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