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Trace minerals
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- 2. The Trace Minerals •Needed in much smaller amounts • Are essential • Difficult to study due to the trace amounts needed by the body • Food content dependent on soil content • Animal sources of mineral are generally better absorbed.
- 3. Trace Minerals Iron Zinc IodineSelenium Fluoride Copper Manganese Chromium Molybdenum Arsenic Nickel Silicon Boron Cobalt
- 4. Iron • Ferrous (Fe++ ) –Reduced • Ferric (Fe+++ ) – Oxidized • Chief functions in the body – Part of the protein hemoglobin, which carries oxygen in the blood – Part of the protein myoglobin in muscles, which makes oxygen available for muscle contraction – Necessary for the utilization of energy as part of the cells’ metabolic machinery Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 5. Iron • Found inminute amount in every cell • 15% is absorbed • Heme iron Vs. Nonheme iron –40% of iron in animal flesh is heme iron –Heme iron is better absorbed than nonheme • Vitamin C enhances absorption
- 6. Iron Absorption Copyright 2005Wadsworth Group, a division of Thomson Learning
- 7. Some iron delivered to myoglobinof muscle cells Some losses if bleeding occurs Iron-containing hemoglobin in red blood cells carries oxygen. Transferrin carries iron in blood. Fig. 13-3, p. 445 Some losses via sweat, skin, and urine Stepped Art Bone marrow incorporates iron into hemoglobin of red blood cells and stores excess iron in ferritin (and hemosiderin). Liver (and spleen) dismantles red blood cells, packages iron into transferrin, and stores excess iron in ferritin (and hemosiderin).
- 8. Iron Sources – twoforms of iron in food 1. Heme iron – meats, poultry, fish; readily absorbed 2. Nonheme iron – plants foods; less absorbed a. Absorption enhanced by Vitamin C b. Absorption diminished by phytates, oxalates, and tannic acid
- 9. Iron: Heme vs.Nonheme Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 10. Functions of Iron •Hemoglobin in red blood cells – Transports oxygen and carbon dioxide – High turnover, high demand for iron • Myoglobin in muscle cells – Binds oxygen • Electron transport chain • Enzyme cofactor • Immune function • Drug-detoxification pathway
- 11. Iron • 2001 RDA –Men: 8 mg/day – Women (19-50 years): 18 mg/day – Women (51+ years): 8 mg/day • Upper level for adults: 45 mg/day • Significant sources – Red meats, fish, poultry, shellfish, eggs – Legumes, dried fruits Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 13. Iron • Iron deficiencyis the most common nutrient deficiency worldwide • Can occur if inadequate intake or blood loss • Females are prone due to menstruation, lower iron intake & pregnancy • Preschoolers also at risk due to high milk diets Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 14. Iron • Deficiency symptoms –Microcytic, hypochromic anemia (low Hgb & Hct): weakness, fatigue, headaches – Impaired work performance and cognitive function – Impaired immunity – Pale skin, nailbeds, mucous membranes, and palm creases – Concave nails – Inability to regulate body temperature – Pica (craving for ice, clay, paste, and other non-food substances) Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 15. • Both sizeand color are normal in these blood cells • Blood cells in iron- deficiency anemia are small and pale because they contain less hemoglobin
- 16. Iron • Toxicity –“iron overload”; more common in men -Hemochromatosis – genetic defect -Hemosiderosis – chronic ingestion of too much iron; more common in alcoholics -Iron poisoning – acute toxicity from overdose of iron supplements; can be deadly in small children • Toxicity symptoms – GI distress – Iron overload: infections, fatigue, joint pain, skin pigmentation, organ damage Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 17. Zinc • Essential nutrient •Better absorption from animal source • Deficiencies cause growth retardation and poor sexual development
