NYU Nutrition

Protein Digestion

Food proteins need to be digested into amino acids before forming body proteins No digestion takes place in mouth Stomach: Acids denature proteins, stomachs enzymes act on peptide bonds (functions best in acidic environment of stomach Lining of stomach protected from strong acids by mucus coating Small intestine: polypeptides and other single amino acids enter from stomach..alkaline juice from pancreas neutralizes stomach acid...enzymes from pancreas and intestine continue to break down proteins until only single amino acids, dipeptides and tripeptides remain

Problem Foods

Foods that are high in moisture and nutrients Foods that are chopped or ground Includes Meat Poultry Eggs Seafood Raw Produce Mad cow disease caused by prion- an unusually folded protein that disrupts normal cell functioning..in cattle, deer, and elk Eggs-salmonella Raw produce threat for foodborne illness Avoid unpasteurized juices When traveling, eat only cooked or canned food

In the kitchen-keeping food safe

Keep hands/kitchen clean Keep raw foods separate Keep hot food hot Keep cold food cold wash hands for 15 seconds before and after handling raw food Prevent cross contamination cooked foods should be refridgerated within 2 hours Thaw frozen foods IN refrigerator

Potassium

Main positively charged ion INSIDE cells Helps maintain fluid and electrolyte balance Maintains cell integrity Critical to maintaining the heartbeat Involved in nerve impulse transmission and muscle contraction Low potassium raises blood pressure Dehydration results in potass. lost inside cells...meaning thirst sensation is lost Losses during fasting or severe diarrhea can result in sudden heart failure to those sensitive Low intakes can worsen glucose intolerance, increase metabolic activity, accelerate calcium bone loss, aid in forming kidney stones From food- safe...injections can stop the heart Supps WILL trigger vomitting Usually only get about 50% of DRI..riches sources are fresh whole foods, processed have much less Orange juice, salmon, banana, baked potato, avocado

Vitamin K

Activates protein involved in blood clotting Improves clotting only when there WAS a vit. k deficiency Assists in synthesis that binds minerals to bone- can result in low bone mineral density Deficiency is rare- intestinal bacteria can synthesize Vit K Single dose given to newborns due to sterile intesintal tract Deficiencies can come from those with fat malabsorption conditions or those who've taken antibiotics to destroy bacteria in intestinal tract Toxicity is rare, can cause hemolytic anemia and increased blood bilirubin concentration Liver releases excess bilirubin into blood rather than excreting it..leads to jaundice (yellowing of skin) and bilirubin in brain of infant can cause death From plants- dark leafy veg. and liver from animal food source

Nutrient additives

Added to improve nutritional value Refined grains and cereals are enriched Iodine added to salt Vitamins A and D added to dairy products Calcium added to orange juice

Importance of Protein

Amino acids must always be available to build proteins of new tissue as well as to replace worn out cells and internal working proteins of cells (RBC live 3-4 weeks, GI Tract only 3 days) Process of breakdown, recovery, synthesis called protein turnover

Antioxidants in food

Antioxidant preservatives can protect food from spoilage due to oxidation Common antioxidant additives include Vitamin C and E Sulfites Butylated hydroxyanisole (BHA) and the related compound butylated hydroxytoluene (BHT)

Riboflavin

Assists in energy metabolism Deficiency- cracks at corners of mouth, sore throat, hypersensitivity to light. Usually accompanies a thiamin deficiency Children and elders at highest risk

Water Soluble Vitamins

Absorbed directly into bloodstream and travel freely. Less risk of toxicity because stored in blood tissue easily absorbed and excreted (urine) must be consumed frequently. Rarely toxic, easily lost during food prep

Fat Soluble Vitamins

Absorbed into lymph and travel in blood with protein carriers. Stored in liver or in fatty tissues. Can build up to toxic concentrations Vitamins ADEK. Founds in fats and oils of food Requires bile for absorption Stored in liver and fatty tissues until needed Not Required everyday Deficiency likely due to fat malabsorption (various disease states or laxatives)

Denaturation of Proteins

Can be denatured by: Heat, radiation, alcohol, acids, bases, salts of heavy metals...these disrupt the folded structure of the proteins Denaturation useful in digestion of food protein...stomach acid opens up protein structure, allowing digestive enzymes to cleave peptide bonds (also occurs during cooking) Well known poisons consist of heavy metal salts (denature any protein strands)....common antidote is milk, as the poison acts on the milk protein rather than those in GI tract

