Micronutrients: Trace Elements

Question 1

Eleven elements account for ______ percent of body weight.

Answer 1

99.7

Question 2

The most critical period of brain development is _______________.

Answer 2

the first 1,000 days

Question 3

The body contains about ______ grams of iron.

Answer 3

5

Question 4

Where is most of the iron in the body?

Answer 4

In hemoglobin (50%)

Question 5

Other than hemoglobin, what enzymes contain iron?

Answer 5

Oxygenases and cytochromes

Question 6

Iron is better absorbed in the _________ state.

Answer 6

heme

Question 7

What molecule in spinach leads to negative absorption of iron?

Answer 7

Phyate, a carbon ring with many phosphates that can chelate cations

Question 8

When hepcidin is increased, ____________ is inhibited.

Answer 8

export of iron from iron-storing cells

Question 9

What stimulates the release of hepcidin?

Answer 9

Inflammation; it serves to sequester iron in cells, thereby hiding it from bacteria

Question 10

The most common micronutrient deficiency in the world (including the U.S.) is _____________.

Answer 10

iron deficiency

Question 11

The neurologic effects of iron deficiency are _____________, even with correction.

Answer 11

irreversible

Question 12

Zinc is important for _______________.

Answer 12

any kind of growth or differentiation: immune cells, wound healing, GI tract integrity, and skin renewal

Question 13

Breastmilk concentrations of zinc do not correlate with __________.

Answer 13

maternal zinc levels

Question 14

____________ is non-toxic, so it’s ok that some people take lozenges of this when they’re sick.

Answer 14

Zinc

Question 15

Breastmilk levels of zinc are low are ________ months.

Answer 15

six

Question 16

________ deficiency can make children not want to eat.

Answer 16

Zinc

Question 17

Micronutrients are those that we need less than __________ of per day.

Answer 17

100 mg

Question 18

How does vitamin C promote iron absorption?

Answer 18

It converts Fe3+ to Fe2+, which is the form in which iron is absorbed.

Question 19

Deficiencies of iron in which two populations warrants investigation for unseen bleeding?

Answer 19

Men and post-menopausal women

Question 20

Again, what lab value can help you differentiate between inflammatory and iron-deficient anemia?

Answer 20

High ferritin indicates inflammatory anemia, while low ferritin indicates iron-deficiency anemia.

Question 21

List three cellular roles of zinc.

Answer 21

• Part of transcription factor in zinc-finger domains
• Part of metalloproteases
• Increases membrane stability

Question 22

True or false: zinc, unlike iron, can be excreted in the GI tract.

Answer 22

True.

Question 23

What category of enzymes require copper: ______________.

Answer 23

oxidases

Question 24

Severe __________ deficiency can lead to hypothyroidism.

Answer 24

iodide

Question 25

Why does milk decrease iron absorption?

Answer 25

Because calcium decreases iron absorption

Question 26

Hepcidin acts by _____________.

Answer 26

inhibiting ferroportin, thereby causing iron to accumulate in cells

Question 27

Inability to develop secondary sexual characteristics is a feature of ______________ deficiency.

Answer 27

zinc

Question 28

Stunting is strongly associated with _____________ deficiency.

Answer 28

zinc

Question 29

Currently, there is no reliable marker for ____________ deficiency.

Answer 29

zinc