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TEXAS STATE / Nutrition and Foods / NUTR 2360 / What are the best food sources of fats?

What are the best food sources of fats?

What are the best food sources of fats?

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School: Texas State University
Department: Nutrition and Foods
Course: Nutrition Science
Professor: Krystle zuniga
Term: Fall 2016
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Cost: 25
Name: unit 2 notes and review
Description: unt 2 notes and review
Uploaded: 07/22/2017
41 Pages 534 Views 0 Unlocks
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∙ How does your body use cholesterol and do we need it in our diet?




∙ How does your body use fat?




∙ What happens to the fat you eat?



CH 5: FATS, OILS, AND OTHER LIPIDS ∙ Lipids o Lipids – category of compounds containing carbon, hydrogen,  and oxygen that are hydrophobic (insoluble in water)  Types: triglycerides, phospholipids, sterols  Function in body ∙ Energy storage ∙ Major component of membranes ∙ Insulation ∙ Transport of proteins in blood  Function inDon't forget about the age old question of Who should be the most important, and why?
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food: taste, texture, flavor, moisture, satiety ∙ Fatty Acids Are Found in Triglycerides and Phospholipids o Fatty acids – chain of carbon and hydrogen atoms acid group  (COOH at one end)  Over 20 different fatty acids  Can vary by ∙ 1. Length of chain ∙ 2. Whether carbons have double or single bonds  between them ∙ 3. Total number of double bonds  ∙ Fatty Acids Vary in Length and Structure o There are 3 main types of fatty acids:   Saturated fatty acids – single bonds between carbons ∙ Solid at room temperature  Monounsaturated fatty acids – one double bond between  carbons ∙ Liquid at room temperature  Polyunsaturated fatty acids – more than one double bond  between carbons ∙ Liquid at room temperature  ∙ Saturated and Unsaturated Fatty Acids Help Shape Foods o Fats are solid at room temperature (higher sat fa content) o Oils are liquid at room temperature (higher unsat fa content) ∙ Triglycerides contain three fatty acid chains o Triglyceride – 3 fatty acids connected to glycerol “backbone”  Most common lipid found in foods or body  Referred to as fats or oils  Stearate, oleate, linoleate  ∙ Phospholipids Contain Phosphate o Phospholipids – have glycerol backbone, but two fatty acids and  phosphorus group  Phosphorus containing head is hydrophilic (likes water)  Fatty acid tail is hydrophobic  Cell membranes made of phospholipid bilayer ∙ Major phospholipid in cell membrane = lecithin ∙ Lecithin used as emulsifier in foods such as salad  dressings to keep oils and water mixed together ∙ Phospholipid’s role in cell membranes o Because phosphorus containing head is polar, it attracts charged  particles such as water located both outside and inside your cells o Its fatty acid containing tail is nonpolar, so it mingles and lines  up with other nonpolar molecules such as the fatty acid  containing ends of other phospholipids o This creates a two layer membrane that surrounds the cell and  acts as a barrier, allowing certain substances to enter the cell but keeping others from leaving ∙ Sterols have a Unique Ring Structure o Sterols – composed mainly of four connecting rings of carbs and  hydrogen  Ex. Cholesterol ∙ Important role in cell membrane structure ∙ Precursor of important compounds in body ∙ Not required in diet since body makes all cholesterol  needed ∙ Digestion and absorption of fats o Large fat gobules are emulsified by bile salts in duodenum o Digestion fat by the pancreatic enzyme lipase yields free fatty  acids and monoglycerides which forms micelles o Fatty acids and monoglycerides leave micelles and enter  epithelial cells by diffusion o Chylomicrons containing fatty substances are transported out of  the epithelial cells and into lacteals, where they are carried away from the intestine by lymph ∙ Lipid Digestion and Absorption o Chylomicrons – deliver FA o VLDs – deliver FA o LDLs – deliver cholesterol (goal is low) o HDL – remove cholesterol (goal is high) ∙ What happens to the fat you eat? o Lipoproteins transport fat through lymph and blood  Chylomicrons – carry digested fat through lymph into  bloodstream  Very low density lipoproteins (VLDL) – deliver fat made in  liver to cells  Low density lipoproteins – (LDL) aka bad cholesterol,  delivers/deposits cholesterol on walls of arteries High density lipoproteins – (HDL) aka good cholesterol,  remove cholesterol from body and deliver to liver for  excretion ∙ How does your body use fat? o Triglycerides  An energy dense source of fuel: 9 calories per gram  Is needed for absorption of fat soluble vitamins A, D, E, K  and carotenoids  Insulates body to maintain body temperature  Cushions bones, organs, nerves o Essential fatty acids  Linoleic acid ( an omega 6 acid)  Alpha linolenic acid (an omega 3 fatty acid) ∙ Eicosanoids – hormone like substances made from  essential fatty aids, which are involved in  inflammation, blood clotting, blood pressure (fatty  fish is a good source) o Eicosapentaenoic acid (EPA) o Docosahexanoic acid (DHA) ∙ How does your body use cholesterol and do we need it in our diet? o Cholesterol has many important roles:   Part of cell membranes (helps keeps them flexible)  Precursor for vitamin D, bile acids, sex hormones o Dietary cholesterol: body makes its own  Not needed in the diet  If consumed use moderation (less than 300mg a day) ∙ Dietary recommendations? o You need to consume a specific percentage of your daily calories  from fat  Triglyceride – ADMR – 20-35% of total daily calories ∙ Saturated fats – less than 10% (ideally less than  7%) of your calories (minimize as much as possible) ∙ Minimize/avoid trans fats as much as possible ∙ Consuming too much saturated/trans fat can lead to  higher levels of the “bad” LDL cholesterol carrier ∙ Trans fats are actually worse for heart health than  saturated fat (raise LDL cholesterol and lower HDL  cholesterol) ∙ Increase sources of essential fatty acids ∙ Creating TRANS fatty acids o Hydrogenation is used to make an unsaturated fat a trans fat  Changes how the hydrogenation are arranged (shape of  molecule) Results in the unsaturated (trans fat) behaving like a  saturated fat ∙ What are the best food sources of fats? o Foods that contain unsaturated fats (both Monounsaturated and  polyunsaturated fats) are better  Good sources: plant and nut oils, fatty fish o Decrease saturated fat, cholesterol, and/or trans fat  Sources: animal fat, hydrogenated fats (shortening), many  packaged foods (read label) ∙ What are fat substitutes and how can they be part of a healthy diet? o Fat substitutes are designed to provide all the creamy properties  of fat for fewer calories and total fat grams  Because fat has more than double the calories per gram of  carbs/protein, fat sustitutes have the potential to reduce  calories from fat by more than 50% o Fat substitutes can be carb, protein, or fat based  Majority are carb based and use plant polysaccharides ∙ What is heart disease and what increases your risk o Heart disease begins with a buildup in the arteries  Atherosclerosis – narrowing of arteries due to buildup of  plaque (hardened debris of cholesterol laden foam cells,  platelets, and other substances) ∙ thought to begin with injury to lining of arteries  contributed by high blood pressure, high cholesterol  levels, and smoking ∙ increases chance of blood clots blocking the vessel,  causing heart attack or stroke ∙ Risk factors for heart disease o Risk factors you cant control  Age, gender, family history and type 1 diabetes o Risk factors you can control  Regular exercise can help lower LDL and raise HDL  Losing excess weight and quitting smoking can help  increase HDL levels o Metabolic syndrome – group of risk factors, including insulin  resistance, that increase the risk of heart disease ∙ Goals to reduce risk of heart disease o Minimize saturated fats, trans fats, cholesterol in diet o Include fish in weekly choices o Eat plenty of plant foods o Select foods rich in antioxidants and phytochemicals o Strive for plenty of exercise and manage your weight o Moderate use of alcohol may reduce risk of heart disease, but  some should avoid alcohol o Want a high HDL level and a low LDL level CH 5 REVIEW ∙ Building blocks of lipids – fatty acids ∙ Major phospholipid in cell is – lecithin ∙ Most of triglycerides in food reach stomach without being chemically  digested ∙ Structure of triglyceride – 3 fatty acids and glycerol backbone ∙ To keep water and fat loving substances together – emulsifier ∙ Which enzyme is responsible for the majority of digestions of lipids –  pancreatic lipase ∙ What are micelles – clusters of fatty acids, monoglycerides, and other  lipids surrounded by bile salts that transport lipids across the cell ∙ Majority of fat digestion occurs in – small intestine (duodenum) ∙ To promote fat digestion, gallbladder releases this to small intestine –  bile ∙ What enters lymph and need transport carrier to circulate in  bloodstream – long chain fatty acids ∙ What class of lipoproteins contains most proteins compared to lipid –  high density lipoproteins ∙ As the very low density lipoproteins (VLDLs) deposit triglycerides in the cells, they become denser and are classified as LDLs ∙ Cholesterol