8 Macrominerals

Question 0

Does the calcium AI change during pregnancy? Why or why not?

Answer 0

It does not. Efficiency of absorption at the level of the gut will be increased, possibly due to increased blood concentration of vit D. Dietary Ca does not appear to influence changes in maternal bone mass during pregnancy also (always see a temporal loss of calcium form bone).

Question 1

When does the fetus have the highest requirement for calcium?

Answer 1

Third trimester.

Question 2

Where does phosphorous occur in the body?

Answer 2

Phospholipids, nucleotides, nucleic acid, and bones (85%).

Question 3

Does the RDA for phosphorous increase during pregnancy? Why or why not?

Answer 3

No change. Intestinal absorption will increase 10% and there is a sufficient amount for the fetus.

Question 4

What are the main functions of magnesium?

Answer 4

50-60% of it is in bone, 1/3 of which is an exchangeable reservoir. Required as a cofactor for many reactions.

Question 5

What do magnesium requirements increase for the elderly?

Answer 5

Lose more magnesium in urine.

Question 6

Is there any change in serum Mg during pregnancy? Why or why not?

Answer 6

Decreases, thought to be from hemodilution.

Question 7

Does the magnesium RDA increase during pregnancy? Why or why not?

Answer 7

It increases slightly, due to higher body mass.

Question 8

What is the calcium AI based on?

Answer 8

Intakes at which small gains in bone mineral content can be achieved.

Question 9

What are the main functions of phosphorous?

Answer 9

Buffers acid or alkali to maintain normal pH, temporary storage and transfer of the energy derived from metabolic fuels, required for phosphorylation to activate catalytic proteins

Question 10

What is the RDA for magnesium based on?

Answer 10

Based on maître enhance of total body Mg as assessed by balance studies.

Question 11

Where is most of the iron found in your body?

Answer 11

2/3 in hemoglobin or circulating RBC, 15% in myoglobin.

Question 12

What factors are included in iron requirement?

Answer 12

Basal iron losses (hair, skin, urine). Menstrual losses. Fetal requirements. Growth (expansion of blood volume and or increase in tissue and storage iron.

Question 13

What is the iron EAR based on?

Answer 13

Need to maintain function iron concentration, but only a minimal store because free iron has a high risk of generating free radical damage.

Question 14

How do other dietary factors influence heme vs nonheme iron?

Answer 14

Heme is only slightly influenced by Phytates, fibre and oxalates. Non heme is strongly influenced.

Question 15

What is the average bioavailability of iron?

Answer 15

18%

Question 16

How is the EAR set for iron?

Answer 16

Estimated requirement for absorbed Fe at the 50th percentile.

Question 17

What issue can arise if blood volume doesn’t expand fast enough?

Answer 17

Preeclampsia

Question 18

What is moderate anemia associated with?

Answer 18

2x risk of maternal death. Premature delivery, low birth weight, high perinatal infant mortality.

Question 19

What adverse effect does high hemoglobin concentration have on pregnancy outcomes?

Answer 19

Small for gestational age (crown to heel measurement).

Question 20

Can a regular Canadian diet meet such a high FE RDA?

Answer 20

No, requires supplementation.

Question 21

Do iron requirements change during pregnancy? Why or why not?

Answer 21

Big increase, even though absorption increases demand still very high.