Study Packet, Chapters 6-8
Study Packet, Chapters 6-8 NTR 213-05
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This 47 page Study Guide was uploaded by Elizabeth Weathers on Monday March 28, 2016. The Study Guide belongs to NTR 213-05 at University of North Carolina - Greensboro taught by Laurie H. Allen in Winter 2016. Since its upload, it has received 21 views. For similar materials see Introductory Nutrition in Environmental Science at University of North Carolina - Greensboro.
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Date Created: 03/28/16
Chapter 6 Protein Functions Structural proteins Cells Cell Membrane Organelles Cell Fluid (cytoplasm) Body Parts Skin Hair Ligaments Tendons Enzymes Enzymes Assist biochemical reactions Most chemical reactions in the body require enzymes Transport other proteins in blood and across membranes Immunity/safety Skin—barrier from bacteria Blood clotting in case of injury Antibodies protect the body from foreign invaders i.e. vaccines stimulate these to improve immunity against disease Movement Skeletal muscles Smooth muscles Hormones Regulate fluid balance Maintain proper acidity of blood Energy The Structure of Protein: Amino Acids Amino acids are the building blocks of proteins Amino acids contain Carbon, hydrogen, acid group, amino group (nitrogen containing), and a side chain There are hundreds of proteins known, but only 20 amino acids commonly occur naturally Nine are essential The body cannot make and must come from the diet Eleven are nonessential The body can make them by using nitrogen from essential AA and pieces of CHO and fats Protein Denaturation Denaturation—alteration of a protein’s three-dimensional structure due to agitation. Proteins uncoil; after this occurs, the protein no longer functions as it naturally did before The stiffening of egg whites when they are whipped Heat Processing, cooking (hardening of an egg when it is cooked), fever Acidic and basic conditions Stomach; the curdling of milk when acid is added Acidosis and alkalosis (low/high blood pH) Heavy metals (mercury, gold, lead) Alcohol Detergents Protein Digestion & Absorption Mechanical digestion begins in the mouth when chewing breaks down the food Chemical digestion begins in the stomach Hydrochloric acid (HCl) denatures (uncoils) proteins HCl activates pepsinogen to pepsin (enzyme) Pepsin breaks peptide bonds leaving shorter polypeptides Chemical digestion continues in the small intestine Pancreatic enzymes and enzymes in the microvilli of the intestine further break down polypeptides for absorption The majority of protein digestion occurs here Single amino acids, dipeptides and tripeptides can be absorbed into the mucosal cells of the small intestine This uses different transport systems and amino acids can compete for absorption Dipeptides and tripeptides are further broken down into single amino acids Single amino acids then pass into the blood and are brought to the liver Protein Synthesis The process of protein synthesis involves two steps Transcription Translation Transcription—a stretch of DNA (in the nucleus) is used as a template to make a strand of RNA (ribonucleic acid) known as messenger RNA (mRNA) After this, the mRNA strand crosses the nuclear membrane into the cytoplasm of the cell, taking the coding instructions with it Translation—the mRNA attaches itself to one of the ribosomes (protein-making machine) mRNA specifies the sequence in which the amino acids line up for synthesis of a protein Transfer RNA (tRNA) collects amino acids from the cell fluid and brings them to the mRNA Each of the 20 amino acids has a specific tRNA Once the protein is made, tRNA is released to be recycled and used again Protein Quality High-quality, or complete dietary, proteins Contain all amino acids to meet body’s needs More easily digested Animal proteins and soy Incomplete proteins Lower in one or more essential amino acids Most plant proteins Use complementary proteins Types of Vegetarian Diets Semivegetarian: Excludes red meat but may include fish and poultry, as well as dairy products and eggs Pescetarian: Excludes all animal flesh except fish Lacto-ovo