Thiamin

Critical to energy metabolism Found on nerve cell membranes (critical to nerve function) Deficiency known as beriberi- loss of sensation of hands and feet, muscular weakness, abnormal heart action, creeping paralysis Wet beriberi-edema dry beriberi- no edema Wernicke-Korsakoff- severe deficiency caused by alcohol abuse All characteristics similar to being drunk

General Vitamin Definition

Essential, non caloric, organic, needed in small amounts, have a variety of roles. Some occur in food as active form. Others found as precursors or provitamins Fall into 2 different classes (fat soluble and water soluble). Can affect digestion, absorption, transport, storage, and losses of vitamins

Protein Excess

Excessive protein intake for weightloss not recommended Overconsumption offers no benefits and may post short and long term health risks (weakened kidneys can't handle excess) Heart Disease risk (red meat and dairy raise heart disease risk) High protein diets may raise homocysteine levels in the blood, which may be associated with heart disease risk

General Water Information

We need more water per day than any other nutrient Can only survive a few days (after a day our body's chemistry and metabolism altered) Makes up 60% of adults weight Water of body fluids is the transport vehicle Nearly universal solvent- dissolves amino acids, glucose, minerals, etc Fat soluble substances travel in body fluid in water soluble proteins Acts as cleansing agent Water molecules resist being crowded together, making a lubricant and cushion, prevents from shock Helps maintain body temp, water from sweat is coolant Active participant in many chemical reactions

Food Safety- Farm to Table

meat processing plants inspected daily by USDA ALL food producers must employ a Hazard Analysis Critical Control Point (HACCP) plan to help prevent foodborne illnesses must identify critical control points where a risk of contamination is possible Danger zone 40-140

Molybdenum and Manganese

Molybdenum-Functions as part of several metal containing enzymes Manganese- works with enzymes that facilitate body processes Found in whole grains, vegetables, fruits, legumes and nuts

Flouride

Nonessential, but prevents development of dental caries Deposits in teeth and bone and form decay resistant crystals... Promotes remineralization of enamel, acts on plaque Primary source is flouridated drinking water...accessible to 70% of US..rarely in bottled deficiency can result in decay Toxicity- discoloration can occur and white spots form on enamel (irreversible)

Protein Synthesis

Nucleus houses DNA...DNA is a template to make strands of messenger RNA Each strand of MRNA exactly copies instructions for making a protein needed by cell MRNA exits nucleus through nuclear membrane..then attaches to ribosomes ("protein making machinery") TRNA collects amino acids from cell fluid, cluster around ribosomes, and deliver the amino acid as directed by MRNA Ribosomes move along MRNA, enzyme bonds amino acids to the growing protein strand Completed protein released...MRNA degraded or reused..TRNA free to collect more amino acids

Kwashiorkor

Often NO severe wasting of body fat Decrease in proteins and hormones involved in maintaining fluid balance Results in edema (distinguishing feature) Fatty liver Caused by lack of protein carriers that transport fat out of liver (see bulging belly) Liver loses ability to filter poisons from the body Changes in hair texture and color Lack of tyrosine for melanin production Skin changes Scaly texture Poor wound healing Weakened immune system Opportunistic infections can weaken child further

Sulfate

Oxidized form as it exists in food and water Required for synthesis of sulfur-containing compounds Sulfur-containing amino acids help proteins assume their functional shapes No rec intake, deficiencies unknown...too much in water can cause diarrhea

Chromium

Participates in carb and lipid metabolism Helps maintain glucose homeostatis by enhancing insulin activity...deficiency can lead to impaired insulin action and diabetes like high glucose Widely distributed in food supply, Especially in unrefined foods, liver, brewer's yeast, and whole grains Lost significantly in processing

Vitamin B6

Participates in over 100 reactions in tissues of body aids trytophan to niacin tryptophan to serotonin hemoglobin synthesis assists in release of stored glucose from glycogen Immune function fetal brain and nervous system development Deficiency symptoms...weakness, depression, confusion, insomnia..can be linked to increase risk of heart disease Toxicity- UL 100mg/day single supp can equal 3000 bananas

