PUBH 1517 - Trace Minerals

PUBH 1517 - Trace Minerals - Iodine Iodine Part of...

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Unformatted text preview: Iodine Iodine Part of thyroxine (regulates basal metabolism) Deficiency – Goiter if severe – Cretinism (extreme mental retardation) in child of deficient pregnant woman – Significant problem in developing nations – Iodization of salt initiated in the U.S. to prevent deficiency In Iodine deficiency, the thyroid gland enlarges--a condition known as simple goiter goiter Iodine Need & Sources Iodine RDA (2001) 150 ug for adults 220 ug for pregnant woman Sources Iodized salt (can buy with/without) Seafood (but NOT sea salt) Baked products (dough conditioners) Milk (disinfectant for milking equip) Iodine Toxicity Iodine UL is 1100 ug for adults Enlarged thyroid – Can cause airway blockage in infants U.S. intakes are high but not toxic – efforts being made to reduce added iodine Iron Iron In every living cell In body, most is component of – Hemoglobin: carries oxygen in RBCs – Myoglobin: stores/carries O2 in muscles Iron essential to the oxygen holding/releasing function of hemoglobin & myoglobin Also helps enzymes to use oxygen Needed for cell reproduction and synthesis of amino acids, hormones, neurotransmitters Iron Deficiency Iron Most common nutritional deficiency Body attempts to prevent by recycling iron & increasing absorption when stores are low Iron deficient: depleted stores Iron­deficiency anemia: stores depleted to point of causing low blood hemoglobin, resulting in poor oxygen supply to cells, limiting energy metabolism (40% world) Plasma ferritin is a sensitive indicator of iron stores, with values < 25 ug/L indicating negative balance Iron Deficiency Anemia Normal Red Blood Cells Iron Deficiency Anemia-Small pale cells Symptoms of Iron Deficiency Symptoms Can occur without anemia Impaired work capacity & productivity, low energy level Impaired brain function (attention deficit, poor learning) Irritability, apathy Sometimes pica: consumption of ice or non­food substances such as clay, paste, ashes Causes of Iron Deficiency Causes Insufficient intake and/or absorption Blood loss – Menstrual – From digestive tract bleeding (various causes, one being parasitic infections) Iron Needs & Sources Iron RDA (2001): based on 10% absorption 8 mg for men age 19 & up 18 mg for women age 19 to 50 8 mg for women over 50 Sources (iron skillet, pots add significantly) Clams, 3 oz steamed 23.8 mg Liver, beef, 3 oz fried 7.1 mg Tofu, ½ c 6.6 mg Beef, 3 oz 2.9 mg Enriched cereal, ¾ c 3.7 mg Navy Beans, ½ c cooked 2.3 mg Iron Absorption Iron Heme iron approx 23% Nonheme iron from 2% to 8%, usually Enhancing factors MFP factor (meat, fish, poultry) Vitamin C (can triple non­heme) Citric, lactic, and HCl acids Sugars (including natural sugars in wine) Impairing factors Tannins in tea, coffee (esp. black tea) Calcium & phosphorus in milk Phytates & tannins in whole grains Oxalates, EDTA Iron Overload/Toxicity Iron Difficult to excrete, although some trapped in intestinal cells & shed Hereditary defect can cause unusually high absorption rate & result in overload Free iron is powerful oxidant & can start damaging free­radical reactions One study showed double risk of heart attack with elevated ferritin, but epidemiological studies have not shown link between high iron intakes & increase in heart disease Zinc Zinc Helps more than 50 enzymes – Synthesis of genetic material & heme – Metabolism of energy nutrients – Pancreatic digestive functions – Liberation of Vitamin A from storage – Disposal of free radicals Affects behavior & learning Assists immune function Essential to wound healing, sperm production, taste perception, growth & development Needed to activate Vit A in visual pigments Zinc Deficiency Zinc First reported in 1960s in Middle East, where caused severely delayed development in adolescent males In these cases, related to diet high in whole grains & legumes, low in animal protein, and using unleavened bread (higher phytates) Zinc Deficiency 17 year old male Zinc Deficiency, cont. Zinc Other effects Impairs digestion, causing diarrhea Impairs immune response Impairs thyroid function Slows wound healing Decreases appetite Impairs taste sensitivity Reduces activity & attention span in lab animals Susceptible Groups for Zinc Deficiency in U.S. Zinc Pregnant women Young children Elderly Observation of poor growth and poor appetite in children should prompt consideration