Week 8

Question 1

How does vitamin K help in the formation of blood clots?

Answer 1

Vitamin K acts as a co-factor of the carboxylase enzyme in the synthesis of a blood-clotting factor in the conversion of pre-prothrombin to prothrombin in the liver

Question 2

How does Warfarin interfere with vitamin K activity?

Answer 2

warfarin works against vitamin K to make your blood clot more slowly.

Warfin stops the enzymes (reductase and epoxide reductase) needed to reduce vit k that aims in blood clotting

Question 3

Why is an excess supplementation of vitamin E and vitamin K of concern in individuals taking daily anti-coagulation medications?

Answer 3

Vitamin E may inhibit vitamin K dependent carboxylase activity and interfere with coagulation cascade by:

1. Vit E competes with the enzyme that shortens K1 side chain
2. Vit E competes with K1 for the enzyme that omega-hydroxylates the K1 side chain
3. Vit E increases pathways that increase vitamin k excretion

Question 4

What are the various forms of Vitamin A in the diet and what foods are these found?

Answer 4

Retinoids: beef, eggs, cod liver, dairy butter, milk/cheese
Carotenoids: sweet potato, carrots, mango

Question 5

What is the biologically active form of Vitamin A

Answer 5

Retinoids

Question 6

What are the signs and symptoms of deficiency with Vitamin A

Answer 6

Night blindness
Xerophthalmia
keratomalacia
follicular hyperkeratosis

Question 7

What are the signs and symptoms of toxicity with Vitamin A

Answer 7

Acute: GIT upset/ nausea, muscular incoordination, headaches
Chronic: liver damage, hemorrhages, dry skin and mucous membrane hair loss, bone loss, coma.

Teratogenic (pregnant women consumes large amounts): fetal malformation, spontaneous abortion.

Question 8

1 international unit of vitamin A equivalent to?

Answer 8

1 UI = 0.3ug Retinol Equivalents

Question 9

What does “Retinol Equivalent” mean?

What is it equivalent to?

Answer 9

Retinol equivalents is defined as the biological activity associated with 1ug of all-trans retinol

1ug retinol equvalent
= 1 ug all-trans retinol
= 6 ug all-trans B-carotene
= 12 ug of a-carotene, b-crytoxanthin and other vitamin A carotenoids

Question 10

What is calcitriol?

Answer 10

calcitriol is the active form of vitamin D

Question 11

What are the various sources of vitamin E? which is most potent?

Answer 11

Tocopherols (alpha, beta, gamma and delta)
Tocotrienols (alpha, beta, gamma and delta)

most potent: natural form: alpha tocopherol

Question 12

What is an international unit of vitamin E worth?

Answer 12

1UI= 0.667 mg alpha-tocopherol (natural form)

1UI - 0.45mg alpha- tocopherol (synthetic form)

Question 13

What are the various sources and forms of vitamin K? which is the most potent?

Answer 13

Phylloquinones (K1): Plants; green leafy vegetables
Menaquinones (K2): From bacterial synthesis therefore fermented food (yogurt)

Most potent: Phylloquinones