From Amino Acids to Proteins

Peptide bonds bind one amino acid to another in a protein strand (formed btw one amine group and one acid group Amino acids may chemically attract one another (resulting in protein coiling) Each spot is attracted or repelled by other spots, forming globular structure or a fibrous structure Amino acids w/ charged side chains attracted to water (oriented on outside of protein structure in body fluids) Amino acids w/ neutral side chains repelled by water (center of protein structure in body fluids Functional protein requires several strands to come together as a functional unit...mineral, vitamin, or carb may join to activate it

Protein Structure

Performs many vital functions Contain nitrogen atoms (key diff. from carbs and fats) Building blocks are amino acids (not all identical)

Antimicrobial Agents

Preservatives protect food from microbial growth Salt and sugar are best known..work by withdrawing water Nitrates added to meats Sulfites prevent oxidation...FDA requires you to list any

Protein Deficiency

Protein deficiency hand in hand with energy deficiency, known as protein energy malnutrition (PEM) Most widespread form of malnutrition in world (developed countries and over 500 million children) Starts early childhood but can affect adults, Results in poor or stunted growth, wasting and weight loss 2 forms: Marasmus- extreme food energy deficiency Kwashiorkor- extreme protein deficiency

Nitrogen Balance

Protein rec's guided by nitrogen balance studies..compares nitrogen lost through excretion with that added with consumption Nitrogen in MUST = nitrogen out Healthy adults are in nitrogen equilibrium, when more nitrogen in, they are positive nitrogen balanced, and vice versa Positive nitrogen balance- more proteins are being built than broken down and lost

Food Additives

Substances added to foods but not consumed by themselves Over 3000 approved in US 700 on GRAS list (gen. recognized as safe) Help prevent mold and bacterial growth Examples: Preservatives Anti-microbial agents Antioxidants Chelating Agents Artificial coloring Artificial flavoring, flavor enhancers Bleaching agents Nutrient additives Stabilizing and thickening agents

Tyrosine/Tryptophan

Tyrosine- Forms part of the neurotransmitters epinephrine and norepinephrine...also used to make pigment melanin...converted to thyroxine Tryptophan-Starting material for the neurotransmitter serotonin Starting material for niacin

Beta carotene

Vit-A in plants. Most abundant in caratenoids Vit. A activity measured in RAE (retinol activity equivalents. 12 mg of beta caratene = 1 mg of retinol Acts as dietary antioxidant..elevated levels associated with reduced cancer risks Can't OD on food..excess causes skin to appear yellow

Body Fluids and Minerals

cells cannot directly regulate passage of water across its membranes, so water passes freely Cells CAN pump minerals across membrane Major minerals form salts that dissolve in body fluids, cells direct where the salts should go and the fluid follows When salts dissolve, separate into electrically charges particles called ions...also known as electrolytes See image in slides (When electrolytes are present in unequal concentrations on either side of a water-permeable membrane, water flows toward the more concentrated side to balance the concentrations) To control water flow, cells move electrolytes from one compartment to another...transport proteins form pumps to do this, this actively regulates fluid and electrolyte balance (image:Transport proteins in cell membranes maintain the proper balance of Na+ and K+) Dehydration pulls fluid from BETWEEN cells, water leaves cell interiors to restore balance Kidneys conserve water by increasing sodium balance outside cells, which leads to further water loss from interior...this results in fluid-electrolyte IMBALANCE, which can be an emergency. Minerals help manage acid-base balance Proteins and some minerals can also act as buffers to acid proper balance Intake req's established for 7 minerals, these found in body greater than 5 grams, all help maintain fluid balance

Vitamin B12

closely related to Folate, depend on one another for activivation Helps maintain sheaths that protect nerve fibers Deficiency- damaged nerve sheaths, creeping paralysis, malfunctioning of nerves and muscles Can also result in failure of folate to make red blood cells...presence of large immature red blood cells Absorption REQUIRES intrinsic factor (compound made by stomach) Stomachs acidic PH liberates B12 from food..intrinsic factor binds the vitamin..then absorbed from small intestine into blood Deficiency caused by lack of intrinsic factor called pernicious anemia Intrinsic factor could be lacking due to gene defects, loss of ability to produce enough stomach acid Then needs to be administered by injection Vegetarians and elderly at greatest risk..b12 found only in animal products

Pesticides

designed to ensure survival of crop Speculation as to whether actually increases plant yield Pesticides kill pests, pollute, survive processing EPA sets limits for max residue allowed on food Some promote survival of pests they intend to kill Create resistant insects Can be limited by choosing organic foods