transported from cells to liver by HDL can then be used to  synthesize bile ∙ What helps remove cholesterol from cells and delivers to liver – high  density lipoprotein ∙ Fat in foods significantly contributes to – texture, flavor, satiety, and  absorption of fat soluble vitamins ∙ Cholesterol is needed to make – bile acids ∙ The enzyme gastric lipase, secreted in the stomach, begins the  digestion of some triglycerides ∙ The most common fat in foods is made up of 3 fatty acids attached to a glycerol backbone and is called a triglyceride ∙ Structures composed of a glycerol backbone and one fatty acid are  called monoglycerides ∙ This enzyme, which breaks down triglycerides into monoglycerides and free fatty acids is called pancreatic lipase ∙ Micelles are carriers that consist of monoglycerides, fatty acids,  lecithin, and serve to transport digested fats from food to intestinal  cells ∙ Glycerol is a compound containing carbons, hydrogens, and hydroxyl  groups (OH) that serves as the “backbone” for various lipids ∙ When fat enters the small intestine, an emulsifier called bile is released into the small intestine to break up the large fat globules into smaller  fat droplets ∙ The gallbladder releases bile through the common bile duct ∙ Cholesterol is a lipid that is made up of four connecting rings of carbon  and hydrogen, and is an important component of cell membranes, as  well as a precursor for other essential compounds ∙ Chylomicrons are large lipoproteins that carry fats and cholesterol from the intestine through the lymph system and to bloodstream ∙ Stomach: gastric lipase ∙ Pancreas: pancreatic lipase ∙ Small intestine: micelles, chylomicrons ∙ Gallbladder: bile ∙ Mouth: lingual lipase ∙ Take a bite of pizza o Mechanical digestion by chewing breaks food down o Lingual lipase begins chemical digestion of food o Gastric lipase breaks down triglycerides into diglycerides and  free fatty acids o The gallbladder secretes bile into the small intestine where the  bile emulsifies fat into smaller globules o With the aid of pancreatic lipase, fats are further broken down  into free fatty acids and monoglycerides o Fat by-products are packages into micelles and transported to  intestinal cells o Micelles separate into their component parts o Short chain fatty acids enter the bloodstream for transport, and  long chain fatty acids are packaged into chylomicrons and  released into lymph vessels ∙ Describe nature of emulsification? – bile acts to emulsify lipids in the  small intestine, which helps pancreatic lipase access fats for further  digestion ∙ Protein is denser than fat, and determines the overall density of a  lipoprotein ∙ Chylomicrons are the only type of lipoprotein that gets circulated in the lymph ∙ VLDLs are the least dense of the lipoproteins produced by the liver ∙ VLDLs are transformed to LDLs after transport of triglycerides and  cholesterol to muscle fat cells ∙ HDLs are the densest type of lipoprotein that circulates in the  bloodstream; they serve to remove cholesterol from cells and deliver it  to the liver∙ Triglycerides are found in the center of lipoproteins and make up the  majority of both chylomicrons and VLDLs composition ∙ Cholesterol is a component of bile, which is stored in the gallbladder  and secreted into the small intestine, where it plays an important role  in emulsifying fats ∙ Chylomicrons transport fat and cholesterol from a meal via the  lymphatic system before entering the bloodstream ∙ The liver is the site of the production of bile and some lipoproteins ∙ Chylomicron – this lipoprotein transports triglycerides and other lipids  from the intestinal wall cell into lymph ∙ VLDL – triglycerides make up the majority of lipids within this  lipoprotein, and it serves to deliver these triglycerides from the liver to  the body’s cells, including fat cells ∙ LDL – this lipoprotein has the highest cholesterol content of all the  lipoproteins, and it deposits this cholesterol to cells of the body ∙ HDL – this lipoprotein is released from the liver and picks up  cholesterol from cells to transport it back to the liver ∙ Cholesterol is a component of bile, cholesterol is a key component of  cell membranes ∙ The current ADMR for fat is 20-35% of daily caloric intake ∙ Trans fats are to be avoided because they – increase LDL cholesterol  and decrease HDL cholesterol ∙ Three good sources of essential fatty acids are – vegetable oils, nuts,  and flaxseeds ∙ Most trans fats are created through the process of – hydrogenation ∙ Small chain fatty acids can enter the bloodstream directly, but large  chain fatty acids must be packaged first before entering the lymph ∙ Fat substitutes can be carb, protein, or fat based ∙ High density lipoproteins remove cholesterol from tissues and deliver it to the liver for use in bile or excretion ∙ Linoleic acid and alpha-linoleic acid are considered essential fatty acids and must be obtained from the diet ∙ Bile is needed to help mix fats with watery fluids ∙ Carriers that transport monoglycerides and fatty acids to intestinal  cells are called micelles ∙ Olestra contains 6-8 fatty acids connected to sucrose, and cannot be  broken down by digestive enzymes ∙ A chylomicron is a lipoprotein carrier that transports digested fat and  other lipids through the lymph system ∙ Monounsaturated fat – these fats contain fatty acids with a max of one  double bond, most abundant type of fat in olive oil ∙ Polyunsaturated fat – contain fatty acids with more than one double  bond, linoleic and alpha-linoleic acids are this type∙ Saturated fat – coconut oil contains mostly this type of fat, these fats  are primarily composed of fatty acids in which all carbons are  saturated with hydrogen ∙ Trans fat – hydrogenation by food manufacturers creates this type of  fat, this fat can raise LDL (bad) cholesterol and lower HDL (good)  cholesterol ∙ Heart disease develops when coronary arteries – narrow due to build  up of LDLs and other substances along their walls ∙ Low density deposits – deposits cholesterol in the walls of the arteries ∙ Regular physical activity – can increase HDL cholesterol ∙ The narrowing of arteries, atherosclerosis is thought to start with an  injury to an artery’s interior wall ∙ The buildup within an artery wall of plaque can greatly obstruct flow  through the artery’s passageway ∙ Once macrophages “gobble up” cholesterol laden LDL and become  enlarged, they transform into foam cells ∙ A person with a blood pressure of 140/90 has hypertension ∙ When a blood vessel leading to the heart is blocked by a clot, a heart  attack can result ∙ The coronary arteries are the large blood vessels that supply oxygen  and other nutrients to the heart ∙ A risk factor is a characteristic, variable, or behavior that increases the  probability of developing injury, infection, or disease (ex. Smoking) ∙ Syndrome X/metabolic syndrome refers to the presence of several risk  factors together that can result in an increased chance of developing  heart disease ∙ 1. Arterial lining in injured o 2. LDL and other substances seep through the injury and deposit  within the arterial wall o 3. LDL cholesterol becomes oxidized o 4. Macrophages travel to the site and engulf the oxidized LDLs,  and foam cells form o 5. Foam cells accumulate to create a fatty streak o 6. Plaque forms, and the artery passageway narrows o 7. Blood flow is slowed or stopped ∙ Risk factors you cannot control o Family history of heart disease, gender, age, type 1 diabetes ∙ Risk factors you can control o Smoking, type 2 diabetes, body weight, physical activity, HDL  level, hypertension ∙ Increasing intake of plant foods may be one of the easiest ways to  decrease LDL cholesterol ∙ Trans fats are worse for health than sat fats because they raise LDL  cholesterol and lower HDL∙ Typically, higher your consumption of sat fats, higher the LDL  cholesterol levels in your bloodCH 6: PROTEINS AND AMINO ACIDS ∙ Protein Structure o Proteins are the predominant structural and functional materials  in every cell  Contain carbon, hydrogen, oxygen (like carbs/fats) and  nitrogen  Each amino acid has ∙ Acid group (COOH) ∙ Amine group (NH2) ∙ Side chain (unique)  All proteins consist of a chain of some combination of 20  unique amino acids ∙ DNA Directs synthesis of new proteins o DNA in the cell nucleus contains instructions for protein synthesis o Gene – DNA segment that codes for specific protein o Specialized RNA molecules carry out instruction for protein  synthesis  Messenger RNA (mRNA) and transfer RNA (tRNA) perform  very specific roles during protein synthesis o When abnormalities occur during protein synthesis, serious  medical conditions may result  Ex. Sickle cell anemia ∙ The making of a protein o DNA contains code instruction for protein o Transcription – mRNA copy of code synthesized and transferred  to the cytoplasm  DNA  RNA o Translation – the mRNA code is used by ribosome to identify  amino acid needed and tRNA delivers the amino acids for  assembly into a polypeptide (protein)  RNA  protein  ∙ Essential, Non-essential, and conditional amino acids o 9 Essential amino acids  Cannot be made by the body  It is “essential” to obtain them from the diet o 11 Non-essential amino acids  Can be synthesized in the body from other amino acids or  by adding nitrogen to carbon containing structures  Conditionally essential amino acids ∙ Denaturation of Proteins Changes their