AAs and are sometimes referred as "complete proteins" - Plant proteins: tend to be limiting in one or more essential AA and are sometimes referred as incomplete proteins REMINDER - Not all animal proteins are the same quality. Not all plant proteins are the same quality. Protein Quality - Complementary PROs - ANS - Low-quality PROs combined with each other to provide adequate levels of essential AAs - Protein quality of combined foods > either food alone - Vegetarians improve protein in diet by combining foods -- Food pairings that make a complete protein: beans and rice, legumes with grains, nuts, seeds or dairy, grains with dairy, dairy with nuts, dairy with nuts/seeds and legumes From Guidelines to Groceries - ANS - Mix n match protein sources (even with animal sources) - Target foods lower in saturated fat -- Grill/cook with saturated fat in mind - Be mindful of protein quality - Be mindful of portion size -- More is not always better P a g e 46 | 54 -- Closed fist -> 4-6 oz. meat (ideal) Protein supplements - ANS - In general, most Americans can achieve even optimal PRO amounts with diet - To build/maintain lean mass, protein supplements can be part of a healthy diet: -- 3 food based meals/d -- 1-2 protein supplements/d - Recommended in those following a vegan diet to achieve RDA amounts! - Protein type recommendation: -- 1 scoop = 24-30 g high quality PRO -- Fast-digesting -- Can have GI issues if allergic -- Drink lots of water -- Pay attention to other ingredients Energy - ANS - Heat: body temperature - Mechanical: movement - Electrical: nerve impulses - Chemical: storied in food and body (powers cellular activity) Metabolism - ANS Release of energy, water and carbon dioxide (as waste) from chemical bonds Energy metabolism - ANS How body obtains and uses energy from food Liver cells - ANS - Most versatile and metabolically active - Superhero! First to receive nutrients and toxins Anabolism - ANS - Buildup of body compounds (e.g. condensation) - Requires energy Catabolism - ANS - Break down of body compounds (e.g. hydrolysis) - Releases energy Transfer of energy in reactions: ATP - ANS Energy is released during breakdown of glucose, fatty acids and amino acids = captured by compound Adenosine triphosphate (ATP) Contains three phosphate groups - Negative charge (vulnerable to hydrolysis; H+) - Hydrolysis: bonds between phosphates break = energy released Provides energy for all cell activities *Coupled reactions* - ATP releases energy + reaction that will use energy: transfer energy from catabolic -> anabolic - Food -> ATP = 50% efficiency - Heat loss: food -> ATP; ATP -> body's work P a g e 47 | 54 - If ATP = abundant - Most efficient way to store energy - All energy nutrients can become ATP = all excess energy nutrients can become fat Generate high-energy compound ATP - If cells need energy and if ATP = low - Process through TCA cycle: inner compartment of mitochondria - Release hydrogen’s and their electrons (H+) -> electron transport chain TCA cycle - ANS Final common metabolic pathway for energy nutrients Circular path (one way) - Acetyl CoA (2-carbon compound) travels one way and releases: - Two carbon dioxide molecules (CO2) - One CoA enzyme - Hydrogen atoms and their electrons (H+) -> carried off by coenzymes (made from niacin and riboflavin) to electron transport chain Oxaloacetate: 4 carbon compound made primarily from pyruvate - Needed to initiate first step and synthesized in last step of cycle - Must be available for acetyl CoA to enter cycle Electron transport chain - ANS Captures energy in bonds of ATP Series of proteins - Electron "carriers" mounted in sequence - Inner membrane of mitochondria Coenzymes deliver electrons - From TCA cycle, glycolysis, and fatty acid oxidation - Electrons passed to next carrier, and next carrier, and next carrier, until... - Oxygen is reached at end of chain (necessary for energy metabolism): Oxygen accepts electrons, combines with H atoms = H2O released - ATP synthesis powered by H ions: pumped out of inner compartment, then rush back in Fat is - ANS - The most efficient fuel source - Body's preferred form of energy storage Fat yields most energy per gram (9 calories vs. 4) - ANS - Fatty acid bonds = mostly between C and H - Oxygen added to form CO2 and H2O -> - H+ released to electron transport chain -> - Energy is captured in bonds of ATP -> - Oxidized 16-carbon fatty acid molecule = 