Role of Body proteins

40% of body's protein found in muscle tissue Muscle protein structure allows body to move..this protein can only be broken down in states of starvation Other structural proteins give shape and strength to bones, teeth, skin, tendons, cartilage, blood vessels, etc Also help build enzymes, hormones, and other compounds (enzymes act as catalysts..hormones act as chemical messengers in body) Also build antibodies- large proteins produced by immune system in response to antigen Also used for transporting substances- Transport proteins carry lipids, vitamins, minerals, and oxygen around the body Travel in the blood, into and out of cells, or around the interior of cells Maintaining Fluid and Electrolyte Balance- cells attract and help maintain water Proteins in vessels attract water and hold it there, when this fails fluid collects in spaces between cells and edema occurs Transport proteins help maintain electrolyte balance Na+ is concentrated outside the cells K+ is concentrated inside the cells Cell proteins maintain balance by holding fluids and electrolytes in their proper chambers Helps maintain acid-base balance- blood proteins act as buffer to maintain normal PH (buffers pick up hydrogen when excess and release in deficit Also used for blood clotting (wounds) Also provides energy and glucose if needed

Microbes + Food Safety

76 million ill from foodborne diseases per year 325,000 hospitalizations Microorganisms (microbes) cause foodborne illness through infection or intoxication Occurs when enter body and multiply in tissue Intoxication occurs when microorganisms in food produce toxins

Phosphorous

85% combined with calcium in crystals of bones and teeth, rest is everywhere else Cells rely on phosphorous for: phos. salts act as buffer for acid base balance Part of RNA and DNA Carry, store, release energy in form of CHO, fat, protein Form parts of phosolipids and parts of proteins and transport molecules Deficiencies are rare..animal protein is best source

Amino acids to Glucose

Can be metabolized for energy and converted to glucose (unlike fats), can help maintain glucose level and provide glucose needed for brain When used for energy, nitrogen containing amine group removed and used elsewhere or excreted in urine (C,H,O remaining) No specialized storage compound for protein...when protein sparing energy is lacking, body breaks down tissue protein for amino acids. This protein taken from diff tissue at diff times. Blood first, then muscles, then liver and other organs. This wastes lean body tissue Excess amino acids cannot be stored by body, amine group removed and excreted. Remainder used for energy..and glucose to be stored as glycogen or fat When excess, body speeds up use of amino acids for fuel instead of fat, so fat remains stored in fat tissue

Chloride

Chief negative ion in body helps with electrolyte and acid base balance Component of hydrochloric acid..which maintains low PH in stomach for protein digestion Main food source is salt..no diets really lack in chloride

Niacin

Critical role in energy metabolism Deficiency can cause serious illness..Pellagra- 4'd's...diarrhea,dermatitis, dementia, death Occurs in malnourished who abuse alcohol Toxicity-high doses of nicotinic (form of niacin) acid may be used to lower blood lipids Large supp doses can result in low blood pressure liver injury peptic ulcers vision loss "niacin flush" Found in foods containing amino acid tryptophan, if you eat adequate protein, won't be deficient Described in terms of niacin equivalents (NE)

Iron deficiency/toxicity

Deficiency occurs when stores are depleted..can lead to iron deficiency anemia characterized by Inadequate hemoglobin production, Small, pale red blood cells In anemia...red blood cells contain too little hemoglobin to deliver sufficient oxygen Limits oxygen + energy metabolism... leading to fatigue, apathytendency to feel cold, pale appearance Iron deficiency- pica..craving and consumption of non nutritive substances..can be corrected with iron repletion those at greatest risk include menstruating or pregnant woman, infants, toddlers, during periods of rapid growth 2.4 million suffer in US...1.6 billion in world...parasitic infections in developing worlds lead to blood loss..iron supps can help Toxicity- Toxic in large amounts..difficult to excrete, body tries to control against iron overload by controlling absorption Excessive alcohol intake can damage intestine and impair regulation ability Hemochromatosis arises from a hereditary defect- excess absorption of iron 6 to 7 mg per 1000 calories currently consumed Good sources..clams, spinach, beef liver