Shape o Denaturation – the alteration (unfolding) of a protein’s shape,  which changes the structure and function of the protein  ex. Cooking meat, eggs changing texture stomach acid untangles proteins to aid in digestion ∙ What happens to the protein you eat? o Dietary proteins are digested and absorbed in stomach and small intestine  Stomach acids denature protein and activate pepsin, which breaks down protein into shorter polypeptides  In the small intestine, polypeptides are broken down into  tripeptides, dipeptides, and amino acids  Amino acids enter blood and travel to liver ∙ Your body degrades and synthesizes proteins o Amino acids come from   Diet  Breakdown of proteins in body  A limited supply of amino acid pools in blood and cells for  needed protein synthesis o Protein turnover – the process of continuous breakdown and  synthesis of protein from its amino acids ∙ The fate of amino acids in body o The foods you eat contain both essential/non-essential amino  acids o Limited supply of amino acids exists in amino acid pools in your  blood and inside cells, supply is used to make proteins o Some amino acids in pools are used to make nonprotein products like some hormones o Protein turnover involves the degradation (breaking down) of  protein and synthesis of its amino acids into new proteins o Amino acids are degraded and their nitrogen containing amine  groups are removed. The nitrogen generates ammonia (NH3)  which is converted to urea and excreted in urine. The carbon  containing remains are either used to make glucose or energy, or are stored as fat ∙ Your body degrades and synthesizes proteins o Amino acids can be used to make  Body proteins  Non-protein substances ∙ Ex. Thyroid hormones, melanin o After amino groups are removed (converted to urea, excreted in  urine), amino acids can also be  Burned for energy  Used to make glucose  Use to make fat ∙ How does your body use proteins? o Proteins provide structural and mechanical support and help  maintain body tissues Collagen - a ropelike, fibrous protein that is the most  abundant protein in your body used in connective tissue  Hemoglobin – binds oxygen in order to carry it through the  circulatory system for delivery to cells o Most enzymes and many hormones are composed of proteins o Proteins contribute to a healthy immune system  Specialized protein “soldiers” called antibodies eliminate  potentially harmful substances o Proteins can provide energy o Protein improves satiety and appetite control o Protein helps maintain fluid balance o Proteins help maintain acid base balance  Buffers – substances that help maintain the proper pH in a  solution by attracting or donating hydrogen ions o Proteins that transport substances throughout the body  Transport proteins – shuttle oxygen, waste products, lipids,  some vitamins, and sodium and potassium through your  blood and into and out of cells through cell membranes ∙ Fluid balance o Normal tissue – blood pressure balanced by counteracting force  of protein o Swollen tissue (edema) – blood pressure exceeds counteracting  force of protein, and so fluid remains in the tissues ∙ Proteins as transport channels o Sodium binds to transport protein o Transport protein releases sodium outside the cell o Potassium binds to transport protein o Transport protein releases potassium inside the cell ∙ Nitrogen balance and imbalance o Positive nitrogen balance – pregnant women, growing children  and adolescents and some athletes tend to be in positive  nitrogen balance o Equilibrium – a healthy adult is typically in nitrogen equilibrium o Negative nitrogen balance – individual experiencing medical  trauma or not eating a healthy diet ∙ Not all protein is created equal o Protein quality is determined by two factors  The protein’s digestibility  The protein’s amino acid profile the types and amounts of  amino acids (essential, non-essential, or both) that the  protein contains ∙ Complete proteins – all essential amino acids, plus  some non-essential amino acids o Sources: soy and animal protein∙ Incomplete proteins – low in one or more essential  amino acids o Sources: most plant foods  Plant proteins “upgraded” to complete proteins by ∙ Consuming modest amounts of soy or animal protein  ∙ OR ∙ Being complemented with other plant proteins that  provide enough of the limiting amino acid o Complementary proteins do not need to be  eaten in the same meal, only the same day  Protein Digestibility Corrected Amino Acid Score (PDCAAS) ∙ Measure of protein quality taking into account  digestibility and amino acid profile ∙ Basis of protein as percent daily value on food labels ∙ Your personal protein needs o Protein recommendations (DRI)  Protein: 10-35% of total daily calories  ∙ Average intake in the US = 15%  0.8g of protein/kg of healthy body weight needed daily o Calculating your daily protein needs  Convert weight to pounds by dividing 2.2 lb/kg  Ex. 130lb/2.2 = 59kg  59kg x 0.8g = 47g of protein/day ∙ What are the best food sources of protein? o Some amount of protein is found in many foods, but It is  particularly abundant in meat, fish, poultry, and meat  alternatives such as dried beans, peanut butter, nuts and soy ∙ Protein supplements: are they necessary? o Varied products promise many benefits, but not needed with  adequate diet o Protein shakes and powder  Made of whey, soy or rice protein  May contain unwanted additives o Amino acid supplements  Sold as remedies for various health issues o Protein and energy bars  Convenient, but expensive and high in calories ∙ What happens if you eat too much protein? o Eating too much protein:  May increase risk of heart disease (due to saturated fat  associated with animal protein)  Kidney stones, calcium loss from bones  Can displace other nutrient and fiber rich foods associated  with a reduced risk of chronic diseases∙ Whole grains, fruits, vegetables  Excess amino acids not used for energy converted to fat ∙ What happens if you eat too little protein? o Eating too little protein  May lead to reduction of lean body mass, especially in  older adults  Risk of increased frailty, impaired healing, decreased  immune system o Protein-energy malnutrition (PEM)  Inadequate calories and/or protein  More common in children, because they are growing  Factors: poverty, poor food quality, insufficient food,  unsanitary living conditions, ignorance, stopping lactation  (nursing) too early ∙ Malnutrition o Kwashiorkor – severe deficiency of dietary protein  Signs: edema, muscle loss, skin rashes, hair changes,  water and electrolyte imbalances  Seen in children weaned to low-protein cereals o Marasmus – severe deficiency of calories  Signs: emaciation, lack of growth, loss of fat stores o Marasmic kwashiorkor – worst of both conditions ∙ How do vegetarians meet protein needs? o Vegetarians can meet protein needs by consuming:  Variety of plant foods ∙ Soy ∙ Dried beans and other legumes ∙ Nuts ∙ Eggs, dairy (lacto-ovo-vegetarians)  ∙ Types of vegetarians o Semi-vegetarians – DOESN’T EAT meat, fish, poultry except on  occasion o Pesco-vegetarians – DOESN’T EAT meat and poultry o Lacto-ovo-vegetarian – DOESN’T EAT meat, fish, poultry o Lacto-vegetarian – DOESN’T EAT meat, fish, poultry, eggs o Ovo-vegetarian – DOESN’T EAT meat, fish, poultry, dairy foods o Vegan – DOESN’T EAT any animal products, meat, fish, poultry,  dairy foods, eggs ∙ Potential benefits and risks of vegetarian diets o Benefits  May reduce risk of heart disease, high blood pressure,  diabetes, cancer, stroke, and obesity  Vegetarian diet food staples are rich in fiber and low in  saturated fat and cholesterolo Risks  Potential deficiencies of nutrients found in animal foods ∙ Protein, iron, zinc, calcium, vitamin D, riboflavin,  vitamins B12 and A, omega 3 fatty acids ∙ Soy menu o Tofu, soy flour, edamame, soy milk, tempeh, soy meat analogs,  miso, textured soy protein CH 6 REVIEW ∙ Protein is absorbed as single amino acids or small peptide chains by  the process of active transport ∙ The side chain of an amino acid differentiates one amino acid from  another ∙ Essential amino acids: lysine, methionine, threonine ∙ Amino acids found in the amino acid pool – can be used for protein  synthesis ∙ Denaturation – the uncoiling of the protein molecule by hydrochloric  acid in the stomach ∙ What secretions are needed to digest complex proteins into single  amino acids for absorption? – hydrochloric acid and pepsin in stomach,  proteases secreted from pancreas and small intestine, saliva from  salivary glands in mouth ∙ All amino acids contain – carbon, hydrogen, oxygen, and nitrogen ∙ Chemical bonds that connect amino acids are called – peptide bonds ∙ The bond that is formed when two amino acids join together is called –  a peptide bond ∙ The chain of two amino acids is referred to as a – dipeptide ∙ A molecule with 4-9 amino acids joined together by peptide bonds is  referred to as – an oligopeptide ∙ What compound carries the blueprint from DNA to the ribosomes  during protein synthesis – mRNA ∙ Proteins are digested by enzymes in the – stomach and small intestine ∙ The organ that determines what happens to the amino acids after they  enter the bloodstream is the – liver ∙ Pepsin is the active form of a digestive enzyme in the stomach that  breaks polypeptide chains into small polypeptides ∙ Cleavage of proteins by pepsin in the stomach results in formation of  polypeptide