Micronutrients and Trace minerals

Question 1

Fxns of iron

Answer 1

1. O2 transport
2. Election transport (cytochromes)
3. Enz for activation of O2
4. Enz for DA synthesis, CNS myelination

Question 2

Food sources of Fe

Answer 2

Heme:

• meats!, liver
• (milk is poor source)

Non heme:

• plant sources: legumes, whole grains, nuts
• Fe-Fortified foods/formula

Question 3

Fxn of Phytic acid

- where are they found?

Answer 3

Inhibit Fe +Zn absorption
- Binds Cations: Zn, Fe, Ca

Anti-oxidant in gut

High in Maize/wheat > Legumes > Rice

Question 4

If you have a deficiency of Fe, what happens to hepcidin (master regulator of Fe)

Answer 4

Fe deficiency –>
Decrease hepcidin –>
Increase Fe uptake/absorption

*absorption will be poor with hepcidin stimulation

Question 5

If you have inflammation, what happens to hepcidin (master regulator of Fe)

Answer 5

Inflammation –>
Increase hepcidin –>
Decrease Uptake/absorption

• inflammation trumps deficiency
• can decrease Fe absorption more so than Fe uptake ability

Question 6

Explain Iron needs in infancy

Answer 6

At birth, baby has high Hct, and as they break down, can use the Fe from RBCs,
- so they have low dietary Fe requirements

But once they use it all, they get this HUGE increase in requirement
- at 4-6 mo, need to start making own RBC/Hb –> Increase requirement

Question 7

Iron deficiency effects

Answer 7

1. Anemia (microcytic, hypochromic)
2. Impaired cognitive fxn in developing brain
3. Impaired growth
4. Fatigue, listlessness, irritability, atten. deficit
5. Shyness

Question 8

Iron toxicity

Answer 8

1. Potent pro-oxidant
   - avoid unnecessary supplementation!
2. Hereditary hemochromatosis (defect in hepcidin)
   - dont have good absorption control –>
   Accumulate Fe –> Liver dmg
3. Hemorrhagic gastroenteritis, shock, liver failure

Question 9

Zn fxns (Lots!)

Answer 9

1. Reg. gene expression
   - Zn fingers
2. Stabilize molecular struct.
3. Cofactor for hundreds of enzymes
4. Mod. activity of hormones & NT
5. Growth & cellular/tissue proliferation
6. Antioxidant
7. Sexual maturation

Question 10

Zn food source

Answer 10

Beef > Poultry > Fish

Question 11

What age does Zn needs increase?

Answer 11

~6 mo of age,

Zn [ ] in milk significantly decreases, so they need other complementary sources of Zn.

Question 12

Inherited defect in Zn absorption

Answer 12

Acrodermatitis enteropathica (AE)
- around orifice, feet, groin

Question 13

Zn deficiency Mod-Severe sx

Answer 13

1. Dermatitis (acro-orificial)
2. Personality changes
3. Immune dysfxn
4. Delayed sexual maturation
5. Anorexia
6. Diarrhea

*inherited = acrodermatitis enteropathica

Question 14

Zn deficiency Mild sx (much much more common)

Answer 14

1. Growth delays
   - STUNTING
2. Anorexia
3. Impaired immune fxn

• much more common than mod-severe deficiency
• 2nd only to Fe deficiency