Magnesium

Question 1

Which mineral is a divalent cation and ranked 6 in overall abundance in the body?

Answer 1

magnesium (Mg)

- 55-60 % found in bone

Question 2

What are 3 foods high in magnesium?

Answer 2

nuts, legumes, and whole-grains

Question 3

Intracellular magnesium is second only to what mineral?

Answer 3

potassium

Question 4

Where is magnesium absorbed?

Answer 4

small intestine

Question 5

What are the two brush boarder transports for magnesium?

Answer 5

1. transient receptor potential M6 (TRPM6)

2. paracellular diffusion

Question 6

The basolateral border uses what system?

Answer 6

Na/Mg ATPase antiport system

Question 7

What 4 things inhibit magnesium absorption?

Answer 7

1. phytates and fiber
2. unabsorbed fatty acids –> soaps
3. Mg - Phosphorus complexes
4. zinc - competes with Mg absorption

Question 8

What mineral competes with magnesium for absorption?

Answer 8

zinc

Question 9

How does PTH increase magnesium absorption?

Answer 9

by increasing TRPM6 concentrations

Question 10

What are the plasma membrane magnesium transports, and where are they found?

Answer 10

1. magnesium transporter 1 (MagT1) –> epithelial cells

2. TRPM7 –> bone, heart, and adipose tissue

Question 11

What % of the body’s magnesium is found in the bone?

Answer 11

55-60 %

Question 12

Up to 90 % of intracellular magnesium is involved with what type of enzymes?

Answer 12

ATP or ADP associated enzymes

- magnesium is required for the majority of the 518 known human kinases

Question 13

What mineral is required for insulin sensitivity, and what enzyme is involved?

Answer 13

magnesium

- cofactor for Tryosine kinase

Question 14

What mineral is a cofactor for tyrosine kinase?

Answer 14

magnesium

Question 15

Magnesium is a cofactor for what enzyme that is required for insulin sensitivity?

Answer 15

tyrosine kinase

Question 16

There is an inverse relationship between type 2 diabetes and which mineral?

Answer 16

magnesium

Question 17

Magnesium depletion is common in what group?

Answer 17

diabetics

- due to excessive Mg urinary excretion

Question 18

What are the 5 enzymes that require magnesium?

Answer 18

• transketolase
• glutamylcysteine synthetase
• glutathione synthetase
• DNA polymerase
• RNA polymerase

Question 19

Magnesium activates pyruvate dehydrogenase phosphatase and inhibits pyruvate dehydrogenase kinase, which in turn will up-regulate what?

Answer 19

the oxidative decarboxylation of E1 complex

Question 20

The oxidative decarboxylation of E1 complex is up-regulated by what mineral?

Answer 20

magnesium

Question 21

How does magnesium function in transmembrane communication and ion channels?

Answer 21

1. membrane stabilization
2. second messenger systems
3. ion channels

Question 22

Adenylate cyclase and Na/K-ATPase pump is activated by what mineral?

Answer 22

magnesium

Question 23

What mineral is needed for PTH effects on bone, kidney, and GI tract?

Answer 23

magnesium

Question 24

Magnesium is required for the hydroxylation of what vitamin?

Answer 24

vitamin D by 25-hydroxylase

- vit D deficiency also requires magnesium supplementation

Question 25

A magnesium deficiency can reduce what mineral plasma levels?

Answer 25

calcium

Question 26

Magnesium is an antagonist to what mineral?

Answer 26

calcium

Question 27

How does Mg antagonize Ca?

Answer 27

1. Mg may inhibit Ca release
2. Mg competes with Ca for troponin binding sites
3. Mg may inhibit acetylcholine release and smooth muscle contraction

Question 28

What mineral may prevent hypercoagulability?

Answer 28

magnesium - impedes process of blood coagulation

Question 29

What hormone inhibits magnesium excretion?

Answer 29

Parathyroid hormone (PTH)

Question 30

What % of the US pop has dietary magnesium intakes below the RDA?

Answer 30

75-80 %

Question 31

What are the most prevalent clinical presentations of a magnesium deficiency?

Answer 31

neuromuscular and cardiovascular complications