NFS 043 Fundamentals of Nutrition Exam 2
NFS 043 Fundamentals of Nutrition Exam 2 NFS 043
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This 23 page Bundle was uploaded by Grace Cotrupi on Tuesday September 20, 2016. The Bundle belongs to NFS 043 at University of Vermont taught by Dr. Lizzy Pope in Fall 2015. Since its upload, it has received 7 views. For similar materials see Fundamentals of Nutrition in Nutrition and Food Sciences at University of Vermont.
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Date Created: 09/20/16
Fat STORING FAT Body conserves fat molecules In fat depots/adipose tissue Without enough available food, energy stores are called o Dismantle Stored Triglycerides Release fatty acids into blood Carbohydrates play a role o When fat is used exclusively for energy, Ketones form Therefore, starvation=acidic blood FAT FROM SUGAR Fat can be formed from carbs Glucose breaks into fragments Fragments reassemble into fatty acids HEART DISEASE + OBESITY Saturated + Trans fats (especially trans) contribute MUFA, Pufa = good fats Refined Carbs = Can become bad fats (see fat from sugar above) Fat is high in calories Overconsumption of fat = overconsumption of calories Leading COD in America Solution: Raise HDL, Lower LDL o HDL can be raised by physical activity and moderate alcohol consumption RECCOMENDATIONS Fat is necessary in diet o Used as isulation o Cushions vital organs o Energy storage DRI- 20-35% of daily calories should be from fats Keeps trans/saturated fats low LIPOPROTEINS Lipoproteins transport fat around the body Low-Density lipoproteins move cholesterol and fat to tissues o Bad o Made of more lipid than protein o Oxidation causes inflammation Thought to be reduced by some phytochemicals High-Density Lipoproteins move it away from tissue to be removed from the body as waste o Good o Made of more protein than lipid o Scavenges for cholesterol and takes it to liver to be removed CHLOESTEROL LEVELS Heavily influenced by genetics Should be consumed in moderation o Recommended 300 mg or less daily Cholesterol In food DOES NOT affect blood cholesterol levels Saturated + Trans fat DOES affect levels ESSENTIAL FATTY ACIDS Linoleic Acid Linolenic Acid o Cannot be produced by the body Provide raw material for Eicosanoids (hormone-like substance, also essential) Without them one would develop deficiency symptoms o Infertility, Skin problems, etc. Linoleic o Omega-6 Fatty acid o Can become arachidonic acids (form of omega-6) Linolenic o Omega-3 Fatty acid o Can be DHA or EPA (fish, fish oil) o Protects against heart disease o Aids brain function and vision o Reduces/protects against inflammation Reccomendations o Most people do not get enough omega-3 There is no shortage of omega-6 in the USA o 2 servings of fatty fish (4oz) per week o Supplements can disrupt medications o Eat Omega-3 enriched food Flaxseed is high in it SEAFOOD SAFETY Watch out for Mercury levels o Especially children or those pregnant/lactating Be cautious of raw fish Benefits outweigh risks Fat Cont. and Proteins TRANS FATS Trans fat are a product of Hydrogenation o Unnatural, man-made o Made by hydrogenating polyunsaturated fatty acid Oxidation of unsaturated oils o Oil becomes rancid o Hydrogenating oils gives them more shelf life Hydrogenation o Unsaturated acid shot with hydrogen o Breaks double bond to create saturated fat o Trans fats are a by-product Still has double bond Shape is twisted Resembles saturated fat in shape and behavior Health effects o Increases LDL lowers HDL o Very similar to saturated fat o FDA ruled trans fats unsafe last summer 3 year compliance period Trans fats gives food new characteristics o Shelf stability o Texture is palatable o Makes food (like margarine, peanut butter) easier to spread o On a food label it would say 'partially hydrogenated oil,' fully hydrogenated is not a trans fat FAT IN DIET Lower recommendation is 20% of kcals-mostly MUFA or PUFA Meat, poultry, fish, dried peas, beans, eggs, nuts o Limit intake to 5-7 oz per day o Choose low-fat meats Ground turkey or chicken vs. beef o Milk, yogurt, cheese o Grains EATING HEALTHY Reduce portion size Read labels Avoid "fat-free" options o Usually same calories Calories come from sugar instead of fat Use oils instead of solid fats "LOW FAT" Seven Countries study o Total fat vs. saturated fat o Heart disease rates were high in countries with high saturated fat consumption, regardless of total fat consumption Type of fat is more important than amount MEDITERRANEAN DIET AND HEART HEALTH Mediterranean diet o Whole foods o Dietary focus rather than nutrient focus o Fish o Nuts Walnuts Almonds PROTEIN AND AMINO ACIDS Different from carbs and fats because… o Contain nitrogen o Lots of different protein