Download BIOL103 Ch 8 Water and Minerals Students SP16

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Water: Crucial to Life Water and Minerals: The Ocean Within BIOL 103, Chapter 8 SP 2016 •  Water is the most essenEal nutrient –  45–75% body weight –  Body water • 2/3 Intracellular • 1/3 Extracellular Water: Crucial to Life •  Electrolytes and water –  When minerals or salts dissolve in water à form ions: • CaEons • Anions –  Osmosis 1
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Intake RecommendaEons •  How much water is enough? –  Men = 3.7 liters/day AI –  Women = 2.7 liters/day AI –  Pregnancy = 3.0 liters/day AI –  LactaEon = 3.8 liters/day –  Increased needs for acEvity and sweaEng Intake RecommendaEons •  Sources –  75-­‐80% from Beverages –  20-­‐25% from Foods –  Small amount from metabolic reacEons (250-­‐350mL/day) Water ExcreEon: Where Does the Water Go? 1.  Insensible water losses: the conEnuous loss of body water by evaporaEon from the lungs and diffusion through skin. –  ¼-­‐ ½ of daily fluid loss 2.  Urine (~1-­‐2 liters per day) 3.  Illness 4.  External factors that contribute to water losses: –  Low humidity –  High alEtude –  High protein/salt foods 2
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Intake RecommendaEons •  Water Balance –  Bodies carefully maintain water balance 1.  Hormonal effects • An1diure1c hormone (ADH) • Aldosterone 2.  Thirst 3.  Alcohol, caffeine, and common medicaEons affect fluid balance Water Balance •  Alcohol, caffeine, and common medicaEons are usually diure1cs –  Alcohol and caffeine are able to inhibit the release of ADH (by the pituitary gland) –  Too much alcohol/
caffeine can lead to dehydraEon Water Balance – How do kidneys know how to conserve water? 1.  Spinal cells in brain sense rising sodium levels in the body à signals pituitary gland to release ADH à signals kidneys to conserve water à water reabsorpEon dilutes sodium levels 2.  Sensors in the kidneys detect a drop in blood pressure à adrenal glands release aldosterone à kidneys retain sodium à water follows sodium à water reabsorpEon Intake RecommendaEons •  DehydraEon –  Early signs: FaEgue, headache, and dark urine with strong odor –  Water loss of 20% can cause coma and death –  Seniors and infants especially vulnerable –  Treatment: water consumpEon (with electrolytes) or IV (moderate to severe cases) 3
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Water IntoxicaEon Understanding Minerals •  Water intoxicaEon: –  Can occur in people who drink too much water –  Over-­‐hydraEon can also occur in people with untreated glandular disorders that cause excessive water retenEon –  Deionized water (without minerals/
electrolytes) –  Causes low blood sodium à headaches à seizures à coma à death •  Minerals –  Inorganic –  Not destroyed by heat, light, acidity, alkalinity –  Micronutrients (needed in small amounts) –  Grouped as: 1.  Major minerals (>100 mg/day) 2.  Trace minerals (<100 mg/day) Minerals in Foods •  Found in plant (soil) and animal (diet) foods •  Found in drinking water: sodium, magnesium, fluoride •  Mineral absorpEon limited by several factors: 1.  GI tract 2.  CompeEng minerals (ex. megadose) 3.  High-­‐fiber diet contain phytates (iron, zinc, manganese, calcium) 4.  Oxalate (calcium) 4
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Major Minerals and Health •  Mineral status significantly affects health •  Play criEcal parts in hypertension and osteoporosis Sodium •  FuncEons: 1.  Fluid balance, blood pressure, and pH 2.  Nerve impulse transmission •  Food sources –  Processed and convenience foods –  Added (table) salt Sodium •  Dietary RecommendaEons –  Daily intake less than 2,400 mg/day –  Daily intake less than 1,500 mg/day desirable •  Dealing with Excess Sodium –  Can contribute to hypertension –  Can worsen dehydraEon Potassium •  FuncEons: 1.  Muscle contracEon 2.  Nerve impulse transmission 3.  Regulates blood pressure and heartbeat •  Food sources: –  People who eat low-­‐sodium, high potassium diets omen have lower blood pressure –  Vegetables and fruits such as potatoes, spinach, melons, bananas –  Meat, poultry, fish, dairy products 5
