Exam Nutrition 1 Study Guide
Estimated Average Requirement (EAR) the average daily amount of nutrient that will maintain a specific biochemical or physiological function in half the healthy people of a given age or gender group Recommended Daily Allowances (RDA) the average daily amount of a nutrient considered adequate to meet the known nutrient needs of practically all healthy people; a goal for dietary intake by individuals. Adequate Intakes (AI) the average daily amount of a nutrient that appears sufficient to maintain a specified criterion; a value used as a guide for nutrient intake when an RDA cannot be determined. Tolerable Upper Intake Levels the maximum daily amount of a nutrient that appears safe for most healthy people and beyond which there is an increased risk of adverse health effects Dietary Reference Intakes (DRI) a set of nutrient intake values for healthy people in the US and Canada. These values are used for planning and assessing diets and include: o Estimated Average Requirements (EAR) o Recommended Dietary Allowances (RDA) o Adequate Intakes (AI) o Tolerable Upper Intake Levels (UL) Nutrient density a measure of the nutrients a food provides relative to the energy it provides. o The more nutrients and the fewer kcalories, the higher the nutrient density. Fiber (dietary) in plant foods, the nonstarch polysaccharides that are not digested by human digestive enzymes, although some are digested by GI tract bacteria o Include cellulose, hemicelluloses, pectins, gums, and mucilages and the nonpolysaccharides lignins, cutins, and tannins Villi fingerlike projections from the folds of the small intestine; singular villus Microvilli tiny, hairlike projections on each cell of every villus that can trap nutrient particles and transport them into the cells; singular microvillus. Bile an emulsifier that prepares fats and oils for digestion; an exocrine secretion made by the liver, stored in the gallbladder, and released into the small intestine when needed. Gallbladder the organ that stores and concentrates bile o When it receives signal that fat is present in the duodenum, the gallbladder contracts and squirts bile through the bile duct into the duodenum Mucus a slippery substance secreted by cells of the GI lining (and other body linings) that protects the cells from exposure to digestive juices (and other destructive agents). o The lining of the GI tract with its coat of mucus is a mucous membrane (adjective = mucous) Pepsin a gastric enzyme that hydrolyzes protein. o Pepsin is secreted in an inactive form, pepsinogen, which is activated by hydrochloric acid in the stomach Hydrochloric acid an acid composed of hydrogen and chloride atoms (HCl) that is normally produced by the gastric glands Mastication the process of chewing Epiglottis cartilage in the throat that guards the entrance to the trachea and prevents fluid or food from entering it when a person swallows Cardiac sphincter the esophageal sphincter at the lower end of the esophagus that leads to the stomach and prevents backflow Chyme the semiliquid mass of partly digested food expelled by the stomach into the duodenum Bolus a portion; with respect to food, the amount swallowed at one time Insulin a hormone secreted by special cells in the pancreas in response to (among other things) increased blood glucose concentration. o Primary role of insulin is to control the transport of glucose from the bloodstream into the muscle and fat cells Glucagon a hormone that is secreted by special cells in the pancreas in response to low blood glucose concentration and elicits release of glucose from liver glycogen stores Cholecystokinin (CCK) a hormone produced by cells of the intestinal wall. o Targeted bladder: gallbladder o Response: release of bile and slowing of GI motility Epinephrine a hormone of the adrenal gland that modulates the stress response; formerly called adrenaline o When administered by injection, epinephrine counteracts anaphylactic shock by opening the airways and maintaining heartbeat a nd blood pressure Glycogen an animal polysaccharide composed of glucose; manufactured and stored in the liver and muscles as a storage form of glucose o Glycogen is not a significant food source of carbohydrate and is not counted as one of the complex carbohydrates in foods Sucrose a disaccharide composed of glucose and fructose; commonly known as table sugar, beet sugar, or cane sugar o Sucrose also occurs in many fruits and some vegetables and grains Lactose a disaccharide composed of glucose and galactose; commonly known as milk sugar Fructose a monosaccharide; sometimes known as fruit sugar or levulose o Found abundantly in fruits, honey, and saps Glucose a monosaccharide; sometimes known as blood sugar or dextrose Galactose a monosaccharide; part of the disaccharide lactose Maltose a disaccharide composed of two glucose units; sometimes known as malt sugar Starch plant polysaccharides composed of glucose Sterols compounds containing a four ring carbon structure with any of a variety of side chains attached