structures Amino acids o 20 kinds o Carbon atoms with amine group (nitrogen group) and acid group o Side chain o Essential amino acids Conditionally essential (usually body can make amino acids, but in some conditions it cant and must be acquired by diet) Ex: In healthy people PHE converts to TYR With the condition PKU, the body cannot convert PHE to TYR, therefore it must be acquired via diet o Recycling Proteins are constantly being formed from AA AA can be disassembled and reassembled into new proteins Body had priority system when not enough protein in diet Break down muscle and blood protein first to reassemble into essential proteins Guard structural proteins of organs o Peptide bonds link amine end of one acid to the acid end of another amino acid o Amino acids strung together are proteins Shape of protein determines function Protein strands can be alone in the cell or associated with each other o One cell can contain 10,000 proteins Inherited amino acid sequences o Alternations in gene sequence can lead to disease Ex: Sickle-celled anemia Lipids: Fats, Oils, Phospholipids, and Sterols INTRODUCTION Lipids are necessary but can harm health Three classes of lipids o Triglycerides o Phospholipids o Sterols Fat is the chief storage form of energy in the body Provides the most energy for the body's work Excess fat is stored in lipocytes, which expand in size until the fat is used Fat cells can increase in number and size, but number of cells never decreases Fat secrets hormones Fat is metabolically active tissue Visceral fat = Fat on the inside of the body Subcutaneous Fat = Fat just under the skin USEFULLNESS Purposes of Fat o Shock absorption, inside and outside (keeps organs from colliding) o Insulation, temperature regulation o Cell membranes, phospholipids, stability and transportation through membrane Fat Soluble nutrients o Vitamins A,D,E, and K, primarily found incased in fat TYPES OF FAT Triglycerides o Glycerol backbone o Three Fatty Acids Fatty Acids differ in chain length and saturation Saturated fat is hard Unsaturated fat is soft/oil Saturation is a process of adding hydrogen atoms Saturated fats have no double bonds because all sites are used for H atoms Monounsaturated has one double bond in its chain Polyunsaturated has more than one double bond in its chain Phosopholipids o Glycerol backbone o Two fatty acids Make phospholipids soluble in fat o One molecule of phosphorous Makes phospholipids soluble in fat o Important in cell membranes and molecule transport Because it is water and fat soluble it can get both through the membrane o Emulsifier Makes mayonnaise! (oil, vinegar, egg yolk) Sterols o Multiple roles in the body o Form basis for some hormones and vitamins o Plant sterols and cholesterol DIGESTION AND ABSPORTION Absorption o Fatty acids split from glycerol o Bile shuttles lipids across mucus layer Bile sticks to fat and brings it into water of small intestine and emulsifies them, exposes them to enzymes in water o Very little digestion of fatty acids occurs in stomach o Most digestion of fatty acids occur in small intestine o Humans absorb 98% of fat in a meal TRANSPORTATION Glycerol and Short fatty acid chains o Travel in bloodstream Larger Lipids o Most are larger o Protein carriers - lipoproteins o Released into lymph o Chylomicrons Allows fat to travel in blood Is a type of lipoprotein Protein and Amino Acids DENATURATION OF PROTEINS Destroys/alters protein structure o Ex: cooking egg whites, turns clear to white Denaturing agents o Heat, radiation, alcohol, acids, bases, salts of heavy metals Dangerous denaturation o Radiation Helpful denaturation o Digestion, cooking PROTEIN DIGESTION Stomach o Acid denatures protein in food Uncoils protein's strands o Enzymes attack peptide bonds Small Intestine o Polypeptides=small piece of protein o Further broken down by pancreatic and intestinal enzymes into mono or di peptides AMINO ACID ABSORPTION Absorbed by cells in small intestine o Large molecules sometimes enter blood without being totally broken down Ex: Hormones or allergens Separate sits for absorption o Each AA has its own site o Large doses of one type of AA can 'block' the absorption of similar types of AA Released into Bloodstream o Carried to liver o Other cells use AA for protein building or energy (not good) IMPORTANCE Amino Acids must be continually available o Building new proteins o Constant regeneration=constant demand Amino acids are needed every day Protein turnover o Break proteins down and recycle AA Protein Roles o Structure and movement Muscle tissue = 40% of body's protein Most structural things have protein o Building enzymes, hormones, other compounds Ex: Insulin o Build antibodies Immunity to disease o Transporting substances