Iron

Found in two proteins, hemoglobin and myoglobin Hemoglobin (in red blood cells)..carries oxygen from lungs to cells Myoglobin (in muscle cells)- holds and stores oxygen in muscles All of bodies cells need oxygen to metabolize energy yielding nutrients Other roles: Needed to make new cells, amino acids, hormones Also parts of enzymes Needs to be contained..if left free..generates free radical reactions..so special proteins transport iron Iron lost in small amounts from GI tract, in nail and hair trimmings, and in shed skin cells Blood loss can result in serious losses 10-15% of dietary iron absorbed..increases when needed...form iron comes in can affect absorption Two forms: Heme and Nonheme Heme- the iron-containing part of hemoglobin and myoglobin in animal food sources Nonheme:, the iron found in foods from plants and in nonheme iron of meats Heme iron more reliably absorbed at rate of 23% whereas nonheme is between 2-20% Meat, fish, protein contain MFP factor..promotes absorption of nonheme iron form other foods eaten at same time Vitamin C triples nonheme absorption + preparation in iron cookware helps as well Aborption impaired by calcium and phosphorous, tannins (tea), and phytates (fiber of lightly processed legumes + whole grain)

Vitamin E

Four tocopherol compounds identified, alpha, beta, gamma, delta Alpha is the standard and are what DRI is expressed in Bodies primary antioxidant Defends body against free radicals and reduces inflammation Deficiency is rare expect w/ those with fat malabsorption diseases or diets with very low fat consumed for years Have been observed in infants- suffer from erythrocyte hemolysis Toxicity- safe in foods,supps can increase effect of anticoagulants Smokers have higher needs US citizens currently NOT getting enough Usually comes from veg. oils and products such as margarine and salad dressing Animal fats have little Destroyed by heat and oxidation

B Vitamins

Function as part of coenzymes (small molecules that combine with enzymes to activate them) Imp. role in metabolism of energy yielding nutrients Vit b6 helps body use amino acids to synthesize protein Folate and b12 help cells multiply Thiamin, riboflavin, niacin, pantothenic acid, and biotin all help release energy stored in the macronutrients Deficiencies affect all cells of body. cell renewal depends on b vits, as well as digestive tract and blood cells

Animal Drugs

Growth hormones given to cattle, deemed safe antibiotics given to lifestock Bacteria may adapt and not respond to antibiotics

Magnesium

Half found in bones...can be tapped to maintain blood levels when dietary intake too low Kidneys can also help conserve Critical for: Operation of more than 300 enzymes, release and use of energy from nutrients Directly affects metabolism of potassium, calcium, and vitamin D Related to proper heart functioning Works with calcium for proper muscle function Deficiency occurs due to vomiting, alcoholism, etc Symptoms include weakness, confusion, hallucinations, uncontrollable muscle contractions Toxicity only occurs from supps and salts...may see in those who abuse laxatives. Can lead to diarrhea, acid-base imbalance, and dehydration Easily lost during food processing

Hard vs Soft Water

Hard water- high concentrations of calcium and magnesium Soft- high concent. of sodium More desirable for homeowners, may aggrevate hypertension, contaminant metals from pipes more easily dissolved in soft water (bad I think)

Copper

Helps with formation of hemoglobin and collagen Many enzymes depend on copper for its oxygen handling ability..assists in reactions leading to release of energy Deficiency is rare..can severly disturb growth..too much zinc interferes with absorption Toxicity unlikely

Protein Quality

High quality proteins provide all essential amino acids If diet does not provide sufficient amount... cells Conserve the essential amino acid by limiting their synthesis of proteins Break down more internal proteins to liberate the needed essential amino acid These actions assure that limiting amino acids are put to best use making new proteins, however protein synthesis is slowed, and if chronically depleted the cell will break down protein making machinery If a cell can't find needed amino acid during protein synthesis, partial protein released and dismantled Good sources of protein are animal products Can also eat complimentary proteins (each protein rich food contains only some essential amino acids)..when eaten together, provide all necessary Digestibility is imp. in determining protein quality...protein in eggs more digestable than protein in oats Animal proteins easily digested (90%) Legumes (80-90%), grains and other plants (70-90) Cooking with moist heat improves protein digestability while dry cooking can impair

