Chapter 15 - Trace Minerals Flashcards
What is the definition of trace mineral?
essential but you don’t need that much of it
What are the functions of iron?
-essential for delivery of oxygen to cells
Where is most iron located?
in hemoglobin
What is hemoglobin?
quaternary structured protein
Iron is also found in myoglobin, which is found where?
muscle tissue
What is the last thing iron functions as?
coenzyme
What are good sources of iron?
Life cereal animal products dark greens dried fruit (b/c of serving sz) fortified foods
What types of foods have the highest iron bioavailability?
meats
fish
poultry
What types of beans offer the most iron?
darker pigmented beans
What is the major iron storage protein?
ferritin
What is the major iron transport protein in the blood?
transferrin
Where is extra iron shed?
in intestinal cells
Where is iron stored?
bone marrow
spleen
liver
What percentage of iron is absorbed?
14-18%
What affects the amount of iron absorbed?
iron status dietary consumption type and amount ingested dietary factors stomach acid
What are the two types of iron?
heme and non-heme
Where is heme iron found?
animal foods
Heme iron makes up how much of the DI?
10%
What is the absorption rate of heme iron?
25%
Non-heme iron is found where?
animal and non-animal foods
Non-heme iron DI?
90%
Non-heme iron absorption rate?
17%
What enhances iron absorption?
- high iron demand/low body stores
- MFP
- Vitamin C
- Acids
How does high iron demand/low body stores enhance iron absorption?
if you’re deficient, you will have a higher absorption rate
What is MFP and where is it found?
Meat Factor Protein
meat, fish, poultry
How does vitamin C enhance iron absorption?
when consumed at the same time, in the same meal
What are the acids that enhance iron absorption and why?
citric, lactic, and stomach acid
make it more soluble
What are the factors that inhibit non-heme iron absorption?
- phytates
- Calcium
- polyphenols
Phytates found where?
legumes
grains
Calcium inhibits absorption how?
cancels out vitamin C in absorption
Polyphenols found where?
tannins in tea
wine
RDA varies based on what?
age
gender
Iron RDA for men?
8 mg/day
Iron RDA for pregnant women?
27 mg/day
What can’t be produced when iron is deficient?
hemoglobin can’t be produced
Iron deficiency anemia
when there is not enough hemoglobin
RBCs are smaller and paler and unable to deliver sufficient oxygen to tissues
How much of the world is deficient in iron and how many suffer from anemia?
80%
30%
Iron deficiencies also affect what?
mental function
pica
Who are most at risk for iron deficiency?
- women of childbearing age, pregnant women, infants, children, adolescents
- diets low in iron, vegetarians, those dieting in general
- those in poverty, or with intestinal parasites
Iron upper limit?
45 mg/day from all sources
Who is more prone to iron toxicity?
children
absorptive mechanisms don’t respond as rapidly
Iron overload can happen over time and accumulate where?
in tissues, such as heart and liver
What is the most common and genetic form of iron overload?
hemochromatosis
Antioxidants work as part of what?
antioxidant enzyme systems
Zinc and superoxide dismutase does what?
catalyes conversion of O2 to H2O2 to H2O
Selenium and Glutathione Peroxidase does what?
reduces H2O2 to H2O lowering need for vitamin E
Zinc essential for what (3)?
- growth and development
- 300+ different enzymes
- part of antioxidant superoxide dismutase
Zinc helps with growth and development how?
gene expression
sexual maturation
Superoxide dismutase does what?
- protects cells from free radical damage
- catalyzes conversion of O2 to H2O2 to H2O
Zinc stored where?
intestinal cells
The more zinc needed, the more what?
absorbed
Excess zinc excreted where?
feces
urine
bodily fluids
Zinc better absorbed in what foods?
animal sources
Zinc bound by what? Affects what?
phytates
bioavailability
Zinc does what when taken in excess?
toxic
Zinc deficiencies rare where?
U.S.
Zinc deficiencies most common in who?
children
elderly
pregnant women
individuals with poor nutrition
Zinc deficiency is common in what types of immune systems?
impaired immune system
The selenium content of plant foods depends on what?
selenium content of soil in which they are grown
Symptoms of selenium deficiency?
muscular discomfort
muscular weakness
Keshan disease (heart muscles)
Fluoride is important for what?
dental health
hardens enamel
fights cavities
Where is fluoride found?
almost all soil
water
plants
animals
Common sources of fluoride?
fluoridated water, tea
marine fish with bones (canned salmon, sardines)
topical toothpaste
Antioxidant minerals are part of?
enzyme systems
Which mineral will shorten the duration of your cold?
Zinc
What are the trace minerals?
Fluoride
Zinc
Selenium
Iron
