Vitamin K

Question 1

Vitamin K is a generic descriptor for family of

Answer 1

-phylloquinone compounds

Question 2

What are the 2 primary vitamers of Vitamin K?

Answer 2

Phyllo Quinone (K1), plant, low absorption (<20%)
Menaquinones (K2), animal source

Question 3

Give an example for a Natural K1 and K2 form

Answer 3

-K1: Kale
-K2: fermented soybeans

Question 4

Highest phylloquinone content in most diets are

Answer 4

-green leafy vegetables(spinach, lettuce, broccoli)

Question 5

What is the molecular role of Vitamin K?

Answer 5

-K is a co-factor for vitamin K dependent carboxylase, y glutamyl carboxylase

Question 6

What is Vitamin K2 labeled as and which one has the longer half-life?

Answer 6

-known as MK-4 or MK-7
-MK-7 seems to have the longer half life so MK-7 is often the standard form used in dietary supplements

Question 7

Vitamin K-Dependent proteins are also known as …

Answer 7

-GLA proteins

Question 8

Summarize the blood clotting cascade

Answer 8

-prothrombin is converted to thrombin and used to convert fibrinogen to fibrin

Question 9

What is the best assessment of Vitamin K status?

Answer 9

-Presence of undercarboxylated proteins (PIVKA-II protein induced in Vitamin K absence)

Question 10

How does Warfarin work to block blood clotting

Answer 10

-It interrupts in the third step of the Vitamin K cycle where the Vitamin K epoxide needs to be reactivated and is reduced to Vitamin K quinone and then Vitamin K quinone is reduced to hydroquinone(active form)
-Warfarin blocks both reductases

Question 11

What is Prothrombin Time? (PT)

Answer 11

-Prothrombin is produced by the liver and is one of the VKDPs involved in blood clotting
-clinically used test determines how long it takes for one’s blood to clot

Question 12

What does it mean to assess INR?

Answer 12

-patient’s PT time/ mean normal patient PT time (prothrombin time)
-inc. INR =increased clotting time
-inc. Vit K intake can cause INR to dec.
-dec. In Vit K intake can cause INR to increase