- 18. Zinc Chief functions inthe body – Part of many enzymes, esp. enzymes for transfer of carbon dioxide – Associated with the hormone insulin – Involved in making genetic material and proteins – Important to wound healing, taste perception, reproduction (the making of sperm), vision (transports and activates Vit. A) & immune function Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 19. Zinc • 2001 RDA –Men: 11 mg/day – Women: 8 mg/day • Upper level for adults: 40 mg/day • Significant sources – Protein-containing foods – Red meats, shellfish – Whole grains Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 21. If the body needszinc If the body does not need zinc Mucosal cells in the intestine store excess zinc in metallothionein. Zinc is not absorbed and is excreted in shed intestinal cells instead. Thus, zinc absorption is reduced when the body does not need zinc. Metallothionein releases zinc to albumin and transferrin for transport to the rest of the body. Zinc in food The pancreas uses zinc to make digestive enzymes and secretes them into the intestine. Fig. 13-6, p. 453 Stepped Art
- 22. Zinc • Deficiency symptoms –In children, growth retardation and delayed sexual maturation – Impaired immune function – Hair loss – Eye and skin lesions – Loss of appetite and abnormal taste – Depressed immune function and poor wound healing - Night blindness
- 23. Zinc • Zinc Absorptionand Metabolism – Zinc Transport • Transported by the protein albumin • Binds to transferrin • Excessive iron and copper can lead to a zinc deficiency and excessive zinc can lead to an iron and copper deficiency.
- 25. Zinc • Toxicity –not likely, unless supplement abuse • Toxicity symptoms –Loss of appetite, impaired immunity, low HDL, copper and iron deficiencies Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 26. Selenium • Readily absorbed •Excreted through the urine and feces • Co-factor for glutathione peroxidase • Protects the heart and other cells from oxidative damage • Works together with vitamin E • Cancer prevention
- 27. Deficiency of Selenium •Muscle pain • Muscle wasting • Cardiomyopathy
- 28. Food Sources ofSelenium • Fish, meat (organ meat), egg, milk, shell fish • Grains, seeds, nuts dependent on soil content • RDA for adults is 55 ug/day • Average intake exceeds RDA
- 29. Toxicity of Selenium •Upper Level is 400 ug/day • Garlicky breath • Hair loss • Nausea, vomiting • Weakness • Rashes • Cirrhosis of the liver
- 30. Iodine • Found inan ion form, iodide • Used for thyroid hormone synthesis • Regulates metabolic rate, growth, development • Thyroid gland enlarges (goiter) with low intake of iodide • Cretinism is the stunting of fetal growth and mental development as a result of low iodine diet
- 31. Iodine • Chief functionsin the body – A component of two thyroid hormones that help to regulate growth, development, and metabolic rate • 2001 RDA for adults: 150 µg/day • Upper level: 1100 µg/day
- 32. Iodine • Significant sources –Iodizedsalt, seafood, bread, dairy products, plants grown in iodine- rich soil and animals fed those plants (content of iodine in soils affects food content) Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 33. Iodine • Deficiency disease -Simplegoiter-enlarged thyroid; affects 200 million people worldwide -Creatinism- severe mental and physical retardation in infants • Deficiency symptoms – Underactive thyroid gland, goiter • Toxicity symptoms – Underactive thyroid gland, elevated TSH, goiter (also causes enlarged thyroid gland) Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 35. Food Sources ofIodine • Iodized salt (1/2 tsp. meets RDA for iodine) • Saltwater fish, seafood, dairy, grains • Sea salt is a poor source (loss during processing) • Plant source dependent on soil content • RDA for adult is 150 ug/day (50ug to prevent goiter) • Average intake exceeds RDA
- 36. Toxicity of Iodine •Thyroid hormone synthesis is inhibited • “Toxic goiter” results • Consumption of seaweed • Upper Level is 1.1 mg/day
- 37. Copper • Aids iniron metabolism • Absorption dependent on body’s needs • Absorption decreased with high intakes of vitamin C, phytic acid, fiber, zinc, iron, certain amino acids