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Potassium •  Dietary RecommendaEons –  AI: 4,700 mg/day •  Deficiency –  Likely factor in hypertension risk –  Can disrupt acid-­‐base balance •  Toxicity –  Rare –  High levels can slow heart Calcium •  FuncEons –  Bone structure • Hydroxyapa1te • Bone cells – Osteoblasts – Osteoclasts • Reserve of calcium and phosphorus Chloride •  FuncEons: 1.  Fluid balance (blood, sweat, tears) 2.  Hydrochloric Acid (stomach acid) •  Food sources: –  Table salt (NaCl – sodium chloride) •  Deficiency: –  Excessive vomiEng (ex. Bulimia nervosa) Calcium •  FuncEons –  Muscles and metabolism • Flow of calcium causes muscles to contract or relax –  Other funcEons • Blood clonng • Nerve impulse transmission 6
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Calcium Calcium •  RegulaEon of blood calcium levels –  Calcitriol/Vitamin D –  Parathyroid hormone –  Calcitonin •  Dietary RecommendaEons –  RDA: 1,300 mg/day (children 9-­‐18) –  RDA: 1,000 mg/day (men 19-­‐70; women 19-­‐50) –  RDA: 1,200 mg/day (men 70+; women 51+) •  RegulaEon of blood calcium levels by three hormones: –  To prevent dips in blood calcium levels, your body will demineralize bone –  If low blood calcium levels à calcitriol increases intesEnal absorpEon of calcium, and parathyroid hormone (PTH) acEvates osteoclasts to release bone calcium –  If high blood calcium levels à thyroid glands release calcitonin to reduce blood calcium RegulaEon of Blood Calcium Calcium •  Food Sources –  Dairy products, green vegetables, processed and forEfied foods –  Oxalate—binds calcium –  Calcium supplementaEon will not interfere with absorpEon of other minerals, but can interfere with absorpEon of some medicaEons 7
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Phosphorus •  FuncEons –  Bone structure –  Component of ATP, DNA, RNA, and phospholipids •  Food sources –  Milk, eggs, beans, lenEls –  Processed foods •  Phosphate balance –  Too much phosphorus and too lisle calcium = increased bone loss Magnesium •  FuncEon –  ParEcipates in more than 300 types of enzyme-­‐driven reacEons •  Food sources –  Whole grains, vegetables, legumes, tofu, seafood, and chocolate Magnesium Sulfur •  FuncEon: –  ParEcipates in more than 300 types of enzyme-­‐driven reacEons, including energy metabolism, blood clonng, muscle contracEon, DNA and protein synthesis •  Food sources: –  Whole grains, vegetables, legumes, tofu, seafood, and chocolate •  Magnesium balance –  We absorb ~50% of dietary magnesium –  At risk for deficiency: chronic diarrhea, poor diet, and heavy alcohol use. •  FuncEon: –  Primarily a component of organic nutrient, including other vitamins/amino acids –  Help proteins maintain their funcEonal shapes •  Food sources: –  Typical diets contain ample sulfur •  Deficiency: –  Unknown 8
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Trace Minerals •  Trace Minerals: –  Iron, Zinc, Selenium, Iodine, Copper, Manganese, Fluoride, Chromium, Molybdenum •  Cofactors for enzymes •  Components of hormones •  ParEcipate in many chemical reacEon •  EssenEal for: –  Growth –  Immune System Iron Iron and Hemoglobin •  FuncEons –  Oxygen transport as part of hemoglobin and myoglobin –  Cofactor for enzymes involved in energy producEon, immune funcEon, and normal brain/nervous system funcEon 9
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Nerve Cells Iron •  Iron AbsorpEon –  Effect of Iron Status • AbsorpEon varies –  Effect of GI FuncEon • Depends on stomach acid/HCl –  Effect of the Amount and Form of Iron in Food • Conserve iron – Heme iron (animal) – Non-­‐heme iron (plant/animal) Iron Iron •  Iron absorpEon –  Dietary Factors Enhancing Iron AbsorpEon • Vitamin C –  Dietary Factors InhibiEng Iron AbsorpEon • Phytate & oxalates bind to non-­‐heme iron • Calcium, zinc, and iron compete for absorpEon •  Iron Transport and Storage –  Transferrin ferries iron through blood –  Most iron stored as ferri1n in body –  Smaller amounts stored as hemosiderin 10