vegetarian: Excludes all animal flesh but includes eggs and dairy products Lacto vegetarian: Excludes animal flesh and eggs but includes dairy products Vegan: Excludes all food of animal origin Protein Requirements 0.8 g/kilogram of body weight for adults With more weight, more protein is needed for maintenance and repair 70 kg (154 lb) adult = 56 g of protein/day Average consumption = 70 g of protein/day Higher needs in infants, during pregnancy and lactation (breast feeding), after injury, and in for athletes Pregnant/lactating women: add 25 g of protein/day Protein in Health & Disease Kwashiorkor—pure protein deficiency Marasmus—overall energy deficiency Nitrogen Balance Nitrogen intake equals nitrogen loss Maintaining body protein and weight Negative nitrogen balance: more nitrogen lost than consumed From illness, injury, or decreased consumption Positive nitrogen balance: more nitrogen consumed than lost From growth, pregnancy, or weight training Chapter 7 Vitamins Organic: contain carbon Micronutrients: essential in small amounts Functions: promote and regulate body processes necessary for growth, reproduction, and the maintenance of health Ex: making hemoglobin, helping harvest energy, assisting with immunity, promoting bone health, helping remove pollutants (oxidants) from the body NOTE: fat soluble vitamins are more likely to be toxic vs. water soluble vitamins because the body stores them while excess water soluble vitamins are excreted Vitamins Water soluble Fat soluble B Vitamins Vitamin C Vitamin A Thiamin Pantothenic acid Vitamin D Riboflavin Vitamin B 6 Vitamin E Niacin Folate Biotin Vitamin B 12 Vitamin K NOTE: if you are looking for fresh, nutrient-dense foods, frozen vegetables may be the best. The high temps used in canning reduce nutrient content, and ‘fresh’ produce often spends about a week being transported from farm to grocery store, while frozen foods are typically frozen in the field to reduce nutrient loss Vitamin Fortification Adds nutrients to foods Government mandated and voluntary Prevents deficiencies leading to diseases but may also cause toxicity Tips for Preserving Vitamins Vitamin Bioavailability Affected by: Absorption Fat-soluble vitamins: need dietary fat Transport in blood Water-soluble vitamins: blood proteins Fat-soluble vitamins: chylomicrons Conversion of inactive provitamins or vitamin precursors into active vitamins Vitamin Absorption Coenzymes Bind enzymes to promote their activity Carriers of electrons, atoms, or chemical groups that participate in the reactions Organic non-protein molecules Ex: B vitamins NOTE: all B Vitamins are coenzymes, but not all coenzymes are B Vitamins Free Radicals & Antioxidants Reactive oxygen molecules: cause oxidative damage by stealing electrons from other compounds, causing changes in their structure and function Examples: Free radicals – generated by the body or from exposure to the environment Antioxidants: destroy reactive oxygen molecules Ex: Vitamin C, vitamin E, and selenium Meeting Vitamin Needs DRIs include RDA, AI, and UL Vitamin A and C (Iron,Calcium) amounts are required on food labels as %DV This would change with proposed new food label: Vitamin A&C could be removed, while Vitamin D could be added Water-Soluble Vitamins B vitamins: involved in converting the energy in carbohydrate, fat, and protein into ATP Vitamin C: needed to make connective tissue and as an antioxidant Choline: vitamin? (will not be on our exam) Not stored - need to be consumed regularly Excreted in urine Thiamin (Vitamin B) Coenzyme needed for glucose breakdown of glucose to provide energy Needed for metabolism of other sugars, certain amino acids and synthesis of ribose (in RNA) Important for nerve function because: Glucose is nerve cell energy source Needed for synthesis of neurotransmitters (chemical signals from neurons) RDA: men = 1.2 mg/day; women = 1.1 mg/day Sources: bran layer of whole grain, enriched grains, pork, legumes, and seeds Deficiency: Beriberi: weakness, nerve degeneration, heart changes Wernicke-Korsakoff syndrome in alcoholics: mental confusion, psychosis, memory disturbances, coma Excess: no reported effects Riboflavin Functions Forms two active coenzymes that act as electron carriers functioning in reactions needed to produce ATP from carbohydrate, fat, and protein Involved in converting folate, niacin, vitamin B and vitamin K into their active forms. 