Vitamin D

Hormone in body to regulate blood calcium and phosphorous Raises blood calcium levels by, draws calcium from bone, increased intestinal absorption, increased calcium retention via kidneys affects how cells grow, multiply, specialize Body can synthesize from exposure to sunlight (UVB rays transforms cholesterol compound to vit. D precursor..then converted by liver and kidneys skin synthesis poses no risk of toxicity excess sun exposure CAN result in dev. of skin cancer however SPF 8 or higher blocks UVB rays Though we can produce it, still risk of deficiency (darker skinned, elderly, children) Deficiency in children can lead to rickets (bowed legs and skeletal deformities Poor bone mineralization in adults can lead to osteomalacia (rickets in adults) Can be the most toxic (high blood calcium levels)..calcium can deposit in soft tissue, form stones, or harden blood vessels

Biotin and Pantothenic Acid

Imp in energy metabolism Biotin cofactor for several enzymes in CHO, protein, fat metabolism Pantothenic acid is part of a key coenzyme that allows the release of energy from CHO, fat and protein Both found abundantly in foods

Iodine

Iodide- form that does the body's work...part of thyroid hormone thyroxine Thyroxine regulates metabolism, temp, reproduction, growth, etc Iodide must be available for thyroxine to be synthesized Deficiency leads to enlarged thyroid gland (goiter) Deficiency during pregnancy can lead to cretinism (extreme irreversable mental and physical retardation) Can be averted if treated in first 6 months of pregnancy Excessive intake can also enlarge thyroid gland and can be deadly Food sources- amount varies with that found in soil where food was grown..seafood is rich...less than half a teaspoon meets entire days rec

Microbial Food Safety

Irradiation Modified Atmospheric Packaging Canning Freezing Drying Irradiation- disrupts DNA, killing them Protects consumers from foodborne illnesses by Controlling mold in grains Sterilizing spices and teas Controlling insects Extending shelf life in fresh fruits and vegetables Destroying disease-causing bacteria in fresh and frozen meat and poultry Exposes foods to controlled doses of radiation Does not change taste, texture, or appearance of foods Some vitamins are destroyed Controversial method of preservation Vacuum packaging or modified atmospheric packaging (MAP) excludes oxygen Reduced growth of oxygen-dependent microbes Prevents spoilage of fats by rancidity Prevents discoloration of cut vegetables and fruits Slows ripening of fruits and vegetables and enzyme induced breakdown of vitamins Canning is a method of preserving food by sterilizing the food and then sealing out air Canned foods have fewer nutrients Freezing preserves food by lowering the food's temperature to a point that halts life processes Microorganisms do not die but remain dormant until the food is thawed Dramatically slows enzymatic reactions Drying preserves food by removing sufficient water from the food to inhibit microbial growth Drying also greatly reduces the weight and volume of foods

Vitamin C

Maintenance of connective tissue, and antioxidant Connective tissue- enzymes involved in formation of collagen require Vit C. Collagen forms base of all connective tissue Antioxidant- immune cells maintain high levels to protect from free radicals In intestine, helps prevent iron oxidation In blood, helps protect dissolved molecules from oxidation Supports immune system function and protect against infection May shorten duration and severity of cold, acts as weak antihistamine Vit. C deficiency- scurvy. Usually due to collagen breakdown. Can lead to loose teeth, bleeding gums, swollen ankles, red spots,anemia Who's at risk? Infants fed cows milk, elderly pop lacking fruits and veg, those addicted to alc or other drugs Toxicity- can act as a prooxidant and activate oxidizing May interfere with anticoagulants, dangerous for people with excess iron. Higher rec's for smokers

Sodium

Major part of body's fluid and electrolyte balance system Chief ion used to maintain volume outside cells Helps maintain acid-base balance Essential to muscle contraction Essential to nerve transmission Body freely absorbs it, kidney filters out/ stores when needed Amount excreted should equal amount ingested each day Blood sodium levels well controlled...blood sodium rises after salty food...triggers thirst, balance restored..kidneys excrete extra water and sodium Adults exceed UL by over a third high salt intake correlates with hypertension and increased risk of heart disease...as sodium increases, so does blood pressure..risk then reduced when sodium reduced Some individuals more sensitive...response can be modified by eating potassium rich foods DASH diet (dietary approaches to stop hypertension)- high on fruits and veg...small portions of red meat and butter, etc Salt shaker only contributes to 15% of total, primary source is processed and fast foods...hide sodium in sodium containing additives