Triglycerides the chief form of fat in the diet and the major storage form of fat in the body; composed of a molecule of glycerol with three fatty acids attached; also called triacylglycerols Saturated fatty acids a fatty acid carrying the maximum possible number of hydrogen atoms o A saturated fat is composed of triglycerides in which most of the fatty acids are saturated Polyunsaturated fatty acid a fatty acid that lacks four or more hydrogen atoms and has two or more double bonds between carbons o A polyunsaturated fat is composed of triglycerides in which most of the fatty acids are polyunsaturated Monounsaturated fatty acid a fatty acid that lacks two hydrogen atoms and has one double bond between carbons o A monounsaturated fat is composed of triglycerides in which most of the fatty acids are monounsaturated Hydrogenated fat polyunsaturated fats made more saturated to protect against oxidation; make liquid fats more solid Phospholipids a compound similar to a triglyceride but having a phosphate group (a phosphorous-containing salt) and choline (or another nitrogencontaining compound) in place of one of the fatty acids Cholesterol one of the sterols containing a four ring carbon structure with a carbon side chain Soluble fiber indigestible food components that dissolve in water to form a gel Micelles tiny spherical complexes of emulsified fat that arise during digestion; most contain bile salts and the products of lipid dig estion, including fatty acids, monoglycerides, and cholesterol Chylomicrons the class of lipoproteins that transport lipids from the intestinal cells to the rest of the body Low-density lipoproteins (LDL) the type of lipoprotein derived from very-low-density lipoproteins as VLDL triglycerides are removed and broken down; composed primarily cholesterol of High-density lipoprotein (HDL) the type of lipoprotein that transports cholesterol back to the liver from the cells; composed primarily of protein Very-low-density lipoprotein (VLDL) the type of lipoprotein made primarily by liver cells to transport lipids to various tissues in the body; composed primarily of triglycerides Ketone bodies the product of the incomplete breakdown of fat when glucose is not available in the cells Kwashiorkor a form of PEM results either from inadequate protein intake or, more commonly, from infections Marasmus a form of PEM that results from a severe deprivation, or impaired absorption, of energy, protein, vitamins, and minerals Limiting amino acid the essential amino acid found in the shortest supply relative to the amounts needed for protein synthesis in the body o Four amino acids are most likely to be limiting: Lysine Methionine Threonine Tryptophan Limiting amino acids in legumes methionine Limiting amino acids in grains lysine Nitrogen balance the amount of nitrogen consumed (N in) as compared with the amount of nitrogen excreted (N out) in a given period of time Proteases enzymes that hydrolyze protein Denaturation the change in a protein's shape and consequent loss of its function brought about by heat, agitation, acid, base, alcohol, heavy metals, or other agents Dipeptide two amino acids bonded together Polypeptide many (ten or more) amino acids bonded together Peristalsis wavelike muscular contractions of the GI tract that push its contents along Edema swelling of body tissue caused by excessive amounts of fluid in the interstitial spaces; seen in protein deficiency (among ot her conditions) Deamination removal of the amino (NH2) group from a compound such as an amino acid Protein-digestibility-corrected amino acid score (PDCAAS) a measure of protein quality assessed by comparing the amino acid score of a good protein with the amino acid requirements of preschool-age children and then correcting for the true digestibility of the protein; recommended by the FAO/WHO and used to establish protein quality of foods for Daily Value percentages on food labels High-quality protein dietary proteins containing all the essential amino acids in relatively the same amounts that human beings require; may also contain nonessential amino acids
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The Nutrition Facts panel must provide nutrient amount/% DV for: %DV: Total food energy (kcalories) 1. Food energy from fat (kcalories) 2. Total fat (grams and %DV) 3. Saturated fat (grams and %DV) 4. Trans fat (grams)
Vitamin A Vitamin C Iron Calcium
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Cholesterol (mgs and %DV) Sodium (mgs and %DV) Total carbs, including starch, sugar, and fiber (g and %DV) Dietary fiber (g and %DV) Sugars, natural and added (g) Protein (g) % Daily Values is determined according to the 2000 kcalories per day reference caloric diet. MyPyramid includes food groups: grains, vegetables, fruits, milk, meat and beans.
