May 7: Trace Minerals - Iron, Zinc, Iodine Flashcards
Iron function
Function: regulation (oxygen)
How does the body combat iron deficiency?
Recycling it (from old red blood cells)
Storing it (in liver)
Changing iron absorption
What can cause iron deficiency and what does it result in?
Poor diet/blood loss can cause iron deficiency.
This can cause anemia (sick blood) and symptoms include fatigue, smooth tongue, and spooned nails
Groups at risk for iron deficiency
Infants, children, females at reproductive age
Bioavailability of iron depending on how much you have (high or low)
If iron stores are low, you have high absorption
If iron stores are high, you have low iron absorption
Forms of iron in food and bioavailability
Heme (meats, blood) is 20-30% available
Nonheme (plants like beans, grains, dairy) is 1-10% available
Factors that change bioavailability of iron
Vitamin C and meat increase bioavailability
Oxalate, phytate, fiber, and tannins decrease bioavailability of non-heme iron
Iron requirement
RDA created assuming 10% bioavailability
8 mg/day men
18 mg/day women
27 mg/day pregnant
Food sources of iron
Heme: liver, meat, blood
Non-heme: plant sources like leafy greens, whole grains
How can you get too much iron?
Hemochromatosis: Fe overload
Supplements: too much iron can decrease zinc absorption
Iron poisoning: leading cause of poisoning death in toddlers
Zinc function
Cofactor in >100 enzyme reactions
Primary role in cell replication, helps with:
Growth/sexual maturation
Wound healing
Taste perception
Reproduction
Factors that change bioavailability of zinc
Phytate and oxalate decreases bioavailability
Zinc requirement
8 mg female
11 mg male
Food sources of zinc
Oysters, fortified breakfast cereal, beef, poultry, milk, kidney and garbanzo beans
Iodine function
Incorporated into thyroid hormones