strands which get broken down further in the small  intestine ∙ An amino acid chain made up of 3 amino acids joined together is called a tripeptides ∙ Dipeptide describes an amino acid chain made up of two amino acids  joined together∙ The 20 different amino acids are the building blocks used to protein  synthesis ∙ Amino acid pools are stockpiles found in the blood and other cells of  the body that can be used to build new proteins ∙ The continual process of degrading and synthesizing protein is called  protein turnover ∙ Denaturation occurs when a protein is exposed to heat, acid, bases, or  mechanical agitation resulting in unfolding the protein, though the  peptide bonds remain intact ∙ The part of an amino acid that contains nitrogen is called the amine  group ∙ The acid group is also know as the carboxyl group ∙ Single amino acids that are absorbed in the small intestine travel to  the liver via portal vein ∙ Mouth: mechanical digestion begins here ∙ Stomach: HCl is secreted here, pepsin is formed from pepsinogen here, HCl denatures protein here ∙ Small intestine: single amino acids, dipepides and tripeptides are  absorbed here ∙ Pancreas: enzymes that digest amino acid chains are produced here  and delivered via a duct to the small intestine ∙ Liver: amino acids that enter the bloodstream from the small intestine  travel to here ∙ Take a bite of pb sandwich o Mechanical digestion in mouth breaks down food o A bolus enters stomach o Hydrochloric acid denatures proteins and activates pepsinogen to form pepsin o Pepsin breaks down proteins into polypeptide strands o Chime travels from the stomach to the small intestine o Enzymes from the pancreas are secreted into the small intestine o Enzymes in the small intestine break down polypeptide strands  into mostly tripeptides and dipeptides o Tripeptides and dipeptides are broken down into single amino  acids that enter the blood and travel to the liver ∙ How does your body use protein once ingested? – amino acids are used to create new proteins, the liver uses amino acids to create glucose, if  calorie intake is inadequate, amino acids can be used for production of  energy ∙ There are 11 nonessential amino acids ∙ Protein synthesis is directed by the – DNA ∙ The primary organ responsible for excreting nitrogen containing waste  is – kidneys∙ When the amine group is removed, the carbon containing component  of amino acids can be – used for energy ∙ A segment of DNA that encodes for the production of a specific protein  called a gene ∙ The ribosome reads the mRNA strand, and with the help of tRNA, builds the corresponding amino acid chain ∙ DNA does not build or synthesize a protein it encodes for; instead, DNA contains information that is copied by an enzyme to make mRNA, which leaves the nucleus and goes to the ribosome where the protein  is build ∙ A type of RNA that plays the important role of transferring specific  amino acids to the growing amino acid chain in the ribosomes is called  tRNA ∙ The structure in the cell that contains DNA is called the nucleus ∙ DNA contains all of the instructions for building the hundreds of  thousands of proteins that are found in the human body ∙ Ribosome – reads the nucleotide sequence and helps build the  corresponding sequence of amino acids, releases the amino acid chain  once the chain is complete ∙ mRNA – it carries a copy of the DNA instructions that dictate the  sequence of amino acids for making a specific protein, the ribosome  moves along this and reads the encoded information  ∙ tRNA – it transfers specific amino acids to the growing amino acid  chain ∙ DNA – instructions on how to build proteins are stored in this molecule,  housed in the nucleus of the cell ∙ Role of DNA in protein synthesis  nuclear DNA cannot leave the  nucleus, an mRNA molecule is a copy of a gene on the DNA molecule ∙ The mutation that causes sickle cell anemia results in production of  hemoglobin proteins which crystalize causing misshapen red blood  cells, making them look like half moons ∙ Substances that speed up reactions without being changed or used up  are – catalysts ∙ The recommended daily protein intake for a healthy adult weight  165lbs is – 60g ∙ Growing children and adolescents are in – positive nitrogen balance ∙ To find amount of protein requirements: xlbs/2.2 x 0.8 (healthy adults),  1.1 (pregnant) ∙ If Sarah consistently exceeded her daily protein requirement – she  could gain weight if the extra protein contributed to excess kilocalories  over her energy needs ∙ An example of complemented proteins is – hummus prepared with  chickpeas and sesame seeds∙ Legumes are in which two USDA MyPlate groups – proteins and  vegetables ∙ Consistently eating too many high protein foods can lead to a higher  risk for – heart disease, kidney problems, and calcium loss from bones ∙ A vegetarian diet may be low in – omega-3 fatty acids and vitamins  B12 and D ∙ What is a benefit of consuming soy foods? – provide high quality  protein ∙ Proteins called antibodies aid the immune system in its fight against  bacteria, viruses, and other foreign substance by binding to them and  helping to inactivate or destroy them ∙ Hormones direct activity in the body and can be made of proteins or  lipids ∙ A high protein diet can increase the risk of kidney stones ∙ Transport proteins carry many substances through the blood or allow  movement of substances in and out of cells ∙ Inadequate intake of protein and/or calories is known as protein-energy malnutrition ∙ Most enzymes are proteins, but some may utilize coenzymes in the  form of vitamins to help with reactions ∙ Proteins help control the acid base balance in the body by acting as  buffers ∙ Kwashiorkor is a severe deficiency of dietary protein, resulting in  swelling in feet, legs, and stomach among other symptoms ∙ Take a bite of scrambled eggs o Mechanical digestion results in the formation of a bolus o Stomach acid denatures proteins o Pepsin breaks the polypeptide chains into shorter chains o Pancreatic enzymes cleave peptide bonds, leaving dipeptides,  tripeptides, and single amino acids o Enzymes from the small intestine lining act on protein remnants,  breaking them into single amino acids, which are absorbed into  the cells of the lining ∙ Vegetarian diets o A lacto ovo vegetarians consumes eggs and dairy products o Vegans must obtain vitamin B12 from supplements or fortified  foodsCH 7: VITAMINS ∙ What are vitamins? o Vitamins are essential nutrients  Tasteless, organic compounds needed in small amounts  So NOT contribute to the energy value  A deficiency or toxicity will cause physiologic changes that  may cause short or long term health complications o Vitamins are either fat-soluble or water-soluble  Fat soluble vitamins (A, D, E, K) are absorbed with dietary  fat and can be stored in the body  Water soluble vitamins (B, C) are absorbed with water and  enter the bloodstream directly ∙ Not stored in body, but excesses can still be harmful  o Some vitamins function as antioxidants which counteract  oxidation by neutralizing substances called free radicals  Vitamins A, C, E and beta-carotene are antioxidants o Free radicals – unstable oxygen containing molecules that can  damage the cells of the body and possibly contribute to  increased risk of chronic disease o Vitamins differ in bioavailability – the degree to which a nutrient  is absorbed from foods and used in the body  Vitamins can be destroyed by air, water, or heat  Don’t expose your produce to air  A little water is enough for cooking  Reduce cooking time  Keep your food cool o Overconsumption of some vitamins can be toxic o Provitamins can be converted to vitamins by the body ∙ Vitamins found widely in food groups o Vegetables: folate, vitamins A, C, E, K o Fruit: folate, vitamin C, A o Grains: folic acid, niacin, vitamin B6, B12 (if fortified), riboflavin,  thiamin  o Protein: niacin, thiamin, vitamin B6, B12 o Dairy: riboflavin, vitamin A, B12, D ∙ Overconsumption of some vitamins can be toxic o Vitamin toxicity does not occur by eating a normal balanced diet o Can result when individuals consume megadose levels of vitamin supplements, usually in the mistaken belief that more is better o To prevent excessive intake, the dietary reference intakes include a tolerable upper level intake for most vitamins ∙ Provitamins can be converted to vitamins by the bodyo Provitamins are substances found in foods that are not in a form  directly usable by the body, but that can be converted into an  active form once they are absorbed  Ex. Beta-carotene, split into two molecules of vitamin A in  small intestinal cell wall or in liver cells o Vitamins found in foods that are already in the active form, called preformed vitamins, do not undergo conversion in the body ∙ Vitamin A o Vitamin A – retinoids (retinol, retinal, retinoic acid)   Preformed vitamin A only found in animal foods, liver,  eggs, fortified milk and cheese  Some plants contain provitamin A carotenoids, which are  converted into retinol in your body ∙    Carotenoids, including beta-carotene, are pigments  that give color to carrots, cantaloupe, sweet  potatoes, spinach, broccoli o Like fat soluble vitamins, are absorbed more  efficiently if fat is present in intestinal tract o Functions:  Essential for healthy eyes: component of rhodopsin and  iodopsin, light sensitive proteins needed for vision  Involved in cell differentiation, reproduction, and