6 RDA: men = 1.3 mg/day; women = 1.1 mg/day Sources: Animal: dairy products, liver, red meat, poultry, fish Plant: whole grains, enriched grains, asparagus, broccoli, mushrooms, leafy greens Deficiency: injuries heal poorly cracking of lips and corners of mouth sensitivity to light eye burning, tearing, itching skin flaking around nose, eyebrows, earlobes Excess: no reported effects but turns urine bright fluorescent yellow Niacin Role: Coenzyme in glucose metabolism and synthesis of fatty acids and cholesterol RDA: men = 16 mg NE/day ; women = 14 mg NE/day Sources: Animal: meats, fish Plant: peanuts, whole and enriched grains, legumes, wheat bran, synthesized from the essential amino acid tryptophan Deficiency: Pellagra: fatigue, decreased appetite, indigestion, 4Ds = dermatitis, diarrhea, dementia, death Excess: no reported effects from food but supplements can be toxic causing skin flushing and rash, tingling in hands and feet, nausea, vomiting, diarrhea, high blood sugar levels, liver function abnormalities, blurred vision Vitamin B6 Important for: amino acid and protein metabolism synthesis of nonessential amino acids, neurotransmitters (myelin sheath), hemoglobin conversion of tryptophan into niacin glycogen breakdown 3 forms: pyridoxal, pyridoxine, pyridoxamine converted into active coenzyme pyridoxal phosphate needed for the activity of >100 enzymes in carbohydrate, fat, and protein metabolism RDA: men and women ages 19 to 50 = 1.3 mg/day Sources: chicken, fish, pork, organ meats, whole grains, legumes, sunflower seeds, bananas, broccoli, spinach, some fortified cereals (refined grains are not good sources) Deficiency: poor growth, skin lesions, decreased immunity, anemia, neurological symptoms Excess: no reported effects from food but supplements can be toxic causing severe nerve impairment Folate (folic acid) functions Folate coenzymes needed for DNA synthesis (especially needed in rapidly-dividing tissues) and some amino acid metabolism Important in early pregnancy for neural tube formation, which develops into the brain and spinal cord Prevent homocysteine levels from rising to prevent heart disease NOTE: synthetic folate (folic acid) is absorbed better than natural folate; excess folate can mask a Vitamin B12 deficiency RDA: men and women = 400 µg/day Sources: enriched grains, leafy greens, asparagus, legumes, nuts, oranges, liver, yeast Deficiency: neural tube defects including spina bifida and anencephaly, macrocytic or megaloblastic anemia, poor growth, nerve development and function problems, diarrhea, tongue inflammation, increased risk of heart disease and some cancers Excess: concerns that excess will prevent folate deficiency symptoms and mask B 12 deficiencies Vitamin B12 (cobalamin) functions Important for: ATP production from certain fatty acids Conversion of homocysteine to methionine Maintenance of myelin coating on nerves Amino acid and protein metabolism RDA: men and women = 2.4 µg/day Sources: found naturally only in animal products, also in fortified products Deficiency: pernicious anemia, increased homocysteine, decreased folate activation, numbness and tingling, gait abnormalities, memory loss, disorientation, paralysis, death Excess: no reported effects from intakes of up to 100 µg/day from food or supplements Folate & Vitamin B12 Needed for synthesis of neurotransmitters, hormones, bile acids, and carnitine (needed for fatty acid breakdown) Antioxidant in blood and body fluids Helps maintain the immune system Regenerates active antioxidant form of vitamin E Enhances iron absorption Vitamin C (ascorbic acid) Synthesis and maintenance of collagen, the base of all connective tissue Needed for synthesis of neurotransmitters, hormones, bile acids, and carnitine (needed for fatty acid breakdown) Antioxidant in blood and body fluids Helps maintain the immune system Regenerates active antioxidant form of vitamin E Enhances