Hemoglobin (carries oxygen) Lipoproteins (carries fat) o Maintain fluid and electrolyte balance Preventing edema (fluid imbalance in response to an injury) o Maintaining acid-base balance as buffers Acidosis vs. alkalosis o Blood clotting o Providing energy and glucose (when carbs/fats unavailable) It is possible to use protein to maintain blood glucose There is no storage compound for protein Must dismantle tissue to get protein (breakdown of muscles) Oversupply of Amino acids (overconsumption of calories) Body will remove amine group (Nitrogen) and use the leftovers PROTEIN DIGESTIBILITY Animal proteins- 90% digested Legumes proteins - 80-90% digested Grains and plants - 70-90% digested PROTEIN DEFICIENCY AND EXCESS Worlds leading form of malnutrition o Combined with energy deficiency (starvation) Protein-energy malnutrition (PEM) o Not enough variety, only a few types of foods o Mostly Africa and lower Asia/ Europe Marasmus o Energy and protein deficiency o Common in children o Muscle wasting o Impairs learning and development Some reversible, many not o Preventing death Heart failure is common Careful re-feeding Slow introduction of food Fast introduction can damage heart Kwashiorkor o Protein deficiency, sometimes energy deficiency as well Unvaried diet o Often happens when babies are weaned o Fluid balance is diminished Changes in body (edema) o Risk of infection (not enough protein to fight sickness) o PEM at home Extreme dieting, AIDS, cancer, addictions Excess o Possible risk o Heart disease o Kidney disease Excess protein does not cause disease Limit protein once you already have kidney disease AMINO ACIDS TO GLUCOS Fate of an amino acid o Cellular use Build protein Make a needed compound Dismantle amino acid for component parts o Wasting amino acids Not using them for above processes Four conditions 1. Body lacks energy from other sources 2. Body has enough protein, doesn’t need more 3. Body has too much of a single amino acid 4. Diet is providing low-quality protein Ex: too few essential AA Ex: Many plants don't have all AA on their own Preventing waste SUPPLEMENTS Protein supplements o Do not improve performance o Not effective for weight loss Amino acid supplements o Body is designed to work with whole proteins o Excess AA can block absorption of other AA o No safe level of AA supplementation (No UL) RECCOMENDATIONS DRI o Depends of body size Infants and growing children are building new cells Bigger people have more cells to support o Recommended intake 0.8 g of protein per kg of body weight o Depends on body's health Infection of malnutrition need more o Protein quality Protein digestibility Animal products are usually easier to digest than plants AA compositions NITROGEN BALANCE Nitrogen excreted vs. nitrogen eaten Variation in nitrogen balance o Positive balance N in > N out Happens in children and pregnant people Pregnant women will breakdown their own tissue before the fetuses development suffers o Negative balance N out > N in Happens during illness or injury Happens to astronauts because gravity HIGH QUALITY PROTEIN Enough of all essential AA If not enough AA in diet, cells breakdown internal proteins, conserve AA by limiting protein production Limiting AA Complementary AA o Ex: rice and beans o Foods that go together so together they have all the AA LOW GLUTEN DIETS Protein in grain foods Gluten allergy Celiac disease Gluten free diet o No special weight loss powers Over hyped, only necessary if you actually HAVE AN ILLNESS DUH VEGETARIAN vs. MEAT-EATTING Vegetarian o Lower heart disease rates o Lower hypertension rates o Lower rates of some cancers o Be careful to get enough nutrients Meat-Eater o Critical times in life, easy to get nutrients Pregnancy Old age Growing children Carbohydrates Part II DIGESTION -Carbs must be broken into monosaccharaides before they can be digested -Cells can only use glucose for energy -Need steady rate of glucose throughout day Begins in mouth with salivary amylase Sweet taste when chewing starchy foods Enzyme stays with food when swallowed and continues to aid digestion at top of stomach Enzyme is broken down at bottom of stomach o Enzymes breakdown in lower stomach o Starch digestion ceases in stomach Other starch-digesting enzymes in small intestine Different starches are harder/easier to digest Refined starches break down rapidly Complex starches take more effort to break down o These types are called resistant starch o Resistant starch is also a type of fiber as much of it passes through colon undigested SUGAR DIGESTION Sucrose, lactose, maltose and small polysaccharides undergo one more split to become mono Occurs by digestive enzymes attached to cells in lining of small intestine Absorbed monosaccharaides