immunity  by promoting gene expression for: ∙    Healthy skin, mucous membranes, bone growth ∙    Fetal development ∙    White blood cells to fight harmful bacteria  Food sources: organ meats (liver), milk, eggs, carrots,  spinach, sweet potatoes, pumpkin  o Too much or too little:  Excessive amounts of preformed vit A can accumulate toxic levels ∙    Usually on seen when excessive supplementation  occurs  Carotenoids in foods are not toxic ∙    Excess carotenoids in diet cause non-threatening  condition: carotenodermia  Chronic vit A deficiency causes night blindness  Prolonged vit A deficiency leads to xerophthalmia – permanent damage to cornea ∙    Main cause of preventable blindness in children ∙    Vitamin E o Functions:  Acts as a powerful antioxidant ∙    Protects cell membranes, prevents oxidation of LDL  cholesterol ∙    Free radicals damage phospholipids, essential  components of cell membrane  vitamin E in cell  membranes can neutralize free radicals, preventing  them from damaging phospholipids  Acts as an anticoagulant, inhibiting formation of harmful  clots inside bloodstream o Food sources: vegetable oil, nuts, seeds, fortified cereals, some  green leafy vegetables  Too much or too little: ∙    No known risk of consuming too much vitamin E from natural food sources o Overconsumption of synthetic form in dietary  supplements and fortified foods can increase  risk of hemorrhage: upper limit is 1000mg/day ∙    Although rare, chronic deficiency of vit E can cause  nerve problems, muscle weakness, and free radical  damage to cell membranes ∙    Vitamin K o Two forms:  One synthesized by intestinal bacteria  Other in green plants o Functions:  Essential for blood clotting ∙    Involved in synthesizing four blood clotting factors o Food sources: green veggies such as broccoli, asparagus,  spinach, salad greens, brussel sprouts, cabbage; also vegetable  oils and margarine o Too much or too little:   No known problems of consuming too much vitamin K from foods or supplements   People taking anticoagulant medications such as warfarin  (Coumadin) need to keep vitamin K intake consistent ∙    Changes in intake can increase or decrease drug  effectiveness  Vit K deficiency that is severe enough to affect blood  clotting is extremely rare ∙    At risk: people with problems absorbing fat ∙    Vitamin D o Called “sunshine vitamin” because it is made in the body with  help of sunlight (UV)  Cholesterol containing compound in skin is converted to  inactive form of vit D People with insufficient sunlight exposure must meet needs through diet; vitamin D in foods is also an inactive form  Inactive form converted to circulating form in liver, then  active form in kidneys o Functions: active form acts as a hormone  Regulates two important bone minerals: calcium (Ca) and  phosphorous (P) ∙    Stimulates intestinal absorption of Ca and P to  maintain healthy blood levels and build and maintain bones o Daily needs:  Sun exposure cannot meet everyone’s vitamin D needs o Food sources: fortified milk and yogurt, cereals, fatty fish (ex.  Sardines, salmon) o Too much or too little:  Overuse of supplements may lead to hypervitaminosis D, which causes hypercalcemia ∙    Damaging calcium deposited in kidneys, lungs, blood vessels, heart   Rickets – vit D deficiency disease in children ∙    On the rise in US due to decreased milk  consumption, other factors ∙    Bones inadequately mineralized with calcium and  phosphorus, causing them to weaken and leading to  bowed legs   Osteomalacia – adult equivalent of rickets ∙    The B Vitamins and Vitamin C are Water soluble o Water soluble vitamins are not stored in body  Excess excreted in urine  However routine intakes of excessive amounts can be  harmful o B vitamins share common role as coenzymes  Help many enzymes produce chemical reactions in cells ∙    Thiamin (B1) o Functions:  Transmission of nerve impulses  Metabolism of carbohydrates and certain amino acids  Plays role in breakdown of alcohol in body o Food sources: enriched and whole grain products, pork, legumes o Too much or too little:  No known toxicity, no UL set   Beriberi – thiamin deficiency disease ∙    Symptoms can include rapid heartbeat, edema,  confusion, loss of coordination∙    Rare in US due to enrichment of grains ∙    Riboflavin (B2) o Light sensitive vitamin, abundant in milk  Opaque containers preserve riboflavin content o Functions  Important for energy metabolism  Keeps cells healthy  Enhances functions of other B vitamins, such as niacin and  B12 o Food sources: milk, yogurt, enriched cereals, grains, vegetables o Too much or too little:  Excess riboflavin excreted in urine: bright yellow  No UL set  Deficiency symptoms rarely seen in healthy individuals  eating balanced diet: sore throat, swelling inside mouth,  inflamed and purplish-red tongue (glossitis), dry and scaly  lips ∙    Niacin (B3) o Functions:  Energy metabolism  Synthesize fat and cholesterol  Keep skin cells and digestive system healthy o Sometimes prescribed in high doses (50 x UL) by physicians to  decrease blood LDL cholesterol and triglycerides, increase HDL o Food sources: meat, fish, poultry, fortified grain products o Too much or too little:  Overconsumption of niacin supplements can cause  flushing, nausea, vomiting, be toxic to liver, raise blood  glucose levels: UL is 35mg/day to prevent flushing   Pellagra – niacin deficiency disease ∙    Four Ds: dermatitis, diarrhea, dementia, death ∙    Once common in south, due to corn based diet ∙    Vitamin B6 o Functions as coenzyme with over 100 enzymes in protein  metabolism needed to  Make non-essential amino acids, convert tryptophan to  niacin  Keep immune and nervous systems healthy  Metabolize fats and carbohydrates and break down  glycogen o Food sources: meat, fish, poultry, nuts, legumes, peanut butter,  many fruits and vegetables o Too much or too little Toxicity: nerve damage usually only seen with extreme  supplementation  Deficiency symptoms: ∙    Sore tongue, skin inflammation, depression,  confusion, anemia ∙    Those with alcoholism are at risk for deficiency due  to poor diet, and because alcohol causes body to lose B6 ∙    Folate o Folate – naturally occurring form in foods   Folic acid – synthetic form of folate added to foods and  supplements o Functions: vital for DNA synthesis  To create and maintain new cells, including red blood cells  To help body use amino acid  Folate deficiency during pregnancy can result in neural  tube birth defects (ex. Spina bifida, anencephaly)  o Daily needs  Women who might become pregnant need extra folate  from fortified foods and/or supplements o Food sources  Enriched grains (pasta, rice, breads, cereals), legumes,  broccoli, asparagus, leafy greens such as spinach o Too much or too little:  Toxicity – too much folic acid (not naturally occurring folate  in foods) masks vit b12 deficiency anemia  Folate deficiency can lead to macrocytic anemia in adults  and during pregnancy neural tube birth defects ∙    Vitamin B12 o Also called cobalamine because it contains the element cobalt o Requires intrinsic factor, protein made in stomach, in order to be  absorbed in small intestine   Pernicious anemia (a specific type of macrocytic anemia)  results in people who cannot make intrinsic factor;  treatment requires B12 injection to bypass intestine  Symptoms may take years to appear since B12 is stored in  the liver o Functions: important healthy nerves and cells, especially red  blood cells o Food sources:  Naturally occurring B12, only found in animal foods (meat,  fish, poultry, dairy)  Synthetic B12 found in fortified foods such as soy milk and  some cerealso Too much/too little  No upper level set since no known risk from consuming too much B12, natural or synthetic  Deficiency can cause macrocytic anemia (because folate  can’t be utilized properly) ∙    Lack of intrinsic factor causes pernicious anemia,  involves nerve damage ∙    Vitamin C o Also known as ascorbic acid o Function: coenzyme to synthesize and use certain amino acids  Needed to make collagen, most abundant protein in body,  present in connective tissue ∙    Important for healthy bones, skin, blood vessels,  teeth  Also acts as an antioxidant  Helps absorb iron from plant foods  Helps to maintain a strong immune system o Food sources: fruits and vegetables o Too much or too little:  Nausea, stomach cramps, diarrhea  People with a history of kidney stones or hemochromatosis  (body stores too much iron) should avoid excess o Deficiency disease: scurvy o Too much or too little  UL = 2000 mg/day to avoid nausea, stomach cramps,  diarrhea ∙    People with a history of kidney stones or  hemochromatosis (body stores too much iron) should avoid excess ∙    Pantothenic Acid and Biotin o Functions assist in energy metabolism of carbohydrates, fats,  protein o Food sources:  Widespread in foods such as whole grains and cereals,  nuts, legumes, peanut butter, meat, milk, eggs  Biotin also synthesized by intestinal bacteria o Too much or too little:   No UL, no known adverse effects from consuming too much of either vitamin  Deficiencies of these vitamins are rare ∙    “Burning feet” syndrome in WWII prisoners of war in  asia due to pantothenic acid deficient diet of polished rice∙    biotin deficiency: hair loss, skin rash, fatigue, nausea, depression o avidin protein in raw egg whites binds biotin,  preventing absorption ∙    Are there other important nutrients?  