of zinc deficiency. Average daily intake fell short of previous RDA by about 2 mg, but RDA has been revised downward. Zinc Needs & Sources Zinc RDA (2001) 8 mg for females ages 19 & up 11 mg for males ages 14 & up Sources Oysters, 3 oz steamed 28 mg Crabmeat, 3 oz steamed 6.5 mg Beef, 3 oz 5.6 mg Soybeans, ½ c dry roasted 4.0 mg Enriched cereal, ¾ c 3.1 mg Yogurt, 1 c plain 2.2 mg Excess Zinc (adult UL = 40 mg) Excess Blocks copper absorption, lowering body copper, which leads to degeneration of heart muscle in lab animals May reduce HDL. Appears to accelerate development of atherosclerosis Can inhibit iron absorption due to competition for protein carrier Can cause serious illness & death in very high doses Possible toxicity symptoms: vomiting, diarrhea, headaches, exhaustion Benefits of Supplemental Zinc Benefits Used in treatment of infections in developing countries. Reduces incidence of disease & death associated with diarrhea Effectiveness in treating common cold inconclusive. Appears to depend on form. Zinc gluconate shortens duration of symptoms. Copper Copper Vital role in forming hemoglobin & collagen Many enzymes need copper Assists in reactions leading to energy release Helps regulate activity of some genes Essential for one of enzymes that controls free­radical damage Copper Needs, Sources, Deficiency Copper RDA 900 ug for adults Best sources: Organ meats, seafood, nuts, seeds Deficiency: rare but not unknown Severely disturbs growth & metabolism May impair immunity May impair blood flow Selenium Selenium Plays role in activating thyroid hormone Assists group of enzymes that, along with Vitamin E, works to prevent formation of free radicals Possible role in protection against some forms of cancer being studied RDA: 55 ug for adults Selenium, cont. Selenium, Deficiency can lead to specific heart disease, first identified in China in areas with selenium­deficient soil Foods grown on U.S. & Canadian soils have adequate selenium Widely distributed in foods, & esp. rich in meats Toxicity symptoms: hair loss, diarrhea, nerve abnormalities UL: 400 ug Chromium Chromium Deficiency results in impaired insulin action, causing a diabetes­like condition that resolves with chromium supplementation Found in complexes with other compounds in foods. Described by terms “biologically active chromium” or “glucose tolerance factor” Chromium Needs & Sources Chromium Adequate Intake 25 ug for women, 35 ug for men Decreases by 5 ug over age 50. Best sources: liver, whole grains, nuts, cheeses Fluoride Fluoride Not essential to life, buy AI of 3­4 mg UL: 10 mg Can replace hydroxy portion of hydroxyapatite, making teeth more resistant to decay as well as larger & more perfectly formed Similar effect in bone Can cause discoloration of teeth if water contains more than 2 parts per million – called fluorosis – irreversible –occurs only during tooth development Fluordidation of Water in the U. S. Fluorosis Fluoride, cont. Fluoride, Incidence of tooth decay is very high without fluoride Fluoridation of water supply raises concentration to 1 part per million Fluoridation of water is endorsed by the National Institute of Dental Health, American Dietetic Association, American Medical Association, National Cancer Institute, & National Nutrition Consortium Other Essential Trace Minerals Other Molybdenum Part of several metal­containing enzymes RDA: 45 ug for adults Manganese Works with dozens of enzymes AI: – 2.3 mg for men – 1.8 mg for women Minerals Recognized Minerals as Important to Health Boron Boron Related to calcium metabolism Sources: non­citrus fruits, leafy vegetables, nuts, legumes Cobalt Part of vitamin B12 Nickel Deficiencies harm liver & other organs Possibly Essential Trace Minerals Possibly Barium Cadmium Lead Lithium Mercury Silicon Silver Tin, Vanadium, maybe Arsenic General Characteristics of Trace Minerals of Much more to learn Toxic in excess Interaction with each other – Ex: Iron deficiency makes body more susceptible to lead poisoning Factors that enhance absorption of one may decrease absorption of another – Ex: Vitamin C enhances iron absorption but decreases copper absorption Note: Organically grown foods may contain more trace minerals ...
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This note was uploaded on 11/21/2011 for the course PUBH 1517 taught by Professor Paula.goldberg during the Winter '11 term at Life Chiropractic College West.

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