iron absorption RDA: men = 90 mg/day, women = 75 mg/day Sources: citrus fruits, strawberries, kiwis, cantaloupe, cabbage-family and dark-green vegetables, green and red peppers, okra, tomatoes, potatoes Deficiency: scurvy (gum and tooth problems, joint pain, bleeding, poor wound healing, bone fractures, fatigue, depression, hysteria) Excess: excessive vitamin C supplementation can cause diarrhea, nausea, abdominal cramps, possible increased kidney stone formation Water-soluble Vitamins B vitamins: involved in converting the energy in carbohydrate, fat, and protein into ATP Vitamin C: needed to make connective tissue and as an antioxidant Choline: vitamin? Not stored - need to be consumed regularly Excreted in urine Fat-soluble Vitamins Vitamins A, D, E, & K Found with fats in foods Require special handling for absorption, transport and excretion Excretion limitations increases the risk of toxicity Stored in the liver and fatty tissues Intakes can vary without a risk of deficiency if average intake over weeks/months meets needs Vitamin A Retinoidschemical forms of preformed vitamin A Retinol, retinal, retinoic acid Carotenoids: yellow-orange pigments synthesized by plants and many microorganisms Some are vitamin A precursors converted to retinoids Example: beta-carotene, provitamin converted into vitamin A Cell differentiation Immature cells change in structure and function to become specialized by changing gene expression (turning genes on and off) Necessary for maintenance of epithelial tissue Part of rhodopsin, a visual pigment in the eye When light strikes rhodopsin, it initiates a series of events that result in a nerve signal being sent to the brain, which allows us to see Carotenoids may function as antioxidants RDA: men = 900 µg/day, women = 700 µg/day Sources: vitamin A in animal products (eggs, dairy), provitamin A in fruits and vegetables, beta-carotene in orange, yellow, and dark green vegetables Deficiency: xerophthalmia (night blindness progressing to permanent blindness), abnormal jaw bone growth in children, increased infections Excess: nausea, vomiting, headache, dizziness, blurred vision, lack of muscle coordination, birth defects, liver damage, bone fractures; excess carotene can cause hypercarotenemia Vitamin D Made in skin with exposure to ultraviolet (UV) light Inactive until modified in liver and kidneys Essential in the diet only when exposure to sunlight is limited or the body’s ability to synthesize it is reduced Vitamin D Activation Vitamin D Functions Maintains normal levels of the minerals calcium and phosphorus in the blood Calcium is needed for bone health and functioning of nerves, muscles, glands, and other tissues Low blood calcium stimulates parathyroid hormone (PTH) release which stimulates vitamin D activation Changes gene expression Intestines: turns on genes for calcium absorption Bone: turns on genes bone breakdown RDA: adults 70 and under = 600 IU (15g)/ day Sources: not widespread in diet, liver, egg yolks, oily fish (for example, salmon), fortified foods Deficiency: low calcium absorption leading to rickets in children (pigeon breast and bowed legs) and osteomalacia, which can lead to osteoporosis in adults Excess: causes high calcium concentrations in blood and urine, deposition of calcium in soft tissues such as the blood vessels and kidneys, and cardiovascular damage Barriers to Meeting Vitamin D Needs Age Geographical Location Use of sunscreen/ cultural body coverings: block skin’s exposure to the sun Skin color: the amount of melanin in your skin can bock some UV rays Vitamin E Antioxidant Protects lipids including those in membranes of red blood cells, white blood cells, nerve cells, lung cells Defends cells against damage caused by heavy metals (lead and mercury) Reduced risk of heart disease, cancer, Alzheimer’s disease, macular degeneration, other chronic diseases Possible anti-inflammatory functions, modulation of immunity, regulation of cell growth and death genes, detoxification of harmful substances RDA: adults = 15 mg alpha-tocopherol/day Sources: seeds, nuts, plant oils, leafy-green vegetables, wheat germ, fortified cereals Deficiency: hemolytic anemia in infants; rare in adults causing poor muscle coordination, weakness, impaired vision Excess: no reported effects from food but large doses can interfere with blood clotting Vitamin K Functions Needed for: production of clotting factors synthesis of proteins involved in bone formation and breakdown Supplements Contain vitamins and minerals, herbs and other plant-derived substances, and/or body compounds not essential in the diet Help obtain adequate amounts of specific nutrients but do not provide all the benefits of foods Herbal Supplements Herb: nonwoody, seed-producing plant that dies at the end of the growing season Also refers to any botanical or plant-derived substance Ex: garlic, ginko, saw palmetto, St. John’s wort Regulation of Supplements Dietary Supplement Health and Education Act (DSHEA) of 1994 defined the term dietary supplement and created labeling standards FDA established “current Good Manufacturing Practice” (cGMP) regulations Requires manufacturers to test their products to ensure identity, purity, strength, and composition FDA pre-market review required if ingredient not sold in the US before October 15, 1994 Choosing Supplements Do not exceed 100% of Daily Values Consider why you want it Compare product costs Read the label Check the expiration date Consider your medical history Approach herbal supplements with caution Report harmful effects What Should you do? Focus on foliage for folate, vitamin A, and vitamin K B (vitamin) sure Get your antioxidants Try for 5 colors of fruits and veggies each day Soak up some D Get outside to stay fit and make some vitamin Have three servings of dairy per day boost intake Chapter 8 Water 60% of body weight 2/3 intracellular (within cells), 1/3 extracellular Cell membranes are permeable to water Water crosses the membrane by osmosis to dilute dissolved solutes Blood pressure – the amount of force exerted by blood against the walls of arteries is generated by the heart to move water through blood vessels and into tissues Water Functions Acts as a solvent: solutes (for example: glucose, proteins, minerals) dissolve in water Participates in chemical reactions Water in the Body Water Balance Water is not stored Water in must equal water out In: consumption of water, fluids, foods and production during cellular respiration Out: excretion in urine and feces, evaporation from the skin and lungs, and sweating Increased Water Loss Stimulates Thirst Kidneys Regulate Body Water • Kidneys act as a filter • Water moves from the blood into kidney tubules • Blood cells and proteins are too large and remain in the blood • Needed substances are reabsorbed back into the blood • Un-needed substances are excreted in urine Antidiuretic Hormone (ADH) Increased ADH Water Decreased Blood Sodium Secretion Reabsorption Blood Sodium If more water is lost than taken in, then the concentration of solutes in the blood increases This stimulates thirst and secretion of ADH from the brain ADH stimulates the kidneys to reabsorb water (to keep the blood from becoming more concentrated The Functions of Water Medium for & participant in metabolic reactions Helps regulate acid-base balance (PH) Transports nutrients & waste Provides protection Regulates body temp Water Helps Cool the Body Dehydration Water loss is greater than water intake Reduces blood volume which reduces blood pressure Reduces the ability of the circulatory system to deliver oxygen and nutrients to muscles Reduces blood flow to the skin and sweat production limiting the body’s ability to cool itself Causes a reduction in blood volume, impairs ability to deliver oxygen and nutrients to cells, and ability to remove waste products Symptoms: Dry mouth, decreased urination, thirst, fatigue, headache, muscle cramps Severe dehydration: increased heart rate, decreased blood pressure, increased respiration, confusion Alcohol and Dehydration Alcohol blocks the secretion of ADH Kidneys do not reabsorb water they excrete it Oral Rehydration Solutions Water Intoxication (Overhydration) Water intake is greater than water loss Sodium in blood is diluted causing hyponatremia Hypo means low, Na is the