o Choline – essential nutrient needed for healthy cells and nerves  Not classified as a vitamin; body can synthesize it, but  dietary sources may be needed  Widely available in foods: milk, eggs, peanuts, liver  Exceed UL: may include hypotension, sweating, vomiting,  fishy odor ∙    How should you get your vitamins? o Food is still the best way to meet your vitamin needs  Dietary guidelines recommend a variety of foods and  increased amounts of fruits, vegetables, whole grains, lean  dairy to meet needs o Fortified foods can provide additional nutrients but should not  displace vitamin/mineral rich foods  Excessive use of fortified foods can increase risk of  overconsumption of some nutrients o Vitamin supplements are not a substitute for healthy eating  Cannot provide all missing substances of a healthy diet o Who might benefit from a supplement?  People who cannot meet their needs through a regular,  varied diet, such as pregnant or lactating women, older  people, strict vegetarians, people with food allergies,  medical conditions, low calorie diets o FDA approval not required for ingredients in use before 1994,  FDA cannot remove supplement from marketplace until shown to be harmful o Consult health professional before taking vitamin/mineral  supplements  Read supplement label carefully  ∙     US Pharmacopoeia (USP) seal of approval ensures  quality and safety, but does not endorse or validate  health claims CH 7 REVIEW ∙ Thiamin – a deficiency of this vitamin causes beriberi, which is  characterized by weakness, swelling, and tingling, or numbness in the  hands and feet ∙ Niacin – a severe deficiency of this vitamin causes the disease pellagra∙ Pantothenic acid – a deficiency of this vitamin is very rare, but those  with inadequate intakes can experience numbness, muscle cramps,  and difficulty walking ∙ Vitamin B6 – a deficiency of this vitamin can lead to sore tongue, skin  inflammation, depression, confusion, or anemia ∙ Folate – neural tube defects, like spina bifita, can occur if this nutrient  is not consumed in adequate amounts during pregnancy ∙ Vitamin B12 – those who follow a vegan diet without supplementation  are at increased risk of deficiency for this vitamin ∙ Vitamin C – scurvy symptoms, caused by a deficiency of this nutrient,  include rough skin rash and wounds that will not heal ∙ Vitamin A o Carotenoids, including beta carotene, are precursors to this  vitamin o The preformed of this vitamin is abundant in liver and dairy  products, but the provitamin form can also be found in orange  vegetables like carrots and sweet potatoes ∙ Vitamin D o This is called the “sunshine vitamin” because the body can  synthesize it from exposure to ultraviolet rays o This vitamin plays an important role in bone health, the immune  system, blood pressure regulation, and cell growth ∙ Vitamin E o This vitamin is a powerful antioxidant and also functions as an  anticoagulant  o Avocados, wheat germ and sunflower oil are sources of this  vitamin ∙ Vitamin K  o Since this vitamin promotes blood clotting, intake needs to be  monitored for those on blood thinning medications o Newborns are typically given shots of this vitamin with blood  clotting until their intestinal bacteria begin to produce the  vitamin  ∙ Dietary supplements o Fortified foods can increase the risk of overconsuming certain  nutrients o Dietary supplements can be beneficial for pregnant women,  vegetarians and vegans, older adults, those with lactose  intolerance, and anyone else who has a difficult time meetings  nutrient needs through food  ∙ Formation of free radicals can increase your risk of cancer and heart  disease ∙ Free radicalso Free radicals can be neutralized by antioxidants, free radicals  steal electrons from phospholipids found in cell membranes, free  radicals contain an unpaired electron ∙ Vitamin E is considered an antioxidant ∙ Vitamin linked with energy metabolism – Vitamin B12 ∙ Vitamin linked to immune system – vitamin A ∙ Antioxidant function – vitamin E ∙ Bone health – Vitamin K ∙ Red blood cell production – folate ∙ Most premade smoothies contain – sugar and water ∙ Which is the healthiest smoothie – homemade with frozen fruit ∙ You can get daily allotment of vitamin C from what serving size of  berries – one cup ∙ About how many calories in one cup of berries? – 40 cals ∙ If you are making smoothie, use – 100% fruit juice ∙ Ultraviolet rays react with what to begin forming vitamin D? – 7- dehydrocholesterol ∙ Active form of vitamin D, hormone – calcitriol  ∙ Fat soluble vitamins – can be stored in the body for later use ∙ Which of the following is true about free radicals? – they can damage  cells ∙ Phytochemicals? – protect against certain chronic diseases ∙ Inactive form of a vitamin that can be converted into an active form  upon absorption is called – provitamin  ∙ People on a low fat diet may not be getting enough – vitamin E ∙ Displacing milk with soft drinks causes many children to have a low  intake of – vitamin D ∙ The intrinsic factor, a protein in the stomach, promotes the absorption  of – vitamin B12 ∙ The role of coenzymes is to – promote the functioning of enzymes ∙ Which vitamin is added to enriched grains and cereals in order to  reduce the risk of a birth defect? – folic acid ∙ Which of the following is a good source of ascorbic acid – red pepper  ∙ The protein in raw egg whites that binds biotin and prevents it from  being absorbed is – avidin  ∙ Which seal on a supplement label indicates purity and accuracy? – USP ∙ The vitamin that enhances iron absorption is – vitamin C ∙ Milk sold in clear bottles might be low in – riboflavin  ∙ Which vitamin is transported in a micelle along with bile and fatty acids – vitamin A ∙ Which of the following conditions will not destroy the vitamin content  of foods – cold ∙ The condition in which the lens of the eye becomes cloudy is called –  cataract ∙ Which about xerophthalmia is correct – defined as permanent damage  to cornea resulting from a vitamin A deficiency ∙ Using retinoids during pregnancy can cause birth defects ∙ Which is essential for blood clotting? – vitamin K ∙ Important in women’s diet before conceiving a baby – folate ∙ Which has been shown to reduce risk of certain cancers, like colon? –  folate ∙ Pellagra is condition deficient in – vitamin B3 (niacin) ∙ Which is vit D deficient in children – rickets ∙ Nerve damage caused by pernicious anemia, if diagnosed early enough can be reversed with treatments of vit B12 ∙ The disease resulting from vit C deficiency is called – scurvy ∙ The signs and symptoms of what include dermatitis, dementia, and  diarrhea – pellagra ∙ What plays role in breaking down alcohol in body – thiamin (B1) ∙ Excessive amounts of water soluble vitamins are often excreted in –  urine ∙ At which sites is the inactive form vitamin D converted to active form –  in the liver and then kidneys ∙ Which form of vitamin A enables eye to react to changes in light –  retinal ∙ Without adequate vitamin A, we would not be able to see in the dark ∙ The pigment responsible for night vision is called – rhodopsin ∙ When light energy hits retina, the retinal changes from – cis to trans  configurationCH 8: MINERALS AND WATER ∙ Your body is mostly water ∙ Why is water so important? o Water is the most abundant substance in body  Average healthy adult is about 60% water ∙ Muscle tissue is 75% water, fat up to 20%  Can survive only a few days without water  Water is balanced among fluid compartments ∙ Intracellular fluids – inside cells ∙ Extracellular fluids – interstitial fluid between cells  and fluid in the blood  Electrolytes – minerals that help maintain fluid balance o Acts as universal solvent and transport medium   Medium for chemical reactions in body  As part of blood, help transport oxygen, nutrients,  hormones to cells  As part of interstitial fluid, helps transport waste products  away from cells for excretion o Helps maintain body temperature  1. Water in blood carries heat to the capillaries at the skin  surface  2. The heat is released at the skin surface, Evaporation of  sweat cools the skin  3. Cooled blood returns to the body core o Lubricant for joints, eyes; part of mucus and saliva o Protective cushion for brain, organs, fetus ∙ The concept of water balance: intake = output ∙ What is water balance and how do you maintain it? o Water balance – water consumed = water lost o You take in water through beverages and food o You lose water through your kidneys (as urine), large intestine,  lungs, skin  Insensible water loss – through evaporation from skin and  when you exhale  Sensible water loss – through urine, feces, and sweat ∙ Losing too much water can cause dehydration  o Dehydration can result from inadequate water intake or too  much water loss from diarrhea, vomiting, high fever, or use of  diuretics o Your thirst mechanism signals dehydration  Dry mouth due to increased electrolyte concentration in  blood: less water available to make saliva Blood volume decreases, sodium concentration increases  in blood ∙ Brain triggers thirst mechanism and secretion of  antidiuretic hormone (ADH) to reduce urine output  ∙ Fluid inside cells moves into blood by osmosis o Other ways to tell if you’re dehydrated  Cornerstone method: measure body weight before and  after exercise ∙ Weight loss = water loss  Monitor urine color ∙ Color darkens with