Calcium

Most abundant mineral in body, about 99% in bones and teeth integral to bone structure Bone calcium serves as reserve to blood calcium levels Calcium + Phosphorous essential to bone formation Calcium phosphate salts crystallize on collagen in forming bone resulting hydroxyapatite crystals invade the collagen and give rigidity to maturing bones Flouride may replace parts of crystals, making flourapatite, which is even stronger 1% in body's fluids Plays a number of major roles: Regulates the transport of ions across cell membranes, particularly important in nerve cells Helps maintain normal blood pressure Plays a role in blood clotting Essential for muscle contraction and heartbeat Allows secretion of hormones, digestive enzymes, and neurotransmitters Activates cellular enzymes Due to importance, blood calcium is tightly controlled so cells can have continuous access Those with inadequate calcium intake maintain due to expense of bone density When increased need for calcium: increased absorption from intestine, more absorbed from bones, kidneys excrete less Bone less inevitable due to aging- imp. to get enough calcium when young or else increase risk of osteoporosis (adult bone loss)...peak bone mass at 30, begin lossing at about 30 unique factors that effect calcium absorption: Vitamin D levels and Fiber, phytate, and oxalate in the diet

Water Balance/ Dehydration/Water intoxication

Must consume enough water to maintain water balance 1450-2800 When blood too concentrated, hypothalmus sends nerve impulse "thirst" Pituitary glands releases hormones to kidneys to conserve water Dehydration- thirst lags behind lack of water loss of 1% body weight in fluid can produce dehydration Check symptoms on slides Water intoxication- too much water, as in many gallons in few hours Symptoms: Headache, muscle weakness, lack of concentration, poor memory Any beverage can help meet fluid needs, but water is the best choice

Vitamin A

Retinal Retinoic Acid Retinol (primary), stored in liver, converted to other active forms as needed Vision, gene expression, cell differentiation, maintenance of body linings, immune function, bone growth, reproduction, vision (process of light perception at retina, maintenance of healthy cornea how? Vision? Light falls on eye, bleaches rhodopsin, vit. a broken off. releases signal of sight, some vitamin a lost....can cause night blindness accumulation of keratin means severe deficiency. Keritinization...can lead to xerosis (drying of cornea). 10 million suffer from severe vit a deficiency..lead to xeropthalmia 275 mild. Can cause joint pain, loss of coordination, stunted growth, damage to liver, fetal damage Usually found in animal meat or fortified foods

Flavoring Agents/ Fat Replacers

Safe when used inside ADI (average daily intake) Sacharin now provides no hazzard Aspartame unsafe for those with PKU MSG- umami Olestra is an artificial fat used to make low fat snack foods Cannot be digested by body

Amino Acids

Same chemical backbone Single carbon atom, amine group, acid group Side chain attached to center carbon is differentiating factor (dictates shape and behavior) 20 amino acids total, differing in size, shape, and electrical charge Body can produce 11, meaning that 9 are essential All are needed for production of body proteins Conditionally essential amino acids are nonessential amino acids that become essential under special circumstances body can digest proteins into individual amino acids (providing raw materials for production of new proteins (preferred by body) (or metabolized for energy)

Natural Toxins in Food

Sassafras- carcinogen and liver toxin Cabbage, turnips, mustard greens contain small quantities of Goitrogens Compounds that can enlarge the thyroid gland and aggravate thyroid disorders Cyanogens are found in lima beans, cassava, and certain seeds and pits of fruits Cyanogens are precursors to the deadly poison cyanide Potatoes contain solanine, a powerful, bitter, narcotic-like substance Can build up to toxic levels when potatoes are exposed to light during storage Red Tide Toxin can contaminate seafood during various times of the year Eating contaminated foods causes paralysis

Selenium

Selenium containing enzymes support thyroxine function..works with Vit E to protect body from oxidative stress....low blood selenium associated with some forms of cancer Sever deficiency can result in muscle disorders, though rare Toxicity can occur during long term supplementation..UL of 400 micrograms/day Food sources include meats, shellfish vegetables, nuts, and grains grown on selenium-rich soil

Variety of Proteins

Shape determines task of protein Globular- water soluble (proteins of the blood) Hollow balls (transport proteins) Fibrous structure (connective tissue) Infinite number of different amino acid sequences Each type of protein has a standard amino acid sequence specified by heredity, one wrong amino acid can have severe repercussions Ex: Sickle Cell disease (one protein strand has single amino acid switch