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Iron •  Iron Turnover and Losses Iron –  RouEne destrucEon of old red blood cells releases iron à recycled to build new red blood cells –  Dietary iron especially important in Emes of rapid growth and blood expansion (infant à young children) –  Lose iron in feces, sweat, skin cells, and menstruaEon –  DigesEve disorders/blood loss increase iron losses •  Food sources: –  Red meat, oyster, legumes, tofu, whole grains •  Deficiency: –  Most common deficiency worldwide –  Iron-­‐deficiency anemia •  Toxicity: –  Adult doses can cause poisoning in children –  Hereditary hemochromatosis – a geneEc disorder in which excessive absorpEon of iron results in abnormal iron deposits in the liver and other Essues. Zinc Zinc •  FuncEons –  Serves as cofactor for major enzymes –  Helps fold proteins into funcEonal shapes –  Helps control diverse funcEons, including gene expression, cell death, and nerve transmission •  Enzymes –  Helps provide structural integrity or acEvate catalyEc ability •  Gene regulaEon –  Enables proteins to fold into a special form that interacts with DNA •  Immune system –  Vital to fighEng infecEon 11
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Zinc •  RegulaEon of Zinc in the Body –  AbsorpEon • Similar to iron • Only about 10-­‐35% of zinc absorbed • Phytate inhibits absorpEon –  Transport, distribuEon, and excreEon • Circulates bound to protein Zinc •  Deficiency –  Uncommon but may occur in people with illnesses that impair absorpEon • Poor growth and delayed development – Zinc deficiency lowers immunity; infecEon causes zinc loss RegulaEon of Zinc in the Body •  AbsorpEon: –  ~10-­‐35% of zinc in diet –  Depends on body’s needs, zinc content of the meal, and presence of compeEng minerals –  Phytate and supplemental calcium inhibit absorpEon •  Transport, distribuEon, and excreEon: –  Zinc circulates in the bloodstream bound to protein, traveling to the liver and Essues. •  Food sources: –  Red meats, seafood Iodine •  FuncEon: Thyroid hormone producEon –  Thyroid hormone helps regulate body temperature, basal metabolic rate, reproducEon, and growth •  Food sources: –  Iodized salt, saltwater fish, seafood, seaweed •  Toxicity –  Usually rare –  Chronic doses may induce copper deficiency 12
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Iodine Iodine and Thyroid Gland •  Deficiency: –  Goiter: enlarged thyroid gland –  Cre1nism: mental retardaEon, stunted growth, deafness, muteness • Occurs in fetus if pregnant woman is deficient •  Toxicity: –  Goiter Selenium •  FuncEons: 1.  Part of anEoxidant enzyme 2.  Thyroid metabolism: convert thyroid hormone to its most acEve form •  AbsorpEon: –  Enhance absorpEon: Vitamins A, C, E –  Inhibits absorpEon: Phytates 13
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Selenium •  Food sources –  Organ meats, fish, seafood, meats, Brazil nuts •  Deficiency –  Increases suscepEbility to some infecEons –  Can worsen hypothyroidism •  Toxicity –  Brisle hair and nails Copper •  Food Sources –  Organ meats, shellfish, nuts, and legumes •  Deficiency –  Causes anemia and poor immune funcEon •  Toxicity –  RelaEvely nontoxic Copper •  FuncEons –  Melanin, collagen, and elasEn producEon –  Immune funcEon –  AnEoxidant enzyme –  Works with ceruloplasmin, a copper-­‐
dependent enzyme required for iron transport •  AbsorpEon and Storage –  Varies from 20% to 50% –  Interferes with absorpEon: Iron, Zinc Manganese •  FuncEons –  CarElage producEon –  AnEoxidant enzyme systems/MnSOD •  Food Sources –  Tea, nuts, cereals 14
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Manganese •  Deficiency – High calcium, magnesium, iron diets can interfere with manganese absorpEon •  Toxicity –  Incidents due to air pollutants • Symptoms: hallucinaEons, memory/
motor coordinaEon. Fluoride •  FuncEons –  Bone and tooth structure •  Food sources –  Fluoridated water •  Balance –  Excess can cause fluorosis: discoloraEon and “specks” on teeth; weakens teeth. •  The fluoridaEon debate Chromium Molybdenum •  FuncEons: –  Glucose metabolism • Enhances insulin’s ability to move glucose into cells. •  Food sources: –  Mushrooms, dark chocolate, nuts, whole grains •  Deficiency and toxicity: –  Difficult to determine deficiency –  No UL •  FuncEons: –  Enzyme cofactor (e.g. ADH) •  Food sources –  Peas, beans, organ meats, some breakfast cereals •  AbsorpEon: –  Inhibit: Copper •  Deficiency/Toxicity: –  Deficiency: Rare –  Toxicity: Unlikely 15
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Other Trace Minerals and Ultratrace Minerals •  Arsenic •  Boron •  Nickel •  Silicon •  Vanadium 16