chemical symbol for sodium, emia means in thesolutes causing tissue swelling, or edema blood Water moves by osmosis from the blood into the tissues to try to dilute the higher concentration of water Hyponatremia Meeting Water Needs • AI: men = 3.7 liters/day, women = 2.7 liters/day • Need increased intake with: Increased activity Increased temperature Decreased humidity Low-calorie diet High-salt diet High-fiber diet Alcohol intake Fluid Recommendations for Exercise Generous amounts of fluid in the 24 hours before an exercise session About 2 cups of fluid 4 hours before exercise 6–12 ounces of fluid every 15–20 minutes for the duration of the exercise After exercise, each pound of weight lost should be replaced with 16–24 oz (2 to 3 cups) For exercise lasting an hour or less, water is the only fluid needed For exercise lasting more than an hour, beverages containing carbohydrate (about 10 to 20 g of carbohydrate/cup) and electrolytes (around 150 milligrams of sodium in a cup) are recommended Fruit juices and soft drinks are not recommended unless diluted with an equal volume of water Minerals 20 needed by the body in small amounts Maintain structure and regulate chemical reactions and body processes Major mineral: need >100 milligrams/day sodium, potassium, chloride, calcium, phosphorus, magnesium, and sulfur Trace mineral: need <100 milligrams/day iron, copper, zinc, selenium, iodine, chromium, fluoride, manganese, molybdenum, and others Mineral Majo Trac Electrolyte Bone Sodiu Calciu Iro Chromiu Potassiu Phosphoru Coppe Fluorid Chlorid Magnesiu Zin Manganes Sulfu Seleniu Molybdemu Minerals from Food From plant and animal sources Affected by: Amount in soil Processing: Added (for example, during fortification) or Removed (for example, by cooking or removing skins, bran, or germ) Absorption & Bioavailability • Inhibited by substances in plants, other minerals, or amount in body Mineral Functions Contribute to body structures Regulate body processes Regulate blood pressure Regulate water balance Regulate energy metabolism Affect growth and development through their role in the expression of certain genes Act as cofactors needed for enzyme activity Electrolytes Positively or negatively charged ion that conducts a current in solution Ions = charged atoms - charge: gained a negative electron + charge: lost a negative electron Fluid balance maintenance, nerve impulse conduction, cellular signaling Sodium + charge: lost a negative electron extracellular: outside of cells Potassium + charge: lost a negative electron intracellular: inside of cells Chloride – charge: gained a negative electron extracellular: outside of cells Electrolyte Imbalance Deficiency: Results in: acid–base imbalance, poor appetite, muscle cramps, confusion, apathy, constipation, irregular heartbeat, death Caused by: heavy/persistent sweating, chronic diarrhea or vomiting, kidney disorders, or medications Excess: Excess potassium from supplements can cause the heart to stop Excess sodium from dehydration/water loss: confusion, headache, and seizures Regulation of Blood Pressure Hypertension Blood pressure consistently at or above 140/90 mm mercury Caused by: increased contractions of the heart, increased blood volume, or decreased radius of blood vessels Results in: atherosclerosis, heart attacks, strokes, death Treated with: diet, exercise, and medication Risks: genetics, race, age, obesity, diet, activity Dietary Approaches for Stopping Hypertension Hypertension and Diet Electrolyte Recommendations Sodium: UL: 2300 mg/day = 1 tsp of salt Over 51 years old, African American or with medical conditions = 1500 mg/day Typical consumption = 3400 mg/day Potassium: DRI = 4700 mg/day DV = 3500 mg/day Typical consumption = 2000-3000 mg/day Sodium in Foods Bones Protein matrix: mostly collagen Hardened by minerals: mostly calcium, phosphorus, also magnesium, sodium, fluoride, other minerals Require: Protein and vitamin C to maintain collagen Calcium and other minerals to ensure solidity Vitamin D to maintain calcium and phosphorus levels Living tissue Support weight and participate in movement Constantly broken down and re-formed during