129 ATP (vs. glucose about 30 ATP) - More ATP = more energy Metabolism favors fat formation - ANS Regardless of excess from protein, fat or carbohydrates - Excess dietary fat -> body fat = direct and efficient (almost all excess is stored as body fat) P a g e 50 | 54 - Carbohydrate and protein have other roles to fulfill before conversion to body fat Cells use mixture of fuels for energy - Amount of each nutrient used depends on dietary availability Excess protein - ANS - Body can't store excess amino acids (must be changed) - First: normal daily losses are replaced - Second: oxidation increases (produces energy) - Third: amino acids delaminated, remaining carbon -> ketone bodies (stored as fat in adipose tissue) Excess carbohydrates - ANS - First: storage as glycogen (limited space) - Second: oxidation increases (produces energy; prevents dietary and body fat from oxidation) - Third: converted and stored as fat Energy Balance: from feasting to fasting - ANS After and between meals... Glucose, glycerol and fatty acids = used then stored - Fasting state (2-3 hours after a meal) body draws on stores - Glycogen and fat are released -> glucose, glycerol, fatty acids for energy Basal metabolism - Energy needed to maintain life processes when body is at complete rest (physical, digestive and emotional) - ⅔ of total energy expended per day Fasting (choose not to eat) vs. starving (no choice) Energy balance: fasting - ANS Carbohydrate, fat and protein - All eventually used for energy In the beginning: - Glucose (from liver's glycogen stores) and fatty acids (from adipose tissue's stored fat) = released to travel to cells - Broken down to acetyl CoA (provide energy) Next phase: - Liver glycogen is depleted, blood glucose levels fall - Cells begin to degrade their components to provide fuel - Fat breakdown -> fatty acids (used by most cells) Glucose: - Needed by nervous system and red blood cells - Gluconeogenesis: some amino acids -> pyruvate -> glucose - Glycerol portion of triglyceride -> glucose - Breakdown of body proteins (lean muscle, liver) -> glucose: *Expensive way to obtain glucose*First few days: body protein provide 90% of needed glucose (glycerol = 10%)* Shift to ketosis - Use fat to fuel brain - Acetyl CoA fragments (from fatty acids) -> ketone bodies - Slows the rate of body protein breakdown (but many areas of brain need glucose) P a g e 51 | 54 Ketosis chemistry - ANS - Ketone body + acid group (COOH) = keno acid - High concentration = blood pH drops (becomes more acidic) Ketosis results - ANS - Fasting hormones slow metabolism - Loss of appetite - Reduces energy output - Conserves lean tissue and fat (weight loss does not equal fat loss) Symptoms of starvation - ANS - Physical: wasting; slowed heart rate, respiration, metabolism; lowered body temperature; impaired vision; organ failure; reduced immunity - Psychological: depression; anxiety; food-related dreams/obsessions Alternate day fasting, modified fasting - ANS - Energy-containing foods: consuming none or 25% of regular consumption on alternate days - A few studies suggest some health benefits, but weight loss = standard low calorie diets Time restricted feeding - ANS - Example: eat freely for 8 hours, fast for 16 hours - Limited research suggest improvements of body weight, blood lipids, blood glucose Energy balance: low-carbohydrate diets - ANS Metabolism shifts (similar to fasting) - Glycogen stores used first: power brain, nerves and blood - Gluconeogenesis (making glucose from amino acids of body and dietary protein): after glycogen is depleted Body tissues used somewhat, even when protein provided in diet Urine monitoring: Glycogen or protein -> glucose = release of water, increased urine Ketosis - Touted as key to weight loss... - No relationship between ketosis and weight loss: *Initial loss of body fluids (+ minerals), glycogen, lean protein*Weight will return if well balanced meals are resumed (body is starving)* Alcohol in beverages - ANS Potential health benefits - Moderation = key - Reduced risks of heart disease, diabetes, osteoporosis Alcohols: organic compounds containing OH (hydroxyl) group - Glycerol vs. ethanol Lipid solvents - Penetrate cells, destroy cell structures = kill cells (alcohol as disinfectant) Moderation - Drink = ½ oz. of pure ethanol: Wine: 5 oz. Beer: 12 oz. Individual: sex, genetics, health, body composition, age, family history P a g e 52 | 54