concentration, indicating water  loss ∙ Consuming too much water can cause hyponatremia o Hyponatremia – a condition of too little sodium in the blood o For healthy individuals who consume a balanced diet, it is  difficult to consume too much water o However, some individuals have experienced water toxicity  Ex. Soldiers in training, endurance athletes ∙ How much water do you need and what are the best sources? o Daily water needs depend on physical activity, environmental  factors, diet o Recommendations based on reported total water intake of  healthy americans o Men: 16 cups/day (13 cups of beverages) o Women: 12 cups/day (9 cups of beverages)  About 80% from beverages, 20% foods  Physical activity increases needs ∙ Tap water or bottled water: is bottled better? o False assumption: bottled water is purer than tap water o Tap water is perfectly safe  Monitored by environmental protection agency (EPA)  Provides fluoride, helps prevent dental caries o Bottled water is very popular  Most products conform to FDA requirements  May actually be tap water  High cost  Various “designer” waters on the market ∙ What are minerals and why do you need them?  o Inorganic elements needed in relatively small amounts o Mineral absorption depends on bioavailability   Some minerals compete for absorption: too much of one  can decrease absorption of another ∙ Ex. Excess zinc can reduce copper absorption Some substances bind minerals, making them unavailable  for absorption ∙ Ex. Oxalates in spinach bind calcium o Major minerals (macrominerals): needed in amounts greater than 100mg/day o Trace minerals (microminerals): needed in amounts less than 20  mg/day o Your need major minerals in larger amounts (more 100 mg)  Sodium, chloride, potassium, magnesium, sulfur play key  roles in fluid balance  Calcium, phosphorus, magnesium work together to  strengthen bones and teeth o Trace minerals are needed in small amounts (less 100 mg)  Play essential roles as important as major minerals  Chromium and iodine help certain hormones  Iron maintains healthy red blood cells  Fluoride protects teeth  Iron, zinc, copper, manganese, and molybdenum are  cofactors that work with enzymes in critical chemical  reactions  ∙ Minerals widely found in MyPlate o Vegetables: potassium, calcium, chromium, magnesium,  manganese o Fruits: potassium, calcium (fortified juice), manganese, boron o Grains: sodium, phosphorus, magnesium, iron, zinc, selenium,  chromium, manganese o Protein: sodium, phosphorus, magnesium, iron, copper, zinc,  selenium o Dairy: potassium, calcium, phosphorus ∙ Major minerals o Sodium – major electrolyte outside the cell; helps regulate body  water and blood pressure  Food sources: processed foods, table salt, meat, seafood,  milk, cheese, eggs  Excessive: hypertension, UL: 2300 mg/day  Deficiency: rare  o Potassium – inside the cell, needed for muscle contraction and  nerve impulses; regulates water and blood pressure  Potatoes, melons, citric fruits, most fruits and vegetables,  milk, meat, legumes  Excessive: hyperkalemia  Deficient: hypokalemia o Calcium – formation of bones and teeth, muscle contraction and  relaxation, blood clotting, heart and nerve function Milk and dairy products, leafy greens, broccoli, salmon,  tofu, sardines  Excessive: hypercalcemia UL: 2500mg/day  Deficient: osteoporosis o Phosphorus – formation of bones and teeth  Meat, fish, poultry, eggs, dairy, cereals o Magnesium – participates in muscle contraction and nerve  conduction  Meat, seafood, nuts, legumes, dairy, whole grains o Chloride – helps maintain fluid and acid base balance  Found as sodium chloride in foods o Sulfur – A part of other compounds in body; helps give some  amino acids their 3D shape  Meats, fish, poultry, eggs, dairy foods, fruits, vegetables o Iron – as major component of hemoglobin and myoglobin, helps  transport oxygen throughout the body, enhances brain function  Meat, fish, poultry, enrich and fortified breads and cereals  Excessive: vomiting, nausea, constipation, organ damage  to kidney/liver, UL: 45mg/day  Deficient: fatigue, iron deficiency anemia, growth  retardation in infants o Copper – a component of several enzymes, involved in iron  transport, needed for healthy connective tissue enzymes, role in  blood clotting and a healthy immune system  Organ meats, nuts, seeds, cocoa, whole grains, legumes,  shellfish  Excessive: vomiting, abdominal pain, nausea, diarrhea,  liver damage, UL: 10000 g/day  Deficient: impaired growth/development o Zinc – cofactor for several enzymes: DNA and RNA synthesis;  needed for a healthy immune system, wound healing, and taste  acuity   Meat, poultry, seafood, whole grains  Excess: nausea, vomiting, cramps, diarrhea, impaired  immune function UL: 40mg/day  Deficient: skin rash and hair loss, diarrhea, loss of taste  and smell o Selenium – a component of enzymes antioxidant  Meat, seafood, fish, eggs, whole grains  Excessive: selenosis, brittle hair and nails, skin rash, garlic  breath odor, fatigue  Deficient: Keshan disease o Fluoride – makes teeth stronger  Fluoridated water, tea Excessive: fluorosis in teeth and skeletal fluorosis, UL:  10mg/day  Deficient: increased susceptibility to dental caries o Chromium – improves insulin response  Pork, egg yolks, whole grains, nuts  Excessive: unconfirmed toxicity effects  Deficient: potential insulin resistance o Iodine – component of a thyroid hormone  Iodized salt, seafood, dairy products  Excessive: impaired functioning of thyroid, UL:1100 g/day  Deficient: goiter, cretinism o Manganese – cofactor involved in metabolism  Beans, oats, nuts, tea  Excessive: abnormal central nervous system effects, UL:11  mg/day o Molybdenum – cofactor for variety of enzymes  Legumes, nuts, leafy vegetables, dairy, cereals  Excess: unknown in humans, UL: 2 mg/day  Deficient: unknown in humans ∙ Exploring sodium o What are sodium and salt?  Sodium is an electrolyte (charged ion) in blood and in the  fluid surrounding cells  About 90 % of sodium consumed is in form of sodium  chloride, table salt o Functions: chief role is regulation of fluid balance  Also transports substances such as amino acids across cell  membranes o Sodium balance in your body  Sodium level is maintained by the kidneys reducing or  increasing sodium excretion as needed  Smaller amounts lost in stool and sweat  o Daily needs: 1500 mg/day for adults under 51 o Food sources: 75% of sodium consumed by Americans comes  from processed foods  About 10% occurs naturally in foods; another 5-10% added during cooking and at table o Adult upper level daily: 2300 mg o Too much or too little:  UL for adults is set at 2300 mg/day to reduce the risk of  hypertension (high blood pressure) ∙ Cut back on processed foods and salt added to foods  to lower sodium intake Sodium deficiency is rare in healthy individuals consuming  a balanced diet ∙ You and your blood pressure o Hypertension is a silent killer  No symptoms – have blood pressure checked regularly  Contributes to atherosclerosis, heart enlarges and weakens  Damages arteries leading to brain and kidneys, increasing  risk of stroke and kidney disease o To control hypertension  Reduce weight, increase physical activity, eat a balanced  diet ∙ The DASH: Dietary Approaches to Stop Hypertension  ∙ Exploring potassium o Important mineral with many functions  Fluid balance: electrolyte inside cells   A blood buffer: helps keep blood pH and acid base balance  correct  Muscle contraction and nerve impulse conduction   Can help lower high blood pressure  Aids in bone health: helps increase bone density o Daily needs:  Adults: 4700 mg/day  Adult females consume only about 2400 mg/day and adult  males only 3170 mg/day on average  o Food sources:  Fruits and vegetables ∙ Minimum of 4.5 cups a day will help meet potassium  needs  Dairy foods, nuts, legumes, also good sources o Too much or too little  Too much from supplements or salt substitutes can cause  hyperkalemia in some individuals  Can cause irregular heart beats, damage heart, and be life  threatening o Too little can cause hypokalemia  Can cause muscle weakness, cramps, irregular heartbeats,  and paralysis  Can occur as result of excessive vomiting and/or diarrhea.  