Absorption of Protein

Single amino acids absorbed by cells lining small intestine..enzymes on cells surface break apart most tripep. and dipep into single amino acids...though some are absorbed as is and broken down inside cells of small intestine Cells of small intestine have diff. absorption sites for diff amino acids..meaning that when supplements are taken, it may limit absorption of other amino acids of same type Amino acids then released into blood stream (few larger peptide molecules can enter bloodstream intact (those that do may play a role in food allergy) Amino acids then transported to liver to either be used or rereleased into blood for use by other cells Cells can use amino acids to make proteins (or energy)

Folate

Synthesize DNA for new cells Necessary for metabolism of several amino acids Deficiency can result from diseases that impair absorption, excretion, increase needs, require meds that interact with folate Immature blood cells and cells of the GI tract divide rapidly, and are most sensitive to a folate deficiency Results in diminished immune function, abnormal digestion, anemia Associated with NTD (neural tube defects) in infants..leads to spine problems, mental retardation, death since all enriched grain fortified with folic acid, amount of NTD has dropped Dietary Folate Equivalents (DFE) convert all forms of folate into micrograms that are equivalent to the folate in food

Environmental Contaminants

The harmfulness of an environmental contaminant is directly related to how persistent it is, the extent to which it lingers in the environment or human body Some contaminants resist breakdown and pass from one species to the next, accumulating at higher concentrations in each level of the food chain, a process known as bioaccumulation Increasing levels of heavy metals (including mercury), PCBs, and other contaminants from industrial sites have been detected in lakes, rivers, and ocean fisheries Farm raised fish have lower levels of mercury than those in the wild Symptoms of methylmercury poisoning include headaches, fatigue, memory loss, muscle or joint pain, and an inability to concentrate

Fate of An Amino Acid

When amino acid reaches cell, can be used to make protein or altered to make another needed compound. Cell can metabolize amino acid and recycle amine group for production of another amino acid When not used to make protein or nitrogen containing compounds, they are "wasted" To prevent wasting and encourage synthesis, consume high quality protein w/ all amino acids in appropriate amounts, get enough CHO for energy, get adequate fat to complete CHO digestion and allow protein sparing Rec's: .8g per kg per day for health adults (10-35% total kcals) factors include: Age/life stage, Body size, Physical activity, Malnutrition, Infection, Protein Quality Infants and children need more Protein quality- influenced by digestibility of the protein and the amino acid composition

Nutrients and Gene Expression

When cell makes protein, gene for that protein has been "expressed" All cells contain DNA to make all proteins (but they won't make all of them some cells specialize in making certain ones (ex: cells in pancreas express genes for insulin Nutrients don't alter DNA structure, but can influence genetic expression

Marasmus

extreme food energy deficiency Often in infants 6-18 months in overpopulated areas Appear to be skin and bones Signs/symptoms Muscle wasting and weakness Stunted brain development Learning impairments Slowed metabolism Low body temperature Little or no subcutaneous fat Often need additional layers to remain warm Stunted overall growth Loss of skin elasticity and moisture Results in cracked skin and sores Poor wound healing Deterioration of digestive tract lining Results in malabsorption of nutrients Anemia Blood proteins are no longer produced Antibodies are degraded to provide free amino acids, leaving the child at increased risk for infection Dysentery causes diarrhea Other infections can be lethal to these already malnourished children Once infected, immune response weakens further Eventually, protein making machinery is degraded..point of no return..often lead to death Marasmus can only be reversed if caught early enough

Zinc

works with proteins in every organ, helping enzymes Make parts of the cells' genetic material, Protect cell structures against damage from oxidation, Make heme in hemoglobin, Assist the pancreas with its digestive and insulin functions, Help metabolize CHO, protein, fat Zinc containing proteins also associate with DNA... Also Affects behavior, learning, and mood Assists in proper immune functioning Is essential to wound healing, sperm production, taste perception, bone growth, normal development in children, etc. Deficiency first reported in 1960's..diets low in zinc and high in phytates Symptoms: Altered digestive function, impaired immune response...zinc therapy can help to a degree Mild deficiency leads to Impaired memory and attention span Abnormal taste Impaired immunity Abnormal vision in the dark Too much can inhibit iron and copper absorption , zinc from foods is nontoxic Found in oysters..beefsteak, yogurt