Micronutrients

Question 1

Iron (fxns)

Answer 1

Oxygen transport in blood and muscle
Electron transfer enzymes
Enzymes for activation of oxygen

Question 2

Zinc (fxns)

Answer 2

Gene expression
Zinc metalloenzymes
Cell membrane structure and fxn
Induction of metallothionein synthesis (anti-oxidant)
Protects against toxicity
ALSO IMMUNE FXN
NEEDED IN GROWTH

Question 3

Iron (severe defic)

Answer 3

Heart failure, anorexia, slow growth

Question 4

Iron (mild defic)

Answer 4

Anemia, impaired cognitive development, decr exercise tolerance

Question 5

Zinc (sever defic)

Answer 5

Acro-orificial DERMATITIS
DIARRHEA
Incr infx
Poor wound healing
Delayed sexual maturation
Personality changes

Question 6

Zinc (mild defic)

Answer 6

GROWTH RETARDATION
ANOREXIA
Incr infx

Question 7

Zinc (fetal defic)

Answer 7

Intra-uterine growth retardation

Congenital malformations

Question 8

Iron (sources)

Answer 8

Heme: cellular animal protein (not milk)
Non-heme: legumes, nuts, whole grains
BUT absorption of non-heme iron is MUCH lower than heme iron

Question 9

Iron (RDA)

Answer 9

8mg/d adult male, 18 adult female, 8 post menopausal, Preg 27

Question 10

Iron absorption factors

Answer 10

Insoluble complexes (with phytate, tannins etc.)
Fe 2+ better absorbed then Fe 3+ (reduced better, ascorbic acid can reduce)
Heme absorbed better than non-heme
How much in meal/gut lumen
Fe defic –> incr absorption
Infl –> incr hepcidin from liver –> decr absoprtion

Question 11

Iron (main site of regulation and loss and stores)

Answer 11

reg: intestinal absorption
loss: bleeding
stores: liver, bone marrow, spleen

Question 12

Iron (transport/storage)

Answer 12

transport: transferrin
storage: ferritin or hemosiderin (aggreagted ferritin)

Question 13

At risk for Fe defic

Answer 13

infants
premies
adolescents
pregnant women
bariatric surgery pts
chronic infestation populations
elderly (hospitalized or in long term care)

Question 14

Iron defic (diagnx)

Answer 14

Low Hb/HCT & microcytic/hypochromic RBC (severe)
LOW ferritin (mild, mod or severe)
Low serum Fe with HIGH TIBC

Question 15

Iron tox

Answer 15

PRO-OXIDANT
excess deposited as hemosiderin in reticuloendothelial cells
Large iron doses interfere with absorption of other micronutrients
1-2grams can be fatal to kids

Question 16

Hereditary hemochromatosis

Answer 16

excessive Fe absorption due to defect in hepcidin, increased Fe stores, damaging to liver

Question 17

Zinc (sources)

Answer 17

ANIMAL PRODUCTS, also whole grains, nuts, legumes

Question 18

Zinc (effect of phytate)

Answer 18

impairs absorption

Question 19

Zinc (effect of defic on absoprtion)

Answer 19

DOES NOT increase absorption (unlike iron)

Question 20

Zinc (RDA)

Answer 20

M 11 mg/d , F 8, Preg 13, Adol 13

Question 21

Zinc (at risk for defic)

Answer 21

Infants (inc breastfed)
Pregant
Montonous, plant based diets (high in phytate)
Bariatric surgery pts
Eledery
GI illness/injury
Wounds/burns

Question 22

Zinc (tox)

Answer 22

Low risk >50 mg/d can decr HDL, impair Fe/Cu absorption, N/V