Anorexia and/or bulimia eating disorders ∙ Exploring calcium  o Most abundant mineral in the body  More than 99% percent located in bones and teeth o Functions  Helps build strong bones and teeth Plays a role in muscles, nerves, and blood  May help lower high blood pressure  May fight colon cancer  May reduce risk of kidney stones (though supplements  have opposite effect)  o Daily needs:  1000 to 1200 mg/day, depending on age o Food sources:  Milk, yogurt, cheese, broccoli, kale, canned salmon (with  bones), tofu processed with calcium, calcium-fortified  juices and cereals o Too much or too little  UL: 2500 mg/day (ages 19-50); 2000 mg (51+)  Too much calcium leads to hypocalcemia – impaired  kidneys, calcium deposits in body   Too little can lead to less dense, weakened, brittle bones,  and increased risk for osteoporosis o Calcium supplements:  Consume in doses of 500mg or less  Some sources (oyster shell, bone meal, dolomite) may  contain lead, other toxic metals  May be inadvisable if consuming enough in foods ∙ Osteoporosis: Not just your grandmother’s problem o Bones are living tissue, constantly changing o Peak bone mass occurs in early adulthood (20s)  Then slowly more bone is lost than added  As bones lose mass, they become more porous and prone  to fractures, leading to osteoporosis o Bone mineral density (BMD) test measures bone density  Low score = osteopenia (low bone mass)  Very low score = osteoporosis o Risk factors  Gender (females at higher risk due to loss of estrogen after menopause)  Ethnicity (Caucasian and Asian American at higher risk)  Age (over 30)  Body type (small-boned/petite women at higher risk)  Family history of fractures increases risk  Level of sex hormones (amenorrhea, menopause, or men  with low levels of sex hormones  Medications: glucocorticoids, antiseizure medications,  aluminum-containing antacids, high amounts of thyroid  replacement hormones  Smoking Low physical activity: 30 minutes per day recommended  Alcohol (more than one drink for women, two for men)  Inadequate calcium and vitamin D (less than 3 cups a day  of vit D fortified milk or yogurt) ∙ Exploring iron o Most abundant mineral on earth and main trace mineral in body o Two forms: heme and nonheme iron  Heme iron from animal sources is part of hemoglobin and  myoglobin and easily absorbed  Nonheme iron in plant foods is not as easily absorbed, due  to phytates and other substances  Body absorbs only 10-15% of iron consumed  Absorption increases if body stores are low  Not excreted in urine or stool, once absorbed, very little  leaves body (95% recycled, reused)  o Functions:  Hemoglobin in red blood cells transports oxygen from lungs to tissues and picks up carbon dioxide waste from cells  Myoglobin transports and stores oxygen in muscle cells  Aids brain function by helping enzymes that make  neurotransmitters o Daily needs:  Men and women > 50:8 mg/day  Women 19-50: 18 mg/day: higher due to iron lost during  menstruation o Food sources  Iron enriched bread and grain products; heme iron in  meats, fish, poultry o Too much or too little:  Too much iron from supplements can cause constipation,  nausea, vomiting, diarrhea  In US,a leading cause of accidental poisoning deaths in  children under 6 years  Iron overload can damage heart, kidneys, liver, nervous  system  Hemochromatosis, a genetic disorder, can cause iron  overload  Iron deficiency: most common nutritional disorder in the  world  Iron deficiency anemia occurs when iron stores are  depleted and hemoglobin levels decrease  CH 8 REVIEW ∙ Electrolytes control fluid balance in the cells∙ TRUE: water follows movement of electrolytes, diffusion is the process  of whereby substances move from a high concentration of solute to an  area of low concentration, sodium and potassium move across cell  membranes by means of special proteins ∙ Which of the following choices most completely describes the functions of water in the body – water is essential for digestion, transporting  nutrients, protection and lubrication ∙ Water carries heat away from the body core to cool the body when  needed through the process known as evaporation  ∙ Water balance? o A woman on a daily diet of 2500 kcal needs approximately  3000mL water o The majority of excess water is excreted through – urine output ∙ Fluid balance – depends on maintaining an equal concentration of  water and electrolytes inside and outside the body’s cells ∙ Charged ions such as sodium, potassium, and chloride are called  electrolytes ∙ The feeling of dry mouth experienced through dehydration is part of  the body’s thirst mechanism ∙ The process of which water (the solvent) moves in and out of cells from an area of low to high concentration of solutes is called osmosis ∙ If you are not consuming enough water or are excreting too much  water from your body, dehydration can occur ∙ Diuretics are substances that cause the body to lose water ∙ The liquid that is between cells is called interstitial fluid ∙ Hyponatremia occurs when the amount of sodium in the blood is too  low ∙ Secretion of antidiuretic hormone (ADH) from the pituitary gland  signals the kidneys to cut down on water lost via urine excretion  ∙ Dehydration o Older adults with vigorous jobs, and individuals who are  physically active are particularly at risk for this state o This state can occur as a result of severe diarrhea and/or  vomiting or abuse of diuretics ∙ Water balance o This state occurs when the thirst mechanism has been successful o This state occurs when enough fluid is consumed to allow for an  equal concentration electrolytes between the intra- and  extracellular fluid compartments ∙ Hyponatremia o This state occurs when too much fluid (particularly pure water) is consumed in a short period of time o This state can result in swelling of tissues, including the brain ∙ Water losso Urine becomes darker in color o The fluid volume in the blood is decreasing o The thirst mechanism is triggered o Antidiuretic hormone is released from the pituitary gland,  causing the kidneys to decrease the volume of water used to  make urine o Net movement of water is out of the cells ∙ Water gain o Urine becomes lighter in color o The fluid volume in blood is increasing o Concentration of electrolytes outside the cells is decreasing  compared to that inside the cells o Net movement of water is into the cells ∙ Hydration o Reduced saliva production can be an indicator of dehydration o Dark urine can be an indicator of water imbalance ∙ Water loss o Water loss through breathing (respiration) is a type of insensible  water loss o The greatest amount of water loss occurs via production of urine  by the kidneys ∙ Calcium: TRUE – calcium makes up approximately 2% of body weight,  Most of the calcium in our bodies, 99%, is found in bones and teeth,  when dietary calcium is low, calcium is removed from the bone to  maintain blood calcium levels ∙ Calcium is actively absorbed in the upper small intestine with the aide  of 1,25 dihydroxyvitamin D ∙ Which describes hormones in calcium metabolism? – parathyroid  hormone is released when dietary calcium levels are low ∙ The thyroid hormone calcitonin inhibits the effects of vitamin D on  calcium metabolism and works to lower calcium levels in the blood ∙ Minimum sodium – 180 mg ∙ Sodium Americans consume – 3000+ mg ∙ Majority of sodium in diet comes from – sodium that added to  processed foods  ∙ Heme iron is found in foods like meat and poultry, whereas nonheme  iron form is found in plant foods like grains and vegetables ∙ The metal and trace mineral copper is part of several enzymes and  proteins ∙ Adequate zinc is important for maintaining a healthy immune system  and may aid wound healing ∙ Selenium acts as an antioxidant and aids in thyroid function ∙ Fluoride is not considered essential, but it is very important for  maintaining strong, healthy teeth∙ The deficiency disease goiter was much more common before iodine was added to salt in the US ∙ Manganese acts as a cofactor for a variety of enzymes and also plays a role in synthesis of bone ∙ Sodium – excess intake may contribute to hypertension (high blood  pressure) in those sensitive to this mineral ∙ Chloride – this mineral participates in digestion as part of hydrochloric  acid in the stomach ∙ Potassium – a deficiency of this mineral may lead to muscle weakness,  cramps, and an irregular heartbeat ∙ Calcium – the body stores 99% of this mineral in the bones and teeth,  may be found in dairy products, leafy greens, and fish like salmon or  sardines ∙ Phosphorus – this mineral helps provide structure for cell membranes,  and is part of the backbone of DNA and RNA ∙ Magnesium – large intakes of this nutrient in supplement form may  cause diarrhea, cramps, and nausea ∙ Water! o Water helps maintain body temperature o Diuretics like alcohol and some medications can cause the body  to lose water ∙ Modifiable hypertension o Sedentary lifestyle, weight, diet rich in restaurant foods ∙ Which of the following blood pressure measurements is hypertension?  – 145/90 ∙ Good source of iron – meat ∙ Best to poorest iron – beef, dark meat chicken, white meat chicken ∙ Vegan needing iron – eat lentils ∙ Good source of iron – spinach ∙ Mineral linked to energy metabolism – chromium ∙ Electrolyte balance – potassium ∙ Antioxidant function – selenium ∙ Blood health – iron ∙ Bone health – phosphorus ∙ Both vitamins + minerals – provide kilocalories for body ∙ Only vitamins – either fat or water soluble ∙ Only minerals – minerals are inorganic, vitamins are organic ∙ Source of potassium – tomato juice ∙ Calcium – dark green, leafy vegetables ∙ Salad with leafy greens, dressing, cheese – calcium and potassium ∙ High amount of iron – roast beef ∙ Non-heme iron – whole and enriched bread∙ Helps body cool off to maintain temperature – evaporation ∙ Mineral absorption from foods depends on their – bioavailability ∙ Mineral toxicity? – mineral toxicities usually result from supplement use ∙ DASH diet – high in potassium and magnesium ∙ One key role of copper is as a component of – enzymes ∙ Selenium is component of enzymes that help regulate – thyroid  ∙ Major function of magnesium – help regulate blood pressure ∙ Chromium may help lower the risk of – type 2 diabetes ∙ A severe deficiency of iodine during adulthood can cause – goiter ∙ Function of phosphorus is – maintain proper pH ∙ Condition known as hyponatremia – presence of too little sodium in  blood due to overconsumption of fluids ∙ Hyperkalemia occurs when person consumes what of too much  supplements – potassium ∙

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