bone remodeling Peak bone mass: maximum bone density attained life, usually in young adulthood Age related bone loss: bone loss that occurs in men and women as they advance in age (Amount of bone broken down starts to exceed amount that is formed) Osteoporosis Osteoporosis- bone disorder characterized by reduced bone mass and increased bone fragility Prevention Achieve a high peak bone mass Diet Weight bearing exercise No smoking Limit alcohol Treatment Supplements Ca and Vitamin D Weight bearing exercises Estrogen Biphosphonates NOTE: those with osteoporosis may be bent over because over time, the front edge of the spinal vertebrae collapses more than the back edge, so the spine bends forward; women also have a higher chance of getting Osteoporosis Calcium 99% in bones and teeth In body cells and fluids, needed for: Muscle contraction Neurotransmitter release Blood pressure regulation Cell communication Blood clotting Levels regulated by hormones: Homeostasis vital Too high: calcitonin “tones” it down Too low: PTH and calcitriol “try” to bring it up RDA: 19-50 years = 1000 mg/day; UL= 2500 mg/day Sources: dairy products, dark green vegetables, fish with bones, foods processed and fortified with calcium Deficiency: Osteoporosis Excess: caused by cancers, increased PTH, excessive calcium and/or vitamin D intake causing altered availability of iron, zinc, magnesium, phosphorus; constipation; loss of appetite, abnormal heartbeat, weight loss, fatigue, frequent urination, soft tissue calcification, kidney stones and damage Calcium Hormones Decreased blood PHT & Calcitriol Stimulates intestinal Increased Blood calcium secretion absorption, kidney Calcium reabsorption, & bone resorption Increased Blood Calcitonin secretion Inhibit bone Decreased Blood Calcium resorption Calcium Calcium Supplements Phosphorus Most found with calcium in bones and teeth In soft tissues, needed for: Phospholipid, DNA, RNA, and ATP structures Enzyme activity regulation Cellular acidity maintenance RDA: adults = 700 mg/day; UL= 4000 mg/day Sources: dairy products; meat; cereal; bran; eggs; nuts; fish; and food additives used in baked goods, cheese, processed meats, and soft drinks Deficiency: rare; due to chronic diarrhea or poor absorption due to overuse of aluminum- containing antacids; causes bone loss, weakness, loss of appetite Excess: high dietary phosphorus does not appear to be harmful for healthy adults, concern with sodas Magnesium 50-60% in bones In cells and fluids, needed for: Calcium regulation Blood pressure regulation ATP structure stabilization which is important for: Energy release from carbohydrate, fat, and protein Nerve and muscle functioning DNA, RNA, and protein synthesis RDA: men = 420 mg/day; women = 320 mg/day Sources: leafy greens, nuts, seeds, legumes, bananas, germ and bran of whole grains Deficiency: rare; causes osteoporosis, nausea, muscle weakness and cramping, irritability, mental derangement, blood pressure, heartbeat changes Excess: no effects from foods; drugs or supplements can cause nausea, vomiting, low blood pressure, and other cardiovascular changes Sulfur Part of: amino acids and proteins glutathione – needed for detoxification B vitamins thiamin and biotin Regulates acidity RDA: none Sources: part of dietary proteins and sulfur-containing vitamins, found in some food preservatives Deficiency: none known Iron Part of hemoglobin which transports oxygen to body cells and carries carbon dioxide away from them for elimination by the lungs Needed for other iron-containing proteins such as myoglobin, a muscle protein which increases oxygen available for contraction Essential for ATP production Heme iron in proteins is absorbed more than twice as efficiently as the nonheme iron in plant sources Iron Availability RDA: adults = 8 mg/day; UL = 45 mg/day Sources: red and organ meats, legumes, leafy greens, whole and enriched grains Deficiency: iron-deficiency anemia causing fatigue, weakness, headache, decreased work capacity, body temperature problems, behavior changes, increased infection, impaired development, lead poisoning Excess: intestinal lining damage, abnormal body acidity, shock, liver