NUTR 300 11/18/09 Nutrition for Today Nutrition and blood health Objectives for today: Define hematopoiesis, erythropoiesis Name the micronutrients required for proper erythropoiesis Describe the absorptive process for vitamin B12 Explain why iron overload is problematic Describe the deficiency signs associated with iron, folate, and vitamin B12 Name the biologic process that requires vitamin K Explain how vitamin A status affects immunocompetence Hematopoiesis Erythropoiesis Functions Transport of oxygen and nutrients to cells Removal of waste products from tissues Nutritional Anemias Microcytic - Iron, Macrocytic - Folate, vitamin B12 Coagulation Vitamin K Immune cell production Vitamin A Nutritional Anemias (iron, folate, vitamin B12) Iron Food sources Meats - Heme iron Plant sources - Non-heme iron Enriched grains Iron skillet Absorption, Transport, Storage, and Excretion Specific carrier proteins into enterocyte Factors that promote absorption Factors that impair absorption Specific transport protein in blood Iron storage protein Excretion?? Functions Component of hemoglobin Component of myoglobin Coenzyme involved in energy metabolism of carbohydrates, fats, and proteins Too little iron? Iron deficiency anemia Reduction in the production of red blood cells and oxygen carrying capacity microcytic (small), hypochromic (pale) Fatigue, pale skin, impaired work performance, brittle nails, impaired memory, difficulty breathing, poor growth, depressed immune function Too much iron? WHY? - Repeated blood transfusions Hemochromatosis (Genetic disease - Overabsorb iron) Consequences of toxicity Stomach irritation, nausea, vomiting, diarrhea, dizziness, confusion Can cause severe damage to the heart, central nervous system, liver, kidneys Accidental iron overdose is the most common cause of poisoning deaths in children Nutritional Anemias ? Macrocytic anemia (folate, vitamin B12) Folate Functions DNA synthesis, amino acid metabolism Critical for cell division of very early embryos Functions with vitamin B12 (B12 regenerates folate) Food sources Liver, enriched breads, flours, pasta, grain products, fortified breakfast cereals, grains, beans, vegetables (foliage) Too little folate? Macrocytic anemia Weakness, fatigue, difficulty concentrating, irritability, headache, shortness of breath Neural tube defects Too much folate? Vitamin B12 Food sources - Animal products Absorption, Transport, Storage, and Excretion Stomach acid important R proteins chaperone B12 into small intestine Intrinsic factor (made in stomach) ? binds B12 in small intestine B12-IF complex interacts with receptor in ileum Transported bound to transcobalamin II Functions Coenzyme for DNA synthesis - Recycles folate Maintains myelin sheath of nerve fibers Energy production Too little B12? Caused primarily by absorption impairment rather than dietary deficiency Nerve degeneration and anemia Pernicious anemia - Results from autoimmune attack on intrinsic factor producing cells Macrocytic anemia (looks like folate deficiency) Cognitive dysfunction - Memory loss, disorientation, delirium, dementia Too much B12? Vitamin K Functions Coagulation Food sources leafy green vegetables, vegetable oils (soybean, cottonseed, canola, olive) Absorption and Transport Lipid soluble vitamin ? absorbed like lipids Requires bile and pancreatic enzymes Incorporated into chylomicrons and delivered to liver via lymphatic system Lipoproteins for transport Too little K? Blood fails to clot, bleeding, hemorrhaging Causes - Fat malabsorption reduces vitamin K absorbed Long term antibiotic use Newborns lack intestinal bacteria Too much K? Immunity Vitamin A Food sources Pre-formed Retinoids (retinal, retinol, retinoic acid) Found in animal products ? milk, eggs, fish, liver Pro-vitamin A Carotenoids (?-carotene) Found in plant products ? colorful fruits and vegetables Absorption, Transport, and Storage Lipid soluble vitamin ? absorbed like lipids Transported via chylomicrons from intestinal cells to the liver Liver stores 90% of vitamin A in the body Adequate for several months Transported from the liver to target tissue as retinol via retinol-binding protein (RBP) Functions Immune system competence Maintenance of epithelial tissue Skin, mucosal linings ? digestive & respiratory tracts Regulation of growth and differentiation of cells Immune cells Vision Too little A? Night blindness Increased susceptibility to infection A nutritionally acquired immunodeficiency disease Too much A? Vocabulary: Hematopoiesis Erythropoiesis Heme iron Non-heme iron Transferrin Ferritin Microcytic anemia Hypochromic Hemochromatosis Macrocytic anemia Neural tube defect R protein Intrinsic factor Transcobalamin II Pernicious anemia Coagulation Retinoids Retinol Retinal Retinoic acid Retinyl esters ?-carotene Pre-formed vitamin A Pro-vitamin A Retinol binding protien E. Kirk PhD, RD PAGE 8
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