the trace minerals. objectives after reading chapter 7 and class discussion, you will be able to:...
Post on 23-Dec-2015
222 Views
Preview:
TRANSCRIPT
The Trace Minerals
Objectives• After reading Chapter 7 and class
discussion, you will be able to:– Identify trace minerals– Define trace minerals– Define hemoglobin and myoglobin– Describe heme and nonheme iron and
its absorption
Objectives• Identify food sources of iron • Identify those at high risk for iron
deficiency • Identify recommendation for daily
iron intake • Describe iron toxicity symptoms
The Trace Minerals
The Trace Minerals• Other Trace Minerals
– Chromium -Selenium -Fluoride– Molybdenum -Nickel -Copper– Manganese -Silicon -Cobalt
• IRON– Functions– Absorption– Deficiency/Toxicity– Recommendations– Food sources
Iron: Functions
• 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
Iron Absorption
Iron: Heme vs. Nonheme
Factors Enhancing Nonheme Iron Absorption
• MFP factor• Vitamin C• Citric acid from
foods & stomach• Lactic acid from
foods• HCl from stomach• Sugars (including wine)
Factors Inhibiting Nonheme Iron Absorption• Phytates – soy products• Fibers – whole grains, nuts• Oxalates – spinach, beets, rhubarb• Calcium• Phosphorus• EDTA (food additive, preservative)• Tanic acid – tea, coffee
Iron Deficiency• High risk for iron deficiency
– Women in reproductive years– Pregnant women– Infants and young children– Teenagers– Blood loss
Iron Deficiency• How is Fe deficiency measured?• How does Fe deficiency develop?• Stages of iron deficiency
– Iron stores diminish– Transport iron decreases– Hemoglobin production declines
Deficiency SymptomsAnemia: weakness, fatigue,
headachesImpaired work performance and
cognitive functionImpaired immunityPale skin, nailbeds, mucous
membranes, and palm creasesConcave nailsInability to regulate body
temperaturePica
Toxicity Symptoms
• GI distress• Iron overload: infections, fatigue,
joint pain, skin pigmentation, organ damage
Recommendations
• 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
Iron: Food Sources• Significant sources
– Red meats, fish, poultry, shellfish, eggs
– Legumes, dried fruits– Enrichment
Non-Food Sources of Iron
• Contamination iron from iron cookware– More acidic the
food– Longer cooking
time– Fe content of
eggs can triple– Poorly absorbed
• 1-2% absorbed
Iron Supplements• Form
– Ferrous sulfate or iron chelate– Less well absorbed so doses high
• Take between meals or bedtime• Take on empty stomach• Take with liquids
– Not milk, tea, coffee
• Take as a single dose
More On Supplements• No benefit to taking supplements
with orange juice (Vitamin C)– Vitamin C converts insoluble ferric
iron in foods to more soluble form of ferrous iron
• Constipation a common side effect of iron supplementation– Increase water intake– Is there a negative impact to
increasing fiber intake?
Objectives• After reading Chapter 7 and class
discussion, you will be able to:– Identify trace minerals– Define trace minerals– Define hemoglobin and myoglobin– Describe heme and nonheme iron and
its absorption
Objectives• Identify food sources of iron • Identify those at high risk for iron
deficiency • Estimate recommendation for daily
iron intake • Describe iron toxicity symptoms
top related