travel to bloodstream FIBER DIGESTION Bacterial fermentation within the colon Byproduct is gas LACTOSE INTOLERENCE Defined as the inability ability to digest lactose Due to reduced amounts of the enzyme lactase Lactase splits disaccharide into glucose and galactose Infants produce abundant amounts of lactase as lactose is their only source of glucose o Some babies don't have enough and they have same symptoms as adult lactose intolerance, very rare. Lactase production decreases with age 75% of world population has decreased ability to produce lactase Symptoms… o Nausea o Pain o Diarrhea o Gas Symptoms occur because o undigested lactose pulls in fluids from surrounding body tissues leading to cramping and pain o Bad bacteria uses lactose of energy *NOT THE SAME AS A MILK ALLERGY* Can result in calcium deficiency Solutions… o Low-lactose dairy products Yogurt, cheese (Particularly hard cheese) o Fortified non-dairy products o Other food sources of Calcium SUGAR ALCOHOLS Sugar-like compounds Made from dextrose or other carbs Absorbed differently Chemically more similar to alcohol Do not damage teeth like other sugars Found in gum or sugar-free products Examples: Sorbitol, xylitol, mannitol Different from non nutritive sweeteners (splenda, equal, etc.) Barely absorbed, mostly passes through tract o Can lead to GI tract issues OBESITY High intakes of added sugar increase risk of obesity 3/4 of added sugars daily on average Nutrition fact labels often don’t correspond USE OF GLUCOSE IN THE BODY Glucose is the basic unit used for energy Internal store to be used when glucose is not coming in through diet Blood concentration of glucose is highly regulated by body A cells use glucose to some degree Brain, nervous and red blood cells use glucose for energy almost exclusively There is no good substitute for glucose GLUCOSE AS ENERGY Glucose is made of six carbons Each time a bond is broken energy is released Water is a by product First is broken in half Two 3-carbon bonds Two halves can be put back together to remake glucose or broken again into smaller molecules These smaller molecules can… Breakdown further for more energy Attach to fat or protein Split into CO2 and H2O GLUCOSE AND FAT Glucose can be converted to fat, but fat cannot be converted back to glucose When there is no glucose n diet, body can use protein to make some glucose Keeps protein from performing its own function This is known as protein-sparing action Ketosis Fat cannot be created correctly, fat fragments combine together Causes build up of acidic ketone bodies Causes ketosis which disturbs the acid-base balance and causes nutrient deficiencies GLUCOSE REGULATION 2 Safeguards for glucose storage Excess glucose from liver and muscles is stored as glycogen and in adipose tissue as fat Glucose replenished from liver glycogen stores Muscles hoard glycogen for energy Brain stores tiny amount of glycogen as emergency reserves Liver stores the rest With no food, stores can be depleted in less than a day Regulated by 2 enzymes Insulin - Stimulates glucose storage as glycogen Glucagon- Stimulates release of glycogen Both released by pancreas Blood glucose rises after a meal, insulin is released and tells cells to take in glucose If to much glucose is taken in, glucagon releases and breaks down glycogen stores Hypoglycemia - Low blood glucose Occurs if someone hasn’t eaten Can be side effect of diabetes Dizzy, shaky, faint EXCESS GLUCOSE AND BODY FAT When too much glucose is in body it is used as energy instead of fat This leaves fat to circulate in blood until its taken up by body's fat stores Fat storage is unlimited GLYCEMIC INDEX Carb-rich foods differing how they elevate blood glucose and insulin This effect is ranked on a scale known the Glycemic index (GI) Individuals own metabolism also greatly affects insulin response Low GI foods help control blood glucose levels better Glycemic load is important for people with diabetes GI is outdated as current guidelines are suggesting low GI foods DIABETES Diabetes is the inability to regulate blood glucose levels 26 million is USA 7 million are undiagnosed 79 million have prediabetes Elevated glucose but not high enough to be diabetes Can lead to severe complications Amputations Kidney failure Nerve damage Heart disease Stroke Death Type 1 5-10% of diabetes cases Autoimmune Pancreas produces no of little insulin Insulin must be received from external source (pump, injections) Genetically based Type 2 90-95% of cases Found in adults and children Tissues become insulin resistant Lose sensitivity to insulin Blood glucose increases, pancreas sends more insulin Pancreas loses ability to produce insulin Obesity increases insulin resistance Often lifestyle based Weight loss of 5-7% for