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The Trace Minerals
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
The Trace Minerals
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Trace Minerals
Iron ZincIodine SeleniumFluoride CopperManganese ChromiumMolybdenum ArsenicNickel SiliconBoron Cobalt
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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Iron Absorption
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
IronSources – two forms 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
Iron: Heme vs. Nonheme
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Iron• Iron deficiency is 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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
• Both size and color are normal in these blood cells
• Blood cells in iron-deficiency anemia are small and pale because they contain less hemoglobin
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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
ZincChief functions in the 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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
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
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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Iodine
• Chief functions in the body– A component of two thyroid hormones
that help to regulate growth, development, and metabolic rate
• 2001 RDA for adults: 150 g/day• Upper level: 1100 g/day
Iodine• Significant sources
– Iodized salt, 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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Iodine• Deficiency disease
-Simple goiter-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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Selenium
• Chief functions in the body– Defends against oxidation– Regulates thyroid hormone
• 2000 RDA for adults: 55 g/day• Upper level for adults: 400 g/day• Significant sources
– Seafood, meat– Whole grains, vegetables (depending
on soil content)
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Selenium• Deficiency symptoms
– Predisposition to heart disease (cardiomyopathy) characterized by cardiac tissue becoming fibrous (Keshan disease)
• Toxicity symptoms -Highly toxic, esp. supplement abuse– Loss and brittleness of hair and nails– Skin rash, fatigue, irritability, and
nervous system disorders– Garlic breath odor
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Copper• Chief functions in the body
– Component of enzymes involved in the absorption and use of iron in the formation of hemoglobin
– Part of several enzymes necessary for collagen, healing wounds, maintaining nerve fiber’s myelin sheath
• Upper level for adults:• 2001 RDA for adults: 900 g/day
10,000 g/day (10 mg/day)
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Copper• Significant sources
– Seafood– Nuts, whole grains, seeds, legumes
• Deficiency symptoms (rare)– Anemia, bone abnormalities
• Toxicity symptoms-only in supplement abuse & abnormal storage in Wilson’s disease -Liver damage
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Manganese• Chief functions in 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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Fluoride• Chief functions in the body
– Involved in the formation of bones and teeth
– Helps to make teeth resistant to decay
• 1997 AI– Men: 3.8 mg/day– Women: 3.1 mg/day
• Upper level for adults: 10 mg/day
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Fluoride• Significant sources
– Drinking water (if fluoride containing or fluoridated)
– Tea, seafood• Deficiency symptoms
– Susceptibility to tooth decay– Higher incidence of dental caries
• Toxicity symptoms– Fluorosis (pitting and discoloration of
tooth enamel)
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
U.S. Population With Fluoridated Water
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Chromium
• Chief functions in the body– Enhances insulin action– CHO & lipid metabolism
• 2001 AI-Men: 35 g/day
– Women: 25 g/day
• Significant sources– Meats (especially liver)– Whole grains, brewer’s yeast
Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
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 LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning
Trace Minerals
• Others – Molybdenum, Nickel, Cobalt, Silicon, Boron, Arsenic
• Known to be important & essential for animals but human requirements under study
• No recommendation is necessary since there is no evidence that intake by humans is ever limiting and unestablished roles in health maintenance