failure; iron overload from inherited hemochromatosis Iron Deficiency Women of childbearing age lose iron due to menstruation Pregnant women, infants, children, & teens have increased iron needs due to growth and development Diets low in meat, which contains the most readily absorbed form of iron (heme iron), & high in phytates and fiber, which reduce iron absorption, increase the risk of deficiency Intestinal parasites cause blood loss, which increases iron loss Those in poverty are less likely to consume adequate iron Iron Excess Iron can be harmful or fatal to children if taken in large doses Excess iron in vital organs, even in mild cases of iron overload, increases the risk for liver disease (cirrhosis, cancer), heart attack or heart failure, diabetes mellitus, osteoarthritis, osteoporosis, metabolic syndrome, hypothyroidism, hypogonadism, numerous symptoms and in some cases premature death Copper A copper-containing protein is needed for iron transport from intestinal cells Component of proteins and enzymes involved in: Connective tissue synthesis Lipid metabolism Heart muscle maintenance Immune and central nervous system functions RDA: adults = 900 micrograms/day; UL = 10 mg/day Sources: organ meats, seafood, nuts, seeds, whole-grain breads and cereals, chocolate Deficiency: iron-deficiency anemia, decreased collagen, high blood cholesterol, impaired growth, heart and nervous system degeneration, hair color and structure changes, increased infections, decreased antioxidants Excess: from supplements, copper containers, contaminated water, causing abdominal pain, vomiting, diarrhea Zinc Involved in the functioning enzymes involved in: Scavenging free radicals DNA and RNA synthesis Carbohydrate metabolism Acid–base balance Absorption of folate from food Storage and release of insulin Mobilization of vitamin A from liver Stabilization of cell membranes Influences hormonal regulation of cell division RDA: men = 11 mg/day; women = 8 mg/day Sources: meat, liver, eggs, dairy products, vegetables, legumes, seeds Deficiency: decreased growth, development and immunity; skin rashes; diarrhea, taste changes Excess: from supplements causing gastrointestinal irritation; vomiting; appetite loss; diarrhea, abdominal cramps; headaches; decreased immunity, HDL, copper and iron absorption Zinc & Gene Expression Selenium Incorporated into the structure of certain proteins: Glutathione peroxidase which decreases oxidative damage A protein needed to make thyroid hormones RDA: adults = 55 mg/day; UL = 400 mg/day Sources: seafood, kidney, liver, eggs, grains, nuts, seeds Deficiency: Keshan disease = heart disease in China; increased risk of cancer Iodine ¾ in the thyroid gland Component of thyroid hormones which regulate metabolic rate, growth, and development and promote protein synthesis RDA: adults = 150 mg/day; UL = 1100 mg/day Sources: seafood, iodinized salt, food contaminants and additives Deficiency: decreased thyroid hormones causing decreased metabolic rate, fatigue, weight gain; goiter (enlarged thyroid); during pregnancy causes spontaneous abortions, stillbirths, cretinism (brain damage) Excess: goiter Chromium Component of “glucose tolerance factor,” a small peptide required to maintain normal blood glucose levels RDA: ages 19–50: men = 35 micrograms/day; women = 25 micrograms/day Sources: liver, brewer’s yeast, nuts, whole grains Deficiency: rare in US Excess: little evidence Fluoride Incorporated into crystals in tooth enamel which protects against cavity-causing acids produced by bacteria In saliva, decreases bacterial acid production, inhibits dissolution of tooth enamel by acid, and increase enamel re-mineralization after acid exposure Incorporated into crystals in bone RDA: 0.05 mg/kg/day; UL = 0.1 mg/kg/day for infants and children less than 9 years old and 10 mg/day between 9 and 70 years Sources: in small amounts in almost all soil, water, plants, and animals; toothpaste; tea; marine fish with bones; fluoridated water Deficiency: tooth decay Excess: fluorosis causing black and brown stains and cracking and pitting of the teeth
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