overweight patients can significantly help Diet of carbs, exercise, glucose monitoring and medications can help Carbohydrates BASICS Carbon and Water (CHO) Compounds made of sugars Digestible vs. indigestibles Digestible = energy yielding Indigestible= very little energy, such as fiber Simple carbs = single sugar units, monosaccharaides Complex carbs = multiple sugars, disaccharides HOW ITS MADE Green plants make carbs via photosynthesis Water + CO2 = simple sugar glucose Glucose provides energy for the cell Sunlight holds chemical bonds together CARB CONTAINING FOODS Unused glucose stays in plant leaves Almost all carb-rich foods are plant-based Milk is one of the only exceptions SIMPLE CARBS 6 types 3 monosaccharaides Glucose- plant and animal tissue, known as blood sugar. Fructose- Very sweet, found in fruits and honey, known as fruit sugar Galactose- found as part of milk sugar (lactose 3 disaccharides Lactose- Milk Sugar, Galactose + Glucose Maltose- Malt Sugar, germinated grains, Glucose + Glucose Sucrose- Table Sugar, Fructose + Glucose All end in -ose Monosaccharaides are used to build disaccharides Mono or disaccharides bond to build polysaccharides Monosaccharaides - Absorbed directing into blood Disaccharides - Must be digested first. Enzymes break di- into mono- Glucose: Energy or stored in liver or muscle glycogen Galactose: Converts to glucose in liver Fructose: Used as energy by liver Polysaccharides= long strands of glucose units Starch -Plants own energy source -Glucose>Starch>Granules>Seeds Raw starch cannot be digested, must be cooked Glycogen -Animal storage of glucose -Highly branched -Not a significant food source S-tored in liver/muscles in humans Fiber -Indigestible parts of plant foods -Humans do not have enzymes to break this down -Ex: Cellulose, hemicellulose, pectin, gums, mucilage, lignan -Bacterial fermentation of fiber Occurs in colon Breakdowns fiber by bacteria that DO have fiber-breakdown enzymes WHY DO WE NEED CARBOHYDRATES? -Fuels bodies functions -Preferred source of energy, especially nervous system and red blood cells -When carbs are used as energy, protein is spared as helps maintain muscles -Prevents Ketosis (Build up of ketones, acidifies blood) -Enables Fat metabolism -Creates mucus that lines body's membranes -Important in disease processes (ex: Diabetes) -Keeps GI tract healthy -Contain other vitamins and minerals INTAKES ADMR: 45%-65% of totally daily calories DRI: 130 g/d for adults Sources: grains, fruits, veggies, milk Added Sugar: purified, refined sugars that contain no other nutrients that are added during food processing for flavor -Highly caloric, low nutrient density Dietary Guidelines -Reduce calories from added sugar USDA -Use foods with added sugars as discretionary calories FIBER RICH FOODS -Soluble and insoluble -Found in grains, fruits, vegetables, legumes -Very low in American Diets -USDA: Increase fiber intake -DRI: 14 g per 1000 kcal. -38g for men up to aged 50 -25 g for women up to age 50 -After aged 50 reccomended intake goes down slightly -Promote normal blood cholesterol levels (soluble fiber) Soluble Fibers: Dissolve in water -Gummy or gel-like texture -Indifestible by humans, but can be broken down by bacteria -Oats, barley, citrus fruits Insoluble Fibers: Do not dissolve in water -Hold shape and texture when cooked -tough fibrous structures in plantss (husks, seed hulls) -less readily fermented, pass through GI tract GI TRACT HEALTH Soluble fibers maintain normal bacteria growth Insoluble fibers alleviate/prevent constipation by enlarging and softening stools Helps prevent Hemorrhoids, Appendicitis, Diverticulitis, GI tract cancers WEIGHT MANAGEMENT Glucose control -Soluble fibers regulate glucose after CHO rich meal (important for diabetics) Fiber-rich foods tend to be low in fat/added sugar Fibers absorb water as they travel though GI Tract -makes you feel fuller, delays hunger TOO MUCH FIBER? -NO upper limit -lots of fiber with low fluid can block intestines -Some fibers contain chelating agents (bind to nutrients and prevent them from being absorbed) PLANT PARTS Seed/kernel: Is what we use to make good. Germ: Nutrient rich Endosperm: edible, starchy Bran: protective coating, fiber Husk: Inedible WHOLE VS REFINED GRAINS Refined Grains remove all but endosperm. -food lasts longer (germ spoils quickly) Whole grains only remove husk -additional fiber and nutrients Enrichment adds nutrients back into refined grains that had been removed -U.S. Enrichment Act, requires enrichment after people got sick from lack of nutrients in refined grains Whole grains -Less hungry -Reduced risk of weight gain -Lower risk of heart disease/type 2 diabetes -Lower cancer risk
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