- 38. Functions of Copper •Increases iron absorption • Formation of connective tissue • In superoxide dismutase • Immune system, blood clot, brain development, cholesterol metabolism
- 39. Deficiency of Copper •Anemia • Decrease WBC • Bone loss • Inadequate growth • Pre-term infants at risk • Cardiovascular disease
- 40. Food Sources ofCopper • Organ meats • Seafood • Cocoa • Mushroom, legumes, seeds, nuts, whole-grain • RDA is 900 ug/day for adults • Daily Value is set at 2000 ug • Average intake is about or slightly below the RDA
- 41. Fluoride • Role inprevention of cavities • Resists acid and dental caries • Fluoride inhibits bacterial growth that may cause cavities • Fluoridated water (1ppm)
- 42. “Food” Sources ofFluoride • Fluoridate water (~0.2 mg/cup) • Tea • Seafood, seaweed • Toothpaste • Adequate intake is 3.1 -3.8 mg/day for adults • Typical fluoridated water contains 0.2 mg/cup
- 43. Toxicity of Fluoride •Fluorosis • Mottling of the teeth in children • Limit toothpaste to pea size for children • In high amounts can weaken teeth in children • Upper Level is 10 mg/day
- 45. U.S. Population With Fluoridated Water Copyright 2005 WadsworthGroup, a division of Thomson Learning
- 46. Manganese • Chief functionsin the body – Cofactor for several enzymes – Component of bones and glands • 2001 AI – Men: 2.3 mg/day – Women: 1.8 mg/day • Upper level for adults: 11 mg/day Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 47. Manganese • Significant sources –Nuts, whole grains, leafy vegetables, tea • Deficiency symptoms – Rare; requirements are low • Toxicity symptoms – Nervous system disorders – Has occurred in miners inhaling large quantities of dust causes brain damage Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 48. Molybdenum • High intakewill inhibit copper absorption • Required by several enzymes • Deficiency rare – Increased heart and respiration rates – Night blindness, mental confusion – Edema, weakness, coma • RDA is 45 ug/day • Average intake is 75-110 ug/day • Toxicity seen in animals • Upper Level is 2 mg/day
- 49. Chromium • Chief functionsin the body – Enhances insulin action – CHO & lipid metabolism • 2001 AI -Men: 35 µg/day – Women: 25 µg/day • Significant sources – Meats (especially liver) – Whole grains, brewer’s yeast Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 50. Chromium • Deficiency symptoms –Diabetes-like condition; mimics symptoms of diabetes, especially in elderly • Toxicity symptoms – None reported Copyright 2005 Wadsworth Group, a division of Thomson Learning
- 51. Other Trace Minerals •Nickel is a cofactor for certain enzymes. • Silicon is used in bone and collagen formation. • Vanadium is for growth, development, and normal reproduction. • Cobalt is a key component of vitamin B12. • Boron may be key in brain activities. • Arsenic is useful in some types of leukemia.
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- 53. Contaminant Minerals • Contaminateminerals are also called heavy metals. • These include mercury, lead, and cadmium. • These minerals enter the food supply through soil, water, and air pollution. • They disrupt body processes and impair nutrition status.
- 54. Contaminant Minerals • Leadtoxicity symptoms in children – Learning disabilities in children – Low IQ – Behavior problems – Slow growth – Dental caries – Iron-deficiency anemia – Sleep disturbances like night walking, restlessness, and head banging – Nervous system disorders and seizures – Slow reaction time and poor coordination – Impaired hearing
Editor's Notes
- #8 Figure 13.3: Animated! Iron Recycled in the Body. Once iron enters the body, most of it is recycled. Some is lost with body tissues and must be replaced by eating iron-containing food.
- #22 Figure 13.6: Animated! Enteropancreatic Circulation of Zinc. Some zinc from food is absorbed by the small intestine and sent to the pancreas to be incorporated into digestive enzymes that return to the small intestine. This cycle is called the enteropancreatic circulation of zinc.