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Water soluble nutrients and small products of fat are released into bloodstream. Fat soluble vitamins and larger fats from ch ylomicrons are released to lymphatic system. Lymphatic system consists of one-way vessels to transport fluids. a. Thoracic duct is lymph's route to heart b. Subclavian vein provides return of lymph to vascular c. Lacteals are lymphatic vessels of intestine that absorb nutrients and pass them to lymphatic system 5. Bacteria in large intestine helps break down some foods and recycle nutrients. Others are for immune protection from harmful bacteria. 6. Sphincters are used to control movement of food through the GI tract 7. Order that food passes through GI: a. Mouth esophagus stomach small intestine (duodenum, jejunum, ileum) large intestine (colon) rectum anus 8. Water-soluble nutrients and small fats are routed to the liver before being transported to cells. Fat-soluble nutrients, entering from lymph, bypass liver at first and eventually enter vascular system. a. Hepatic portal vein directs blood from GI to liver b. Hepatic vein takes blood from liver to heart c. Liver protects against toxic substances 9. It is recommended that 45-65% of kcalorie intake should be from carbs. 10. Digestion of starches take place mainly in the mouth and the small intestine 11. Calories per gram: a. Carbs: 4 cal/g b. Protein: 4 cal/g c. Alcohol: 7 cal/g d. Fat: 9 cal/g 12. Read Omega packet 13. Glucose contains carbon, hydrogen, and oxygen. We get the word `carbohydrates' from the chemical makeup of CHO. 14. Carbs: Simple Carbs Complex Carbs Monosaccharides (most are hexoses) Dietary fibers provide structure in plants Glucose serves as essential source of energy (blood Cannot be broken down by human enzymes sugar) Soluble fibers (fruits and veggies) Fructose is sweetest (honey and fruits) Insoluble fibers (grain and veggies) Galactose rarely occurs naturally 15. Cholesterol is a precursor to hormones, bile, and vitamin D 16. The main site of dietary fat hydrolysis is in the small intestine 17. Long chain fatty acids are the only fat component that cannot be absorbed directly into the bloodstream. 18. DRI and 2005 Dietary Guidelines recommend fat at 20-35% of energy intake. FDA recommends 10% of energy intake from saturated fat and 30% of energy intake from total fat. 19. 20. 9 essential amino acids: a. Histidine, isoleucine, leucine, lysine, methionine, phenyalanine, threonine, tryptophan, and valine 21. Roles of protein in our body: a. Blood clotting by producing fibrin which forms solid clot b. Vision by creating light-sensitive pigments in retina c. Building materials for growth and maintenance (bones, teeth, skin, hair, nails, and GI lining) d. Enzymes are proteins that facilitate anabolic (building up) and catabolic (breaking down) chemical reactions e. Hormones regulate body processes and some hormones are proteins (insulin) f. Regulators of fluid balance i. Plasma proteins attract water ii. Maintain volume of body fluids to prevent edema g. Transporters i. Carry lipids, vitamins, minerals and oxygen in body ii. Act as pumps in cell membranes, transferring compounds from one side of membrane to the other h. Buffering i. Proteins help solutions resist extreme pH 1. Due to amphoteric nature a. Can donate or accept proton b. Chemically reacting either like acid or base 2. Acid-base regulation a. Act as buffers by keeping solutions acidic or alkaline b. Acids release and bases accept hydrogen ions in solution c. Acidosis and alkalosis are high levels of acid and alkalinity in blood and body fluids i. Antibodies i. Fight antigens that invade body ii. Provide immunity to fight an antigen more quickly second time exposure occurs 22. Essential nutrients are those that must be supplied by an appropriate diet. Non-essential nutrients are those that can be manufactured by the body. 23. Mucus protects stomach and GI tract from acidic and other enzymes.